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ABSTRACT

A GEOBOTANIGAL STUDY IN THE ATLIN REGION IN
NORTHWESTERN BRITISH COLUMBIA AND SOUTH-CENTRAL YUKON TERRITORY

By
James Hugh Anderson

A vegetation and palynological study was conducted in
the Atlin region, northwestern British Columbia/south-central
Yukon Territory, with emphasis on the glaciated Atlin Lake
valley. Results include a preliminary catalog of plants,
descriptive analyses of upland plant communities, a discus-
sion of the regional importance of various arboreal species,
qualitative descriptions of bog plant communities, a vege-
tation-pollen rain comparison, and five radiocarbon-dated
pollen and spore diagrams and a late Pleistocene-Holocene
geobotanical chronology based upon them.

The catalog of plants is believed to be the first for
the Atlin region but is only preliminary since most collecting
was secondary to other activities. Included are 11 lichen,
14 bryophyte, and 237 vascular species and subspecies.

A general vegetation survey, incorporating a modifi-
cation of methods of the Braun-Blanquet school, has made
possible the definition of 12 upland plant communities lying
between the valley floor at 2,200 ft ASL and the 3,000 ft
level on the valley side slopes. In descending order of
areal importance these are: (l) mixedwood forest association,

(2) White spruce association/shrub-herb faciation, (3) aspen

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association, (h) white spruce association/feather moss
faciation, the climatic climax vegetation on mesic sites,

(5) lodgepole pine brfilé (associes), (6) white spruce-
lodgepole pine association, (7) lodgepole pine association,
(8) herb-heath association, (9) white spruce brfilé (associes),
(10) depression shrub association, (ll) mixed woodland
association, and (12) alpine fir association. In addition,
lodgepole pine-lichen woodland, mixed coniferous forest,

and, above the #,000-4,200 ft timberline, spruce-fir woodland,
shrub tundra, herbaceous tundra, and fell-field vegetation
types are recognized.

A tree survey utilizing the point-quarter technique
yielded frequency and basal area data for regional forest
trees at lower elevations. 0n the basis of these data the
trees can be arranged in descending order of importance as
follows: white spruce, aspen, lodgepole pine, fire-killed
pine, tree willow, balsam poplar, fire-killed spruce, alpine
fir, alder.

Six bogs in various parts of the Atlin valley were
studied. Nine roughly concentric bog vegetation zones,
occurring along a hygric-mesic moisture gradient, are recog-
nized, any two or more of which may occur in a given‘bog.
Classified in terms of dominant plants, these are the EEEEE

aquatilis-Drepanocladus spp., Carex aquatilis, Scirpus

 

‘validus, Salix spp., Salix spp.-Betulagglandulosa, Picea

 

glance-Salix spp., and three Gramineae zones.

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Comparisons of bog surface sample pollen spectra with
tree survey basal area data and qualitative vegetation
information show that certain aspects of bog and local vs.
regional upland vegetation may be distinguished in the pollen
record. It is believed that the most reliable interpretations
are those of regional vegetation based on composite spectra
from several bogs.

The palynological record helps clarify the Helocene
phytogeography of white spruce and lodgepole pine. In addi-
tion, it permits construction of a tentative, nine-zone
geobotanical chronOlogy for the Atlin region. Major features
of each zone, including time in years B.P., regional vegeta-
tion type, climatic characterization relative to the present
(considered warm/wet), and suggested glacial activity are as
follows: (IX) 211,000-10,500; shrub tundra; cooler/drier;
stillstand at late Wisconsinan maximum. (VIII) 10,500 (Helo-
cene boundary)-10,000; spruce woodland; cool/dry; retreat.
(VII) 10,000-9,000; shrub tundra; cooler/drier; still-
stand. (VI) 9,000-8,000; spruce woodland; cool/dry;
intermittent retreat. (V) 8,000-5,500; spruce forest;
‘warm/wet; general retreat. (IV) 5,500-3,250; spruce
forest with alder; warmer/wetter; maximum.retreat. (III)
3,250-2,500; spruce forest with fir; ‘warm/wet. (II)
2,500-750; spruce forest with pine; cool/dry; Neoglacial
advances. (I) 750-0; spruce forest with pine; warm/wet;

minor retreat .

‘A GEOBOTANICAL STUDY IN THE ATLIN REGION IN
NORTHWESTERN BRITISH COLUMBIA AND SOME-CENTRAL YUKON TERRITORY

By

James Hugh Anderson

A THESIS

Submitted to
Michigan State university
in partial fulfillment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY

Department of Botany and Plant Pathology

1970

-/) /' oi
L7 - ce‘/O 7 :73

This dissertation

is respectfully dedicated to my stepmother

Ione H. Anderson

11

ACKNOWLEDGEMENTS

I have been unusually fortunate in terms of assistance
and guidance in carrying out the Atlin project. A consider-
able number of outstanding individuals have been involved at
various times, and I feel deeply indebted to each of them.

In 1966 I was ably assisted in the field by Bab Dilts,
Dudley Field, Bert Useem, and Dave Lietzke. Dave later made
available results of his soil studies, some incorporated
herein, and I thank him.for this.

The project benefited greatly from the assistance of
Tim Hushen, Bill Lokey, June and Larry Onesti, and
van Sundberg in the summer of 1967. I am grateful to these
persons for a most profitable and memorable season.

In 1968 field efforts were furthered with the substan-
tial help of Dick warren.

Several residents of Atlin, particularly Clyde and Anna
Cox and Ed Michayluk, RCMP, extended many courtesies during
the course of field activities which my assistants and I
greatly appreciated.

cliff Randall volunteered to perform some of the lab-
oratory preparations of bog samples. I thank him for con-
siderably reducing my work in this area.

111

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To Ann Tallman, Ken Jehnson, Ross Mack, Stan Miller,
Barry Prather, and Tink Taylor I extend my warmest regards
for their help in many and various ways.

Carol Eames performed, in a highly competent manner, a
major undertaking in the final typing of the manuscript in
an all-too-short time period. I am.very thankful to have
obtained Carol's services.

I thank Dr. Henry Imshaug and John Engel of Michigan
State University for identifying lichen and liverwort col-
lections. In addition I thank Dr. Howard A. Crum of the
university of Michigan for identifying the moss collections
and Dr. H. J. Scoggan of the National Herbarium of Canada
for identifying a significant portion of the vascular
plant collections. I also thank Dr. Stephen N. Stephenson
of.Michigan State university for identifying some of the
grasses.

I gratefully acknowledge receipt of a Grant in Aid of
Research from.The Society of the Sigma Xi. The university
of Michigan Mbmorial-Phoenix Project Laboratory provided
radiocarbon dating services for which I am also grateful.

I apologize to all of my students for a second-rate job
of teaching, resulting from.preoccupation with the Atlin
project, during two years as an Instructor at Michigan State
university.

:My deepest and everlasting appreciation is extended to
the members of my doctoral guidance committee for their

valued counsel, intellectual discourse, and assistance in

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academic and other university matters. These persons are
Dr..Aureal T. Cross, Chairman, Dr. John H. Beaman,

Dr. Jehn E. Cantlon, Dr. William.B. Drew, Dr. Maynard M.
Miller, and Dr. Stephen N. Stephenson.

I hold in highest esteem Dr. Cross' efforts in further-
ing the Atlin project and his concern for and contributions
to my education since our first meeting on the Juneau Ice-
field when I was still an undergraduate. Of equal regard is
the long-time, unrelenting encouragement and the generosity
of Dr. Miller in support of my work. He has provided the
lion's share of financial and logistical aid with his grants
from the National Geographic Society and with funds and
facilities of the Foundation for Glacier and Environmental
Research of which he is director. The value of my associa-
tion with these two great men in numerous classroom and field
situations is inestimable.

In spite of all this, weaknesses, idiosyncracies, and
errors in this dissertation are my sole responsibility.

TABLE OF CONTENTS

MODUflI ON C O O O O O O O O O O O 0
PHYSICAL SETTING . . . . . . . . . . .

I.
II.
III.

V.

PHYSIOGRAPHIC DELINEATION
GENERAL GEOLOGY

GLACIATION AND GLACIAL GEOLOGY

Pre-Wisconsinan glaciation

Wisconsinan glaciation

Helocene glaciation and glacial

CLIMATE

Regional climatology
Classification . . .

SOILS

Meteorological observations and

mmTI ON 0 C O O O O O O O O O O O O O O O O O O 0

VI.

VII.

INTRODUCTION TO VEGETATION

REIGN O O O O O O O O

Generaloeeoeeoo
Previous work . . . . .

GENERAL VEGETATION SURVEY

Purposes.......
Methods........

Field activities . .
Association table .

Discussion . . . . . .
The plant communities .

Sites

OF THE ATLIN

White spruce association

vi

h.

vii

Feather moss faciation . . . . . . . 81
Shrub-herb faciation . . . . . . . . 83
a Herb phase . . . . . . . . . 84

b Shrub-herb-mcss phase . . . . 84
Lodgepole pine association . . . . . 86
Emlé O O O O C C O C O O O O O O C 89
White spruce brfilé . . . . . . . 89

Lodgepole pine brulé . . . . . . 90

White spruce-lodgepole pine
forest association . . .
Alpine fir association . . .
Aspen association . . . . .
deedwood forest association
Mixed woodland association .
Depression shrub association
Herb-heath association . . .
unclassified stands . . . .

O O O O C O O O
I O C O O O O O
O O O O O O O O
O O C O O O O O

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Summary and discussion of general
vegetation survey . . . . . . . . . 106

VIII. TREE SM 0 O O O O O O O O O O O O O O 126
Purposes e e o e o e e o o o e o o o 126
Methada O O O O O O O O O O O O O O O O 128
Discussion..............129

IX. BOG VEGETATION . . . . . . . . . . . . . . 135

Genera- O O O O O O O O O O O O O O O O 136
Moose Bones Bog . . . . . . . . . . . . 137
Mile 16 308 e o e e e e o e o o e o o o 1
Mile ”'7 308 e e o e e e e o o e o o o o 1
l Bulrush zone . . . 145

2 Sedge-moss zone .
a Shrub willow zone
Bog spruce zone .

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Jasper Creek Bog . . . . . . . . . . 157
WilsonCreekBog ........... 161
PALYNOWYQQOQ0.0000000000000000166

x. PALYNOLOGICALMETHODS . . . . . . . . . . 166

Bog smlmg O O O O O O O O O O O O O 166

XI.

XII.
XIII.

XIV.

viii

Preparation of samples

Pollen and spore counts . . .

POLLEN AND SPORE DIAGRAMS .

Construction of the diagrams

Description of the diagrams .

Shrub zone . . .
Spruce zone . .
Pine zone . . .

RADIOCARBON DATING . . . . . . . . . . . .

COMPARISONS OF SURFACE POLLEN ASSEMBLAGES

m WEATION O O O O O O O O O O O 0

Regional comparisons . .
Local comparisons . . . .

Moose Bones Bog

Mile l6 Bog . .
Mile #7 Bog . .
Mile 52 Bog . .
Jasper Creek Bog
Wilson Creek Bog

Weoeooeooe

HOLOCENE ENVIRONMENTS.AND CHRONOLOGY

Prev10us work 0 e e e e 0
Local interpretations .

Moose Bones Bog

Mile 16 308 o 0
Mile 47 308 o e
Jasper Greek Bog
Wilson Creek Bog

Regional interpretations

Zone IX .
Zone‘VIII
Zone‘VII .
Zone VI .
Zone V . .
Zone IV .
Zone III .
Zone II .
Zone I . .

SUMMARY AND CONCLUSIONS

169
171

172
ES

181
182

185
188

195
203

20

208
210
211
212
213

216

222

295
296

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FOOTNOTES
ILITERATURE
.APPENDIX A.

APPENDIX C.
APPENDIX D.

IHTENDIX E.

ARHHHHIIFS

ix

CITED. 0 O O O O O O O O O I O O O O O O 0
Selected soil profile descriptions . . .

Boralfic cryorthods, coarse loamy, mixed .
Typic Cryochrepts, coarse loamy, mixed . .
Entic Cryorthods, coarse loamy, mixed . . .
Typic cryopsamments, sandy mixed . . . . .
Boralfic Cryorthods, loamy skeletal, mixed
Histic Cryaquepts, coarse loamy, mixed
calcareous . . . . . . . . . . . . . . .
Terric Cryosaprists, euic. . . . . . . . .

Tree common names used in this disser-
tation and equivalent scientific names .

The Domin cover-abundance scale . . . . .
Procedure for preparation of bog sediment
samples, including peats, marls, and

partially inorganic materials . . . . . .

Plants of the Atlin region used in the
preparation of pollen reference slides .

Preliminary catalog of the flora of
the Atlin region . . . . . . . . . . . .

Index of groups and families . . . . . .

319
320
327

327
328

330
330

331
332

333
335
335

340

343
343

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10.

12.

13.

14.

15.
16.

LIST OF TABLES

Climatological data summary for five stations in
theAtlinregion..............

Wind speeds (percentage frequencies) at four
stations in the Atlin region . . . . . . . .

Species encountered by La Roi (1967 in a stand
located near the Atlin region, th data on
relative population sizes . . . . . . . . . .

Association table for the white spruce
association/feather moss faciation . . . . .

Association table for the white spruce
association/shrub-herb faciation . . . . . .

‘Association table for the lodgepole pine
association . . . . . . . . . . . . . . . . .

.Association table for the white spruce brfilé
(“8°C168) O O O C O O O C O O O O O C O O 0

Association table for the lodgepole pine
brfile (associes) . . . . . . . . . . . . . .

Association table for the white spruce-
1odgepole pine forest association . . . . . .

Association table for the alpine fir association
Association table for the aspen association . .

Association table for the mixedwood forest
association.................

{Association table for the mixed woodland
association.................

.Association table for the depression shrub
“amiation O O O O O O O O O O O O O O O O 0

Association table for the herb-heath association

Relevés from.two unclassified stands . . . . . .

39

41

60

108

109

110

111

112

113
114
115

116

117

118
119
120

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17.
18.

19.
20.

22.

xi

General vegetation survey data summary . . . .

Distribution of plant communities and sampled
bogs along the Atlin-Carcross road transect

Treesurveydatasummary...........

Comparison of general vegetation survey and
treesurveydata .............

Moose Bones Bog vegetation zonation . . . . .

Basal areas and pollen representation of the
four major tree species in the Atlin valley

121

127
131

131+
142

199

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10.

12.
13.
14.
15.

16.

LIST OF FIGURES

Map of the Atlin region . . . . . . . . . . . .

‘View south in the Atlin valley from a short
distance west of the Atlin road at mile 22.6

Atlin village, Atlin Lake, and surrounding
terrain and vegetation . . . . . . . . . . .

Terminus of Llewellyn Glacier and adjacent
terrain O O O O O O O O O O O O O O O O O 0

Mean monthly temperatures, total precipitation,
snowfall, and relative humidity at Atlin,
Teslin, Carcross, and Whitehorse . . . . . .

Annual and June-July wind direction percentage
frequencies at Atlin, Dease Lake, Teslin,
and Whitehorse . . . . . . . . . . . . . . .

A mosaic of Atlin valley plant communities . .

Opening in the white spruce association/shrub-
herb faciation at stand 59E . . . . . . . .

The lodgepole pine association at stand 24E . .

The lodgepole pine brfilé (associes) at
at md 20E C C C C C C C C C C C C C C C C C

The mixed woodland association at stand 02E . .
The depression shrub association at stand 59W .
MooseBonesBog................
M11816BOSOOOOOOOOOOOO0.0.00
Generalized sketch map of Mile 47 Bog vegetation
zones and surrounding upland vegetation in
eight compass sectors . . . . . . . . . . .

m852Bog..................

xii

10
12

14

42
49

79
88

88
101
101
139
139

146
155

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17.
18.
19.
20.

22.
23.

28.

29.

30.
31 .

32.

xiii

VegetationinMile52Bog............
Jasper Creek Bog . . . . . . . . . . . . . . . .
‘View east from Jasper Creek Bog . . . . . . . . .
WilsonCreekBog ................
Pollen and spore diagram for Moose Bones Bog . .
Pollen and spore diagram.for Mile l6 Bog . . . .
Pollen and spore diagram for Mile 47 Bog . . . .
Pollen and spore diagram.for Jasper Creek Bog . .
Pollen and spore diagram for Wilson Creek Bog . .

Pollen and spore percentages in surface samples
from 6 bogs in the Atlin valley . . . . . . .

Basal area distribution of white spruce,
lodgepole pine, aspen/paplar, and alpine
fir along the Carcross/Atlin road transect . .

Comparisons of surface sample pollen percentages
with tree basal area percentages . . . . . . .

GeObotanical chronology for southeastern
Alaska and north-coastal British Columbia
(after Heusser, 1966, 1967b) 0 e e e e o o o o

UpperRubyCreekvalley.............
Hypothetical effects of changes in levels of

bog water tables on sizes of sedge

vegetation zones . . . . . . . . . . . . . . .

A tentative Holocene gedbotanical chronology
for the Atlin region . . . . . . . . . . . . .

155
159
159
163
174

175
176

177
178

198

201

202

218
253

283

286

INTRODUCTION

The topic of this dissertation is the vegetation and
the Holocene geobotanical history of the Atlin region in
northwestern British Columbia and southwestern Yukon Terri-
tory. Emphasis is placed on the Atlin valley where the bulk
01’ the field work was carried out (Fig. 1).

Specific contributions include the following: (1) a
preliminary catalog of the flora, including 262 species and
subspecies (Appendix F), (2) an analysis and definition of
upland plant connnunities based on an original modification
of methods of the Braun-Blanquet school, (3) a discussion of
the regional importance of arboreal species based on a tree
Survey utilizing the point-quarter method, (4) a qualitative
description of bog plant communities and vegetation zonation,
(5) an analysis of relationships between vegetation and
POllen rain, (6) five radiocarbon-dated pollen and spore
diagrams, and (7) a tentative Holocene geobotanical chron-
010gy for the Atlin region, based on interpretations of these
dlagrams and incorporating aspects of Holocene climates,
Glaciation and glacial geology, phytogeography, and cliseral
development of major vegetation types (Fig. 32).

The term "Holocene" is used here to designate the inter-

val between the present and the time in the past when certain
Climatic changes initiated world-wide retreat of the latest

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substage of Wisconsinan glacial ice. The Holocene is con-
sidered to be the second of two chronological subdivisions
of epoch rank of the Quaternary Period, the first being the
Pleistocene Epoch. "Holocene" replaces the older term
"Recent", but not "postglacial" (or "post-Glacial") which
is considered to be a landscape and ecological term
(Neustadt, 1967). The term "postglacial" is used in this
dissertation in reference to geobotanical features of the
Atlin region following deglaciation. The present usage of
"Holocene" is consistent with much current thinking in the
field of Quaternary paleoecology. Unequivocal use is made
01’ the term by Ritchie (1964, 1967, 1969) in his palyno-
logical studies in west-central Canada, by Terasmae (1967d),
by LeOpold (1967), and by several Russian authors in a
V01ume edited by Cushing and Wright (1967). The term was
officially endorsed by the American Committee on Strati-
graphic Nomenclature in 1967 , and its use has been offi-
cially adopted by the United States Geological Survey
(cOhee, 1968).

The discovery of gold in the Atlin region in 1896
at"ltnulated early geological studies (Gwillim, 1901; Cairnes,
1913; Cockfield, 1925). More recent work has provided
detailed information on bedrock geology over a broader area
(Aitken, 1959; Wheeler, 1961; Mulligan, 1963; Monger,
1968). Glacial geology has been dealt with by these authors
and others cited below only in a general way. Observations
by the writer indicate a complex late Quaternary history of

3

glacial erosion and deposition, and an attempt will be made
to relate some of this activity to the geobotanical chron-
ology established for the Atlin region (Fig. 32).

The Atlin region centers on Atlin Lake and Little
Atlin Lake in the far northwestern corner of British Columbia
(exclusive of the northwesternmost "peninsula" of the pro-
vince) and the adjacent south-central portion of Yukon Terri-
tory (Fig. 1). For present purposes the region is considered,
somewhat arbitrarily, to comprise the area between latitude
59°oo' and 60°30! N and longitude 132030! and 134°3o' w.
Atlin Lake is nearly 65 miles long, averages about two and
one-half miles in width, and lies at a mean elevation of
2,197 ft.

The village of Atlin (Fig. 3) formerly a lively center
01' gold mining activity, is located about midway on the
e“tern shore of Atlin Lake. In 1899 Atlin and the mining
camps of the surrounding Atlin district had a population
Peak of about 5,000 people (Bilsland, 1952), but at the pre-
sent time Atlin's population is approximately 150. It is the
(”fly populated place in the study area.

An all-weather gravel road extends 60 miles from Jake's
COz'ner, at mile 866 on the Alaska Highway, south to Atlin.
For purposes of convenience in this dissertation, the Atlin
r Oad is defined as the Atlin road prOper, plus the approxi-
nmtely 22 miles of road south and east from Atlin to the

a-'bandoned mining town of O'Donnel.

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Several gravel and dirt mining roads radiate northeast,

east, and south from the vicinity of the town. Most of

these have remained passable by truck, and renewed mining
activity in the past few years has brought about the im-

provement of some of them as well as the construction of a
Access to more remote places can be

An old trail, the Ashcroft-

few additional miles .
made by float plane from Atlin.
Yukon telegraph-line trail, built in 1901, traverses the

region from southeast to northwest, but is mostly grown over

now. Much of the region, except for poorly drained valley

bottoms, is passable on foot and horseback.

Groceries, mechanical repairs, and other major supplies

can be obtained in Whitehorse, Yukon Territory, 110 miles

from Atlin. Whitehorse lies at mile 916 on the Alaska High-

Way, Minor items can be bought at several stores in Atlin.

The writer's attention was first drawn to the Atlin

r eSion during a 1961 expedition to the Juneau Icefield in the

nearby Northern Boundary Range. In late August, 1965, a

brief reconnaissance trip was made by car into the region to
e*"tplore the possibility of developing a geobotanical research

Preject there. At that time initial impressions on the

n8.1:ure of the vegetation and glacial geology were developed,

several bogs for palynological study were located, and a few

Vascular plants were collected. It was decided that a con-

8iderable amount of work could be done in the region because
of the lack of human disturbance of the vegetation and

glacial deposits in most areas, the existence of a number of

7
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5

bogs, and the relative simplicity of logistics. Furthermore,

it was concluded that the development of a research project
would be especially desirable in view of the scarcity of
previous botanical, ecological, paleoecological, and glacial

geological studies in the region.
In 1966 two and one-half weeks were spent collecting

Plants, sampling bogs, and outlining the basic nature of the

Plant communities in the Atlin valley. With float plane

support a reconnaissance was carried out in the tributary

Valleys of Kuthai and Simpson Lakes south of O'Donnel in
conjunction with glacial geological and pedological studies

of several field associates.
In 1967 field work totaled seven weeks, from 23 June to

11 July and from 14 August to 12 September. Further plant

ecllections were made and additional bogs were sampled for

Palynological purposes, including Mile 47, Mile 52, and

Jasper Creek Bogs. The major activities of this summer in-

VOlved two different vegetation surveys carried out along a
75 mile north-south transect of the Atlin valley, from a

Point about two miles northwest of Little Atlin Lake south-

Ward nearly to the O'Donnel River. One of these, the general

vegetation survey, involved an application of field methods

91‘ the Braun-Blanquet school to the study of plant cormnuni-

1Tiles distributed along the transect. The other, the tree

8urvey, concentrated on trees and utilized the point-quarter

Illethod to obtain data on the composition of the arboreal
Stratum and the distribution and relative importance of the

 

various tree species in terms of relative area occupied and
pollen production.

Laboratory analyses were carried out between October,
1967, and June, 1968, including preparations and counting of
palynological samples and identification of a portion of the
plants collected.

In the summer of 1968 about ten more days were devoted
to field work in the Atlin region. Two new bogs were
located and sampled (Mile l6 and Wilson Creek Bogs) and a
third was resampled (Moose Bones Bogl). Additional eco-
logical observations were made, and a few trips were carried
out with a four-wheeldrive vehicle and by foot into the
higher alpine areas for plant collecting and geobotanical
reconnaissance. The Llewellyn Glacier terminus and its
valley train at the south end of Atlin Lake (Fig. 4) were
also visited, where observations were made regarding the
distribution of alpine fir and ideas for future research on
plant succession were developed. In addition, two three-
hour flights were made over a large area south and east of
Atlin Lake for vegetation Observations and aerial photography.

Between January and June, 1969, a major portion of the
palynological laboratory work was carried out, including the
preparation of pollen diagrams. During this period addi-
tional plants were identified and some were sent away for
examination by specialists.

In this dissertation English units of measure are used

for geographic distances and elevations and in the vegetation

7

surveys. Metric units are used in the vegetation zonation
study of Moose Bones Bog as well as in the palynological
investigations .

" means "years

In the palynology section "years B.P.
before present", where "present" is taken as 1950 A.D.

All photographs used in this dissertation are from
35 mm Kodachrome slides and were taken by the writer unless

otherwise indicated.

)17

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THE ATLIN REGION

MAJOR PHYSICAL AND CULTURAL FEATURES
AND SAMPLING SITES

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PHYSICAL SETTING

I. PHYSIOGRAPHIC DELINEATION

The Atlin region lies within the Canadian Cordilleran
This province com-

Physiographic Province (Bostock, 1948).
Prises the extensive system of mountain ranges and inter-

montane plateaus and valleys occupying westernmost Canada
Most of the Atlin region is in the

arid southeastern Alaska.
Interior Physiographic System of this province, with the

3<>nthwestern end of Atlin Lake extending into the northern

B{Tannery Range of the Western Physiographic System.
In the Interior System the Atlin valley occupies parts

Qt two lesser physiographic subdivisions, the Tagish Highland
These make up the southcentral por-

Ql-xd the Teslin Plateau.
t: ion of a major physiographic subdivision, the Yukon Plateau

( Holland, 1961.).
The Atlin valley is one of several large, glacier-

Q alved valleys which dissect the Tagish Highland and the
33% alin Plateau into large, upland blocks and tablelands,
‘h‘Qz-e or less isolated highland massifs which are remnants
Q? a late Tertiary erosion surface (Aitken, 1959; Holland,
19610. The largest valleys trend generally north-south.

Lil‘s Atlin valley, they contain large lakes comparable in
The Lakes range in elevation

'3 3. 2e and shape to Atlin Lake.
15

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from the 2,151 ft of Tagish Lake and 2,197 ft of Atlin Lake
to 2,985 ft at Surprise Lake. The intervening highlands lie
at elevations between 5 ,000 and 6,000 ft, with individual
peaks rising several hundred feet higher. The highest moun-
tain in the immediate study area is Mount Minto at 6,913 ft.
The Atlin valley is recognized here as a minor .physio- '
graphic unit, delimited by mountains and highlands sur-
rounding Atlin and Little Atlin Lakes as well as lower ter-
rain adjacent to their shores (Fig. 2). 0n the east the
Valley is bordered from north to south by White Mountain
(5,016 ft), Mount Hitchcock (5,878 ft), Union Mountain
(about 5,500 ft), Sentinel Mountain (6,316 ft), and Mount
Me Callum (6,046 ft). An area of low terrain lying in the
broad valley of the O'Donnel and Pike Rivers extends about
elght miles to the southeast between the latter two mountains.
This area represents a transection valley connecting through
to the Taku valley to the south (Fig. 3). The O'Donnel-Pike
RIl-ver lowland is more or less continuous with the Atlin
valley and, for present purposes, is considered a part of it.
Peaks on the west side of the Atlin valley are, from
no:nz-th to south, Jubilee Mountain (5,952 ft), Mount Minto
(6,913 ft), Atlin Mountain (6,711 ft), and Birch Mountain
(6,758 ft). The area lying adjacent to the southwestern
I)a-I‘t of Atlin Lake, beyond Birch Mountain and Mount McCallum,
13 considered, in this study, to be separate from the Atlin

Valley proper (Fig. l).

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Farther to the southwest, Atlin Lake extends into the
eastern flank of the Northern Boundary Range, a subdivision
of the Western Physiographic System as defined by Bostock
(19118). The major feature of this area is the terminus and
proglacial outwash or valley train sector of the Llewellyn
Glacier. This glacier extends to within two miles of the
head of Atlin Lake from a source 25 miles to the south-
southwest in the 6,200 foot ne’ve’ at the crest of the Boundary

Range, in the central highland area of the Juneau Icefield.
Eastern, outlying peaks of the range bear smaller glaciers
and include Mount Mussen (6,600 ft) and The Cathedral (6,950
1” t), situated close to the southwestern shore of Atlin Lake
(Fig. 1). From here the Northern Boundary Range, as a part
or the Coast Mountain complex, extends northwestward into
the Yukon Territory, forming an important climatic barrier
between the Atlin region and maritime regions southwest of
the Coast Mountains.

The Atlin valley and surrounding highlands contain the
ultimate headwaters of the Yukon river system. All local
drainage is into Atlin Lake, thence via the Atlin River into
Tfigish Lake, Marsh Lake, and the Yukon River. The major
E“Ezreams tributary to the Atlin valley and which empty into
Atlin Lake are Hitchcock, Fourth of July, and Pine Creeks,
the O'Donnel and Pike Rivers, and meltwater streams from the
Llewellyn and Williston Glaciers. About 15 miles south and

BOutheast of the valley a drainage divide separates the
Atlin watershed from that of the Taku River. The Taku flows

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18

through the Taku District of the Coast Mountains to the
Pacific, thus separating the Northern from the Southern

Boundary Range .

II. GENERAL GEOLOGY

Topographic maps of the Canadian National Topographic

Series, at a scale of 1:50,000, cover parts of the Atlin

region, including the Atlin valley. The entire region is

covered by parts of the Atlin, Teslin, Whitehorse, and

Bennett (Skagway) 1:250,000 sheets. The geology of the

map-areas corresponding to these sheets has been described

in a reconnaissance manner and has been mapped in the above-

noted order by Aitken (1959), Mulligan (1963), Wheeler

(1961), and Christie (1957).
The Teslin Plateau, including the northern and eastern

Parts of the Atlin region, is made up largely of sedimentary

ailfld volcanic rocks of late Paleozoic and Mesozoic ages.
Most of these rocks belong to the chiefly Permian Cache
creek Group (Aitken, 1959; Mulligan, 1963). Rock types in
this group are cherts, argillites, graywackes, sandstones,
B:Lates, and greenstones. In addition, limestone is a wide-
BI>read and frequently outcropping member of the group, being

eSpecially common in the south-central, southeastern, and

h~<>:rthwestern parts of the Atlin region. Limestone bedrock

18 also exposed over a large area of the adjoining Taku
District southeast of the Nakina River, and in the study

area it outcrops extensively in the O'Donnel River valley

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and in the Laurie, Johnson, and Lina Ranges (Fig. 1). White

Mountain, at the north end of the Atlin valley, is made of
limestone, as is most of the adjacent highland area around
Jubilee Mountain to the west.

Major bodies of crystalline rocks belonging to the
Coast intrusion complex of Jurassic and Cretaceous ages
occur east of Atlin Lake. Particularly prominent are the
Mount McMaster Body of undifferentiated granitic rocks in
the upper O'Donnel River area and the group of mountains

around Surprise Lake comprising the Surprise Lake Batholith,

composed largely of alaskite. Bedrock in the Atlin valley

between Como Lake and the northern end of Atlin Lake con-

Bists of undifferentiated granites of the Black Mountain

and Fourth of July Creek Bodies. Mount Hitchcock, Black

M<>‘u.ntain, and the southeastern portion of Mount Minto are
1“axle of granitic rocks (Fig. 2).

The geology of the northern part of the Tagish Highland,
1rlvzzluding the west-central and most of the southwestern por-
tion of the Atlin region, is similar to that of the Teslin
Plateau, but it includes a higher proportion of volcanic
rocks. Principal rock types are Permian andesites, basalts,
cherts, and limestone (Christie, 1957). The central and
3°'Lzlthern parts contain sedimentary rocks of early Jurassic

age, including greywackes, siltstones, argillites, slates,

anglomerates, and limestone. Basic volcanic rocks of the

late Cretaceous or early Tertiary Sloko Group outcrOp over

20

a considerable area around Sloko Lake in the southern part
cfl’the Tagish Highland immediately south of the Atlin valley.
The southwestern corner of the Atlin region, lying
Idthin the eastern flank of the Northern Boundary Range,
contains a high percentage of metamorphic rocks, most of
which are considered pre-Permian in age (Aitken, 1959).
This area lies adjacent to the Coast Range Batholith and

contains many eXposures of crystalline rocks related to this

extensive Mesozoic and early Cenozoic intrusion. A belt of

late Paleozoic sedimentary and basic volcanic rocks with
some limestone, possibly related to the Cache Creek Group,
occurs in the narrow belt lying between the Llewellyn Gla-
cier terminus and the southwestern shore of Atlin Lake.

In summary, the northern portion of the Atlin valley
is underlain and flanked primarily by limestones and, in
the area east of the south end of Little Atlin Lake and the

Io‘I.:l'bbock River, by argillaceous and quartzitic siltstones,

8<andstones, and greywackes. The central part of the valley,

from the north end of Atlin Lake to about two miles north
0:? Atlin village, is underlain largely by granitic rocks.
1bhue southern portion of the valley is underlain by a variety
91" volcanic, metamorphic and sedimentary rock types, in-
Q:-I..uding major proportions of limestone, particularly in the

sentinel Mountain-0' Donnel River area.

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21
III. GLACIATION AND GLACIAL GEOLOGY

A variety of erosional and depositional features occur
throughout the Atlin region as evidence of former glaciation.
Besides the broad, glacier-carved valleys, rounded and
relatively smooth highland tapography indicates the effect
of overriding glacial ice. Glacially polished and striated
erosional rock surfaces and crag-and-tail tepography occur
in various places, and there are abandoned meltwater chan-

nels and drumlins in others. Much of the region is covered
by glacial drift of various kinds and thicknesses. There
are end moraines and morainal series, lateral moraines,
eskers and esker complexes, kames and kame terraces, kettles,
and areas of pitted outwash. Erratic boulders have been de-
Poaited in some places, and there are a few remnants of
a-:|-.‘.luvia1 fans, eroded deltaic deposits, and sections of
a-Tleient, glacial lake shorelines. The terrain of much of
the Atlin valley, as viewed from the air, is fluted and

bears a distinct linearity.

Pre-Wisconsinan glaciation
Glaciation in the Atlin region and neighboring areas

has been studied by Johnston (1926), Kerr (1931:, 1936),
Watson and Mathews (191414), Armstrong and Tipper (1948),
Denny (1952), Aitken (1959), Wheeler (1961), Mulligan (1963),
34'16 Miller (1963, 1961-1 a, b). There is a consensus that
northwestern British Columbia and adjacent Alaskan and Yukon

aareas were covered by a Cordilleran Pleistocene ice sheet

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22

at least once prior to the Wisconsinan Age, one which was

far more extensive than any Wisconsinan advance. The area

of buildup of this ice sheet is believed to have been in the
general region of the northern Cassiar Mountains to the east
of the Atlin region, about 150 miles from the Coast Moun-

Watson and Mathews (194k) believe that the center of
From

tains.
this ice sheet was along the axis of the Cassiars.
.here ice may have moved in all directions, but the majority

flowed to the west and south. It flowed across the Coast

Mountains, primarily through the lower trans-range river

valleys, such as the Taku, and presumably formed an extensive

ice shelf along the present southeastern Alaskan coast. Much

of the westward moving ice was probably deflected by the

COast Mountains far to the south and eventually to the sea

Via valleys of the Nass and Skeena Rivers. Some was pro-

bably also deflected to the north, through the Atlin region

and into southwestern Yukon Territory (Miller, 1961La). The

surface of the ice during this stage may have been around

8.. 000 feet above sea level in some places. Johnston (1926)

be2|.ieved that the highest summits in the region between the

Cassiar and Coast Mountains were covered by up to 3 ,000 feet

of ice.
The time of the maximum develOpment of Pleistocene ice

in the northern Cordilleran region is not yet known with

Qertainty. Deposits and other evidence of this ice sheet

a~1li‘e scarce, most having been obliterated by the later,

Wisconsinan Age advances .

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Kerr (193“), in a classification of glaciations in
northern British Columbia, terms the maximum development of
Cordilleran ice the Continental Icesheet Stage. Miller
(l96ha) designates it an Intermontane Icecap Glaciation,
emphasizing regional accumulation in the Coast Mountains as
well as in the Cassiars. He explains, in addition, that the
Cbrdilleran ice sheet, although larger than the present
Greenland Icecap, was of sub-continental, rather than con-
tinental proportions as interpreted by earlier authors. The
maximum Keewatin Icesheet, with which it may have been in
contact in a few places (Hansen, 1949c, 1950) and the
Laurentide Ice Sheet, along with lesser ice sheets in Alaska

and elsewhere, were in existence at the same time.

Wisconsinan glaciation
Mbst of the glacial action which was instrumental in

creating existing landforms in the Atlin region took place
during the Wisconsinan Age and early Holocene time. Glacial
ice again covered the region, deriving from accumulation
a'l‘eas in the Northern Boundary Range, probably some distance
northeast of the range axis (Miller, 1964a), as well as
tram the northern Cassiar Mountains lying parallel to the
Bo‘I.:Indary Range about 150 miles to the east. Aitken (1959)
B‘l‘oates that two major Wisconsinan ice streams entered the
Atlin map-area. One of these was from a high center in the
“Orthern Boundary Range and moved northward through the

Atlin valley. The other entered the region from the

 
 

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southeast and moved northwestward through the Teslin depres-
sion (Fig. 1). In addition, Mulligan (1963) describes evi-
dence of former ice in the Teslin map-area flowing in a
west-southwest- to west-northwestward direction and affecting
the eastern and northeastern areas of the Atlin region. The
source of the latter ice was probably also the northern
Cassiars. It apparently joined the Teslin depression ice,
itself of a somewhat more southerly source in the Cassiars,
to continue northwestward, forming what Wheeler (1961), in
the Whitehorse map-area, called the Cassiar Lobe. Northwest-
ward flowing ice from.the upper Taku River area south of the
Atlin region appears also to have contributed to the Teslin
depression stream (Armstrong and Tipper, 1948).

In the northwestern corner of the Atlin region, Atlin
valley ice in maximum.Wisconsinan time probably joined an
adjacent stream in the Taku Arm valley to continue as a huge
coalesced ice stream toward the north-northwest as a part of
the main Coast Mbuntains Lobe (Wheeler, 1961). Thus the
Atlin valley ice was bracketed by major contiguous ice to
the west as well as to the east. Both the Cassiar Lobe and
this Coast Mbuntain Lobe apparently terminated at the south-
eastern edge of a large region in west-central Yukon Terri-
tory and Alaska which escaped Pleistocene glaciation altogether
(Bostock, l9h8; Heusser, 1960).

Within the Atlin region, the Atlin valley-Coast Mbun-
tains ice stream and the Teslin depression ice stream spread

out into intervening lowland areas connecting these two

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25

main valleys. One such location is manifest by inter-lobate
material in the O'Donnel River-Pike River valley brought in
by ice of the former stream branching off in a southeasterly
direction (Aitken, 1959).

Aitken gives evidence for an additional local ice
source located within the Atlin region, in the highlands
around Surprise Lake. He concluded that ice flowed radially
from this source area to join the surrounding valley ice
streams during maximum stages of glaciation.

Certain higher peaks in the Atlin region may have re-
mained unglaciated throughout the Wisconsinan. Various
authors have indicated this possibility. Holland (1964),
for example, states that the maximum.elevation of ice in
the Tagish Highland was 6,000 to 6,500 ft. Several moun-
tains there are higher than this. Mbunt Minto, at nearly
7,000 ft, an isolated peak on the west shore of Atlin Lake,
appears to be worthy of further investigation in this regard.
Miller (1963) has also pointed out the probable existence of
certain high nunataks near the crest of the Boundary Range
during the Wisconsinan maximum.

The maximum Wisconsinan ice cover of northwestern British
Columbia and adjacent regions was nearly as complete as that
of the pre-Wisconsinan Inter-Mentane Icecap Glaciation, even
though the thickness and volume of the ice may not have been
as great. Kerr (193h) designates the main Wisconsinan

advance in the British Columbia-Alaska Coast Mountains as

 

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26

rthe Mbuntain Ice-Sheet Stage. Miller (1964a) recognizes a
Greater Stage of the Mountain Ice-Sheet Phase of glaciation
corresponding to the Wisconsinan maximum, and also less
extensive ice buildups designated as Intermediate and Lesser

Stages of the Mbuntain Ice-Sheet Phase.

Holocene glaciation and glacial geology

The downwastage and retreat of the last significant sub-
stage of Wisconsinan ice is considered to be the initial
event of the Helocene Epoch in the Atlin valley. Bog studies
and radiocarbon dating which will be discussed later indicate
that this event was well underway in the northern part of the
Atlin valley by 10,000 years ago. In the course of this
study several features related to the general recession in
the valley and adjacent areas were observed. A knowledge of
these in terms of mode and time of origin and geologic com-
position is basic to an understanding of geobotanical pro-
cesses and the evolution of the present landscape, as well
as the development of a chronology of Holocene events.

A broad and dominating kame terrace lies between 2,400
and 2,550 ft in elevation along the eastern flank of the
Atlin valley in the area between the south end of Little
Atlin Lake and the north end of Atlin Lake. The western
and southwestern edges of this terrace slope steeply down
to the broad valley between the two lakes (Fig. 2). Strand
lines occur along this slope, indicating successively lower
levels of impounded water along the ice margin. The ter-

race indicates an interval of stagnation in the general

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27

course of ice retreat (Flint, 1957). It is composed of a
light, gravelly alluvium.and supports the largest continuous
lodgepole pine forest in the Atlin valley. A number of
kettle ponds and bogs occur on the terrace, including Mile
l6 Bog.

Denny (1952) found gravel terraces a common feature
along the Alaska Highway. He reports that around Squanga
Lake, in the north-central part of the Atlin region, rem-
nants of terraces occur along valley walls, and an intricate
knOb and kettle topography characterizes the valley floor.
These features extend southwestward in the valley containing
Summit Lake and Little Atlin Creek to a point northeast of
White Mbuntain (Fig. l). The valley directly north of White
Mountain, in contrast, is relatively free of glacial drift.
In the region northwest of Little Atlin Lake, where Moose
Bones Bog is located, pitted outwash and drumlins occur, as
described by Wheeler (1961). These various depositional
features in and near the northern part of the Atlin valley
could have been made during a long interval of stagnation
in the retreat of ice from.this area. A time of faster re-
treat and downwasting may have followed, with the deglacia-
tion of the Little Atlin Creek valley north of White Moun-
tain and the Little Atlin Lake portion of the main valley.
After this, another interval of stillstand appears to have
begun.when the terminus reached the area of the kame terrace
discussed above. It is suggested that these events, namely

stagnation-active retreat-stagnation, occurred in response

28

to a significant climatic oscillation during the early
Holocene.

Coincident with these events in the Atlin valley a
portion of a large proglacial lake, glacial Lake Carcross,
occupied the Tagish Lake and northern Taku Arm valley in
the northwestern corner of the Atlin region (Wheeler, 1961).
Deming by ice farther south in Taku Arm probably was
partly responsible for this lake, along with blockage by
ice and complex ice front deposits farther to the northwest
in the direction of present day drainage. At least two
shorelines of this ancient lake are known. These too may
be related to major intervals of stillstand during the
general course of retreat of the ice blocking the drainage-
way.

At the north end of Atlin Lake a series of even,
closely-spaced, recessional moraines extends about three
quarters of a mile upvalley from the edge of the water.
Aerial photographs show additional moraines, less regular,
but closely-spaced, occurring throughout a zone extending
to approximately three miles from the lake. These appear
to indicate lesser climatic fluctuations preceding a more
pronounced change when recession of the ice front became
more rapid and continuous.

Abundant early Holocene depositional features are found
in other valleys tributary to the Atlin valley. The upper
or eastern end of Fourth of July creek valley, for example,

contains terminal and lateral moraines, an extensive kame

II.

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29

complex, and a remarkable nest of sinuous eskers. According
to Aitken (1959) these deposits were produced by two differ-
ent ice fronts. One of these entered the southwest or
proximal portion of the valley as an offshoot of the main
Atlin.valley stream. The other moved into the upper, distal
section of the valley from the trunk glacier in the Teslin
depression to the east. Deposition relating to stagnation

of these ice bodies in the Fourth of July Creek valley may
have been contemporaneous with similar events in the northern
part of the Atlin valley described above.

Aitken (1959) has suggested that a large terminal mor-
aine a few miles west of Surprise Lake in the Pine Creek
valley and an esker-kame complex in the adjacent Spruce
Creek valley were produced by ice which accumulated in and
flowed outward from the central highland area around Sur-
prise Lake. Lake sediments around lower Pine Creek indicate
that ice extended at least as far north in the Atlin valley
as the Pine Creek area at the time of formation of these
features. Aitken further concludes that these were de-
posited in a body of water created by blockage of drainage
from.the glaciers to the east by extensive ice in the Atlin
valley. Correlation of these deposits and others associated
with ice front and ice margin deposits at various places in
the Atlin valley remains to be done.

By the time that deglaciation was well underway in the
major, low level valleys in early Holocene time, an alpine

type of glaciation had developed in highland areas following

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30

the previous Wisconsinan ice-sheet stages. This glaciation
is considered correlative with the Extended Icefield Glacia-
tion of the early and late post-Glacial times in the Coast
Mountains (Miller, 1964a). Most evidence for alpine glacia-
tion in the Atlin region is in the form.of rejuvenated pre-
or early Wisconsinan cirques (Aitken, 1959; Mulligan,
1963). This would presumably correspond with the lowest
cirque level system, with a superimposed latest cirque
deveIOpment (the Cl and C5 systems), as described by Miller
(1961) on the maritime flanks of the Juneau Icefield. At
this time the high cirque basins on Mount Minto and Atlin
Mountain.probably supported alpine glaciers, and a rather
extensive mountain glacier system, perhaps resembling one
or two small ice caps, may have existed in the high area
around Surprise Lake. A well developed abandoned cirque,
with a floor at the 6,000 to 6,500 ft level, occurs on the
northwest side of Mount Minto. Similarly, an abandoned set
of tandem.cirques at 5,500 and 6,000 ft on the east side of
Atlin Mountain gives rise to a rock glacier today. Many
rejuvenated cirques also occur on the mountains in the
Surprise Lake area (Aitken, 1959: Plate 1).

It is known, on the basis of abundant evidence from
other areas, that a world-wide interval of climate which
was warmer and, in many places, drier than the present, the
Hypsithermal or Thermal Maximum, occurred during middle
Holocene time (e.g. Sears, 19h2; Deevey and Flint, 1957;
Heusser, 1960, 1966, 1967b). Polynological evidence from

31

the.Atlin region for this interval is presented in Chapter
XIV. Between the beginning of Holocene time and the Thermal
thimum, glaciation in the Atlin region.is believed to have
decreased from extensive alpine stages through reduced
alpine stages, correlative with the present Retracted Ice-
field Stage in the Coast Mountains (Miller, 1964a), in which
only a few very small glaciers or glacierets occupied some
of the higher cirques. After this there develOped a condi-
tion of relatively complete deglaciation corresponding to
the Local Glacier Phase in the higher reaches of the Coast
Mountains. By this time the Llewellyn Glacier terminus as
well as its transection counterpart, the Taku Glacier on the
Alaskan side of the Icefield, presumably had receded to a
point far up its valley and hence some miles south-southwest
othtlin Lake. Then too, the higher mountains near the
southwestern shores of the lake were practically devoid of
ice.

After the Thermal Maximum the climate, in most places,
became cooler again, or more moist, or both, depending on
the area of concern. This resulted in the readvance of
shrunken main valley glaciers and the formation anew of
others flanking high level cirques. This culminated in the
so-called Neoglaciation, the maximum.advance of which has,
during the past few thousand years, ranged widely in time
from one place to another (Miller, 1969). In most areas a
number of Neoglacial fluctuations of glaciers and climate
are recognized, and the pattern has been particularly well

32

documented throughout south-central and southeastern Alaska
by Miller (1963, 1967) and by Miller, Egan, and Beschel
(1968).

Neoglacial activity in the Atlin region has been mani-
fest primarily in the southwestern corner, in the NOrthern
Boundary Range. Concentrated studies on the Juneau Icefield
(Miller, 1963, 1964b) reveal continuing regime fluctuations
in the main Llewellyn Glacier accumulation area during at
least the past few hundred years. The terminus of the
glacier is known, from.historical records, to have reached
a Neoglacial maximum considerably beyond its current position
about 1925. This is also shown by a distinct trim line and
well-developed scour zone on the valley walls in the terminal
area. A similar situation pertains at the termini of other
distributary glacier tongues in the Sloko valley and Hoboe
Creek valley, as well as on the Williston Glacier at the
head of Torres Channel west of the main Llewellyn Glacier
terminus (M. M; Miller, personal oral communication 1969;
Fig. 1).

With regard to the rest of the Atlin region, a few
small glacierets or perennial snow patches exist in some
of the higher cirques at the present time, and these have
no doubt formed anew in late Holocene, post-Thermal Maximum.
times. The maximum Neoglacial develOpment of these and
their fluctuational history has not yet been studied.

33

IV. CLIMATE

The Atlin region lies within the South West Yukon
Climatic Division (Kendrew and Kerr, 1955) and the Cor-
dillera Climatic Region (Boughner and Thomas, 1967). The
climate is basically of an interior, or continental type,
but with a certain amount of oceanic influence penetrating
by way of passes and river valleys through the Coast Moun-
tains. Summers are generally warm and winters cold.
Temperatures are not as extreme as deeper in the Yukon
or interior of northern British Columbia, however. Pre-
cipitation is low along the base of the eastern slope of
the Nbrthern Boundary Range, revealing a "rain shadow"
effect. It increases somewhat across the region toward
the Cassiar Mountains. A steep precipitation gradient ex-
tends about 120 miles northeastward across the range from
the coastal maritime areas, where annual precipitation is
in excess of 100 inches per year, into the Atlin region,
where some places receive less than nine inches. valleys,
such as the Atlin valley, are especially dry. During the
summer orographic effects make for higher rainfall in the
interior highlands, such as in the mountains around Surprise
Lake. prography exerts a major influence on the climate
of the region, particularly the wind. The primary roles of
air masses, pressure systems, and frontal zones in deter-
mining the climate of northwestern British Columbia and
southern Yukon Territory are discussed by Kendrew and Kerr

(1955) and Boughner and Thomas (1967) .

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34

Regional climatology

Climate-glacier relationships and climatic history in
the Northern Boundary Range and surrounding areas are dis-
cussed by Miller (1963). Of fundamental importance is the
movement of cyclonic storms, generally in a southeast-north-
west direction, along the Arctic Front. This is the zone
of interaction‘between the north Pacific low pressure system
and the continental, high pressure cell of the Arctic inter-
ior. The paths followed by storms passing along the frontal
zone are called storm.tracks. Over long periods of time the
positions of these are believed to change, in a generally
eastdwest direction, as the two major pressure systems are
modified by variations in the solar energy flux in the
atmosphere. When the storm tracks are considerably west of
the axis of the Northern Boundary Range the Atlin region
receives comparatively little precipitation, and glaciers in
the southwestern part of the region, particularly the
Llewellyn, tend to shrink. When the storm.tracks are dis-
placed eastward or northeastward, precipitation on the lee
side of the range tends to increase.

At the present time the storm.tracks occupy a westerly
position, and conditions in the interior are comparatively
drier (Miller, 1963) and apparently also warmer. That they
were located farther to the east during much of the 19th
century is indicated by the fact that the Llewellyn Glacier
was in a state of maximum.post-Glacia1 advance between

approximately 1900 and 1925. In the early to mid 1800's

t
I

35

a.precipitation maximum.on the lee side of the range
accounted for a relatively high amount of snowfall in the
glacier's main accumulation area, the effect of which
reached the terminal sector after a 50 to 100 year flow lag
period. During Pleistocene glacial maxima the major storm
track positions are believed to have been shifted much
farther to the east, to interior positions where primary
centers of the major ice sheets were located. Similar
storm track shifts from late-Glacial (pro-Holocene) through
Neoglacial times have been postulated by Miller (1963).

Classification

In the Koeppen.system.the climate of the Atlin region
is classified ch - a cold, snow-forest type, moist in all
seasons, with short, cool summers (Petterson, 1958).

In the Thornthwaite system a more precise and useful
classification is possible using data and maps published by
Sanderson (1948). The notation for the climate of the
Atlin valley is Clc'ldb'l. This means that, with respect
to moisture, the valley is dry subhumid (Cl) and experiences
little or no water surplus (d). Potential evapo-transpira-
tion is in the 11 to 17 inch range, placing the valley in
the cold microthermal (0'1) category from the standpoint of
thermal efficiency. Summer concentration of annual water
need is 62 to 68 percent (b'l). The climate is somewhat on

C
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36

the dry side and, from.the standpoint of plant growth,
moderate water deficiencies are the rule. The climate does
not approach aridity, although summer droughts occur. It
is similar, from.the moisture standpoint, to the Canadian
prairies and the Mackenzie valley, as well as most other
interior valleys of British Columbia and Yukon Territory.
With regard to temperature, the cold microthermal climatic
type is characteristic of the northern boreal forest zone
all across Canada. .

In most places a summer concentration of annual water
need in the 76 to 88 percent range is associated with the
cold microthermal climatic type (Sanderson, 1948). The
fact that in the southern two thirds of the Atlin region
the percentage summer concentration of annual water need is
lower than this is an indication of minor maritime influence
on the temperature regime. Apparently summer temperatures
are not so high as to cause evapotranspiration to remove
excessive amounts of moisture from.the ground here. In the
northeastern part of the region, however, the percentage
summer concentration of annual water need is higher, more
nearly corresponding to values associated with the conti-
nental, cold microthermal climatic type in most other areas
where this type occurs.

The highlands around the Atlin valley are more moist.
Surrounding the dry subhumid area of the valley proper is
a narrow zone classified as moist subhumid (02) (Sanderson,

19%). Most of the rest of the region is occupied by a

37

so-called humid climatic type (B) with four subdivisions
(B1 through Bh)' 0n the scale of Sanderson's maps it is
difficult to tell the exact location of these zones with
respect to features in the region. It appears, however,
that the Atlin.valley and probably also the valley of Taku
Arm experience dry subhumid climates, that the lower slopes
of these valleys as well as those in the Teslin area are of
the moist subhumid type, and that all highlands in the
region are of the humid climatic type. Although there are
significant differences in.precipitation regimes between
these various zones, seasonal fluctuations among them.tend
to be parallel.

With respect to thermal efficiency, the regions of
higher elevation are classified as tundra climate (D').
Since thermal efficiency is based on potential evapotrans-
piration or water need, which in turn is controlled by
temperature and daylength, tundra (as used by Thornthwaite)
is defined in terms of the water needs of the vegetation,
rather than in the more common reference to the vegetation
itself.

In summary, the two major Thornthwaite climatic types
of the Atlin region are (1) dry subhumid-cold microthermal
in.the lowlands, with little or no water surplus and a
moderate summer concentration of water need, and (2) humid-
tundra in the highlands, with seasonal distributions of
temperature and precipitation parallel to distributions in

theiunflends.

38

Meteorological observations and records

Standard weather Observations have been made for various
lengths of time at several stations in the Atlin region. A
41-year record, from.August, 1905 to September, 1946, is
available for Atlin. At Carcross the record spans the
period from.January, 1907 to December, 1946. A short
record, from January, 1926 to September, 1929, is available
from.the Engineer mining camp on Taku Arm.and another, from
July 1898 to August, 1900, for Tagish (Canada Department of
Transport - Meteorological Branch, unpublished data 1969).

Table 1 contains basic meteorological data for five
stations in and near the Atlin region. Graphs of tempera-
ture, precipitation, snowfall, and relative humidity in the
region are presented in Figure 5. Wind data are given in
Table 2, and wind direction frequencies are shown in Figure
6. Data are from Porsild (1951), Kendrew and Kerr (1955),
Boughner (1956), and the Canada Department of Transport -
Meteorological Branch (unpublished).

39

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Figure 5

41

Table 2. Wind speeds (percentage frequencies)
at four stations in the Atlin region.*

 

 

Station *Month Hour(LST) CEIET I-I§ MPH I3-38 MPH
Atlin Jan. 2230 43 48 9
(1941-6) 1630 45 44 1%

July 2230 35 5
1630 26 62 10
Dease Lake Jan. 0430 5 94 1
(1945. 1947-51) 1630 5 9o 4
July 0430 ll 83 0
1630 93 4
Teslin Jan. 0330 29 67 4
(1946-52) 1530 21 73 6
July 0330 38 62 0
1530 5 82 13
Whitehorse Jan. 0330 25 45 30
(1943-52) 1530 19 45 36
July 0330 27 63 10
1530 12 63 25

 

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V. SOILS

According to Chapman and Turner (1956) the Atlin region
belongs to the Mbuntainous Soil Area, where Gray Wooded
soils, Brown Wooded soils, Podsols, Alpine Meadow soils,
Lithosols, Alluvial soils, Rendzinas, and Peats have
developed.

Leahy's (1949) discussion of the general nature of
soils in Yukon Territory bears upon the Atlin region. Upland
soils are broadly differentiated into two groups on the
basis of presence or absence of permafrost. Most of those
without permafrost are well-drained and vary from dark brown
grassland soils to reddish-brown forested soils which pro-
bably belong to the Brown Podsolic Great Soil Group. Although
these are the most fully developed soils in the Yukon, their
profiles are generally immature.

The Atlin region is located in the zone of discontinuous
permafrost (Péwé, 1967). Although it is generally rare in
the lowlands, permafrost, along with seasonally frozen ground,
probably occurs in some valleys and broad, abandoned cirque
basins into which cold air tends to drain. Such is undoubt-
edly common at higher elevations. Regarding soils affected
by permafrost Leahy (1949) writes:

. . . (they) are imperfectly to poorly
drained and they usually have a thick covering

of peat and muck. Mineral soils with perma-
frost horizons occur to a lesser extent. Such

43

44

soils show little profile development beyond
the fact that the upper few inches of mineral
material under the thin moss cover is weathered
to a reddish-brown colour.

With respect to recent alluvial soils Leahy writes:

. . . (they show little or no profile
development and heir characteristics depend
chiefly on the nature of their parent material.
The effect of permafrost on these soils is
not well marked.

Rowe (1959), in discussing the Central Yukon Forest
Section, within which much of the Atlin region lies, gives
some information on parent materials and soil formation:

Throughout . . . there is evidence of
recent strong glaciation, and the soils are
predominantly of unmodified or water-worked
glacial drift. Soil deve10pment is generally
weak, due to the youthfulness of the surface
materials and to the dry climate. Brown
wooded soils are usual but grey wooded and
degraded dark brown profiles also occur. The
rooting depth of trees and other plants is in

A some areas affected by layers of volcanic ash
in the soils, and in other places, particu-
larly northward, by permanently frozen ground.

Lietzke (1970) has made a preliminary investigation of
soils in the Atlin valley. Regarding his findings, he states:

A wide range of well-drained soils, some
exhibiting only subsurface Cca horizons, some
exhibiting only spodic or spodic-like horizons,
and some exhibiting both a spodic horizon and
a Cca horizon occur in the Atlin valley area
of British Columbia.

Besides these well-drained soils, many
areas of more poorly drained soils occur in a
complex pattern in the valley.

Upland soils, largely in the northern part of the Atlin
region, were studied by Lietzke (1970) and included Spodosols,
Inceptisols, and Entisols (U.S. Dept. of Agriculture, 8011
Survey Staff, 1967). These had develOped in parent materials

t"‘—-‘-'-‘1

45

ranging from lacustrine silts and fine sands to loam till,
sandy loam till, sand and gravel outwash, and boulder
fields. In areas adjacent to the eastern shore of Atlin
Lake a thin capping of loess was frequently observed as a
major component of the parent material.

The lime content of these soils was found to vary con-
siderably, depending on texture of the glacial parent
material and location. Glacial ice which passed over moun-
tainous limestone bedrock in the southern part of the Atlin
region gave rise to drift containing larger proportions of
calcareous material than that which moved across areas where
limestone outcrops were not prevalent or were absent. Ice
streams in both categories have deposited material in the
Atlin region. For this reason the Cca horizon, as exposed
in cuts along the Carcross road, is spotty in occurrence.
Along the Atlin road and the Alaska Highway between Jakes
Corner and Whitehorse the lime content is quite variable,
but all profiles show at least a minor Cca horizon develop-
ment. The Cca horizon usually occurs between 12 and 20
inches in depth and is often the most prominent feature of
a soil profile.

A very noticeable Bir horizon, occurring Just beneath
the surface, was found in most areas. An A2 horizon, on
the other hand, was found in only a few profiles, and then
was thin and poorly developed. Lietzke points out that

this horizon seemed to be . . . dependent on an Optimum

climate - a micro-climatic variation necessary for maximizing

46

the podzolization process in this area."

A spodic horizon, occurring in profiles throughout the
region, was found to be from two to six inches thick, begin;
ning four to eight inches below the surface.

In finer textured parent materials a Gray Wooded sequum,
containing a distinct clay accumulation in a B't horizon,
was found to occur beneath the spodic sequum and above the
Cca horizon. It was found that an A'2 horizon may occur
Just above the B't horizon. In some profiles the spodic
horizon was observed resting upon the lower B't horizon.

Such besequal profiles were observed at many locations in
the region.

Lietzke also has found soil-vegetation relationships to
be quite pronounced in the Atlin valley. He notes that well-
drained soils having either a high pH throughout the profile
or a Cca horizon typically support a mixed type of vegetation
where aspen and lodgepole pine are prominent components.
Relative pr0portions of these two species are believed to be,
in part, a function of soil texture, with pine being favored
by the coarser, and aspen by the finer materials. Also the
coarser textured soils were commonly found to be less well
developed, presumably because of light vegetation cover and
the arid climate.

Some relatively well-drained soils have developed in
parent materials ranging from loam.tills to coarse sands and
gravels. These were found to bear a thick, almost peaty
organic layer and an alpine fir vegetation type (see below).

47

It is assumed that such a development of peaty material in
upland areas requires the prolonged absence of fire or other
disturbances.

Many poorly drained sites were found by Lietzke to sup-
port (white spruce vegetation. Moderately drained sites
usually support a mixedwood forest vegetation type.

Additional information from Lietzke's unpublished manu-
script (1970) is given below in: connection with discussions
of the plant communities. Detailed descriptions of key soil
profiles studied in selected vegetation stands are contained
in Appendix A.

48

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49

 

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{rubies-:9... L

VEGETATION
VI. INTRODUCTION TO VEGETATION OF THE ATLIN REGION

General

According to Shelford (1963) the Atlin region lies
within the zone of the transcontinental Boreal-Montane
Coniferous Forest Biome. Three large, natural subdivisions
of this biome are recognized. The northwesternmost one is
called "The forest of the valleys and lower mountain slopes
of the northern Rocky Mountains which is transitional be-
tween the boreal forest and the mountain forests in the
west." This subdivision comprises three types of forest
including, "The white spruceelodgepole pine forest of northern
British Columbia and southern Yukon." This is the basic type
of forest in the Atlin region. Shelford also refers to the
northwestern portion of the transcontinental boreal forest,
from British Columbia to Alaska, as the "spruce-giant moose-
lodgepole pine-paper birch faciation."

The Atlin region lies within the Interior Spruce and
Birch Forest Region as defined by Sigafoos (1958). Rowe
(1959) maps it as part of the Central Yukon Section of the
Boreal Fbrest Region.

The boreal forest in northwestern Canada is notably
simpler in species diversity than in other parts of the

50

51

country. The few important trees are lodgepole pine, white
spruce, black spruce, alpine fir, balsam poplar, aspen,
paper birch, plus one or more species of tree willow. All
except black spruce and paper birch are important members
or the general Atlin valley vegetation. White spruce,
lodgepole pine, alpine fir, and aspen dominate, either
Singly or in various mixtures, in the associations recog-
nized there (see below). Black spruce and paper birch were
not observed in the course of this study, and the writer
Knows of no report of their occurrence in the valley. Raup
(1915) reports a stand containing black spruce Just east of
Teslin along the Alaska Highway, and this is to date the
nearest known occurrence of this species.

The following shrubs and subshrubs are important com-
Ponents of the forest vegetation in northwestern Canada:
.BStula glandulosa, Rosa acicularis, Shepherdia canadensis,
Ledum palustre subsp. groenlandicum, Arctostaphylos uva-ursi,
A. rubra, Vaccinium vitis-idaea subsp. 313112, and Viburnum
e‘lule, along with various species of willow. All of these
occur in the Atlin valley.

The nomenclature used in this dissertation follows
Hultén (1968). Most groupings or lists of plant names are
arranged in the phylogenetic order used by Hultén. Trees
are referred to by common names, and all other plants by
botanical names. Appendix B lists the tree coxmnon names
and their botanical equivalents. Author abbreviations for

other botanical names used in the text are to be found in

52

the preliminary catalog of the flora, Appendix F.2

For present purposes, tree species up to about 18
inches in height in the herb stratum are referred to as
seedlings. Tree species in the shrub stratum, up to about
12 feet in height, are referred to as saplings.

Previous work

After several years of studying the boreal coniferous
forest of northwestern Canada, Raup (1941), in an important
Qaper, smmnarized most of the geobotanical work done there
by himself and others and attempted to elucidate some of the
major problems remaining for future workers. The paper deals
Partly with questions regarding the origin and distribution
01‘ the flora and the deve10pment and distribution of plant
c<>Immunities following Wisconsinan glaciation. In particular,
difficulties involved in attempting to describe the present
boreal vegetation (including arctic and subarctic vegetation)
in terms of ordinary ecological units are pointed out. Des-
Pite the relatively few Species involved, ecological rela-
tionships among them are complex. The delimitation of asso-
Ciations, by which generalizations regarding vegetation
composition and structure should apply over large areas, is
considered to be more difficult than in temperate regions
where community relationships are usually more clear-cut.
Raup discusses the problem of applying climax theory to
boreal vegetation. He suggests, as did Griggs (1934), that
aretic plant communities are still adjusting to the

53

environment and that the forests have not yet attained an
equilibrium with it. He believes, however, that equilibria
with "conditions in general" do exist and that edaphic sub-
climaxes can be recognized. The writer has studied and
attempted to classify the Atlin valley vegetation with this
view in mind.

Earlier, Raup (1934) reported on his phytogeographical
studies in the Peace River and upper Liard River regions.
Important accounts of the history of botanical exploration
and of geology, physiography, and climate, are given. A
geographical analysis of the vegetation is discussed, and
maJor vegetation types, some designated associations, are
defined. A catalog of the vascular plants is included.

In a later paper, Raup (1945) discusses forest species
and communities along the Alaska Highway in northern British
cOlumbia and southern Yukon Territory. Here the complexity
Of’ vegetational relationships is again pointed out, but a
178-11‘ amount of order in classification is achieved through
a consideration of some of the underlying complicating
flutters, the major one being fire. It is recognized that
1Odgepole pine and aspen, although ubiquitous, are "oppor-
tunists" of only temporary significance. These species are
unable to regenerate in the absence of further burning and
thereby maintain their status as major forest types. On this
baa is Raup explains that white spruce, black spruce, alpine

fir, and balsam poplar would, as nearly pure stands devele

oping in the absence of such disturbances, form only four

54

basic forest vegetation types. The first three of these
species are capable of reproducing generation after genera-
tion on the same site, and each shows a well-defined segre-
gation from the others according to habitat. White spruce
prefers better drained uplands and alluvial soils of river
flood plains 3 black spruce characteristically grows in
muskegs or mossy bogs; alpine fir is found primarily on high
slopes and in the foothills of mountains; and balsam poplar
prefers recent flood plains and gravel bars where it forms
a. stage in the deve10pment of white spruce forest.
Raup, in his 1945 paper, writes,

In view of these facts, and because the

white spruce is widely and rather evenly dis-

tributed throughout the area, the principal

criterion for the definition of natural re-

gions in terms of forest types becomes the

presence or absence of large quantities of

black spruce, alpine fir, or balsam poplar

in the upland timber.

Six forest cover types or associations have been recog-
nized by Raup (1945) along the Alaska Highway. (1) The
White spruce-lodgepole pine-aspen association is the most
abundant and widespread. (2) The next most important, in
terms of area covered, is the black spruce-white spruce-pine
association, sometimes containing aspen. The others are (3)
1She white spruce-balsam poplar (on flood plains), (4) the
white spruce-alpine fir-black spruce-lodgepole pine, (5) the
White spruce-balsam p0plar- aspen, and (6) the aspen groves-
Prairie Openings associations. The only one of these six

Which is important along the highway through the Atlin

i!

r———x*i_

55

region is the white spruce-lodgepole pine-aspen association.

Another comprehensive botanical study by Raup was pub-
lished in 1947, this time dealing with the southwestern
portion of the Northwest Territories. In that paper, a
number of plant communities are defined, primarily in terms
of the habitat type with which they are associated. As an
example of the nomenclature which Raup used and an indication
of his method, three of the communities are: (1) plants of
loose slide rock and turf-banked terraces, (2) plants of
ravines and gorges below timberline, and (3) flood plain
communities. His study also includes comprehensive lists
Of primary and secondary species in the various community
types, along with discussions of plant succession and a phyto-
geographical analysis.

Halliday and Brown (1943) discuss the distribution of
some important forest trees in Canada. These authors deal,
as did Raup, with the phytogeography of forest species in
terms of reinvasion of deglaciated terrain outward from
Wisconsinan refugia. The paper also attempts to show the
Percentage relative abundance (not actual abundance) or pop-
L'L'lation intensity of the major species in the forests through-
out Canada. Of interest here are the following statistics
13‘ or forests in northwestern Canada: spruce (white and black),
31-60 percent (medium intensity); lodgepole pine, 1-20 per-
cent (light); alpine fir, 11-30 percent (medium); and aspen
and balsam poplar, l-lO percent (light intensity). The

Atlin valley generally parallels the pattern except for

56

aspen, which is found to have a higher relative abundance,
as discussed below.

Porsild (1951) considers plant communities along the
Yukon sector of the Canol Road (Fig. 1). His mile-to-mile
transect of the road shows the distribution of five main
forest types: (1) white spruce-lodgepole pine-aspen (domi-
nant on well-drained soil of the valleys and lower slopes),
(2) white spruce—balsam poplar, (3) white spruce forest with
scattered paper birch and occasional black spruce, (4) black
Spruce forest mixed with some paper birch (a climax type on
Poorly drained glacial boulder clay where permafrost is
close to the surface and where the forest floor remains wet
Bind swampy throughout the summer), and (5) alpine fir forest
(at timberline, on moist north and east slopes).

Mbst of the non-forest vegetation types are described
by" Porsild (1951) more on the basis of habitat or physi—
C>gnomy than of species composition. These include (1) copses
(including several low shrub formations); (2) meadows and
grassland; (3) alpine plant communities; (4) vegetation of
lakes, ponds, lake shores, and sloughs; (5) vegetation of
bogs and mires; (6) vegetation of burnt-over land (with a
consideration of succession following fire); and (7) vegeta-
1"ion of disturbed sites, including apOphytes and anthropo-
Chorous plants. Porsild delineates seven phytogeographical
Provinces for the Yukon, discusses the age and origin of the
flora of southeastern Yukon, and provides an annotated list

of 894 species of vascular plants, covering the entire

57

territory to the extent of floristic knowledge at the time.
Porsild's study is the most comprehensive concerning flor-
istics, vegetation, and phytogeography in the immediate
vicinity of the Atlin valley.

Mcss (1953a, b) discusses forest communities and marsh
and bog vegetation of northwestern Alberta. The present
writer believes that here there are fundamental vegetational
similarities with the Atlin valley. Forest vegetation is
Classified and described by Moss in terms of floristic
composition and ecological relationships, the categories
used being the association, faciation, and associes. This
work involved regional reconnaissance, close study of
Selected stands, and the tabulation of species prevalence
in each stand using an eight-category scale from rare to
dominant.

According to Mess (1953a), dominance in the tree stratum
determines the association to which the stand belongs. The
faciation is based on the composition and relative importance
of the lower strata. Associes include stands which were
burned and are presently in earlier stages of succession.
Climax vegetation is recognized, in the Clementsian sense,
811d some stands are designated subclimax. The latter include
vegetation which is favored by prevailing edaphic conditions,
c-g. high water table, exceptionally pervious substrate, etc.,
or‘ periodic fires. Although there are some important flor-
istic differences between the vegetation of northwestern

Alberta and the Atlin valley, certain communities are believed

58

to be comparable in each area on the basis of the leading
species in equivalent strata.

Mess' study of marsh and bog vegetation (1953b) recog-
nizes a wide range of conditions, often intergrading, from
aquatic through subaquatic and moist. Terminology of wet-
land habitats and vegetation in general is clarified. In
most cases vegetation types are not defined in terms of
associations, etc., as in the uplands, but instead are dis-
cussed in terms of habitat types, e.g. muskeg and saline
meadow, or habitat type and a characteristic species group,
e.g. Drepanocladus bog and AgrOpyron-Carex grassland. Bog
Seres and their climax forest associations are considered,
as are seral retrogressions caused by burning. An important
distinction is made between Drepanocladus—m bogs and
§phagnum bogs. Only the former bog type has been found in
the Atlin valley, even though the Sphagnum type is very

 

Common elsewhere .

A further paper relevant to the present study is one by
Jeffrey (1961) in which 24 vegetation types in four topo-
graphic divisions of the lower Liard River region in the
Northwest Territories are discussed. This paper also in-
Cllludes an annotated list of plants. The basis of Jeffrey's
description of the vegetation is the layered physiognomy of
each type. Within each of five layers (tree, underwood,
Shrub, herb, and lichen and bryophyte) primary, secondary,

and occasional species are recognized.

"his ...:lll|r... . .
ail. ,.
1...! I .. , .7

59

LaRoi (1967) discussed preliminary work in a quanti-

tative ecological study of boreal spruce-fir ecosystems in

North America. Vegetation in stands of white spruce-fir

and black spruce forests, from Alaska to Newfoundland, is

described and the stands are classified on the basis of
floristic criteria and coincidence of distribution patterns.

One of LaRoi's stands was located in the Central Yukon
Forest Section, as defined by Rowe (1959). This includes
most of the Atlin region. LaRoi's stand appears to be

representative of the main forest type in the region, and

Species encountered in it and data about their relative

population sizes are assembled in Table 3. The stand is

classified in the Populus/Salix/Shepherdia stand-group of

the boreal white spruce-fir stands. The present writer

c-‘-<31risiders it equivalent to the shrub-herb faciation of the

white spruce association in the Atlin valley study (Table 5).
Lutz' 1956 paper dealing with the ecological effects

of forest fires in the interior of Alaska is of fundamental

importance to vegetation studies throughout the boreal coni—

ferous forest biome. Again the complex relationships of

a relatively few forest species are brought under consid-

eration, and it is noted that, "Only when the influence of
Past fires is recognized can one begin to account for the

seemingly haphazard mosaic of vegetation." Lutz points out
that fires have always occurred because of lightning and

the activities of prehistoric man. He makes three important

points regarding the nature of the vegetation mosaic: (l)

u e
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60

Table 3. Species encountered by LaRoi (1967) in a
stand located near the Atlin region*, with data
on relative population sizes.

 

Tree stratum.(square feet per acre)

Populus tremuloides 0-10
cea glauca 101-150
Low tree and tall shrub stratum (stems per 100
square meters)

 

Salix glauca 6-15

 

Medium and low shrub stratum (percent areal
coverage)

Shepherdia canadensis 2.1 -3.3
Rosa acicularis " ”

 

 

Herb and dwarf shrub stratum (percent areal
coverage)

Solidago multiradiata 060 “0533
Gentiana ro in ua

IrctostapEons ru5ra " "
AChillea milIefBIIfifi " "
Hedysarum alpinum
Arct0staphylos uva-ursi

O
O
Nbrtensia paniculata 0
Galfum boreale O
O
O
2

 

 

 

o ium angustifolium
Fragaria virgihiana

Eyrola secunda
nnaea BoreaIis

*This is LaRoi's white spruce-fir stand no. 5
and occurs at an elevation of approximately 2,500
ft, at latitude 60°49' N and longitude 136 39'w.
This is approximately 75 miles west-northwest of

the northwestern corner of the Atlin region
(Fig. l).

 

 

61

sharp boundaries between stands of aspen and spruce are the
edges of burns, (2) isolated patches, upland stringers, or
even scattered individuals of spruce (and other species)

are relicts of formerly extensive stands which were destroyed
by fire, and (3) areas that are now treeless may have sup-
ported well-developed forest vegetation which was completely
destroyed by fire. Lutz discusses in detail the effect of
fire on different forest vegetation types as well as on
soils, wildlife, and human welfare. He also presents a
useful analysis of plant succession following fire.

A study by Horton (1956) in Alberta also provides useful
information about the ecology of lodgepole pine and its rela-
tionships to burning.

In a more recent paper Oberle (1969) discusses the eco-
logical role of forest fires, both in temperate and boreal
forests. The necessity of fires for the maintenance of
desirable vegetation types as well as wildlife habitats and
a natural ecological balance is reiterated.

As far as the writer has been able to determine, no
significant botanical work had been done in the Atlin valley
prior to the present study, and very little appears to have
been done elsewhere in the region except along the Alaska
Highway, The only published report of a plant collection in
the valley appears in Hultén's (1940) comprehensive history
of botanical eXploration in Alaska and Yukon Territory. This
concerns the visit of Alice Eastwood, curator of the Herbarium

of the California Academy of Science, to the Llewellyn

.e n.’
pl.

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adv-v.

 

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.o fifl
«to vy-_

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We“.

'II

b—. g.-.
Q

VV.

‘0
( r)

l‘-'

(I)

 

62

Glacier terminus area and also to Taku Lake (Taku Arm of
Tagish Lake?) on Wednesday, July 15, 1914. Eastwood was
concerned primarily with shrubs and trees, and the size of
her collection apparently was not large.

It seems a safe guess that a number of miscellaneous,
unpublished, private collections have been made in the Atlin
valley, especially since completion of the Atlin road in
1949.

Other from this, personal communication with several
Canadian scientists, including, among others, T. M. C.
Taylor in 1967, A. E. Porsild in 1968, and J. Terasmae in
1969, shows that botanical, as well as palynological work
in the Atlin valley and nearby areas has been lacking.

Very little information on other aspects of the natural
history of the Atlin region is available. Swarth (1936)
gives an account of mammals and birds in the Atlin Lake
area. McTaggart-Cowan (1941) reports on a fossil partial

cranium of Bison bison subsp. (cf. subsp. athabasce) (B. C.

 

P. M. No. 678) of Holocene age found four feet below the
surface in a muskeg at Wilson Creek. Whether this site is

the Wilson Creek Bog of the present study is not known.

VII. GENERAL VEGETATION SURVEY

Purposes
Vegetation in the Atlin valley has been surveyed with

'bwo objectives in mind. First, in the absence of any

 

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63

previous formal or published botanical work in the valley,
it was desired to learn something of the fundamental nature
of the vegetation there and to compare it with similar,
previously studied vegetation in nearby areas. In this
connection, it was desired to establish a preliminary
classification of the major vegetational units, based pri-
marily on physiognomy and species composition, to serve as
a guideline for the development of future ecological re-
search.

Secondly, information about the composition and spatial
organization of the general plant cover was needed for a
comparison with modern pollen deposition as seen in surface
samples. In a palynological study, knowledge of any quali-
tative or quantitative relationships between modern regional
vegetation and the pollen rain produced by it is, of course,
helpful in determining the nature of former vegetation from

fossil pollen assemblages.

Methods
Field activities. Poore (1955, 1956) reviews and

 

criticizes the methods of the Braun-Blanquet school of
phytosociology, and Kershaw (1964) and Daubenmire (1968)
provide further discussion and useful information on the
application of these methods in the field. Field work in-
volves, in part, the subjective selection of stands of
vegetation for detailed study. This is considered to be a
worthwhile technique, capable of yielding much relevant in-

formation about the vegetation, provided that the area being

 

 

 

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studied has been adequately reconnoitered and the flora is
fairly well known.

Hansen (1949a) and Davis (1963) deal with the need for
quantitative vegetational data to compare with percentages
of pollen in surface samples and to establish a measure of
the representation therein of various species. These studies,
and others, make use of sample plots located randomly or sys—
tematically throughout the area of investigation.

The survey reported here employed a sampling procedure
with both subjective and systematic aspects. The intent was
twofold: (l) to apply basic field methods of the Braun-
Blanquet school, particularly the subjective selection of
stands, in order to be certain that in each case the assem—
blage of plants studied (the stand) represented a single
vegetation type and was not a mixture of two or more types
and (2) to obtain a measure of the relative importance, in
terms of area covered, of each vegetation type.

After a certain amount of time had been spent collecting
plants in the Atlin valley and reconnoitering the vegetation
in general, the writer concluded that nearly all of the
variations in vegetational development between lake level
and about 3,000 feet were observable from points on the
Atlin road. Furthermore it appeared that the relative amount
of distance along the road occupied by a vegetation type was
a rough function of the proportion of the total area occupied
by the type in a broad zone on either side of the road.
Within its elevation range (2,197 feet to approximately

I’-

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_.

 

65

2,575 feet), the road follows most t0pographic irregularities,
and all habitat types, including bogs, are traversed or
skirted. It appeared that sampling at apprOpriate intervals
along the Atlin road could provide reasonably representative
information on plant community organization and distribution
in the valley.

For these reasons the Atlin road, and the first six
miles of the Carcross road, was chosen as a base line.

Stands of vegetation were systematically located at two-mile
intervals. Every other milepost, beginning at mile two,
marked the center of a small area within which two stands
were located, one east and one west of the road. These
areas were usually not more than about 300 feet in radius.
Each stand was designated by milepost number and direction.
For example, stand 2E was situated east of the road at mile
two. Stands on the Carcross road were distinguished by a
"C" (e.g. C2E), and stands on the road south of Atlin 1 the
mileposts do not extend beyond Atlin - were designated by an
"S" (e.g. 82E). Here the field truck odometer was used to
determine twoémile intervals.

Since the general vegetation and the tree surveys were
conducted in 1967, the Atlin road has been "improved." Alter-
ations and relocations have been made in many places. There-
fore some of the mileposts mentioned here do not correspond
to actual mileposts on the present Atlin road.

Although each stand had to be located, according to this

system, within a certain predetermined small area, the

66

precise position depended on the surveyor's discretion. No
predetermined spacing between milepost and stand was used.
Instead, the most homogeneous appearing assemblage of plants
closest to the post, on the side of the road in question, was
selected. The quadrat size was 900 square feet, and each
stand, therefore, had to be at least this large. This method
precluded consideration of small stands in certain micro-
habitats, such as in moist gullies, etc., but this was justi-
fied on grounds that only the more important vegetation
types, in terms of area covered, were of immediate interest.
In each case care was taken to locate the quadrat well away
from the disturbed zone marginal to the road. Even so, weedy

species, e.g. Achillea sp., Polemonium.pylcherrimum, etc.,

 

 

were often encountered. Logged areas, which were rare, were
avoided, except in a few instances where compromise seemed

in order and quadrats were allowed to contain one or two very
old cut stumps.

It is emphasized that in stand selection no form of
vegetation or habitat was consciously discriminated against
as long as a quadrat 30 feet square could be located within
a contiguous unit of vegetation. It was intended to avoid
laying out the quadrat in such a way that it would contain
more than one vegetation type, including the ecotone between.
This could happen if a quadrat were placed, according to a
predetermined system, across the foot of a $10pe. Here,

the portion lying on the slope might contain, for example,

 

 

67

vegetation of the aspen association, and that on the basal
flat, depression shrub vegetation.

After the stand was selected a list of species and
groups in it was made. Although every plant seen was
accounted for, it was not possible to identify them all to
species. Some, therefore, were relegated to genera, families
(e.g. Gramineae) or other groups (e.g. foliose lichens).

Each quadrat was established by pacing out a 30-foot
square in what was judged to be a representative part of
the stand. Paper markers were placed at the corners on con-
venient pieces of foliage. Within the quadrat the status of
every species or group on the stand list was assessed. The
measure employed was one of cover and abundance according to
the Domin scale (Kershaw, 1964; V. J. Krajina, personal oral
communication 1969). The Domin scale is reproduced as
Appendix C for the convenience of the reader. This measure,
the cover-abundance (C-A) value, along with constancy
(Kershaw, 1964), are the statistics upon which the vegetation
classification presented in this dissertation is based. The
quadrat lists are the relevés of the Braun-Blanquet method.

If representatives of 85 percent or more of the names
on the stand list were found in the quadrat, the sample was
considered to adequately represent the stand. If fewer than
85 percent were found, an adjacent quadrat of equal size was
marked off and searched for additional species. If the number
of new species was ten percent or more of the total found in

the first quadrat, the assigning of C-A values to names on

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68

the stand list was repeated for the double quadrat. If less
than ten percent, the double quadrat was doubled again. In
the few cases that a second doubling had to be made, the
quadruple quadrat was considered representative of the stand
and was used without further doubling, irrespective of the
number of additional species.

All together 86 sites and quadrats were examined, from
mile six on the Carcross road to mile l9-south on the Atlin
road (see map, Fig. 1). Whereas time and equipment for the
systematic study of soils and microclimate were not available,
a few general notes were made regarding physical character-
istics of each stand. Where appropriate, soil information
of Lietzke (1970) is incorporated, and several of his soil
profile descriptions are presented in Appendix A.

Association table. An association table was constructed

 

by listing all species and groups in a column along each
vertical margin of a large sheet of paper. All stand numbers
were written across the top, heading a series of 86 columns
which made up the body of the table. The data from each
relevé were then written onto the table in the apprOpriate
column (Poore, 1955).

By studying the association table it was possible to
identify the relevés which were floristically similar and
contained the same dominant species in the upper (usually
the tree) stratum. Dominants were recognized on the basis
of high C-A values. Relevés which appeared similar with

respect to dominants were grouped together. If a group

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69

consisted of four or more relevés, mean C-A values and con-
stancy values were determined for all the species and
species groups. Several relevés together were considered
to represent a distinct vegetational unit if they contained
additional species, besides the dominants, with a combi—
nation of high mean C-A and constancy values, and if the
same species were found, upon examination of other relevé
groupings, to be less common or absent there. Fidelity was
noted in a few instances, but was not used to aid in estab-
lishing the groups.

The vegetation units or communities defined in this
manner were classified either as associations or as associes.
An association is considered to be the fundamental unit of
more or less stable vegetation and characteristic of a par-
ticular ecosystem type. An associes, on the other hand, con-
sists of vegetation in an early stage of succession, often
following a fire. One association, the white spruce associa-
tion, was subdivided into two faciations (Daubenmire, 1968).
The various data for 12 communities in the Atlin valley are
presented in Tables 4 through 15. Table 17 summarizes im-

portant data for each of the 12 communities.

Discussion

The abstraction of relevés from the association table
and grouping them into associations is a subjective pro-~
cedure and has been widely criticized on this basis. Poore
(fi5955) refers to it as the "muddled and haphazard phase” of

the Braun-Blanquet method. The reality of the communities

7O

determined in this manner is a function of the patience of
the investigator and the extent to which the table is
critically studied.

The three categories of community organization and
development recognized here (association, faciation, and
associes) constitute units of vegetation or plant cover
which are distinguished in the field as follows: (1) Each
exhibits a characteristic physiognomy with respect to four
major strata - arboreal, shrub and subshrub, herb, and
lichen and moss. (2) Within each there is floristic con-
tinuity from stand to stand. (3) Every community occupies
a significant area, either in the valley or in other regions
as determined from.the literature and the writer's observa-
tions. Each, therefore, is important as a landscape com-
ponent and potentially important as a producer of a char-
acteristic pollen rain. (4) Each community is more or less
directly related to a particular set of edaphic and historical
factors. The edaphic factors, e.g. soil and water relations,
change significantly only over periods of time measurable in
terms of several generations of plant communities. Histor-
ical factors, e.g. fire and subsequent secondary succession,
tend to recur, with varying intensities, at a frequency which
may be greater than the frequency of community regeneration.
(5) In some cases there are rather specific relationships
between certain habitat factors and the plant community.
Important among these are: (a) the shrub-herb-moss phase

of the white spruce association - acid bedrock, (b) the

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71

alpine fir association - higher precipitation and soil pH,
(c) the depression shrub association - high water table, (d)
the mixed woodland association - exceptionally pervious
substrate, and (e) marsh and bog communities - water table
perennially higher than ground surface; the influence of
drainage basin geochemistry. (6) Each association, therefore,
is believed to persist, with perhaps minor compositional
changes, over major time intervals measurable in terms of a
few hundred years or more. Persistence, or regeneration,

is shown by the presence of fair proportions of seedlings

and saplings of the dominant species in most stands studied
and the relative absence of offspring of dominants of differ-
ent associations.

The associations, including the two faciations of the
white spruce association, can be looked upon as climax vege-
tation on the basis of the six criteria enumerated above.
Climax in the Clementsian sense is not implied. Rather, a
polyclimax concept is intended wherein several factors
besides macroclimate act to perpetuate certain vegetation
types. These are the edaphic climaxes of Raup (1941).
Because of the prevalence of fire, this is believed to be
an especially important approach in the Atlin region, as
throughout the boreal forest zone. The youthfulness of the
soils, the immaturity of surface drainage in some areas, the
irregular glacial t0pography, and other factors are also
important.

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72

All but two of the 86 stands were classified or tenta-
tively classified. This is not so much a reflection of wide-
spread vegetational organization as of the selectiveness of
the sampling procedure. Observations indicate that vege-
tation units in the Atlin valley, as in most places, are not
sharply outlined, but instead grade into one another across
transition zones or ecotones, some of which are quite broad
(Fig. 7). Stand 12W, for example, falls into this category.
The valley is occupied by "a variety of merging vegetation
types of different successional status" (Daubenmire, 1968).
Furthermore, transitional vegetation is considerably more
important than is revealed by the sampling procedure alone.

Any classification which pigeonholes vegetational units
must take these circumstances into account. The writer be-
lieves that strictly defining vegetation units, such as
associations, must be done in terms of clusters of Species
or "nods" along ecological gradients (Janssen, 1967). These
clusters must be defined, somewhat arbitrarily, on the basis
of selected criteria such as the six listed above. In a way,
plant communities (associations, etc.) are merely points
along continua of constantly changing plant assemblages,
where the amount of change per unit distance depends on the
steepness of the ecological gradient.

The writer adheres to this view, but the associations
(the "noda" or clusters) are defined broadly enough that they
encompass practicable segments of actual vegetation. An
examination of Tables 4 through 15 will show that, in many

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73

cases, a certain range in C-A values is allowed for dominant
species in an association as well as for less diagnostic
species. In certain stands no particular amount of dominance
is shown by species which are clearly dominant in other
stands of the same association. Nevertheless, these stands
could be included in the association because of overall
floristic similarity or because the species in question was
actually of higher C-A value in the stand than the quadrat
data indicated. The quadrat happened to be located where the
forest was thinner. Reference to field notes as well as
quadrat data was ordinarily necessary to classify a stand.

It should be mentioned that aerial photographs of the
entire Atlin region, at a scale of about two inches to the
mile, are available from the Department of Lands, Forests,
and Water Resources in Victoria and the National Air Photo
Library in Ottawa. Some of these were obtained in connection
with the present study for certain parts of the Atlin valley.
Although an aerial photographic interpretation of landforms
and vegetation was not intended as an adjunct to the present
study, the potential value of aerial photos to future
studies of this type is recognized. Terasmae and Mott
(1964, 1965), for example, believe that aerial photograph
studies are the only feasible way to adequately survey
regional vegetation for palynological purposes.

Stone (1948) and Hegg (1967) show how major vegetation
types can be recognized on aerial photos in parts of Alaska

where the vegetation is similar to that of the Atlin region.

.,. .
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74

With this information the present writer has been able to
distinguish several broad vegetation types according to tone
(shade of gray) and texture on aerial photos of the Atlin
region. These are: (l) coniferous forests, including spruce,
pine, or mixtures of these and, in some cases, of alpine
fir; (2) broad-leaved forests, including aspen, poplar, or
mixtures of these; (3) depression shrub vegetation; (4)
upland herbaceous vegetation; and (5) marsh and bog vege-
tation, including differentiation of the various herbaceous
and shrub zones. The aerial photos illustrate the irregular
topography and diverse landforms throughout the region.
These are a result of widespread glacial activity and of the
effects of postglacial erosion. The natural result of this
geomorphic diversity and topographic irregularity is a
general lack of continuity in single vegetation types or
stands over large areas. An exception is the system of kame
terraces between mile 16 and 23, where lodgepole pine forest
is rather continuous. Also, in the southern part of the
valley, upland mixed coniferous forests appear to be more
extensive and continuous than elsewhere.

Generally, however, stands of vegetation are seen on
aerial photos to be patchy and spotted across the landscape.
Thus it would be difficult to measure the relative areas
occupied by each vegetation type, a kind of information
which is important in the present survey. Furthermore, on
the photos it is not possible to make a reliable distinction

between spruce, pine, and mixed coniferous forests in most

v.

a.-

.-

75

areas. Since these are the major pollen contributors, as
well as dominants in major communities, the usefulness of
the photos is limited in this respect too.

Examination of the aerial photos has, however, provided
support for the simplifying assumption made earlier that the
relative amount of distance occupied by a vegetation type
along the Atlin road is, roughly, a function of the prOpor-
tion of the total area that the type occupies in a broad
zone on either side of the road. The photos have also been
useful in obtaining a more complete view of the vegetation

within and in the Vicinity of the six bogs discussed later.

The plant communities

.§$EE§' Most of the upland forest stands studied occupy
sites which are flat or gently sloping to the west. Many
of these are on raised swells with flanks which slope down-
ward in two or more directions from the edges of the stand.
A few sites occur on fairly steep lepes. Drainage is
generally good and the sites are mesic in nature, although
some are more moist than others, and many have a rather dry
aspect. The most widespread soil parent material is a cal-
careous glacial till consisting of pervious sands and pockets
of pebbles. The deposits vary in thickness from site to
site. At a few there is relatively little or no glacial
material so that soil is developing on bedrock.

Although there is considerable variation in substrate

among the forested sites, this does not seem to be as

76

important a factor in the differential deve10pment of forest

vegetation types as is the past history of fire and subsequent

successional development. The writer suggests that the re-
gional climax vegetation type in the Atlin valley is the
feather moss faciation of the white spruce association (see
below). It is suggested further that, in the absence of
future disturbances, succession would continue until all
mesic sites eventually supported this community type. An
indication of this is the fact that there is almost as much
variation among the ten sites bearing stands of the white
spruce association/feather moss faciation as among all the
upland sites studied. To illustrate, the stand numbers are
listed below with brief site characteristics.
6E very gentle slope west; poorly drained;
below limestone cliffs of Mt. White
6W near edge of lake (Atlin Lake); moist;
small, sluggish stream
26E gentle slope west
28W gentle slope west; dry
30E moderate slope west; boulders
30W steep slope west
4W moderate slope (20°) west
OW high ground - upper region of a broad
swell
48W very gentle lepe east; well drained
52E gentle slope; damp
It is to be noted that stand 30W occupies the steepest
forested site studied, yet has developed into the regional
climatic climax vegetation type, rather than an edaphic
climax.
Following Raup's (1941) discussion, all other forest
associations are considered to be edaphic climaxes where site

conditions, along with fire and post-fire successional

 

 

 

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77

history, are involved.

Hygric habitats are widespread in the Atlin valley, and
they and the plant communities in them are very important
in terms of overall Holocene landscape evolution. They range
from.marshes and begs to moist places bearing stands of the
depression shrub association. In this study only the latter
vegetation type was measured and classified, three stands
being encountered in the survey. Marsh vegetation has not
yet been examined. Bog vegetation is described in general
qualitative terms below.

Four of the sites studied are considered xeric in terms
of their exPosure, excess drainage, and, in places, rocky
substrate. These bear stands of the herb-heath association,
the perpetuation of which is discussed below. At these
sites the gentler slopes are believed also to be potentially

capable of supporting climax forests.

White Spruce association

White spruce forests are more widespread than any other
plant community in the Atlin valley (Tables 17, 19, 20). In
the survey 27 percent of the stands were of this vegetation
type.

White spruce is clearly dominant in the arboreal stratum
of all stands, having an average cover of about 30 percent.
Tree willow occurs in a majority of the stands, but never
with a cover of more than about five percent. Pine, aspen,

and balsam p0plar form light admixtures in a few stands.

78

Figure 8. Opening in the white spruce association/
Shrub-herb faciation at stand 59E.

View east from near mile 59 on the Atlin road. Rela-
tively lar e, Old-growth white spruce (Picea glauca var.
albertiana? are shown which are typical In aspec of mature
spruce in the Atlin valley. The Open nature of the arboreal
stratum and the dense shrub stratum are characteristic of
this vegetation type. Shrubs include Salix spp., Betula
‘%%andulosa, Shepherdia canadensis, and Potentilla frutIcosa.

e blOssoms in the‘fOreground belong to the latter species.

Glacial drift is thin or non-existent in this area and
nearly bare patches, as at the lower right, are where bed-
rock is exposed at the surface. The absence of a calcareous
substrate, unlike at most stands of this community type, is
probably the major factor favoring the relatively important
status of Betula and Potentilla. Table 5 (p. 109), which
gives compIete Informatibn on the vegetational composition
of this stand, shows that other plants characteristic Of
acid substrate, including Ledum.palustre sap. groenlandicum
and Empetrum nigrum, also occur here.

This community shares tOp importance, in terms Of area
occupied, with the mixedwood forest association at lower
elevations in the Atlin valley. It is discussed on pages

77-85 0
Midday. 30 June 1967.

79

 

Figure 8. Opening in the white spruce association/shrub-herb faciation
at stand 59E.

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The shrub and subshrub stratum varies from almost non-
existent in some stands (40W) to dense (59E, 87E, and 87W).
The usual situation is a light shrub cover containing five
or six scattered species. The more important members of

the stratum are Salix spp., Shepherdia canadensis, and

 

Arctostaphylos uva-ursi, each of which are ubiquitous in the

 

 

Atlin valley, and Arctostaphylos 3333a, which occurs only
rarely in other communities and therefore is of high fidelity
in the white spruce association. [Alggg sp., occurring in

the shrub layer of three stands (6W, 30E, and 30W) and the
arboreal layer of one (6W), is 100 percent faithful to the
association. Diversity and density of the shrub layer

appear to be a function of the moistness of the site and

soil pH. Dry sites ordinarily support sparse shrub layers.
USually, the moist sites, especially those with Lgdgm
palustre subsp. groenlandicum and Empetrum nigrum, which

 

 

indicate lower pH, have dense shrub strata. In others,
particularly those with thick patches of feather mosses,
shrubs are scarce.

The herb stratum is more diverse than that of any other
community except the mixedwood forest association. The large
number of species and groups is, however, at least partly a
reflection of the larger number of stands Of these two asso-
ciations encountered in the survey. There are no 100 per-
cent constants, but Gramineae, Geocaulon lividum, Pyrola sp.
and Linnaea borealis occur in all but two or three stands.

Since these also have high constancy values in other

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81

communities, their presence does little to characterize the
white spruce association.

In the lichen and moss stratum feather mosses are common
to dominant, and lichens form major admixtures in most
stands.

MOSS (1953) found the white spruce association to be
the most prevalent as well as the best defined vegetation
type in northwestern Alberta. He considered it to be the
regional climax vegetation there. A similar interpretation
may be applied to the Atlin valley where white spruce forests
are believed to approach the status of a climatic climax.
This takes into account the significant areal extent of the
association as well as factors in the autecology of white
spruce which enable it ultimately to replace most other forms
of upland vegetation and to persist indefinitely in the
absence of natural disturbances or climatic change (Hansen,
1953).

Two major variations of the white spruce association
are recognized on the basis of differences in the relative
importance of each of the four strata (Table 17). These
variations are the feather moss and the shrub-herb faciations.

Feather moss faciation. This faciation is the more

 

precisely defined (Table 4). The arboreal stratum contains
old and mature spruce trees and the canopy is sometimes so
dense that little direct sunlight reaches the forest floor.
Shrubs and herbs are scarce, and the ground is thickly car-

peted by large patches of feather mosses, primarily Pleurozium

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82

schreberi and flylocomium splendens. The moss cover is often

 

 

absent around the bases of trees, especially where several
trees grow in a clump and there is a thick litter layer.

Patches of Geocaulon lividum and Linnaea borealis occupy

 

 

significant portions of most quadrats, and scattered Lupinus
arcticus, Arctostaphylos uva-ursi, Eyrola spp., and seedlings

 

 

or small individuals of Shepherdia canadensis, Rosa acicularis,

 

Mertensia paniculata, and others are sometimes encountered.

 

Several of the sites occupy sloping terrain, some quite steep.
At others, drainage is noticeably impeded. This factor

appears to be responsible for the dense growths of Equisetum

 

spp. encountered at sites 6E and 6w. The only alders found
in the survey are in stands of this faciation, specifically

at 6W, 30E, and 30W. Alders are associated with a small
sluggish stream at 6W, and where they occur in the other

sites the water table is shallow, as noted by the ground being
wet at the surface.

Moss (1953) discusses the ecology of the feather moss
faciation and states that, of the four white spruce facia-
tions which he recognizes in northwestern Alberta, it is
probably the climax of the association in the Clementsian
sense. The writer considers the status of this community
to be similar in the Atlin valley for the following reasons:
(1) Charred wood was not observed in any of the ten stands
studied, which indicates that, unlike other communities, fire
has played no role in the perpetuation of this vegetation
type. (2) The stands were made up of large and apparently

83

old to mature trees, comparable only to trees seen in the
shrub-herb-moss phase of the white spruce association/shrub-
herb faciation and the white spruce-lodgepole pine forest
association (see below). (3) The stands occupy sites which
are level (6W) to fairly steep (30w), indicating that, on
upland terrain, there is no direct control by the topography,
exposure, or drainage over the type of vegetation which
eventually develops in the continuing absence of disturbances.

Lietzke (1970) studied the soils in stands 48W and 52B
and found actual soil deve10pment to be minimal. Parent
material is a poorly drained sandy loam till beneath stand
48W and a fine-grained lacustrine material mantling till or
outwash at 52E. The parent material is little altered by
soil formation processes and is overlain by several inches of
peat derived from the feather moss stratum. In August, 1969,
a frozen layer was found at a depth of 30 inches beneath
stand 48W, extending downward to at least 66 inches. At the
same time of the year a frozen layer was also found between
23 and 36 inches at 52E. These may be examples of transient
frozen ground, rather than stable permafrost. A description
of the 52E profile is contained in Appendix A. This soil,
plus that in stand ABW, is classified by Lietzke (1970) as a
Histic Cryaquept, coarse-loamy, mixed calcareous.

Shrub-herb faciation. It is possible that two facia-

 

tions, an herb faciation and a shrub-herb-moss faciation,
could be recognized here instead of a single faciation (Table
5;Fig. 8). Only three of the stands studied, however, would

84

fall into the latter category, and the evidence to date is
not considered adequate to make such a separation at the
faciation level. Instead, the shrub-herb faciation will be
discussed in terms of two phases, a phase being an informal
and tentative community category for purposes of discussion.

(a) Herb phase. Stands of this community type include
all but 59E, 87E, and 37W in Table 5. It is distinguished
from the feather moss faciation by a comparatively full herb
layer and less luxuriant lichen and moss development. It
differs from the shrub—herb-moss phase (see below) by its
relatively sparse shrub and its lighter moss layers. The
canOpy is more open than in the former community, and most
sites are drier than in either of the others.

Evidence of fire occurs in six of the ten stands, whereas
none was found in the other white spruce forest stands. This
indicates the importance of the fire factor in the develop-
ment of vegetation of the herb phase. It is probable that
at sites where no future disturbances occur, succession will
continue until either a feather moss faciation or shrub-herb-
moss phase results. Although the fire factor is recognized,
the vegetation of the herb phase differs from brulé in that
succession has reached a later and slower stage, the arboreal
stratum is well deve10ped, and community relationships are
generally more stable.

(b) Shrub-herb-moss phase. Stands 59E, 87E, and 37w,
belong to this phase. These are grouped in the middle of
Table 5 where they can easily be compared with the others.

n.

'00—

‘1'
{II
III

--
'-

...-

o...

'I!

l

 

 

85

This phase differs from the other two communities of the
association in having a dense shrub and subshrub stratum in
addition to moderate to dense herb and lichen-moss strata.
This community also differs in the shrub stratum by a lower

importance of the ubiquitous Shepherdia canadensis, Rosa

 

acicularis, and Arctostaphylos uva-ursi and by the occurrence,

 

with relatively high C-A values, of Betula glandulosa,

 

Potentilla fruticosa, Ledumpalustre subsp. groenlandicum,

 

 

 

and Empetrum nigrum. A possible eXplanation for the presence
of the two ericaceous shrubs is the development of soil from
an acidic bedrock, rather than from calcareous drift which
underlies the majority of sites along the Atlin road.

Aitken (1959) maps greenstone and volcanic greywacke in the
vicinity of mile 59, small outcroppings of which occur near
stand 59E, and siliceous bedrock (high quartz content) occurs
in the vicinity of stands 87E and 87W.

It is probable that the shrub-herb-moss phase of the
white spruce association persists indefinitely as edaphic
subclimax stands within the white spruce forests. From
the writer's general observations and survey measurements,
it is suggested that this phase is of minor areal extent,
being restricted to geochemically acidic locales as dis-
cussed above and also to poorly drained situations. Stands
S7E and S7W are quite moist, and other stands were observed
to occur along small streams. The largest white spruce
encountered in the Atlin valley, with DBH (diameter at

breaSt height) measurements up to 30 inches, grow in stands

 

‘fivn.

'vow-

I
0D.- A
'

'.'-v

 

\.‘

86
at tree survey sites 28E, 29E, and 813W (see below).

Lodgepole pine association

The lodgepole pine association has been difficult to
define in the Atlin valley, but, as a community type wherein
either middle-aged or mature pine trees are dominant, it is
considered to be an important component of the regional vege-
tation (Table 17 and Fig. 9). Pure, old growth lodgepole
pine forests are rare. Five of the stands studied are con-
Sidered to belong to the association, and two of these still
show signs of former burning. Only stand 36E fits well the
lodgepole pine association concept (Fig. 9). A large amount
or terrain in the northern part of the valley, including the
kame terraces previously noted, is occupied by burned or
Partially burned forests consisting primarily of young pines
and apparently redeveloping into pine forests. This will be
discussed further under brfilé. Also it is noted that rather
large, living pine trees are important in mixed coniferous
forests in the southern part of the valley and at inter-
mediate elevations on the valley walls.

The arboreal stratum varies from sparse, in older stands,
to Cllzite dense in the young, even-aged stand at 24E (Fig. 9).
Shrub development is light to moderate, with M Spp.,

 

Wlos uva-ursi, Shepherdia canadensis, and Rosa
W the only important components. Density is usually
low in the herb layer too, consisting primarily of Gramineae,
%bium angustifolium, Linnaea borealis, and several
compOsites.

87

Figure 9. The lodgepole pine association at stand 24E.

This view shows a fairly dense stand of even-aged lodge-
pole pine, a situation indicative of origin on a surface
cleared of former vegetation by fire. The substrate here is
light and well-drained. The Openness of the forest at lower
levels is particularly noticeable, herbs and shrubs being
scarce. The forest floor is densely covered by lichens,
including reindeer lichens, and mosses.

This community type is discussed on pages 86 and 89,
and phytosociological data are included in Table 6.

Late afternoon. 3 July 1967.

Figure 10. The lodgepole pine brfilé (associes) at stand
20E.

View east from near the Atlin road at mile 20. A stand
of nearly even-aged lodgepole pine, killed by a fire in 1958,
is shown. The roots of the trees are partially decayed and
it is possible to work the trees loose from the soil and push
them over by hand. A few trees survived the fire, foliage
of one of which shows in the upper right of the view. The
plants bearing white fuzzballs (seed structures) in the fore—
ground are Anemone sp.

This vegetation type is discussed on pages 90-91 and
phytosociological data are included in Table 8.

Early evening. 3 July 1967.

/’/ 1}?"
’5‘ 21‘s...

 

Figure9.. The lodgepole pine association at stand 24E.

 

Figure MO. The lodgepole pine brfilé (associes) at stand 20E.

r
0..
PRO.
b. . 5"
i1. do
’ a
a
.'.§Ar

u.
'-
If.
C j
5"

i J

I

a.

\ “’3‘

a. :1. v.
v

u“" 1

 

 

A
h
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I‘ l)
(I:

 

v
a u
‘t
‘1
‘u
‘ O
-_.‘1"
‘1 \3
\, A
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89

The lichen-moss layer may be sparse, as at 24w, 38w, and
50W, or quite dense, as at 2ME (Fig. 9) and 36E. The vege-,
tation of the latter two sites suggests a lichen-moss phase,
analogous to the feather moss faciation of the white spruce
association.

A soil profile description by Lietzke (1970) for a
lodgepole pine stand in the lower Fourth of July Creek valley
is presented in Appendix A. This soil is classified as a

Typic Cryopsamment, sandy mixed.

Brfilé 3

The brfile vegetation type so characteristic of the
boreal forest biome is common in the Atlin valley, particu-
larly in the northern part. It is divisible into two types
depending on whether the burned wood and the seedlings are
mostly Spruce or lodgepole pine.

White spruce brfile. Four of the sites encountered in

 

the survey support stands of this vegetation type (Table 7).
None appear to have been burned recently, and mature spruce
trees are present. All stands contain a clutter of downed
trees. The arboreal stratum is not dense, and a light ad-
mixture of aspen and tree willow is common. Good spruce
regeneration is characteristic, but pine and aspen seedlings
also occur.

It is suggested that forest fires can vary considerably
111 intensity over short distances because of vagaries of
true wind coupled with topographic irregularities and the

condition, whether moist or dry, of the vegetation. It is

0.)! O

5.3-“

'DO .h'
‘

‘51....
' J~au

8"“.-

"a.

‘
cl -
h
.‘u

n"
(I.

90

possible that the present stands were severely burned, hence
the large amount of downed wood (blow-down of dead trees),
yet with nearby white spruce stands being only lightly
burned. Trees that survived in the latter places could
have been immediate seed sources for the present stands.
Coupled with an absence of nearby aspen or pine, this cir-
cumstance has enabled the stands to regenerate directly to
Spruce, rather than to stands of aspen, pine, or the mixed
Ctommunities which are more commonly the case.

Lodgepole pine brfile’. This community type was en-
countered at most of the sites on the kame terraces between
mile 1A and 22 and also at stand 383. At the latter, the
burn is fairly old, but at the others the fire responsible
was one which local residents say occurred in 1958 (Fig. 10).

Surviving older pine trees in these stands are absent
01' quite scattered, a situation which reflects differences
in blaze intensity from one place to another. Dead and
blackened pine trees, many still standing, are a common sight.
Often these are found in dense, young, even-aged stands,
indicating that at the time they were killed it had not been
more than a few decades since a previous fire. Pine seed-
lings are abundant throughout the burn area, and aspen seed-
lings are also common. Most stands as well contain a few
SpPlace seedlings.

In the shrub and subshrub stratum, lodgepole pine

(dead), Salix spp., Rosa acicularis, and Arctostaphylos

W typically have fairly high constancy values. Only

a I
OH- 0“
p n
nu -Ov

v I
0A.!“12‘u-
huh-echo.

I
Q n A
' :n‘l-n"
to. Ofiub
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oaA

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.“"" b...
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UV“, '0.
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A
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91

the latter species, however, is of significant cover and
abundance, and since it is prostrate, shrub density is light
in aspect.

The herb layer is also light, with scattered grasses,
Epilobium angustifolium, Anemone spp., Polemonium pulcherri-
111L113, Linnaea borealis, and composites in most stands. At
38E, where the stand is older, the herb layer is denser.

The lichen-moss layer is characteristically moderate to
dense, consisting of species especially adapted to dry and
Sunny conditions.

Brfilé is an important component of the regional vege-
ttation. In brfilé communities ecological relationships are
temporarily out of balance, with succession leading to the
reestablishment of a stable ecosystem. Accordingly, this
Vegetation type is considered an associes (Daubenmire, 1968),
with white spruce, lodgepole pine, and aspen associes recog-

nized in the Atlin valley.

WILite spruce-lodgepole pine forest association

Spruce and pine share dominance in this community,
(Table 9). These make up an arboreal stratum with an Open
to nearly closed canOpy, in some cases comparable only with
the feather moss faciation of the white spruce association
(Table 4). In all stands one or the other or both species
Show good regeneration. A light admixture of tree willow

is characteristic, and a few aspens and balsam p0plars occur

“- 56E and 56w.

he.

' ' vav

"F AH“
*OH JV
0' '

"G rt-

cut 5‘-

‘
'33];

’1

92

The shrub stratum is sparse to moderate at 36E, 56B,
and 56W, which are all fairly dry sites.
the

At Sl9N and 8198

Shrub layer is denser and more diverse, containing the

infrequent Ledum palustre subSp. groenlandicum and Empetrum
nigrum. As in the shrub-herb-moss phase of the white spruce

association, a geochemical factor again may be responsible

here . On the whole, the shrub layer is seen to be more

diverse in this association than in any other, including

the rich mixedwood forest association (Table 12). This is

despite the fact that only five stands were included in the
SUI‘Vey. This is taken to indicate that only a few carefully
Selected stands may fairly represent a given vegetation type.

The herb layer is also of moderate density at the three

drier sites mentioned above, but it is quite dense at the

other two sites. Lupinus arcticus is more important here

than in any other community. Outside of the alpine fir

Sta.nds at mile 815 and two nearby stands of the mixedwood
forfist association (discussed below), alpine fir was found
only in the herb and shrub strata of stands 56E, Sl9N, and
$193 of the present community during the general vegetation
S‘-11‘vey.

The lichen and moss stratum is dense at all sites and
18 Usually dominated by feather mosses, except at 56E where
foliose lichens are considerably more abundant than mosses.

It may be significant too that stands 56E and Sl9N con—

tain very old charred wood indicating earlier forest fire
eff e"31:3.

1
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n
A“; --
.

Qfinufi

du-Aq

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i'v‘.a

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93

Alp :ine fir association

The two sites bearing this vegetation type (Table 10)

occur in an area of thermal and travertine springs 15 miles

south of Atlin. Besides stands of pure alpine fir forest,

the area contains Species which were not found elsewhere in

the valley. Also the vegetation here appears to be some-

what more lush.

Luxuriant shrub and herb vegetation in low areas near
the springs outside the fir stands is probably related to
the abundance of moisture and warmer substrate conditions.
This may also be coupled with higher levels of inorganic

nutrients carried to the plant root zone by seepage from the

Spring sources. Porsild and Crum (1961) describe a similar

haTbitat at Liard Hotsprings in northeastern British Columbia
Where they assume that conditions for plant growth are
especially favorable because of higher ambient temperatures,
higher specific humidity, a more abundant snow cover in
Winter due to rime deposits and possibly a related longer
growing season and a local absence of winter ground frost.
It is probable that one or more of these factors is involved

in the growth of alpine fir in pure and dense stands in the

viczinity of the warm springs. In this connection it should

be noted that precipitation is higher throughout the southern
pOrtion of the Atlin valley because of proximity to the
Coast Mountains. The maritime climatic influence would also

be greater here because of the movement of air masses up the

Taku River valley, up the Gilkey Glacier trench, and across

.
”A“. 1
.-

:v-l'-
v

QQ'A:

9
u-av .-

.,.:'....

voolld

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‘7'” I

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" -

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51.

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AC

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94

gently sloping névés of the Taku-Llewellyn transection

Glacier system of the Juneau Icefield. That alpine fir dis-

tribution in the Atlin valley is controlled, in part, by
the moisture factor is further indicated by its occurrence
throughout the valley at elevations of 800 to 1,000 feet
above the lake level and its abundance at lower elevations
in the vicinity of the Llewellyn Glacier terminus (Fig. 4).

Soil pH is probably also a factor controlling alpine

fir distribution in the Atlin valley. Porsild (1951) and

Hultén (1968) state that the species is found primarily on

acid soils in the Yukon and Alaska. At most places in the

Atlin valley the soils are develOped from a calcareous
gla01al drift and have pH values of 7.0 or more (Appendix A).
In some places, however, the drift is thin or nonexistent

and soils may be develOping from crystalline rocks or from

other non-calcareous bedrock types. Such a possibility was

men-t: ioned in connection with the shrub-herb-moss phase of
the white spruce/shrub-herb community type (p. 84-85). This
is Probably the case at higher elevations throughout most

of the valley where glacial drift is less abundant than on

the Valley floor and lower valley walls. The absence Of a

cmice-reous substrate may also be an important factor in the
common occurrence of alpine fir in the area of the Llewellyn
Glacier terminus (Fig. 4).
Lietzke (1970) described a soil profile in the 815W
Stand. Here the drainage was found to be "good to perhaps

EXQ
esGive" and pH was low, from 4.8 to 5.5 in the A and

95

upper B horizons, ranging to 7.0 in the C horizon. The soil

here is classified as a Boralfic Cryorthod, loamy skeletal,

mixed. Lietzke also notes that alpine fir forests in general

grow in soils developed from a variety of well-drained

parent material types and that pH in these soils is lower

than in soils associated with most other vegetation types.

The complete profile description for the 815W stand is con-

tained in Appendix A.
Alpine fir is clearly dominant in each of the two stands

studied (Table 10). Quadrat measurements give high C—A

values for each of the size categories, and the canopy is

closed in most places. Each stand contains slight admix-

tures of pine and tree willow, and the stands grade into

Other, rather diverse stands consisting of mixtures of

Spruce, pine, and balsam p0plar.

Where the canopy is closed the shrubs are very scat-

tered, but where open shrubs are abundant. Amelanchier

iLnifolia and Viburnum edule appear to be important only in

 

this vegetation type, and Actaea rubra and Sorbus sp. were
only found here. The herb layer is sparse in alpine fir

StaJids, but mosses are dense. Conditions in the lower two

layers are analagous to the feather moss faciation of the
"Mtg. spruce association.

Although relatively little information on the alpine
fir Vegetation type is available from the present survey,

Stan
as of this type having been encountered at only two sites,

it
is nevertheless designated an association. This is

 

96

because at the two sites studied it exhibits a structulal

integrity and an ecological stability. Alpine fir forests

are widespread in areas outside of the Atlin region, es-
pecially in the Babine—Stikine region to the south (Halliday
and Brown, 1943) and at intermediate to higher elevations
throughout the interior sectors of the western Cordillera.
Alpine fir was not observed in pure stands elsewhere
in the Atlin valley, but it is found as a component, along

With white spruce and lodgepole pine, of mixed coniferous

forests at several locations. The mixed coniferous forest

vegetation type cannot be discussed in the same context as

the other community types since it was not encountered and

measured in the general vegetation survey. Its existence is

recognized as a community type, however, which may be
<31assified at the association level after further ecological
studies. A brief description of a stand of this type
located near Jasper Creek Bog is given on page 161 in con-

nection with a discussion of bog vegetation (Fig. 18).

Aspen association
In this community the density of the arboreal stratum

is high in young stands and decreases progressively in older
ones, which in general are rather open and light (Table 11).

white spruce often forms an admixture with the aspen, but

seldOm appears to be reproducing. Balsam poplar is also a

common admixture, and tree willow is frequent enough to be
considered characteristic of the association. In all stands

A
Span shows good to vigorous regeneration.

A

 

97

A possible variation of the aspen association is seen in
stands 04W, 42W, 83E, and 85E where aspen, balsam poplar, and
This can be designated the
At

tree willow are each important.
mixed broadleaf forest phase of the aspen association.
this point there is not enough evidence to consider the

mixed broadleaf forest situation at the faciation or asso-

ciation level. Instead, it is treated in the broader con-

text of the aspen association.
The shrub and subshrub stratum is typically dense,

usually more so than in coniferous forests. Besides aspen

Saplings, Shepherdia canadensis and Arctostaphylos uva-ursi
are abundant or dominant, and Salix spp. and Rosa acicularis

are common.
The herb layer is quite full too, with Gramineae,

Luginus arcticus, Epilobium angustifolium, Eyrola spp.,

Etensia paniculata, Linnaea borealis, and various con.-

POSites scattered to abundant. Fragaria virginiana is more

1mPortant than in any other association except the herb-
heath. The only Polypodiaceous fern seen during the survey

Was in an aspen stand of 42E.

The lichen and moss stratum is relatively insignificant,
being of lower total mean C-A value than in any other com-
munity. The older, mature stands are nearly devoid of cover
in this stratum (42E through 44W).

Only stand 2W contains obvious signs of former burning,
but InOst aspen association stands, except those bearing; large,

Old growth trees, are undoubtedly the direct result of

98

The typically dense shrub stratum
The

succession following fire.

probably obscures most charred wood in aspen stands.
younger aspen stands discussed in this section are actually
a form of brfilé, where aspen, instead of pine, because of

proximity of seed source or suckering from roots of burned
trees, became the pioneer seedling species following fire.
These stands were not, however, discussed as a third brfile’

category, along with spruce and pine brfilé, because the

arboreal stratum is more fully develOped and succession has

Progressed beyond the initial, rapid stages. Floristically

and structurally they bear a closer resemblance to their

mature counterparts than does typical brfilé. The best

eXamples of mature, old growth aspen stands are 42w, 44E,

and 44W. True aspen brfilé, with dense seedlings and saplings,

was tobserved at several places in the Atlin valley, but was

not encountered in the survey.

Mixedwood forest association

A mixture of spruce and broadleaf trees, primarily

aspen, in the arboreal stratum characterizes this associa-

tion (Table 12). In some cases, as at stands 46E, 58E, 317E,

and arm, balsam poplar replaces aspen as the major broad-

leaf member, and in others both aspen and balsam share domi-

mEmcee with spruce, as at 58w and 53w. Tree willow is typi-

cally a significant admixture. Pine, on the other hand, is

generally absent; it was found only in stand SlE, and then

out 8 1 d e the quadrat .

99

The shrub and subshrub stratum is quite diverse and

moderately dense. Rosa acicularis, Shepherdia canadensis,

 

and Arctostaphylos uva-ursi are dominant, and white spruce

saplings, Salix spp., and Viburnum edule are of intermediate

 

inmnortance. Floristically, and in general aspect, it is
similar to the aspen association shrub layer.

The herb stratum is especially important, having the
highest number of species and groups and the highest total
Of'lnean C-A values (Table 17) of any community. This is,

Ihl part, a reflection of the larger number of stands studied,
second only to the white spruce association. It is also
reliited to a high diversity of site characteristics and
Probably to larger differences in historical development
fronl stand to stand than are involved in other associations.

Sites vary from nearly flat or gently leping to steep
and-Irocky. Stand 85W is in the latter category and has
b(‘lt‘hr'ock outcroppings. This stand contains five species or
grcDups which were found in no other stand of the mixedwood
fc>I‘est community and are quite rare in other communities,

e’CCIept for the herb-heath association. These are Aquilegia

 

\formosa, Sedum lanceolatum, Potentilla spp., Antennaria sp.,

 

and Artemisia sp .

 

The high diversity of the herb layer, as well as of the
Shrub layer, coupled with differing prOportions of dominants
in the arboreal stratum from stand to stand, may be explained
by'historical factors. These include (1) different dates of

past fires, hence different stages of successional development,

100

Figure 11. The mixed woodland association at stand C2E.

This community type is characterized by nearly equal
abundances of white spruce and lodgepole pine with aspen as
an important admixture. Stands typically are open and sunny
with trees thinly spaced in most areas. Shrub stratum come
ponents are scarce and herbs are usually of only moderate
abundance. Subshrubs or prostrate herbs, such as Arcto-
staphylos uva-ursi and Linnaea borealis frequently cover sig-
n can portions of the ground, andfmosses and lichens,
particularly Cladonia spp., are abundant.

 

 

 

In this view the three arboreal components are shown
along with several patches of reindeer lichen.

The mixed woodland association is discussed on pages 102-
103 and phytosociological data are contained in table 13.

Late afternoon. 27 August 1967.

Figure 12. The depression shrub association at stand 59W.

View west across poorly drained area near mile 59 on the
Atlin road. Atlin Mbuntain is in the right background.

The substrate in this stand is moist, but the water table is
usually below the surface.

The community is characterized by shrub willows, shrub
birch and, in the herb stratum, by a dense cover of grasses
and sedges. The community contains many species of herbaceous
dicots, though most are of low importance individually.

Mosses are abundant. White spruce trees shown within the
stand proper grow on minor topographic highs where drainage
is somewhat better.

The depression shrub association is discussed on pages
103-104, and phytosociological data are contained in table 14.

.Mid-morning. 30 June 1967.

_ J, .1 J‘ V .I ' ~ - *1: ‘

 

Figure 10. The mixed woodland association at stand CZE.

 

Figure El. The depression shrub association at stand 59W.

~

102

(2) different fire intensities, and (3) different seed
sources following fires, depending on the nature of adjacent
unburned vegetation as well as the presence of unkilled
plants and serotinous seed-bearing structures (e.g. lodge-
pole pine cones) within the stand.

The lichen and moss stratum is of minor importance and
comparable to the aspen association.

The mixedwood forest type is the most heterogeneous of
all the communities in the Atlin valley, and, for this
reason, it may not be well regarded as an association.
Further study may require subdivisions to be recognized.
These might include, for example, a tree willow faciation
(Cf. 817W) and a balsam p0plar faciation (cf. 46B and 817E,
Table 12).

A soil profile in a mixedwood forest stand at mile 3
on the Atlin road was described by Lietzke (1970). The soil
here is classified as a Boralfic Cryorthod, coarse loamy,
mixed. A profile description is contained in Appendix A.

Mixed woodland association

The three stands of this vegetation type were studied
on the pitted outwash northwest of Little Atlin Lake (Table
135 Fig. 11). These sites are generally flat and contain
an especially light, sandy soil. Fortunately, a relevant
3011 profile description by Lietzke (1970) is available here
too

’ as given in Appendix A, representing the substrate for

a Ruled woodland stand along the Alaska HighwaY-

 

103

The arboreal stratum is characterized by approximately
equal proportions of spruce, pine, and one or more of the
broadleaf species. Except for occasional clumps, the trees
are sparsely distributed, hence the name woodland. In
addition, shrubs and herbs are generally only scarce to
scattered, and the ground is covered by conspicuous patches
035' yellow lichens, i.e. Cladonia subgen. Cladina spp. (the
"reindeer" lichens).

This vegetation type is rare in the Atlin valley, al-
though it is widespread elsewhere. Hansen (1953) reports
the occurrence of similar substrate conditions and vege-
tat ional development along the Alaska Highway approximately
100 miles to the northwest between Whitehorse and Haines
Ju-nCtion.

In the same general region, at mile 896 on the Alaska
Highway, Lietzke (1970) studied a soil profile in a stand of
vegetation which he considered to be of the mixed woodland
a'SSOCiation. This soil was classified as a Typic Cryochrepts,

coarse loamy, mixed. The profile description is contained in
Appendix A.

Depression shrub association

This vegetation type is characteristic of poorly drained
and moist, but not necessarily saturated areas. It usually
forms a prominent zone between forest and marsh or bog vege-
tation. A moderate to dense willow shrub layer is invariably
present, and in many cases shrub birch shares dominance with

w
1110‘" (Table 14; Fig. 12). Trees are absent, except on

104

drier swells which sometimes occur within a stand and hence
do not belong to the community proper. The herb stratum is
quite diverse but of only light to moderate density. The
major exceptions to this are thick patches of Juncus spp.
and Carex spp. The lichen and moss stratum is typically
thick and includes major proportions of Bryum pseudotri-
guetrum, Tomenthypnum nitens, Mnium affine, and Ceratodon
W. The only Sphagum found in the course of the
general vegetation survey was in stand 54W of this associa-
tion.

Lietzke (1970) has studied a soil profile in stand 59W,
"hi-Ch he terms a shallow bog profile. He suggests on the
basis of decreasing pH with depth that a recent trend toward
a. Illore moist climate has brought about increased runoff and
drainage into the stand with the deposition of lime at the
s“lil‘face.

The soil in this stand was classified as a Terric
cI'VOSaprist, euic., and the complete profile description
may be seen in Appendix A.

Herb~~heath association
Four stands of this vegetation type were encountered in

the Survey (Table 15). stand 4E and 16E occur on steep,
Weshemly slopes, and the other two, at mile 8, are on 8-
18" 8e , moraine-like swell with a more gentle slope. The
substrate is loose glacial sand and gravel with occasional
cobbles and boulders at the surface. All stands but ’43
cor“18in a few pieces of charred wood. The sites are high

105

and exposed, and it is believed that they, as on similar
intervening terrain, are subject to frequent and sometimes
strong winds blowing north up the long fetch of Atlin Lake
(Fig. 2).

This vegetation type lacks trees but in some cases

contains aspen seedlings. The subshrubs Juniperus horizon-

 

tglig and Arctostaphylos uva-ursi are common enough to be
considered a distinguishing feature (the heath component),
but other shrubs are scarce. The herb stratum is diverse
and often moderately dense. Lichens and mosses are rela-
tively rare, and the stands contain quite a bit of barren
surface.

In the general vegetation survey this association was
found to include 13 species with high fidelity values.

These are indicated in Table 15 with a plus (+).

The herb-heath association is believed to be perpet-
uated by periodic fires of considerable intensity sweeping
across these windy sites. There is a good fuel supply in
the dry grasses and other herbaceous vegetation late in the
summer. Edaphic conditions, primarily lack of surface
moisture, are probably unfavorable for tree seed sprouting,
and those that do take hold are killed by the fires. Nearby
ravines and low areas contain shrubby vegetation plus aspen
and pine seedlings, saplings, and a few trees. This indi-
cates that fires are less intense in sites protected from the
wind. Also it is possible that tree seeds tend to be blown

across the raised sites and dropped into these lower areas.

 

106

unclassified stands

The vegetation at two final sites could not be placed
in.any one category. At site Aw the topography is quite
irregular and edaphic and microclimatic conditions appear
to change over short distances. Nb homogeneous stand large
enough to contain a quadrat was found. The quadrat list
for this site, such as it is, is reproduced in Table 16,
along with one for the other unclassified stand, 12W. At the
latter site the vegetation is transitional between depression
shrub and white spruce forest. No recognizably homogeneous
stand of either type which could be used for measurement
occurred within a reasonable distance of the mile 12 post.
It is possible that the 12W stand will eventually succeed
to the white spruce vegetation type.

Summary and discussion of general vegetation survey

Data from the general vegetation survey are summarized
in Table 17. Here the 12 upland plant communities are listed
in the order of their relative importance, where importance
of a community is based primarily on the frequency at which
representative stands were encountered in the survey and, to
a lesser degree, on their species diversity (i.e. total number
of species and species groups per community). Data on the
species diversity of each community and of the four physiog-
nomic strata are presented, and a total mean cover-abundance
value is given as a measure of relative importance for each

stratum.in each community. With these data comparisons of

107

Tables 4 through 15. Association tables for plant
communities in the Atlin valley.

These tables consist of the releves abstracted from the
original association table (not reproduced in this disserta-
tion) and grouped into associations, faciations or associes.

All species and species groups (genera, families, etc.)
are arranged according to stratum in phylogenetic order.

For calculation purposes, the C-A symbol x is used
numerically as 0.5. In rounding off mean C-A.values, any
value less than 0.75 is written X, and above 0.75, 1. values
of exactly 0.75 are rounded off to x if less than half the
quadrats contain the species and to 1 if one-half or more.
mean values exactly midway between 1 and 2, 2 and 3, etc. are
similarly rounded off.

An asterisk (*) indicates that the species or species
group appeared on the stand list but not in the quadrat.
These were not considered in calculations.

In Table 15, a + with a plant name, in the species
column only, indicates high fidelity.

Constancy is the percentage of quadrats in a community
containing the species in estion. Constanc classes are
as follows: Class 1, 0- 3 class 2 21-32%? class 3, #1-
605; class 4, 61-805; and class 5, 81-10 . Where there
are fewer than four releves in a community, as in Tables 10,
13, and l#, constancy values would have little meaning.

H
0.

Reading of column of mean cover-abundance values.

II: Heading of column of constancy classes.

108

1. Table 4. Association table for the white spruce
association/feather moss faciation.

 

 

agggies orggrogfi

Pinus contorta . . .
Picea glauea . . . .

P. g1:uc:jsapling)

O O I O

P. glauca seedling)
POpulus samifera .
P. balsamifera (seedling)
P. tremuloides . . . . . .
P. ere-uloides (seedling)
mu .pp. 0 O O O O I O O
Alnus sp. . . . . . . . .

nycopodiun sp. . .
Salix spp. (shrub;

IIIIIIH‘U‘I

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trunnilmv-lau
IHIIIIwwOH
IHIIIIHHUH
IHHXIIHwNI
Illlutlvmflfo

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Ialullxafll

N I

s. spp. (subshrub
Alnus spp. (shrub
Ribes spp. . . . .
Rubus sp. . . . . .
Potentilla fruticosa
Rosa acicularis . .
Shepherdia canadensis
Empetrum nigrum . . .
Ledum palustre asp.
groenlandicum . . . .
Arctostaphylos uva-ursi
Arctostaphylos rubra . .
vacciniul vitis-idaea .

swxsxxxxmx xwxxaxmmmx H
um HHHmmH HwHH chmw d

..........
..........
..........
..........
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lquisetul scirpoides . .
Bo’ppooeeeeeee

Ora-ineae . . . .
Torieldis spp. . .
Zygadenus elegan-
Orchidacue . . .

Geocaulon lividum
stellaria sp. . .
Delphiniun glaucul
lupinus arcticus .
Sedysarum alpinum
Lsguninosae . . .
lpilobium angustifo
Oomulcarudensis
Pyrola asarifolia
P. grandiflora . .
P. secunda . . . .
P.9pp......
laneses uniflora .
Gentiana prepinqua
Polemonium pulcherrimul
lsrtensia paniculata . .
Pedicularis labradorica
P. sudetica . . . . .
Po'ppeoooesso
Linnaea borealis . . .
Solidago multiradiata
3.Ipp...o...
Antennaris sp. .
Achilles spp. .
Arnica louiseans

Ann-es...

Senecio spp. . .

Pbliose lichens . . . . . .
Cladonia subgen. Cladina spp.
c. subgen. Cladonia spp. . .
Steroocaulen sp. . . . . . .
Cetraria sp. . . . . . . . .

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IIIIIIIUJIIIOIIINIIIWMIIIIIfi
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Table 5.

109

association/shrub- herb faciation.

 

Association table for the white spruce

3

 

Picea glance . . . . .
seedling) : 2
P. tremloides “plies;

P. tremloides (seedling)
mu m. s e e e s e s e

 

Igoopodiu spp. . .
Salix spp. (shrub .
8. tspp. “1‘18:st .

uloss .
Mb“. e e

Pbtenti
Rose acicularis . .
Shepherdia canadensis
”strum . . .
Ledum palustre ssp.
groenlendicus . . . .
Arctostaphylos uva-ursi
A. mbr‘ e e 0
Vscciniul vitis-idsee .

Equisetu scirpoides
3. 313]).

Triglochin mariti-u-
Orelineae .
Ceres spp. .
Jumus spp.

Lusula spp.
Torieldis s .

I I I I I I I
I I I I I I I I I
I I I I I I I I I
I O I . . . . O I

IIII
IIII

Geocaulon lividu
Stellaria sp. . .
Delphiniul gleucul
Anemone sp p. .
Palestine petens
Cruciferse . . . .
Basin-age tricuspidst
Parnassis palustris
Fragaria virginiana
minus arcticus . .

pinul .
hilobiul sngustitoliu
Germs canadensis .
Pyrole grandinore .
P. secuma . . . . .
Pe.pseeeeeee
Isneses uniflore . . .
Androsace septentrionelis
Gentisna propinqus . . . .
Polenmiun pusher-rim-
Ihrtensia paniculste . .
Pedicularis labradorica
P. sudetics . .
Po .po 0 e e e e
Scrophulariaceae

IIIIIIIIIIIIIIIIII

a
Solidego spp. .
Achilles sp. . .
mica louisesns
A. spp.

Term sp. 2

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Cladonia sum. Cladina spp.
c. subgen. unis spp. . .
Stereocsulon spp. . . . . .

Cetmissp.......
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110

Table 6. Association table for the lodgepole
pine association.

I I0?

Pines contorta . . . .
P. eontorta sapling) .
P. contorta seedling)
Picea glausa . . . . .
P. glauca (sapling) . .

(seedling) .
Populue trcmloides . .
P. tremloides sapling)
P. tremloides seedling)
Salix spp. . . . . . . .

 

 

e e e e e e e e e e
e e e e e e a e e a
I.IIIIxIIQ‘

NIIIIIHIIO
XIIIHHHNPW

unxxuxanu

Juniper-us co-unis
J. horizontalis . .
Salix spp. (shrub
s. spp. (subshrub
nose acicularis . .
Shepherdia canadensi
Ledum palustre esp.
nlandicum . . .
Arc ostapmlos uva-ursi
‘I mm I I I I I I I
Vaccinium vitis-idaea .
Viburn- edule . . . .

mutual scirpoides . .

Oren-see........
m‘pesleeeeee
Emmelmns....

Geocaulon lividm
Aquilegia tormea
Anemone spp. . .
Crucirerae . . . .
Saxirraga tricuspidata
Inpinus arcticus . . .
bilebim angustifolium
role secunda . . . .

Gentianasp. . . . . .
Polemonium pulcherri-n
hrtensia paniculata
Linnaea borealis .
Solidago spp. . .
Antennaria sp. .
.MMINII eee
Amide 1 seems
A. It. 0 e e e e
Caflflflul...

Poliose lichens . . . . . . .

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wNIUIN MIIIMXKMIU

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IIIIIIIIIIIIIIIIIII

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Stereocaulon spp. . . .
GItl'IriII”. e e e e e

mm.eeeeeeeeee

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R ”muck PH MPWUMHHMNWNNHUHH UPW H MP W

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Q NIWMM

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111

Table 7. Association table for the white
spruce brule (associes).

 

3

IEOCIOB or EPOEE

Pinus contorta . . . . .
P. contorta (seedling) .
Picea glance . . . . . .
P. glauca sapling) . .
P. glance seedling) . .
Populus tre-uloides . .
P. treuuloides sapling)
P. treauloides seedling)
Salix spp. . . . . . . . .

Salix spp. (shrub .
s. spp. (subshrub .
Rosa acicularis . .
Shepherdia canadensis
Arctostaphylos uva-ursi
‘I mbr. I I I I I I I I

II-‘H IWWWI I

INMNXN HHMHMWRXI A
wmmka ###¢UWWM

IHHHHI NHNHMNRII
IW3MI= MIwNMWHWI

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Imxwxx

Equisetun spp. . . . . . . .

Gramineae . . .
mu.peeee eesaa
Zygadenus elegans . . . . .

a e
.W

IIP N

Geocaulon lividul .
Anemone spp. . . . .
Pragaria virginiana
Lupinus arcticus . .
Epilobium angustifoliu-
COrnus canadensis . . .
molIIpp. eeeeee
Gentiana spp. . . . . .
Pblesoniua pulcherrilul
Isrtensia paniculata
Oelium boreale . . .
Linnaea borealis
Solidago sp. . .
Achillea spp. .
Conpositae . . .

Pbliose lichens . . . . . .
Cladonia subgen. Cladina sp.
0. subgen. Cladonia spp. . .
stereocaulon spp. . . . . .

mpm.eeeeeeeee

e e e e e e e e e e e e e e e
e e a e e e e e e e e e e e e
IIIWI.XI~waIxH

Izlm xIIuIHHHxxHIMIe xIH m
xth lemeIxXIIMHIXH HIw
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XWIM

N xwx: XNXUIHXNHXNHXNN KIM X

M

112

Table 8. Association table for the lodgepole
pine brule (associes).

 

ti

14E 14W lb" 185 189 :63 26" 223 22! E!

1

—-——1—'— W gong

Pims center-ta . . . .
P. center-ta sapling)
P. contorta seedling)
P. contorta dead

P. contorta sapl ): (
Pic" 918110. e s a e
P. glauca sapling)

P. glauca seedling).
Populus sanifera sapling)
P. balsa-itera (seed ing) .
P. treauloides . . .
P. ere-noides sapling) . .
P. tremloides seedling) .
mu .pp. I I I I I I I I I

Salix s . (shrub .
s. spp. subshrub .
Rub“. 'pe e e e e e
Rosa acicul
Shepherdia canadensis
etrus nigru- .
Arctostaphylos uvs-ursi
A. mbr. I I I I I I I I
Viburn- edule . . . . .

lqullotullp. .....

0m e e s s e e e
CII‘IX .”s s e e e e e s
Zygadems elegans . . .

seeneees
III IIII
seeéeeae
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Stellar-is sp. . . .
Caryophyllsceae . .
Anemone spp. . . . .
Arabia Bolboellii .
Sedu lanceolatm .
Suits-age tricuspidata
mpinus arcticus . . .
asytropis spp. . . .
bilabial angustifoliu-
mOla spp p. . . . .
Androsace septentrionalis
Gentisna propinqua. . .
Polemoniu- pulcherri-Ia
Phscelia spp. .
IIsrtensia paniculata
Pedicularis s p. . .
Linnaea bore is . .
Solidago decumbens .
Solidago spp. . . .

eeess
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”IIIHII

Achillea spp. . .
Arnica sp. . . . .
Composites . . .

IIIINNIIIMIMIU’IIMIHNII
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Poliose lichens . . . . . . .
Cladonia subgen. Cladina spp.
c. subgen. Cladonia spp. . . .

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IIH

4 HXM HXXXXMXXNIOXXNwl-‘HXIKHXX XXU X
I HIU)

u NH: wwmwwwwwwawwwmmmm HmHH me H
#U‘IwHIIIII—‘IIIIIIIIIIIIII—‘II
Os XI“: NIIIIFHIIMIIIWIWIIINII

Ox flu“
(D
\O
\O
\O
\D

113

Table 9. Association table for the white spruce-lodgepole
pine forest association.

 

_—E"-I——_—"— W

Pinus contorta . . . .
P. contorta sapling)

P. contorta seedling)
Picea glauca . . . . .
P. glauca sapling) .
P. glauca seedling) .
Abies lasiocarpa (sapling)
A. lasiocarpa seedling) .
Populus bals rera . . .
P. balsamitera sapling) .
P. balsamifera seedling)

P. tremuloides . . . . . .
P. tremuloides (sapling .

3

NM NMU‘IUIUII-‘NUI d

P. tremuloides seedling)
Salix spp. . . . . . . . .

eeseeeeeeeee
eseeseseeees
NIIIIIIIINUU‘IIW
“IIIHNIIXHmep
INIINHIIIXHWIIQ

IIIIIIIXI

Juniperus communis .
Salix spp. (shrub .
8. spp. subshrub .
Betula andulosa .
Rubus sp. . . . . .
Potentilla frutico a
Rosa acicularis . .
Shepherdia canadensis
Empetrum nigrun . . .
Ledum palustre asp.
groenlandicun . . . .
Arctostaphylos uva-ursi
A.rubra . . . . . . . .
vaccinium vitis-idaea .
Viburnum edule . . . . .

s e s e e e e
e e e e e e e s e
e s e e e e e e s
I I I I I I I I I
I I I I I I I I I
e s s e e s e e e
IWMI I I INI
IXWI I IXI-‘I

emwmm mmmxxxmmx Hxasxxexxwmcwxc H
umrm wmawpwamm up

Iu’I-‘Nk NNIIIIUIU‘X WIIIIIIXHHNkI-‘IUJ

IO‘IwI MHC’I I IHXX
IMWPJ‘: WNNWHWUMPI

IIII’OI
IIIII

Equisetum scirpoides . . . .
BI .ppe I I I I I I I I I I I e

I
IUJ
I

Gramineae . . . . .
Zygadenus elegans . . . . . . .
Orchidaceae . . . . . . . .

IMG’
IMU‘I
IIN I-‘I
XII:- u):

Geocaulon lividum
Delphinium glaucum
Anemone sp. . . .
Lupinus arcticus .
Epilobium angustifo
Cornus canadensis
Pyrola spp. . . .
Oentiana spp. . .
Polemonium pulcherrimum
Nertensia paniculata . .
Pedicularis labradorica
P. spp. . . . . . . .
Galium boreale .
Linnaea borealis
Solidago sp. . .
Achillea spp. .
Arnica louiseana
A.Ip....o.
Coupesitae . . .

Poliose lichens . . . . . .
Cladonia subgen. Cladina spp.
c. subgen. Cladonia spp. . . .
stereocaulon spp. . . . . . .
OItrIrltlp..........

mmIeeeeeeeess

eeee
eeee
NIHI

ium

eeeHeeee

IIIIIOIIXIIIMIU’WIINI—‘XW
MIP‘NWNWIXX

IIMIXklltweImemllk
HIIIIMIIIIIIIIwkllk

I I I I I I I I I I I I I I I I I I I
I I I I I I I I I I I I I I I I I I I
I I I I I I I I I I I I I I I I I I I

N333 UHHI-‘I-‘UH-‘IOI-‘U HC'NN N: IOU-DUI (0H

lI-‘I-‘MU UIINIWXMIMI IHMI

IIFva XNI IIU'IINI

IINIU
INNS!
IIII-‘I

O\ IHWPU) HXXXXkNHXHINPI—‘NU’INN NH? I-‘X

U!
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k
a)
(I)

114

Table 10. Association table for the alpine fir association.

 

species or group? I SIBE SISW
Pinus contorta . . . . . l
Abies lasiocarpa . . . .
A. lasiocarpa sapling)

A. lasiocarpa seedling)
Sal-ix .ppI I I I I I I I

I I I I I
I I I I I
I I I I I
IWNOI

Hus-:03

nycopodium sp.
Actaea rubra .
Ribes sp. . .
Sorbus spp. . . . .
Amelanchier alnifolia
Rosa acicularis . . .
Shepherdia canadensis
Arctostaphylos uva-ursi
Viburnum edule . . . . .

WI IMMIIMI

Graminsae . . . . . . .
Zygadsnus elegans . . .
OTC hi due .‘0 I I I I I

IIX J-‘II-‘NwI-‘IHI meflx
I IH assures-mass

III

Geocaulon lividum .
Aquilegia formosa .
Ranunculaceae (7) .
Fragaria virginiana
Epilobium angustifolium
Cornus canadensis .
Pyrola spp. . . . .
Mertensia paniculata
Galium boreale . . .
Linnaea borealis . .
Achillea sp. . . . .
Arnica cordifolia .

s s s s s s s s s s a s
s s s s s s s s s a e s
I IWMNHWMII PW

IIIIIII
IIIIIII

f0 HI cmmwuw II-‘Nw

Pbliose lichens . . . . . .
Cladonia subgen. Cladina spp.
C. subgen. Cladonia spp. . . .

Bryopmrta..........

\O “H” XI¢NMMWWIXMW

\o «yvuw
(Dun

115

Table 11. Association table for the aspen association.

 

 

ago!» or yam I If WWW—m
P1>1T.1.coflt°rt.»sssssss. ' - ' . " "' ' " " " "
HG..81IRCI........X 2 1 2 " " 1 - . . " " 2
P. m. .‘pllm s s s s x 3 1 2 " ' X - ' X X 2 -
P. glaucs seedling) . . . . X 2 1 2 X - — - - - - - -
Pbpulus samitera . . . . X 2 1 * - - x - - - l X -
P. bIlIsmitera sapling) . . 1 3 3 1 - - 3 - i’ - 2 X —
P. monitors seddling) . P i' - - - - - - - - - -
P-tromuloides.......6 5 6 6 8 2 6 6 5 u 6 6 6
P. trenmloides sapling) . . 2 5 1 5 x u 3 2 X 2 1 2 3
P. tremloides seedling) . 2 a l 3 2 2 2 2 1 2 X l 1
sunspp..........1 x - 5 - 3 a x a 1 1 3
mp0mcossmmis.....x 2 - - - 2 X - - 1 1 - -
8:111 Ipp. (Unrub s s s s s 1 u - 3 3 2 3 - 2 1 - . 2
s. Opp. subshrub . . . . . x 2 - 2 1 - 1 x - - - - -
Anslmch er alnifolia . . . X 1 - - - 2 - - - - l - -
Rosa acicularis . . . . . . 3 5 g - * 3 it h h h g 2 h
herdia canadensis . . . 5 5 6 5 3 g 5 7 h 7 2
mtoltaphylos uva-ursi . . 5 5 u a 3 5 1o 9 6 3 1 7
A. Nb“ I I I I I I s s s s x 1 ' . " " " " - " ' " 2
Viburmnneduio.......x 1 - - - - - - - - 6 x -
m.°tu .ps s s s s I s I x 1 - 1 " - - " " -
POWiICIII sssssss x 1 " ' - -
“mm.........h 5 3 x u 3 u 7 u 5 u
“gum 11V1d‘m I s s s s x 1 "' " " - " - - - - - [I
St.lt;flw1.'ps sss ssss X 1 - " 2 - " " " " ' ' '-
11.0080 I s s s s s x 1 ' " - " - - X - - - '
azuuegia tormosa . . . . . ' - * * - - - - - - - -
“lphihium glaucum . . . . . x 2 - - . - 1 2 2 1 - - -
a“ MIOIItm I s s s s . " . i ' g - " - ; "' ' -
OIppsssssssssx 2 - - - - - - - '
8:11?th tricuspidata . . . X l - - - 2 - - - - - - -
N‘Buis virginiana . . . . X 2 5 2 h 2 - - - G - - -
tentin‘ Ipps s s I s s s X 1 - " - 2 " - - . - " -
..m “pi-m s s I s s X 1 . ' "' " - " - - " X -
:29 arcticus......2 1: - - g - 2 3 2 3 - 2 3
b 0.... s s s s s s s s x 1 " " " 1 - " " - " - '
11°b1un angustifolium . . u 5 a 2 u 3 3 5 5 u x u u
m'canadensis.....x 1 - - - - - - — - - 3 -
Ispp.........1 h 2 — - - 2 2 - 1 3 2 2
hllwsppssssssssx 1 ' " - " " " " 1 ' 1 -
Is an'01'1ium pulcherrimum . . X E l X i 2 - - - X -— X -
rtenua psniculata . . . . 1 3 e 3 - 2 - 1 1 x 3 3
cutilleja 8p. s s s s s s s . ' ' " . . ' " " " ' "
1c“lax-is labradorica . . * - - - - - * - - - - -
8; .pp0 I I I I I I I I s s x 2 2 - 3 - * ' - - " - 2
«imam riaceae . . . . . . X l - - - - - - - - - l -
1mIllaox'sale.......1 2 2 * - 2 G - - 3 2 - -
gma borealis . . . . . . 3 5 3 1 6 1 2 5 - 1 3 3 6
11museum). .......x 3 - - a 1 x 1 x 3 - - -
:ntQRnariasp........X l - 1 - 1 - - - - - - -
°h111easpp........2 5 3 x 2 2 3 3 1 2 2 1 1
Arm(alouiseana...... X 2 - - 3 - - 3 x - - - -
“Mes-pp.........x 2 - - - - 3 - - - x x 1
semc1°IPIIIIIssssx 1 - - X - ' - " - - - -
IltlI.........X 2 3 1 ' ‘ - ' " - 1 - "
b110.. lien.” s s s s s s 1 3 ll 2 3 - " - 1 " .
onis subgen. Cladina app X 1 - - - - - X - -
Mona subgen.
clumIIPPsssssssx 2 1 3 1 ' - ' - . ' - 1
8t.wm.psssssss . ’ " ‘ . ' ' " " - ’ -
Mist-1W1 u 3 1 1 1 x - - G 3 2 2

116

Association table for the mixedwood
forest association.

Table 12.

 

____2m__._s_.L Ieaorr'ou

Plans contorta . . . .
P. contorts (seedling)
Picea glance . . . . .
P. glance isspling) .

P. glance seedling).

Abies lasiocsrpa (sapling)
seedling) .

A. lasiocarps.

Populus bale tern . .

P. balsanitera sapling) .
seedling)

P. balsanifera
P. tremloides . . . . .

P. tremloides
aux.mhsss«sses

P. tremloides (sapling) .

Junipems conuni .
Salix spp. (shrub; .
S. spp. (subshrub .
Ribes spp. . . . .
AIelanchier alnifolia
Rubus spp. . . . . .
Potentilla truticosa .
Rose acicularis . . .
shepherdia canadensis
bedt- palustre esp.
groenlandicun . . . .
Arctostaphylos uva-ursi
‘0 ”hr. I I I I I I I I
Viburnul edule . . . . .

Bquisstu- scirpoides . .

unisetun spp. . . . . .
Batrychiu- sp. . . . . .

are-ins” . .
Care: sp. . .
Tofieldis sp.
Zygadenus elegans
Orchidacsss . . .

Geocaulon lividum
egia tomes
Delphiniul glaucul
Anemone spp. . . .
Sedu- lanceolatu
Satin-age tricuspidat
Psrnassia palustris
Pragaria virginiana
Potentilla spp. . .
Lupinus arcticus . .
Oxytropis spp. . . .
nedysam slpimn .
Epilobium angustifolium
Cox-nus canadensis .
Pyrola asarifolia
P. grandiflora . .
P. secunda . . . .
PI I”. I I
loneses minors .
Gentiana spp. .
261mm pulcherriu
IIsrtensis paniculata . .
Pediculeris labredorics
Pediculsris spp.
Scrophulerisceas
Callus boreale .
Linnaea borealis
Solidago spp. .
”um.” es
Antenna-is sp.
Achilles spp.
Artuisia sp.
Arnice louisssne
Arnies spp. . .
Senseio sp. . .
acquit“ . . .
Pblioss lichens

IIIIII.IIIII

mm

seedling)

I I I I I
I I I I I
I I I I I

IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII.

I0 III-INF XXXNIM”.X¢>¢IXXMXXIFXXXHmXXNXXXXXXI-‘XN XXXIUI XXX I-‘XUJX WXXXNXHNI NXXMXPMXXHXMXI H

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IIII‘I PHI

MIIIIWIIU’IIIIINHIW

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INI XINI

IIIIH

IXIH HIMIIWIIIklIIIWIHIU’IIIWkIIMII-‘IIII-‘NIN

p

117

Table 13. Association table for the mixed
woodland association.

 

3

s'fieciee or gray

Pines sontorts . . . .
P. contorta (seedling)
MCII “Iuc. I I e I I
P. glance sapling) .
P. glance seedling) .
Populus trsmloides .
P. tressloidee sapling)
P. trmloidee seedling)
mu .ppI I I I I I I I I

Salix s . (shrub .
8. spp. subshrub .
noes acicularis . .
Shepherdia canadensis
Arctostaphylos ave-mi
‘Imneesesese
Veecinius vitis-idses .
Vibumuedule . . . . .

mlIt- I”. I I I e e

Ore-ins“ .......

Zygedemsslsgsns ....
Orchidsesee ......

OIOCIIIJO“ 11V1du I I I
MM..”IIIIIII
Lupims arcticus . . . .
hilabiun angustifoliu-
Pyrols spp. . . . .
Osntisne propinque .
IIertensie peniculsta
Pedicularis sp. . .
Linnaea borealis . .
Osmositee . . . . .

Poliole 11cm . . . . . .
Cladonia s n. Cladin spp.
C. IMInI ”1‘ I”. e s I
Stereoeeulon I”. e . s s o o

Weeesssssse

I HNMWUXW

I I IONDHN ”NIHPIDB’NUI
IIIUIHNIN PINNHHU‘IM

I s I s I I I I
s I e s I I I I
II I #meI-I

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nut» to

I I I I I I
I I I I I I
I I I I I I I I I I
I I I I I I I I I I
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I
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IHXU‘I le INHHMIW

UI XNUUI PHIIXMHMHH

M
a

118

Table l#. Association table for the depression
shrub association.

 

species or group» ’I_’ SHE' SEW’ 59F

Pinus contorte . . . . .
P. contorta sapling) .
P. contorta seedling) .
Picea glauca . . . . . .
P. glauca sapling) . .
P. glauca seedling) . .
POpulus treuuloides (sapl
Salix apI I I I I I I I

Salix spp. (shrub
S. spp. (subshrub
Betula glandulosa
Ribes sp. . . . .
Rubus spp. . . . . .
Potentilla truticosa
Rosa acicularis . .
Shepherdia canadensis
Eupetrum nigrum . . .
Ledum palustre ssp.
groenlandicum . . . .
Arctostaphylos uva-ursi
A. rubra . . . . . . . .
Vaccinium vitis-idaea .

ns)

eexewxxx
Ismllxml
Ileswuul

IIIIIII

i

IIIeIIIeI
IssseIIsI
IssseIIsI
esesesseI
INNHWXWWN
IXWIWXINN
IXMWWI‘IM‘I
IIIWWIfltm

I I I I
e e I e
I s I I
I I N I
IzII

Equisetum scirpoides . .
E. spp. . . . . . . .

NH XI—‘XI
PM ”III

I
Is
I
WI

Triglochin maritimum
Gramineae .
Carex spp. .
Juncus sp. .
Lusula spp.

Tofieldia sp.
Zygadenus elegans
Orchidaceae . . .

MWI

I I I I I

e I e s s s I I

I e I I I e s I

I s I I I I I I

I e I I s e e s

s I I s I e s I

I I INI

I I II-‘I IwI
IIIIWWII mm

Geocaulon lividum
Stellaria sp. . .
Delphinium glaucum
Anemone sp. . . .
Pulsatilla patens
Parnassia palustris
Saxifragaceae . . .
Potentilla spp. .
Sanguisorba sp. .
Lupinus arcticus .
OxytrOpis sp. . .
Hedysarun alpinum .
1

Epilobium angustifo ium
Cornus canadensis .
Pyrola spp. . . . . .
Gentiana propinqua . .
Polemonium pulcherrimum
Mertensia paniculata
Penstenon sp. . . .
Pedicularis sudetica
P. labradorica . . .
Scrophulariaceae . .
Galina boreale . . .
Linnaea borealis . .
Solidago unltirediata
Seuhes1esses
Aster sp. . . . . .
Antennaris sp. . . .
Achilles spp. . .
Petesitee sagittatu

Senecio spp. . .
‘ Taraxacu- sp. .
Composites . . .

I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I
I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I
I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I
IIIIIIIIIIIIIIIIIIHIHIIIIIIIIIIII

I I I I I I I I I I I I I I I I

HIH HINMNXNXIHXXIIXMNHXNNIXIXHIIIxHII
HIP wlimwmllIMIHIIIwHHIwwIIIMIIIIHmII
n XIHwMIMMIxMIIImemxmeMIlwnlIIHII

Poliose lichens . . . . . . . *
c1edonie eu en. Cladina sp. . - *
c. subgen. onie spp. . . . 2 -

meesssseeee. ‘ . ""
ggwmm:{ IIIII IIII 6 3 6 8

119

Table 15. Association table for the herb-heath association.

 

3

species or group

Pinus contorte (seedling) . . .
Populus tremuloides (sapling) .
P. tremuloides (seedling) . . .

><l><

Juniperue communis . .
+J. horizontalis . . . .
Salix sp. (shrub) . . .
Amelanchier elnifolie .
Ross acicularis . . . .
Shepherdia canadensis .
Arctostaphylos uvs-ursi

I I I I I I I
I I I I I I I
I I I . . . I

MI I

Gremineee . . . . . . .
Cerex spp. . . . . . .

lUl QXWIIWX WXI
NU‘ HIUJIIHI WK!

IU'I Ohm: IHI

Stellsris sp. . .
+Cerastiun ervense
Anemone spp. . .
+Arebis Holboellii
Cruciferee . . .
Sedum lenceoletum .
Sexifrega tricuspidate
Fragaria virginiana . .
+Potentills Hookeriene .
P. spp. . . . . . . . .
Astragslus sp. . . . .
Oxytropis campestris .
Epilobium angustifolium
+Androsace septentrionsli
Polemonium pulcherri-un
+Lsppu1a myosotis . .
Mertensis paniculata
+Penstemon Gormenii .
+P. procerus . . . . .
Scrophuleriaceee . .
Oeliun boreale . . .

MIX! lull

INN! l I ILUI-‘Hl IN!

+Solidsgo decunbena

SIsppIIIIIII
+Erigeron compositus
+Antenneris roses ver.
Achilles spp. . . . .
+Artenisis trigids .
+A. srctice . . . .

AI .pI I I I I I
Arnice sp. . . .

IIIINIINIWIWIHHWkfi-‘XIIIIHIIIWIH UJU‘ O‘HWI

IIIII(OIIIIIIIIIIDIIIIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIIIIIIIIII
HI IPU’UJNLHIWIHI I I II-‘lI-‘II INNWIXC’NI
I IHWJ‘JIU) NH! OMI IMUJMHO le HHIUJH“!

IIIIIQIIIIIIIIIIIIIIIIIIIIIIII

IIIII=IIIIIIIII
IIIINII

Pbliose lichens .
cetruia .p I I I I I I I I I I

mwm‘IIIIIIIIIII

I
I
I
I
I
I
I
I

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I
ax way
I M
I

N
3:

L» XH XIXHWXHHXMXHXXXMNHXIXXPHHIHUJNX HUI UIXU’IXMX ”XX '4

120

Table 16. Relevés from two unclassified stands.

 

 

 

STAND “H STAND 12"
species or grogp ’41 species or group ’I
Picea glauca . . . . . . . 1 Picea glauca . . . . . . . h
P. glauca sapling) . . . 2 P. glauca sapling) . . . 3
P. glauca seedling) . . . 1 P. glauca seedling) . . . 3
Populus balsanifera . . . 3
P. balsanifera sapling) . 1 Salix spp. (shrub . . . . 7
P. balsanifera seedling) X S. spp. (subshrub . . . . 5
P. tremuloides . . . . . 3 Rubus sp. . . . . . . 3
P. tremuloides (seedling) 2 Shepherdia canadensis . . 3
Arctostaphylos rubra . . . 5
Rosa acicularis . . . . . 2
Shepherdia canadensis . . 2 Equisetun scirpoides . . . 3
Cornus stolonifera . . . . * 2. sp. . . . . . . . . . . 2
Arctostaphylos uva-ursi . 6
Vibumunedule......8 Granineae........2
Eriphorun sp. . . . . . . 1
Ora-ineae . . . . . . . . 2 Carex sp. . . . . . . . . 3
Zygadenus elegans . . . . 1 Orchidaceae . . . . . . . *
Orchidaceae . . . . . . . 2
Parnassia palustris . . . 2
Caryophyllaceae . . . . . 1 Fragaria virginiana . . . 2
Aquilegia fornosa . . . . l Leguminosae . . . . . . 3
Anemone sp. . . . . . 2 Epilobium angustifolium . 3
Epilobium angustifolium . X Gentiana sp. . . . . . . . l
Pyrola sp. . . . . . . . . l Mertensia paniculata . . . *
Gentiana sp. . . . . . . . 1 Pedicularis sudetica . . . 3
Galiun boreale . . . . . . 2 Linnaea borealis . . . . . 1
. Linnaea borealis . . . . . 1 Solidago sp. . . . . . . . x
Achillea sp. . . . . . . . 1 Aster sp. . . . . . . . . 2
Composites . . . . . . . . 2 Achillea sp. . . . . . . . 2
Petasites sagittatus . . . 2
Fbliose lichens . . . . . l Senecio sp. . . . . . . . 3
unknown herb . . . . . . . 3
Bryophyta . . . . . . . . 2
Poliose lichens . . . h
Cladonia subgen.Clsd1na q; x
Bryophyta . . . . . . . . 9

121.

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122

whole communities and of strata within and among communities
may be made.

According to the general vegetation survey and Table 17,
the white spruce association/shrub-herb faciation and the
mixedwood forest association share top importance in the
Atlin valley. These two communities each contain vegetation
representative of 15 percent of the total stands. In addi-
tion they contain larger numbers of species and species
groups than any of the other communities.

In an attempt to evaluate the effect of number of stands
on the total species diversity shown for each community type,
a correlation coefficient, r, for the relative abundance
data and the total number of species and species groups data
(see the first two data columns of Table 17) was calculated
according to the product-moment formula (Spiegel, 1961).

As this value, 0.761, is fairly high, it indicates that more
meaningful comparisons of vegetation types on the basis of
species diversity would require the study of more nearly
equal numbers of stands of each type.

The third most important vegetation type, encountered
in 13 percent of the stands, is the aspen association. This
is followed by the white spruce association/feather moss
faciation and the lodgepole pine brfiié, encountered in 12
and 11 percent of the stands, respectively. or these, the
white spruce/feather moss community contains the most species
and species groups and ranks fourth among all communities in

this regard. The aspen association is fifth, and the

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123

lodgepole pine brfilé appears to be seventh in species diver-
sity in the Atlin valley.

The white spruce-lodgepole pine and the lodgepole pine
vegetation types each occur in six percent of the 86 stands
studied. The former contains a larger number, 59, of species
and species groups and ranks sixth in overall importance,
whereas the latter community, with 50, is in eighth place.

There is a prominent break in the range of relative
abundances between values, from ll to 15 percent, of the
several communities listed in the preceding paragraphs and
the values, from.two to six percent, of the white spruce-
lodgepole pine and lodgepole pine associations and of the
several even less abundant vegetation types mentioned below.
Because of this break, the mixedwood forest association,
white spruce association/shrub-herb faciation, aspen asso-
ciation, white spruce association/feather moss faciation,
and lodgepole pine brule are considered as major Atlin valley
community types. Those communities which the general vegeta-
tion survey has shown to be less abundant are designated as
minor types.

The herb-heath association is the eighth most important
vegetation type, followed by the white spruce brfilé. These
are followed in importance by the depression shrub, mixed
woodland, and alpine fir communities. Importance values for
each of these, except the depression shrub association,
correspond to species diversity values which are considerably

lower than those of the major communities. This, again, is

12h

believed to be largely a function of low stand number. A
major exception, however, is the depression shrub community
wherein only three stands, constituting four percent of the
survey total, contained 69 species and species groups, thus
ranking third after the mixedwood forest and white spruce/
shrub-herb communities.

The white spruce association/feather moss faciation
contains an arboreal stratum with six members, the total
number of tree types in the Atlin valley, making it the
most diverse of any community. The total mean C-A (cover-
abundance) value is 9, indicating a fuller canopy than in
any other community except the white spruce-lodgepole pine
association which, although containing one fewer species,
also has a total mean C-A value of 9 in the arboreal stratum.
Other forest communities have values ranging from 7.5 to 8,
except for the white spruce brule and the white spruce asso-
ciation/shrub-herb faciation. Whereas the low value of 6
for the brfilé is easily accounted for by the higher propor-
tions of dead and fallen trees in the stands, the total mean
C-A value of 6.5 for the latter reflects the open nature of
these white spruce forests and corresponds with the high
species diversity and total mean C-A values in the herb
stratum.

In the shrub and subshrub stratum the greatest diversity
is seen in the white spruce-lodgepole pine community where
19 species and species groups were found in a relatively low

number of stands. This diversity value corresponds to a

125

total mean C-A value which is only slightly lower than the
depression shrub value of 24.5, the highest of any community.
Other communities containing prominent shrub and subshrub
layers are the white spruce association/shrub-herb faciation,
aspen association, and the mixedwood forest association.

The white spruce association/feather moss faciation, white
Spruce brule, lodgepole pine brule, and mixed woodland
association all have relatively unimportant shrub and sub-
shrub strata.

The herb stratum is most diverse and dense in the
mixedwood forest and herb-heath associations and the white
spruce association/shrub-herb faciation. The aspen and
depression shrub associations also contain prominent herb
strata. The layer is relatively unimportant in the white
spruce brule and mixed woodland association.

Diversity in the lichen and moss stratum cannot be
meaningfully assessed because a total of only six groups
were employed to account for what is probably a large number
of species. Total mean C-A values were quite variable,
however, ranging from a low of 3 in the aspen association
to a high of 15 in the alpine fir association. Low values
are also seen for the mixedwood forest and the herb-heath
associations, and additional high values are associated with
the white spruce association/feather moss faciation and the
lodgepole pine and the white spruce-lodgepole pine associa-

tions.

SCSE

126

To date soil studies have been made in a few sites and
some understanding of vegetation and soil relationships is
beginning to emerge. Single stands representative of six
plant communities have been examined. Associated soil
types, classified according to the Seventh Approximation of
the Soil Survey Staff, USDA, are: (1) White spruce asso-
ciation/feather moss faciation - Histic Cryaquept, coarse-
loamy, mdxed calcareous. (2) Lodgepole pine association -
Typic Cryopsamment, sandy mixed. (3) Alpine fir association -
Boralfic Cryorthod, loamy skeletal, mixed. (4) Mixedwood
forest association - Typic Cryochrepts, coarse loamy, mixed.
(5) Depression shrub association - Terric Cryosaprist, euic.
Soil studies are needed for the other six upland communities
discussed in this dissertation as well as for additional

stands of the communities listed above.

VIII. TREE SURVEY

Purposes

A tree survey was conducted in order to obtain addi-
tional data for comparison with the pollen rain. These
data are useful in assessing the relative status of the
various tree species in the vegetation of the Atlin valley
and in supplementing the results of the general vegetation
survey. In addition, they make possible comparisons of the
Atlin valley forests with forests in neighboring areas.

127

 

 

Table 18. Distribution of plant communities and sampled
bogs along the Atlin-Carcross road transect.
WEST MILE EAST
White spruce brfilé C6 White spruce brfilé
MOOSE BONES BOG
Aspen association Mixed woodland association
Mixed woodland association C2 Mixed woodland association
Aspen association 2 White spruce association
- herb phase
(unclassified) h Herb-heath association
White spruce association 6 White spruce association
- feather moss faciation - feather moss faciation
Herb-heath association 8 Herb-heath association
White spruce brule 10 White spruce association
- herb phase
White spruce-depression shrub l2 Aspen association
transition ,
Lodgepole pine brfilé 1h Lodgepole pine brule
Lodgepole gag; MILE 16 BOG l6 Herb-heath association
b
Lodgepole pine brfilé 18 Lodgepole pine brfilé
Lodgepole pine brfilé 2O Lodgepole pine brule
Lodgepole pine brfilé 22 Lodgepole pine brfilé
Lodgepole pine association 2U Lodgepole pine association
White spruce association 26 White spruce association
- herb phase - feather moss faciation
White spruce association 28 White spruce association
- feather moss faciation - herb phase
White spruce association 30 White spruce association
- feather moss faciation - feather moss faciation
Mixedwood forest association 32 Mixedwood forest association
White spruce association 3“ Mixedwood forest association
- feather moss faciation
White spruce-lodgepole pine ass'n. 36 Lodgepole pine association
Lodgepole pine association 8 Lodgepole pine brule
White spruce association 0 White spruce association
- feather moss faciation - herb phase
Aspen association #2 Aspen association
Aspen association uh Aspen association
Aspen association h6 Mixedwood forest association
MILE h? BOG
White spruce association #8 White spruce association
- feather moss faciation - herb phase
Lodgepole pine association 50 White spruce brule
MILE 52 BOG 52 White spruce association
- feather moss faciation
Depression shrub association 5“ Depression shrub association
White spruce-lodgepole pine ass'n. 56 White spruce-lodgepole pine ass'n.
Mixedwood forest association 58 Mixedwood forest association
Depression shrub association 59 White spruce association
- shrub-herb-moss phase
Mixedwood forest association Sl Mixedwood forest association
Mixedwood forest association S3 Aspen association
Mixedwood forest association 85 Aspen association
White spruce association S7 White spruce association
- ahrub-herb-moss phase - shrub-herb-moss phase
Aspen association S9 Mixedwood forest association
White spruce association 811 White spruce association
- herb phase - herb phase
White spruce association 313 White spruce association
- herb phase - herb phase
Alpine fir association 815 Alpine fir association
JASPER CREEK soc 316 White spruce-lodgepole pine ass'n. (7)
Mixedwood forest association $17 Mixedwood forest association
White spruce-lodgepole pine ass'n. 819 White spruce-lodgepole pine ass'n.

 

128

Methods

Again the Atlin road is used as a base line, the
rationale for this being the same as in the general vege-
tation survey. At one-mile intervals along the road, except
for two-mile intervals south of Atlin, two sites were
located, one on each side of the road. A site consisted
of a transect line run by compass directly east or west
from the milepost into the forest. This line was followed
from the road to a point which appeared to be well within
the natural vegetation, so as to be away from the disturbed
zone marginal to the road. From this point the line was
followed 15 paces farther to another point which served as
number one of a series of ten survey points located at

u

l5-pace (approximately 45-foot) intervals. The area around
each survey point was then divided into quadrants according
to the point-quarter technique (Curtis, 1959).

The distance from the survey point to the closest tree
in each quadrant was measured, and the species and circum-
ference at breast height were noted. The minimum tree size
measured was eight inches circumference (2.55 inches diameter).
This size was chosen because smaller trees were believed to
be relativelyunimportant contributOrs to the pollen rain.
Curtis (1959) considers mature trees to be those which are
four inches DBH (diameter at breast height) or more. Hansen

(1949a) and Davis and Goodlett (1960) take into account all
tree species one inch DBH and above. In the Atlin valley,

129

few conifers smaller than about three inches DBH were observed
with cones.

If, in a quadrant, no tree occurred within 100 feet of
the point, the quadrant was considered treeless. In areas
of widely spaced trees, the closest tree in a quadrant at a
given point may also have been the closest tree in a quadrant
on the same side of the transect line at the preceding point,
and sometimes also at the next point. The various distances
to the tree from each of the two or three points were noted,
but the tree, as a resident of more than one quadrant, was
not counted more than once in frequency and basal area cal-
culations.

All together 146 transect lines were run for a total
of 1,460 survey points and 5,840 quadrants. This survey
provides a sampling of forest trees in the Atlin valley
through a zone about 1,000 feet wide, centering on the road
from mile six on the Carcross road to mile 19-south on the
Atlin road. Trees were encountered in 4,819 of the 5,840
quadrants, thus giving a total tree frequency of 83 percent.
Data for individual species are presented in Table 19.
Basal areas were determined from circumference at breast

height data using a computer-printed conversion table.

Discussion
In addition to the palynological significance discussed
below, data from the tree survey encourage further consid-

erations of the nature of the forests in the Atlin valley.

130

Of all the terrain covered and trees examined, no species
other than those in Table 19 were found. Paper birch, tama-
rack, and black spruce, although common elsewhere in the
boreal forest zone, were absent. For this reason, and on
the basis of information in Halliday (1937), Porsild (1951),
Raup (1945), Hansen (1953), and Hultén (1968), the writer
concludes that it is unlikely that either paper birch or
tamarack will be found in the valley. With respect to black
spruce, it is predicted that it will be yet found, probably
growing in bogs or muskegs where the local lithology has
caused conditions of lower pH and the growth of Sphagnum spp.
That such conditions probably occur is indicated by the
stands of the shrub-herb-moss phase of the white spruce
association encountered in the general vegetation survey.

using the figures in column one of Table 19 as indica-
tors of relative abundance or population intensity, compari-
sons can be made with the data of Halliday and Brown (1943),
presented on page 55 of this dissertation. The figure, 45
percent, for white spruce fits nearly midway in the popula-
tion intensity range cited by Halliday and Brown for white
and black spruce together. The fact that these authors'
data are for both species of spruce encourages the hypothesis
that white spruce replaces black spruce in the Atlin valley.
Some support for this is also available from field observa-
tions. Where spruce occurs in bogs it is always found to be
white spruce. Often the trees or saplings are stunted and

unhealthy in appearance, or dead, and the bog spruce

. . 3“.
hr.— sut—

M-
v“

131

Table 19. Tree survey data summary.l

 

Species % of Trees % Total Ba a1 % of Total
Measured Freq. Area (in ) Basal Area2

 

 

 

 

 

 

Eggs: glauca 45 37 81,952 56

2. glauca (dead) 2 2 ‘

£1395 contorta - 15 13 13,0673 253
.2. contorta (dead) 11 9

'Abigg lasiocarpa l 1 3,202 2

Populus tremuloides 18 15 25,1824 174
[3. balsamifera 2 2

S311; spp. 7 5

51225 spp. l 1

Dead trees

(eXC- 2.1218. 8= 31.929.) 2 2

 

1All figures rounded off to nearest whole number.

2Percent of total of Picea, Pinus, Abies, and Populus
only.

3Includes the dead trees of the 1958 burn between mile
14 and 23. This includes all but a small percentage of the
dead pines encountered.

ulncludes Populus balsamifera.

132

population is probably not as dense as if black spruce, often
a bog species, could grow there. The usual habitat of the
latter species seems to be at least partially filled by the
former. Rowe (1959) mentions that in northwestern Canada
white spruce sometimes invades sites which are also occupied
by black spruce and that the ecological distinctions in such
cases may be unclear.

The figure, 15 percent, for living lodgepole pine fits
well within the range given by Halliday and Brown. If the
figure for dead pine trees (most of which derive from the
1958 fire) is added, pine would appear to be somewhat
heavier in population intensity in the Atlin valley than
these authors show for the regional forests. It is not
known whether their figures include recent, fire-killed
trees. If they do not, corroboration of the writer's data
would be good.

Although the alpine fir figure, 1 percent, is well
below the range given by Halliday and Brown, there is pro-
bably no major discrepancy with respect to the total Atlin
valley forest vegetation because the present survey was
carried out belOw the usual lower elevation limit for this
species. Observations at and near timberline indicate that
alpine fir is more important than the survey shows. However,
the writer doubts that it would fall in the “medium" inten-
sity category given by Halliday and Brown.

Halliday and Brown (1943) indicate that the relative

population intensity of aspen and balsam poplar in

133

northwestern Canada is "light," i.e. in the one to ten per-
cent range. The present survey shows that aspen, but not
balsam.poplar, is considerably more abundant in the Atlin
valley. An explanation of this has not yet been developed
since there is no reason to believe that conditions favoring
aspen are more prevalent in the valley than elsewhere.

It should also be noted that conditions for balsam
poplar, which is primarily a flood plain succession species
(Raup 1945), are not common in the Atlin valley. Except for
the appearance of unimposing individuals of balsam poplar
in significant proportions in only a few stands of the mixed-
wood forest association (Table 12), the only pure stands of
large (up to 12 inches DBH), old growth poplars observed are
along Haunka Creek at mile 8.9 and in the vicinity of mile 4,
where the vegetation is unusual in other respects too (Table
16).

There are two factors which may be at least partially
responsible for apparent discrepancies between the data of
Halliday and Brown and the present survey. First (1) the
information used by these authors was obtained 30 to 40 years
or more prior to the writer's 1967 survey. An increased fre-
quency of man-caused fires in the intervening years would
favor the development of higher proportions of both pine and
aspen stands. In the survey many trees were encountered which,
although at least the required 2.55 inches DBH were still
small enough to be not more than 25 or 30 years old. Also
(2) the Halliday and Brown figures were developed from a

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‘ 131;

Table 20. Comparison of general vegetation survey
and tree survey data.

 

 

 

 

 

 

 

 

Species Freq. of Stands, Freq. of Species
C-A Value 2 4 in Tree Survey
‘giggg glauca 42 37
Pinus contorta* 15 21
Abies lasiocarpa 2 l
Populus tremuloides 16 15
_P_. balsamifera 4
_S_a_1_i_1_c_ spp. 8 6

 

*Includes dead trees

l34-A

form of data, i.e. relative volume of a species per unit
area, somewhat different from the frequency data of the 1967
survey. Frequency, which accounts for all sizes of a species
in the same category, would tend to overemphasize the species’
importance. This is especially true in the case of aspen,
where many individuals are young, and even most older ones
don't compare in volume with spruce or pine. In this regard,
the basal area figure of 17 percent for aspen and balsam
poplar (Table 19) compares somewhat better with the Halliday
and Brown range of up to ten percent for the population
intensity of these species.

For comparison purposes Table 20 gives the frequency
of general vegetation survey stands wherein the quadrat C-A
values for the various tree species were four or more, along
with frequency data from the tree survey. A high correlation
coefficient, r, of 0.965 for these two sets of data, (calcu-
lated according to the product-moment formula of Spiegel,
1961), shows a significant relationship. Thus the two
surveys corroborate each other in terms of prevalence and
relative importance of these species.

As a summary of the data in Tables 19 and 20, and the
tree survey in general, the following is clear: (1) Almost
half (47 percent) of the trees in the Atlin valley are white
spruce. With a frequency of 37 percent, this species occupies
over a third of the landscape within range of the survey.
With respect to basal area, white spruce is more important

than all other species combined. (2) Lodgepole pine,

135

although slightly less important than aspen in terms of
numbers and area occupied, is second only to white spruce
in basal area. Even so, it comprises less than half the
basal area of spruce. (3) Dead (fire-killed), but standing
lodgepole pine is quite important in terms of numbers and
amount of occupied terrain, being fourth in both respects.
The data indicate that over eight percent of the valley
area has been recently burned. Observations along the
Alaska Highway and elsewhere indicate that this may be a
conservative measure of the effect of fire.) (4) Aspen is
the second most abundant tree in the valley and occupies
slightly more land area than pine (disregarding dead pine
trees). It is considerably less important in terms of basal
area than spruce or pine, however. (5) Tree willow is
common as an admixture in most forest types. (6) Alpine fir
appears to be relatively unimportant compared to spruce,
pine, aspen, and tree willow. As discussed above, however,
it is believed to be an important component of the total
regional forest vegetation when the higher elevation stands
and those around the southwest end of the lake are considered.
(7) Balsam poplar is relatively unimportant, although it is
widespread. (8) Alder is insignificant as a tree species in
the Atlin valley.

‘Figure 27 shows the distribution, in terms of basal
area, of the four_main tree species throughout the survey

transect zone along the Atlin road. The significance of

136

this distribution is considered further in the section on

pollen-vegetation comparisons.

IX. BOG VEGETATION

General

Hygric habitats, including marshes and bogs, are impor-
tant features of the Atlin region landscape. Detailed study
of the vegetation of these habitats has only begun, but the
work to date is discussed for general ecological purposes and
as background for palynological sampling and interpreting
the pollen and spore diagrams. The discussion is based pri-
marily on qualitative surveys made in and around six bogs in
the Atlin valley and, to a lesser extent, on aerial photograph
studies.

Hansen (1953) discusses three major types of organic
depositional formations along the Alaska Highway. These are
muskegs, tussock muskegs, and bogs. Muskeg, although occur-
ring in nearby areas, is not important in the Atlin valley,
prdbably because of minimal permafrost conditions coupled with
low precipitation and enhanced drainage in.a pervious sub-
strate. A kind of tussock muskeg has developed in some flat
areas, apparently where the substrate is a finer-grained,
clayey or silty material and where there may also be seasonal
or residual frost layers which help to maintain a high water
table. Prdbing and pits dug in such areas, which ordinarily

are not wet, show that organic accumulation is shallow. At

rf

I c')

D-fi

~41

137

mile 50, for example, there is a grass tussock muskeg con-
taining approximately three feet of peat underlain by a
silty clay.

Moss (1953) and Hansen (1953) recognize two fundamental
types of bogs. One is characterized by Sphagnumeericad-

 

black spruce vegetation and the other by Drepanocladus-

 

.ggggx-bog birch vegetation. The former type has not been
found in the Atlin valley except, perhaps, in incipient
stages. Although the six bogs discussed here differ in
various ways, they all are generally of the latter type.

The major factor in the development of a Drepanocladus-Carex-

 

bog birch bog is an abundance of calcium carbonate in the
drainage basin. Marly sediments, making up a significant
portion of the bog cores discussed below, indicate an abun-
dant source of calcium carbonate in the earlier, aquatic

stages of succession.

Mbose Bones Bog

This bog is located near mile 4.5 on the Carcross road
at an elevation of approximately 2,350 feet (Fig. 13). It
is roughly teardrOp shaped and is about 500 feet across the
longest dimension. A small pond, about 75 feet in diameter,
occupies the center. The bog surface slopes very gradually
up from the pond in most directions and becomes increasingly
drier toward the surrounding forest. The bog is located
Upon a pitted outwash just over one mile northwest of Little

Atlin Lake. There are a few calcareous seeps upon otherwise

138

Figure 13. Moose Bones Bog.

View northeast across Moose Bones Bog. Several distinct
vegetation zones are shown. The outermost, zone 6 (Table 21,
page 142) is of forest vegetation, the composition of which
is variable around the bog. White spruce dominates in some
areas, as in the right background. Here the vegetation
approximates the white spruce association/feather moss facia-
tion (see pages 81- 83) except that the forest floor is
covered primarily by a thick accumulation of litter, and
plants are scarce in the lower strata. In the center and
left background there are stands of spruce which intergrade
with stands of the aspen association. -

A narrow shrub zone (zone 5) occurs around the periphery
of the bog. The major component of this zone is shrub birch
(Betula landulosa), as shown in the foreground. Shrub
wIIIows orm important admixtures in some places, particu-
larly in outer parts of the zone.

Inside this zone there is a Poa palustris zone zone 4)
which is discontinuous around the Bog. *A’part of th a zone
is shown at the right at the inside edge of the shrub zone.

The more extensive, light-toned herbaceous zone (zone 3)
is dominated by Desch sia caespitosa. The mediumptoned
zone (zone 2) next toward the center of the bog is dominated
by Calamagrostis neglects. A somewhat narrower and darker
zone adjacent to the pond at the center of the bog (the dark
patch at the right edge of the photo) is a Carex gguatilis
zone. Only the latter two zones are continuous aroun e

bog.

The presence of grass-dominated zones 2, 3, and 4 is
believed to be related to grazing by domestic livestock. (A
fence can be seen at the forest's edge in the background.)
no other bogs were observed with these vegetation zones. On
the other hand, no other bog contained as broad an area of
medium to well-drained substrate inside the forest edge as
Moose Bones Bog, and for this reason it is probable that
vegetation zonation would be different here anyway. The
lack of encroachment into this mesic terrain by arboreal
species is not understood yet. Although trees may have been
removed by logging several decades ago, few seedlings are
found in the drier parts of the bog at present.

 

The palynological record for Moose Bones Bog is shown in
Figure 21 and is discussed on pages 222-231.

Mid-afternoon. 6 September.l968.

 

 

Vin-nu.

 

 

 

139

 

Moose Bones Bog.

Figure 13.

 

Mile 16 Bog.

Figure 14.

be

140

Figure 14. Mile l6 Bog.

View southeast across Mile l6 Bog. Atlin road in
background.

This bog has developed in a glacial kettle. The small
pond in the center is surrounded by a Carex aquatilis ssp.
aguatilis zone. This is surrounded by a narrower shrub

ow zone which grades abruptly into the adjacent forest
vegetation where the level surface of the bog meets the
moderately steep wall of the kettle.

The forest vegetation is lodggsile pine, burned in 1 58,
and classified as lodgepole pine b e (associes) (Table ).
A few trees remain alive, as the one in the upper left
corner, and are believed to have a major influence on the
pollen rain, particularly in the absence of spruce (Fig. 26).
Shrubby vegetation in the foreground consists of aspen seed-

lings.

Open areas just beyond the road bear stands of the
herb-heath association (Table 15). This plant community
type, along with pine, s widespread in this part of the
Atlin valley because of the highly pervious substrate and
the exposed condition of the slopes.

' The palynological record for Mile l6 Bog is shown in
Figure 22 and discussed on pages 231-243.

Midday. 9 July 1968.

141

mesic terrain in the western part of the bog. The pond
itself, however, does not appear to be particularly cal-
careous as there are no lime-encrusted aquatic plants nor
any mineral deposits on the shore as at other bogs. The
bog is located at the head of a very minor drainage divide.
Drainage from it is to the northeast and into a creek about
one-fourth mile away which flows south to Little Atlin Lake.

Late in the 1968 season a detailed vegetation survey of
this bog was begun. Use was made of one-meter-square
quadrats at five-meter intervals along compass line transects
run from the edge of the water at the center of the bog out
into the surrounding forest. Species within the quadrats
were evaluated in terms of cover and abundance on the Domin
scale (see Appendix C).

On the basis of the four transects which have been run
to date, six distinct, roughly concentric vegetation zones
have been characterized according to dominant species. The
dominants plus some of the other species found in each zone
are listed in Table 21. .

The forest in the immediate vicinity of the bog is quite
heterogeneous. A mature spruce stand lies on the north (zone
six in Table 21 is based on this stand), a young spruce
forest with aspen and shrub willow lies to the east, the
vegetation to the south is mainly of the depression shrub
type, and there is an aspen stand on the west. Another bog

lies a short distance farther to the west. Figure 27 gives

 

 

 

143

an idea of the relative importance of the three main tree

species in the vicinity of Moose Bones Bog.

Mile l6 Bog

Mile l6 Bog, at mile 16 on the Atlin road, occupies a
glacial kettle in an area of thick drift at the northern end
of the kame terrace discussed on pages 26-28. It is sur-
rounded on three sides by steep, sandy slopes and, on the
south, by more gently rising terrain. The bog is circular,
about 200 feet in diameter, and contains a small pond
approximately 25 feet in diameter in the middle. The ele-
vation is approximately 2,400 feet. The bog is quite level,
and the periphery is well-defined where the surrounding ter-
rain rises rather abruptly. Open, shallow water between
sedge tussocks extends from.the pond about two-thirds of the
way to the periphery (Fig. 14).

The dominant species throughout most of the bog is
(gaggx agggtilis ssp. aquatilis, occurring in large tussocks
and forming a thick mat which is springy near the middle.
Associated with the sedge, of co-dominant status, is
Drepanocladus aduncus. Near the periphery of the bog there
is a narrow zone which is not as wet and contains scattered
shrub willows. A small, more mesic, northwestward extension
of this outer shrub zone contains four species of Epilobium,
several grasses, and, under a tip-up mound, Merchantia
W, along. with several other herbaceous species
which are not of the bog proper nor of the surrounding,

xeric slopes (lower left corner of Fig. 14).

10
ab

002
80"

81a

144

Reconnaissance and qualitative observations in the
vicinity of Mile l6 Bog indicate that the information from
the general vegetation and tree surveys, presented in Table
18 and Figure 27 portrays the upland vegetation very well.
Detailed information is given in Table 8, which includes the
relevé for stand 16W (lodgepole pine brfilé) and Table 15,
containing the 16E relevé (herb-heath association).

An important local feature which the surveys do not show
is the vegetation along Snafu Creek. This creek flows west,
cutting a small canyon into the glacial drift, to a point a
little over one-tenth mile south of the bog where it turns
to flow south for approximately two-fifths of a mile. This
latter stretch of the creek is in line with the lower terrain
on the south side of the bog, and the alder and bog birch
here are believed to be a significant pollen source. Rela-
tively high percentages of these types were found in the
surface sample for Mile l6 Bog (Fig. 26).

Mule 47 Bog

Mile 47 Bog, at approximately 2,400 feet elevation, is
in the shape of a letter "V", opening to the north. The
longer, western arm is about 675 feet, and the eastern arm
about 500 feet long. The arms are separated by a bedrock
knoll which rises steeply to about 75 feet above bog level.
The bog is quite wet throughout a large, central portion and
contains a small, oval—shaped pond about 75 feet long in the
southern part. The bog lies near the head of a minor topo-
graphic divide with drainage from.the tip of the eastern

[hi

145

arm through moist lowlands to swamps along Telegraph Creek
about one-fourth mile to the northwest. The bog is highly
calcareous as is shown by deposits of a light-brownish
orange limonitic marl throughout the wetter areas and,
particularly, in and around the pond.

Marl is defined here as a precipitate of calcium.car-
bonate which may be nearly pure, in which case it is almost
white in color, or contain admixtures of partially decayed
organic material in various prOportions. Clay and silt
particles may constitute a minor fraction of some samples.
The material may be colored various shades of brown, orange,
pink, gray or green by the presence of iron oxides and per-
haps oxides of magnesium, aluminum, or other metals. In
most cases the precipitation of marl appears to be due
primarily to the extraction of calcium.carbonate from.the
water by‘ghgrg spp. In some instances £2355 appears to be
absent and marl precipitation may be under the influence of
blue-green algae (Pollock, 1918). This seems to be the
case in Mile 47 Bog.

Four vegetation zones are recognized (Fig. 15):

(l) Bulrush zone. This is the central and largest zone,
about 125 by 350 feet in size, in the western arm and south-
ern.part of the bog. Scirpus validus is dominant here.
There are few other species present except for an occasional
Hippuris zyggaris and a few mosses and small willows on drier

swells. The pond is on the southern edge of this zone.

146

SPRUCE
ASPEN

SPRUCE

aspen
bsham poer
tree willow

SPRUCE
aspen

SPRUCE

POPLAR
aspen

SPRUCE SPRUCE
ASPEN

BALSAM POPLAR
aspen

 

@

ZONE

 

0 200
l n

I

0

Plant names in upper case letters indicate dominant types.
Lower case letters indicate secondary types.

Figure 15.

Generalized sketch map of Mile 47 Bog vegetation zones
and surrounding upland vegetation in eight compass sectors.

147

(2) Sedge-moss zone. This zone is more or less con-
tinuous around the bulrush zone, is about 90 feet wide, and
occupies a significant portion of the eastern arm of the
bog in the southeastern part. The boundary between this
and the bulrush zone is ordinarily sharply defined. Sedge
hummocks are common but not large, and there are barren, wet
mud pockets between the better developed hummocks. The zone
contains little standing surface water, in contrast to the
sedge zone in Mile l6 Bog where the same species, 02555

aquatilis ssp. aquatilis, is dominant. The zone contains

 

a few stunted or dead white spruce. Xanthoria candelaria

 

is abundant on one of these. Many spruce were examined
closely for black spruce characteristics, as at other bogs,
but none were found.

The plants, grouped according to prevalence in the

sedge-moss zone, are: Dominant - Carex aquatilis ssp.

 

aquatilis, Egygm_pseudotriquetrum, B. rodlii; Abundant -

Drepanocladus aduncus, Mnium affine; Common - Triglochin

 

maritimum, Carex diandra, Salix gyrtillifolia; uncommon -

 

Hippuris vulgaris, Ranunculus sp.; Rare - Triglochin palustris,

 

 

.Epilobium.palustre (common locally), gyrola sp., Galium tri-
fidum.ssp. trifidum.(abundant with Ranunculus sp. on small,

 

 

mossy hummocks in mud near the edge of the pond).

Within this zone, near the scutheast edge of the pond,
there is a linear swell which is 18 to 20 inches higher than
the general level. The following species grow upon it:
'giggg glauca (seedling), Arctagrostis latifolia var.

AWN 8.x

148

arundinacea, Festuca altaica, Salix myrtillifolia var.

 

 

 

pseudomyrsinitis, S. glauca ssp. glabrescens, §. glauca ssp.

 

 

acutifolia, gyrola asarifolia var. purpurea, and Mertensia

 

 

 

paniculata, along with several of the mosses and sedges
characteristic of the main zone.

(3) Shrub willow zone. A narrow shrub willow zone is
of variable status around the bog. In some places it is
absent, and the sedge-moss and bog spruce zones intergrade.
In other places it is transitional between these two zones,
or it may occur as a well defined zone between the bulrush
zone and adjacent upland spruce forests, as along the western
edge of the bog where both the sedge-moss and bog spruce
zones are lacking. The willows are primarily the same
species as occur in the sedge-moss and bog spruce zones but
are more prevalent here.

(4) Bog spruce zone. From the south and southeast
sectors of the bog the vegetation transition into the adja-
cent upland area is more gradual than elsewhere because of
the low slope angle. Conditions here favor a bog spruce
forest, characterized by mature white spruce and abundant
mosses. The zone is rich in species as follows:

Dominant - giggg glauca

Abundant - Egyumjpseudotriquetrum.(dominant locally)
and Tomenthypnum.nitens (dominant locally).

Common - Juncus arcticus ssp. ater, Carex nardina,

 

Geocaulon lividum, Equisetum scirpoides, Salix yrtillifolia,
.§. glauca ssp. glabrescens, S. glauca ssp. acutifolia.

149

uncommon - Parnassia sp., Pedicularis sudetica,

 

 

Arctostaphylos rubra, Arctagrostis latifolia var. arundina-

 

cea, Festuca altaica, Petasites sagittatus, Cladonia sp.,

 

Peltigeraaphthosa, Betula glandulosa, Carex aquatilis ssp.

 

aquatilis, Picea glauca (seedling).
Rare - Carex capillaris, g. dioica ssp. gynocrates,

 

 

Ezrola asarifolia var. purpurea, Platanthera obtusata,

Erigeron elatus, gygadenus elegans, Rubus stellatus, Cla-

 

donia gracilis (abundant locally), Moneses uniflora, Ledum

 

palustre ssp. groenlandicum, Shepherdia canadensis.

Isolated - Parmeliella praetermissa, Eriophorum sp.,

 

Senecio lggen .

The upland forests around Mile 47 Bog are quite vari-
able. Some idea as to their nature can be obtained from
Table 18 and Figure 27. A more detailed, qualitative des-
cription of the forest stands in the immediate vicinity of
the bog can give an idea of the variability of Atlin valley
forests in general. Such a description can be made in terms
of 45-degree sectors, extending outward from.the edge of
the bog, as observed on a circumnavigation of the bog at
distances up to about 200 feet (Fig. 15).

Nbrth sector. This sector includes the rounded bedrock
knoll which separates the two arms of the bog, plus the
slopes which trend down into the low areas, which are ex-
tensions of the arms of the bog, on either side. Trees on

the knoll and its upper slopes are very scattered and include

150

a few mature lodgepole pine and some aspen. Common herbs are

Antennaria sp., Potentilla sp., Arctostaphylos uva-ursi,

 

 

 

Saxifraga tricuspidata, Artemisia sp., Galium.boreale,

 

Anemone sp., and Polemonium pulcherrimum, all characteristic

 

of well-drained to dry sites. On the south lepe of the
knoll, above the central part of the bog, aspen is abundant,
and this grades downward into a narrow zone of mature spruce
just above the north edge of the bog between its two arms.
The west slope of the knoll is nearly devoid of trees, but
extends down into a narrow spruce zone just above the east
edge of the west arm of the bog. Farther to the north, be-
yond the end of the west arm of the bog proper, this slope
bears abundant aspen. At the bottom the slope is continuous
with a broad, moist swale where there is a mixed and rather
lush stand of spruce saplings, balsam poplars, and large
aspens up to 18 inches in diameter. There is a light admix-
ture here of mature spruce and large balsam poplars. 0n

the east the knoll slopes steeply down into the swale beyond
the east arm of the bog. In this swale there is a dense
stand of shrub willow, grass, and a few spruce saplings. The
slope itself bears aspen and poplar, with a few large aspen
near the bottom in the transition between dry and moist
terrain./

Nbrtheast sector. This includes the east side of the

 

moist swale lying north of the east arm of the bog plus a
portion of a more extensive, west-facing upland slope. The

depression shrub vegetation of the swale grades directly

151

into herb phase white spruce forest (see Table 5) which is
more or less continuous through the sector. The stand con—
tains a light admixture of balsam poplar, aspen, and tree
willow. Large aspens are present in a ratio of about one
per 100 large spruce. The shrub layer is scattered, with
Shepherdia canadensis being dominant. Locally there are
patches of thick moss. Toward the east side of the sector
balsam.poplar becomes abundant. There are only a few large
spruce and aspen here.

East sector. Continuing into this sector, from the

 

northeast, balsam.poplar becomes dominant, with trees up
to 10 inches in diameter and 30 feet tall. About half of

these are dead, however, apparently of old age. Shepherdia

 

canadensis is abundant with the p0plar. Spruce is scattered
at first, but as the central part of the sector is approached,
i.e. due east, it becomes dominant again, and poplar drops
to the status of a light admixture. The spruce forest here
is largely of the herb phase, but intergrades locally with
small stands of the feather moss faciation. In a shallow
swale spruce trees are smaller but denser, shrub willow is
common, and mosses are abundant. On a swell spruce are
sparser, and aspen of all sizes are common. Farther upslope
to the east the spruce forest grades rather aburptly into a
large aspen stand.

Southeast sector. The topography and vegetation here

 

are similar to the east sector. Toward the south side of

152

the sector the forest is rather open and contains quite
large trees. 1

South sector. This sector is occupied by a broad,
moist, low area which is continuous with the south end of
the bog. The spruce forest extends into this area, but is
considerably sparser than on the adjacent upland, being
mixed with abundant shrub willow. A thick moss carpet occurs
throughout. The willow and moss are continuous with the
shrub willow zone of the beg.

Southwest sector. This sector is occupied by a well-
developed stand of the feather moss faciation of the white
spruce association. The forest is dense, spruce seedlings
and saplings are common, herbs are scarce, and feather mosses
are abundant. A few tree willows are present, plus occa-
sional old aspens. The forest extends to the edge of the bog.

West sector. As this sector is approached from the SW

 

sector old aspen become increasingly frequent in the spruce
forest. Within the sector the spruce forest grades rather
quickly into aspen forest across a small swale extending
west from the bog and bisecting the sector. This aspen forest
is located on a broad ridge which extends north from the
swale, parallel to the west arm of the bog and extending into
the northwest sector. The aspen forest grades downslope to
the east into a rather well-developed shrub willow zone in
the outer part of the bog.

NOrthwest sector. The aspen forest is continuous into

this sector and grades into the mixed vegetation of the swale

153

in the west side of the north sector as described above.
The aspen forest is well-developed and open and, on the
higher parts of the ridge, is representative of the aspen
association (see page 96 and Table 11).

On the slope leading down from the ridge southeastward
into the bog large clumps of shrub and tree willow appear.
Farther downslope aspen drops out and tree willow becomes
increasingly abundant until there is a nearly pure, old
growth, tree willow forest. This forest is about 150 feet
'wide, from the transition with aspen higher on the ridge to
the northwest down to a narrow spruce zone just above the
edge of the bog. It has an open aspect, with few shrubs,
herbs, or mosses. Spruce saplings are very scattered
throughout. This is the only stand of nearly pure tree
willow vegetation encountered in the Atlin valley.

Mile 52 Bog

This bog is somewhat rectangular in shape, oriented
with its long axis trending north-northwest to south-south-
east, and is approximately 650 to 1500 feet in size (Figure
16). A shallow pond, about 150 by 400 feet in size, is
situated in the north part of the bog. As in Mile 47 Bog,
the pond is bordered in certain places by "beaches" of light-
brownish orange calcareous organic deposits. Aquatic vege-
tation is encrusted with calcium.carbonate. A few small
ponds and pools occur elsewhere in the bog. Except for
narrow zones adjacent to these, the bog is dryer than Mile

l6 and.Mile 47 Bogs.

154

Figure 16. Mile 52 Bog.

View east into Mile 52 Bog from near the summit of a bed-
rock hill about 200 ft higher in elevation.

Vegetation in the foreground is of the herb-heath type.
Next is a zone of aspen brule, with a strong admixture of
shrub willow on the near side, which merges into the white
spruce zone along the west edge of the bog. The large tree
at the left is a lodgepole pine. A few other pines are scat-
tered among the spruce.

The light colored material along the near edge of the
pond, behind the tops of the white spruce, plus a few small
patches on the far side, are marl-organic deposits.

On the far edge of the pond, somewhat left of center, is
a patch of stunted white spruce, most of which are dead.

Patches of lighter tone in the north and northeast parts
of the bog are sedge vegetation, dominated by Carex aquatilis
ssp. a uatilis. Medium toned areas around them are small
shrub w ows and a few shrub birch.

 

A major shrub zone containing large Salix spp. and
Betula glandulosa occupies the east, southeast, and southern
parts 0 the bog. Ybung white spruce appear to be advancing,
along with shrubs, across the bog just south of the pond.

 

A small pond is seen at the right of the photograph. In
1966 a residual frost layer, at a depth of 12-15 inches, which
could only be penetrated with a special permafrost coring
device, was encountered within a few feet of this pond as
late as July 6.

A ’Beyond the shrub zone is a stand of young white spruce
brule with a strong admixture of Salix spp. This Stand con-
tains a great deal of charred wood and clutter.

Across the upper part of the photograph is the Atlin
road, and beyond this, the edge of a stand of the feather
moss faciation of the white spruce association.

The palynological sampling site is situated at the
southern tip of the pond, about 3 feet from the water's edge.

The white spot at the upper right is the field truck,
parked at milepost 52.

23 June 1967.

155

 

Figure 16. Mile 52 Bog.

 

Figure 17. Vegetation in Mile 52 Bog.

156

Figure 17. Vegetation in Mile 52 Bog.
‘View north from.near the northeast shore of the pond.

Vegetation in the foreground is predominantly Carex

a ustilis ssp. aquatilis with an admixture of Salix spp. and
agpandulosa.

Across the middle of the photo is a shrub willow zone.

This grades into typically heterogeneous upland forest
vegetation.

The tri le-shaped mountain on the left skyline is
Mt. Hitchcoc;n%6,878 ft).

Afternoon. 4 July 1967.

157

Vegetation zonation is not as concentric nor distinct
in this bog as in the others. Basically there are patches

of sedge zone, dominated by Carex aquatilis ssp. aquatilis

 

 

and of shrub zone, containing at least six species of willow
and including significant admixtures of bog birch (Fig. 17).
Northeast of the pond there is a large area of nearly pure
sedge vegetation, but at most other places in the bog sedge
and shrub vegetation is mixed. Shrubs are generally less
abundant in the central parts of the bog and increase in
abundance and size toward the periphery. There is a signifi-
cant proportion of bog birch in the vicinity of the pond. A
few stunted white spruce occur in the bog, and on the eastern
edge of the pond there is an area about two acres in size
containing scattered dead white spruce, some around six
inches in diameter. A possible explanation for the death

of these trees is that the water table has risen in recent
times.

The upland vegetation surrounding the bog is similar to
that around Mile 47 Bog except that the proportion of spruce
is less. A considerable amount of lodgepole pine occurs
higher on a bedrock hill adjacent to the bog on the west and
also on higher sIOpes of the mountains immediately to the

east.

Jasper Creek Bog
This bog is located a short distance west of the road
approximately 16 miles south of Atlin (Fig. 18). It is

158

Figure 18. Jasper Creek Bog.

View south-southeast from Atlin road approximately 17
miles south of Atlin. An interconnected bog and pond appear
in the distance at the left.

The sedge vegetation zone adjacent to the pond is domi-
nated by Carex rgynchophysa and Drepanocladus vernicosus. The
bog water taBIe s a ove e surface throughout most of‘this
zone.

In the foreground and on the far side of the bog is a
shrub willow zone. White spruce seems to have begun to en-
croach upon this zone in the past. More recently a change in
habitat conditions, possibly a rise of the water table,
caused these spruce seedlings and saplings to die. In addi-
tion, a number of dead young spruce can be seen about midway
between the two ponds in the left part of the photo. In the
right foreground is an older lodgepole pine which also has
died.

The forest vegetation on the hillside west of the bog
is of the mixed coniferous forest type. Although white spruce
is most abundant here, alpine fir and lodgepole pine form
important admixtures in most places.

Afternoon. 11 July 1968.

Figure 19. View east from Jasper Creek Bog.

View from within the bog near the palynological sampling
site, shown in the right foreground. This site is located in
the middle of the open area shown in Figure 18 south of the
pond.

The forest in the middleground is composed almost exclu-
sively of lodgepole pine, in contrast to the mixed coniferous
forest on the opposite side of the bog.

The mountain in the background is the southernmost peak
in the Jehnson Range and is composed largely of limestone.

9 September 1967.

159

 

Figure 19. View toward Sentinel Mountain from Jasper Creek Bog.

about
north
eleva

ter
bog c
by 50
the e
depth
Alan

160

about 400 by 1300 feet in size and is situated in a small
north-northwest to south-southeast trending valley at an
elevation of about 2,400 feet. It drains south into an
interconnected bog at the headwaters of Jasper Creek. The
bog contains a comparatively large pond, approximately 200
by 500 feet in size. Except for narrow peripheral areas,
the entire bog is wet, with standing water up to a foot in
depth in places well away from.the pond. The surrounding
upland terrain rises rather abruptly from the bog except
where it is continuous through a narrower area with the next
bog to the south. Standing water is continuous between the
ponds in each of the bogs, and a lagg type of stream about
two feet deep also connects them. Flow in this stream was
not perceptible.

The bog is occupied almost entirely by a sedge-moss
zone dominated by 92335 rgynehgphysa and Drepanocladus
vernicosus (Fig. 19). There is no significant tussock
development. Associated with these species are Cinclidium.
stygium,'gggg§’aguatilis ssp. aquatilis, g. diandra, g.
limosa, Eriophorumugggpstifolium, Utricularia intermedia,
Potentilla palustris and, near the edge of the pond,
Mementhes trifoliata.

A narrow shrub willow zone is discontinuous around the
bog. vaccinium.ggycoccus is abundant locally on thick moss
hummocks in this zone on the west side of the bog. Empetrum

31.1.5125! was also found here, and Ledum Eustre ssp.
‘groenlandicum.is abundant at the nearby forest edge.

161

The forests around Jasper Creek Bog are comparatively
mature and continuous. On the north and west they are
dominated by white spruce, alpine fir, and lodgepole pine.
The relative abundance of these three Species appears to
change with elevation, with spruce somewhat more frequent
at lower levels, fir more abundant at intermediate levels,
and pine assuming dominance at higher levels. In general,
the most vigorously regenerating species is alpine fir.
The Species composition and structure of the lower three
layers of this forest are similar to the feather moss
faciation of the white spruce association (Table 4). With
Pleurozium schreberi and Mylocomium splendens forming thick

 

mats, this forest could also be designated a feather moss
type.

East and northeast of the bog, on the lower slopes of
the Jehnson Range, there is a fairly extensive, old-growth
lodgepole pine forest (Fig. 19). Spruce is of minor impor-
tance here, and fir is absent. Spruce and fir seedlings
are rare. Aspen and tree willow occur as minor admixtures.
The soil here is sandy and light. The forest on this west-
facing slope, although apparently mature, is much different
from that on the east-facing slope a short distance away

across the bog where the mixed coniferous forest occurs.

Wilson Creek Bog
This bog lies approximately six miles by road east of
Jasper Creek Bog, about 200 feet north of the road, at

162

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163

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.om ousmna

 

164

approximately 3,050 feet in elevation (Fig. 20). The bog

is roughly circular in shape and 600 feet in diameter. It
contains a pond around 200 feet in diameter. The pond con-
tains calcium carbonate-encrusted algae, and there are cal-
careous surface deposits around the pond similar to those

at Mule 47 and Mile 52 Bogs. It is to be noted that lime-
stone outcrops are extensive on the mountainsides around the
bog, and this is probably the source area of much of the cal-
careous glacial material deposited farther north in the Atlin
valley as well as of the marl in Wilson Creek Bog.

The bog vegetation is contained primarily within a
sedge-moss zone, and there are narrow, discontinuous shrub
and bog spruce zones which intergrade in places. Betula
glandulosa and Potentilla fruticosa, along with Salix_spp.,
are important members of the shrub zone and are also found

in moist swales in the surrounding forest. Ledum palustre

 

ssp. decumbens also occurs here.

 

Although the upland terrain surrounding the bog is
irregular, the vegetation is more homogeneous than in areas
described above, consisting predominantly of an old growth
mixed coniferous forest. It appears to be similar to the
white spruce-lodgepole pine forest association described in
the general vegetation survey, particularly stands Sl9N and
8193 (Table 8), except for the greater prevalence of pine
and a light admixture of mature alpine fir. Most stands
have not developed to the feather moss stage characteristic

of mixed coniferous forest west of Jasper Creek Bog, however.

165

In many places pine appears to lead in dominance and in

regeneration. Aspen is of low frequency in the vicinity of

the bog. This forest type appears on aerial photographs to

be almost continuous around the bog within a radius of at

least a half mile. In this respect it is noted that forest

fires appear to be much less frequent in the Atlin valley

south of Atlin than in the northern portion.

PALYNOLOGY

This section deals with (l) the deve10pment of a
palynological record for the Atlin valley, (2) the inter-
pretation of this record on the basis of the ecology of
individual Species and plant assemblages represented in it,
and (3) the preparation of a Holocene chronology of post-

gZLa-Qial botanical and climatic events.

X. PALYNOLOGICAL METHODS

30% sampling

The six bogs whose vegetation is discussed above were
Ba'511ljpled for a palynological study. These bogs were, in
fact, originally selected, not for their vegetation, but
for their potential palynological value. This potential
was estimated on the basis of the depth to which they could
be probed, their apparent major sediment types, and their
locations. ,

It was assumed that the deepest bogs generally have the
longest record and that these were to be chosen for sampling.
That this assumption is not always valid has since been
Show by the Mile 16 Bog core which, although the longest
(8- 2 m), is also the youngest, except for the Moose Bones

Beg Short core. Nevertheless, sediments near the bottom of

166

167

all the cores except for these two are believed to have been
laid down when the ice front was still near the respective
bogs. In general, glacial ice is thought to have been near
the site of the future bog when clays or other mineral sedi-
ments were being deposited (Fulton, 1965). Since clay and
silt or sand ordinarily are deposited at a relatively rapid
rate, at least during early stages of deglaciation, and
since pollen and spore preparations of this kind of material
are difficult, peats and marls were preferred.

With respect to location, the major consideration was
to sample several regularly spaced bogs whose interred pollen
assemblages would, it was hOped, collectively reflect the
general history of the Atlin valley vegetation.

In each bog, except Jasper Creek Bog, sampling was done
at the edge of the pond, where the deepest probes were made
(no probing or sampling was done in the ponds). In Jasper
Creek Bog the deepest part of the basin was some distance
away from the pond. The lowest sediments in the deepest
par-1; of a bog basin are presumed to date from the time of
“it Elation of basin filling (Potzger, 1956). Pest and some
marl samples were obtained with a Hiller sampler, and most
marl and all clay samples were taken with a Davis sampler.
Sn(“'Qessive barrelfuls were taken alternately from two holes
appz'i‘oximately one-half meter apart. Where sampling was done
in B“handing water, as in Mile l6 and Jasper Creek Bogs, the
water surface was used as a reference level. Otherwise a

Stick was laid on the surface next to the hole. At JasPer

168

Greek Bog a working platform was made of logs dragged in
from the forest.

Care was taken that the samples did not become con-
taminated. In removing samples from the Hiller, only mater-
ial from near the center of the barrel was taken in order to
avoid foreign material which had been carried down from
above, apparently lodged against the flange, and sc00ped
in ahead of the material of the sample level. This was
especially noticeable when marl was sampled with the Hiller.
The light-colored marl was seen to form a core in the center
0f the barrel with dark-colored peat surrounding it. Both
the Hiller and Davis samplers were rinsed in pond water each
time before pushing them down again. The Hiller samples
were put into plastic bags which were numbered with a felt-
tip pen. Plug samples from the Davis were wrapped in Saran
Wrap and aluminum foil. The level and general sediment type
or each sample was recorded in a field notebook.

After a complete core had been taken and there was some
kno"‘WILedge of the general bog stratigraphy, a decision was
made as to which levels it might be desirable to have radio-
carb On dated. These levels were then resampled, usually
sevel‘al times each in different, nearby holes until it
appeawed that enough material for dating was at hand.

There were a few variations in sampling procedure. In
MooaeiBones Bog the sedimentary material, a firm, fine-

gra‘ihed peat (see below), was too stiff to sample in the
usual way. Instead, a pit was dug and samples were obtained

169

from one wall. Samples could be taken only down to the one-
meter level because it was here that the rate of inseepage
of water caught up with the digging rate. In Wilson Creek
1303, the upper samples were taken from the side of a plug
cut from the sod with a shovel.

Surface samples consist either of mud sc00ped up near
the sampling site or of a clump of moss. The surface sample
from Jasper Creek Bog consists of the upper 25 cm of loose,

watery, moss material taken with the Hiller sampler.

Px‘eparation of samples

Most of the samples prepared and counted were selected
at 15.24 cm (six inch) intervals, each sample being four to
five cm thick. The laboratory procedure for macerating and
Preparing them for counting included deflocculation with
Potassium hydroxide, sieving to remove larger particles,
8c’l‘laflsion of carbonates with hydrochloric acid and of sili-
cates with hydrofluoric acid, and acetolysis. Residues were
8133'31-11ed with Safranin-O and placed in one-dram vials in a
three to one mixture of water and hydroxyethyl cellulose
(REC ). Slides were made using Harleco Synthetic Resin (HSR)
as e. mounting medium. A complete maceration and slide-
malting schedule is included as Appendix D. This schedule
was Varied according to the nature of the samples. For
example, either the hydrochloric acid or the hydrofluoric
acid step or both were eliminated for samples lacking car ‘
b0“ates, silicates, or both.

170

Samples of glacial clays, occupying the lower portions
Of Mile ’47, Mile 52, and Jasper Creek Bogs, were rather
difficult to prepare, even though several different pro-
cedures and variations of them were tried. In every case a
black, colloidal precipitate formed after treatment with
hydrofluoric acid. It was not possible to make adequate
Preparations of clay samples without using this reagent,
even with heavy liquid flotation techniques (e.g. Frey, 1951).
It is possible that the clay accumulated relatively fast,
When the ice front was still near by, and that only a short
tZLIne period is represented by them. If this is true, they
may not be particularly important to the overall record of
POBtglacial environments, except to indicate some of the
Fla-tits involved in invading the recently deglaciated terrain.
Terasmae (personal communication 1969) told of similar diffi-
cult 1es with samples from various other places in Canada.

After deflocculation and sieving, but prior to treatment
with hydrofluoric acid, most of the residues were inspected
for volcanic ash shards using wet, temporary microscope slide
mounts. None were found, although, as Hansen (1953) and
Aitlien (1959) indicate, there is good reason to expect at
least two different volcanic ash layers in Holocene bog sedi-
ments in the Atlin area. It is possible that the ash layers,
if M, occur at levels between those from which samples were
Belefizzt'ed. However, the major pollen profiles and the stra-
tigraphy of the Atlin valley bogs are similar enough that

t
hey can, in conjunction with the radiocarbon dates, be

17].

rather closely correlated without knowing the levels in them
of volcanic ash horizons.

In addition to the bog samples, pollen preparations of
a number of modern species were made for reference purposes.
The procedure used was devised by N. G. Miller (1969), and
APpendix E comprises a list of the Atlin valley species so
Prepared. Slides of each of these have been deposited in the
Pollen and spore reference collection of the Departments of
Geology and of Botany and Plant Pathology at Michigan State
University. All other bog sample residues and microscope
slides are also filed there.

Pollen and spore counts

Counts were made with the use of an E. Leitz Wetzlar
microscope and a Lab-Count - Denominator counter. Some
Photography for reference purposes was done with a Leitz
orthomat automatic camera.

Slides were traversed at-250 power and all pollen and
spol‘es except moss and fungus spores were counted. The tra-
verses were adjacent and were continued, beginning across
the middle of the slide, until the desired total was reached.
If an entity or a recognizable fragment of one did not extend
One‘I'ialf way or more into the field of view, it was not
counted. Magnifications of 400 and 950 power were used for
deta«filled examination of entities. Identifications were made
with the aid of published photographs and descriptions and

t
he reference collections of Michigan State University and

172

of N. G. Miller, as well as the writer's own reference
collections.

Early counts, involving the Mile #7 Bog samples and
Part of the Jasper Creek Bog samples, were made until totals
were obtained of not less than 200 entities of the non-
aquatic bog and extra-bog types (NEB). Counts of aquatic
and semi-aquatic bog types (ASB) were additional to these
30 that total counts ranged from just over 200 to over 1400
in a. few cases. Later it was decided, primarily on an
intuitive basis, that higher counts should be made to provide
for a more substantial base for percentage calculations. The
minimum total for non-aquatic bog and extra-bog types was
r8-:Lsed to 300, but usually from 325 to 350 were counted,
depending on the quality of the preparation. Total counts
ranged up to 907 (at the 300-305 cm level in Wilson Creek
B08) , and most were over l+00, with many over 500. In con-
tra-8t, counts of clay samples were necessarily low, usually
less than 100. In a few cases total counts were from four
to ten.

All together 154 samples from five bogs were counted.
3311-19188 from Mile 52 Bog were not counted, although a few
Ba‘In-IE>les at critical levels were examined in conjunction with

intezrpreting the Mile ’4? Bog section.

XI. POLLEN AND SPORE DIAGRAMS

C
onstruction of the diagrams

Pollen and spore diagrams for the five bogs are included

173

as Figures 21 through 25. Each diagram is a composite of
adjacent graphs of percentages of each pollen and spore
type plotted against depth. The graph for a type is called
its profile. Recurring percentage scales, one for each
PrOfile, are placed along the bottom of the diagrams, and
depth scales are positioned along the vertical margins.
Ra-<i:!.ocarbon dates (see below) are placed, at the appropriate
levels, at the far left, with extrapolated dates in paren-
theses. A column showing sediment type is also included.

The entities appearing on the diagrams are arranged in
Several different groups. The two fundamental groups are
agit—latic and semi-aquatic bog (ASB) types and non-aquatic and
e3‘=".:.‘z‘a-bog (NEB) types. The former include pollen and spores
or plants which ordinarily are submerged or emergent in the
beg pond or in shallower water near it or are otherwise
dependent on wet conditions for at least part of the growing
Sea-Son. In the bogs, as discussed above, these plants are
fo'u-rld primarily in the ponds, the sedge-moss zones and, in
Mile 1+7 Bog, the bulrush zone. NEB types include pollen and
813°:l‘es of plants which ordinarily grow in the less wet zones
or the bog and in upland areas. These include shrub and bog
Spruce zones as well as all forest vegetation.

ASB and NEB types are distinguished because it is be-
lie"‘ed that the abundance and the physiological condition of
plants, both of which affect pollen and spore production, vary
indetpendently‘between the two groups. For example, a period
or dry years could bring about a lowering of the bog water

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174

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179

table and cause poor growing conditions in the sedge-moss and
aquatic zones. Simultaneous vegetation changes in upland
areas would probably not occur in a way, or at a rate, that
would balance the decrease in pollen and spores deriving
from the bog zones, although it is known that pollen pro-
duction by forest species varies greatly from.year to year,
depending on climatic conditions and individual species'
physiological characteristics (Faegri and Iversen, l96#).
Conversely, a major forest fire could cause pollen produc-
tion by upland vegetation to be much lower than usual for

a period of several decades, whereas the vegetation of the
wetter bog zones might be little affected during the same
period. Mbst importantly, the bog vegetation is only a
local feature of limited areal extent and, because of prox-
imity to the deposition site, is overrepresented in terms

of its importance in the regional vegetation. For purposes
of past climatic determinations, overall regional vegetation
conditions are considered more significant, and the distinc—
tion must be made for this reason.

It could be argued that Salix spp. should be placed in
the A83, rather than the NEB group. Willows are relatively
poor pollen producers (Colinvaux, l96u), and are generally
non-anemophilous. Therefore it is likely that most of the
willow pollen found was contributed by plants growing in the
vicinity of the deposition site, i.e. in the shrub zone of
the bog. However, a certain amount of willow pollen may be

blown about by the wind (J. H. Beaman, personal oral

180

communication 1969). This leaves Open the possibility that
some of the willow pollen in bog samples may have been de-
rived from the larger tree willows in surrounding forests

as well as from stands of depression shrub vegetation in
neighboring places. This, coupled with the fact that willows
in the bogs, and also bog birch, usually occupy the drier
zones and appear, therefore, to be more closely related to
the upland vegetation seems to justify placing them in the
NEB category. As a group willows are of greater regional
importance than are plants of the ASB type.

Percentages for NEB types are calculated on the basis
of totals for this group alone so that they will not be
affected by fluctuations in the numbers of ASB types. Per-
centages for ASB types are based on total pollen and spore
counts. Counts of colonies and fragments of colonies of

Pediastrum.spp., which are extremely variable, were kept

 

separate from total pollen and spore counts. In order to
show its-abundance relative to the other entities, ratios

of Pediastrum.spp. counts to total counts are plotted in a

 

column on theright side of each diagram.

Description of the diagrams

The pollen and spore diagrams can be divided into three
zones on the basis of major changes, at two key levels, in
the shapes of the profiles of the major pollen types. Radio-
carbon dating shows that the boundaries between these zones

are not, in most cases, contemporaneous from one bog to

181

another. Nevertheless, the zonation is useful as a basis
for description and discussion at this point.

Shrub zone. The lowest zone is characterized by high

 

percentages of alder and birch pollen and relatively high
percentages of willow, grass, Artemisia spp., and Compositae
(Fig. 23, 2a, and 25). Very low frequencies of tree pollen
occur in this zone. Shrub pollen makes up the largest per-
centage of the total throughout the zone, and it is more
abundant here than at any other level. Herb pollen, too,

is highest in this zone. Other notable features are highs
for Shepherdia sp., Unknown type A, and Egygg sp., with a
rather remarkable high for m in the lowest samples from
Mile #7 Bog. A number of spruce grains were counted in the
lowest two samples from Wilson Creek Bog, and an isolated
spruce peak occurs atabout the middle of the zone in Jasper
Creek Bog. A few pine grains were seen in samples from this
zone. Because of the prevalence of alder, birch, and willow
pollen, this zone is designated the shrub zone.

Among aquatic and semi-aquatic bog types in the shrub
zone Isoétes-type spores appear early and reach their highest
percentages here. Cyperaceous pollen is moderately high in
the lowest samples, drops off in the middle of the zone, and
regains its status in the upper portion. In Mile #7 Bog a
major peak for Typha sp. occurs in the upper part of the
shrub zone.

. In Mile #7, Jasper Creek, and Wilson Creek Bogs the
shrub zone begins at the bottom.and extends upward through

182

the blue-gray clay sediments to from one-half to three-fourths
of a meter into the overlying marl. Only low total counts
of pollen and spores could be obtained from the clay samples.
For this reason the statistical basis of the diagrams at
these levels is not good. Nevertheless, the occurrence of
such non-anemophilous grains as Caryophyllaceae, Cruciferae,
and a number of undifferentiated dicots, along with the
occurrence of high percentages of shrubs, indicates that
these sediments were receptive to pollen deposition. It is
believed that these assemblages provide an indication of the
basic nature of the contemporaneous vegetation which is not
too much less credible than indications from higher pollen
counts. It should also be noted that there do not appear
to be any profile changes across the clay-marl transition
which are any more irregular than some other changes between
adjacent samples within a single sediment type. This, too,
indicates that the percentages calculated on the basis of
low counts in clay samples can reasonably be compared with
those based on higher counts in samples from marl and peat.
In spite of the length of the Mile l6 Bog core, it pro-
bably does not reach even the upper part of the shrub zone.
The pollen assemblages in the bottommost samples correspond
with those in the lower part of the next zone above, i.e.,
the spruce zone.

Spruce zone. This zone begins with a rapid rise of

 

spruce pollen percentages. These remain high throughout the

zone, in excess of 80 percent at some levels, and are considered

183
be most characteristic of it. The pollen percentages of
2 three major shrubs, willow, alder, and birch, decrease
levels which are, in most cases, intermediate between
>se of the shrub zone and the overlying pine zone.

tmineae pollen remains approximately the same percentage

in the shrub zone, but Artemisia spp. and Compositae drOp

 

?. Total herb pollen decreases to a lower level in the
ruce zone but is still present in significant quantities, J
2raging about ten percent.

The Mile l6 Bog core appears to begin in the lower part
the spruce zone. This is indicated by the fact that the
ruce profile appears to be undergoing its initial rise in
2 lowest approximately one meter of the core. Furthermore,

2 overlying zone, which is well defined in all five bogs
a marked decrease of spruce and increase of pine pollen,
approximately twice as thick in Mile l6 Bog as in the other
.r bogs. This indicates that the rate of peat accumulation
approximately twice as fast. The sediments in the spruce
e of Mile l6 Bog are primarily peat. Hence, assuming the
her rate here too, this zone should be about twice as
{ck as in the other bogs. In Mile #7 Bog the spruce zone
tabout 1.75 meters thick, in Jasper Creek Bog about 2.25
cars, and in Wilson Creek Bog it is thicker yet. If the
lace zone in Mile l6 Bog does in fact begin below the bottom
‘the section, at well over eight meters in depth, then it
at over six meters in thickness, more than twice as thick

Iln the other bogs studied. This apparent inconsistency

 

18#

can be explained by the fact that the peat, occuring through
most of the Mile 16 Bog section, has mixed with it at several
levels sand and silt in various proportions (Fig. 22). The
admixture of this material increases the thickness of the

zone over what it would be if the only sediment were peat.
Furthermore, the spruce zone sediments of Mile #7 and Jasper f

Creek Bogs are mostly marl, which has a slower accumulation
In Wilson Creek Bog the zone contains marl 3.4--

rate than peat .
The spruce zone

only near the bottom, the rest being peat.
here, consequently, is thicker than in Mile #7 and Jasper

Creek Bogs, more nearly approaching one-half the thickness

of the spruce zone in Mile l6 Bog.
Although the spruce zone is readily defined by changes

in the profiles of the major non-aquatic bog and extra-bog

tyres, its boundaries are also marked by changes in profiles
or certain semi-aquatic and aquatic types. Isoétes-type,

which occurs in substantial percentages in the shrub zone,
dr ops off across the shrub/spruce zone boundary and maintains

10", although consistent percentages, usually less than two

DeI‘oent, upwards in the cores.
The Cyperaceae profiles in the spruce zone are somewhat

erratic from section to section, but there appears to be a
getleral pattern in Mile #7, Jasper Creek, and Wilson Creek
39%8. A peak is reached somewhere around the shrub/spruce
the boundary. Then the percentages decrease to consistently
LQ‘V levels, as in Jasper Creek Bog, or to variable but, on
thg average, intermediate levels through the major portion

 

185

of the spruce zone in Mile #7 and Wilson Creek Bogs. Near

the top of the zone there is another increase in Cyperaceae

percentages in all three bogs. In Mile l6 Bog the Cyper-

aceae profile rises gradually in the lower portion of the

spruce zone and then stays at consistently high levels

through the major portion of the zone.
The Pediastrum spp./total count ratio also helps to

characterize the spruce zone. After sporadic occurrences

of Pediastrum colonies in the shrub zone, the ratio begins

 

to rise in the upper part of this zone and, in all but the

Wilson Creek Bog profile, maintains intermediate to high

levels throughout the spruce zone. Near the top of this zone

it again drops off, except in the Mile 16‘ Bog section where

it occurs in moderate numbers well into the overlying zone.

Pine zone. The third and uppermost zone is characterized

by a major increase in pine pollen and a corresponding de-

c31!‘ee.se in percentages of spruce pollen. Fir grains, appear-

ing occasionally in the spruce zone, make a substantial
a'3plDt-.arance across the spruce/pine zone boundary, especially

in Wilson Creek Bog where a peak of 9.5 percent is reached

at the boundary level. This is fairly high for fir, which

ordinarily is poorly represented in pollen assemblages
(F‘Qegri and Iversen, l96#; see below). Fir retains its

Ste-‘I:.us through most of the pine zone in all sections, drop-
Pit-1g off near the surface. Willow, alder, and birch profiles

(1
eQI-ease noticeably upon entering the pine zone except in
‘le #7 Bog where willow increases. Herbaceous pollen is

186

quite low in the pine zone, dropping to zero in some samples.

Here, too, the Mile #7 Bog diagram shows an exception with
The pine zone

an increase of herb pollen in the pine zone.
in Moose Bones Bog contains grass pollen in higher quantities

than in the other bogs. Unfortunately, because of the short-
ness of the core from this bog, the relative status of the

grass, as well as other types, cannot be assessed with

respect to their profile appearances in the other two zones.
The extent to which decreases in percentages of various

pollen types in the pine zone are only apparent and due to
suppression by the considerable increase of pine pollen

itself, rather than being real and due to actual decreases

of those elements of the vegetation which produced them, is
a. problem which is difficult to evaluate. Some indication

of the extent to which pine pollen does influence the other
Here the

Percentages is seen in the Mile #7 Bog diagram.
As

Pine increase is not as great as in the other bogs.
n<-7“1:ed abOVe, willow and herb pollen percentages are actually

higher than in the underlying spruce zone, rather than lower
These higher percentages are probably

as in the other bogs.
due _, at least in part, to the relatively low pine percentages.

”he :I:-e pine does reach higher percentages at the very top of
its profile in Mile #7 Bog, willow and herb, as well as alder

IQ birch pollen percentages drop.
Other notable features of the pine zone include the

o
QQ‘l-Irrence of a few Ts_u_ga sp. grains in Mile #7 and Wilson
b
Q'ek Bogs. Also, the only significant occurrence of Populus

187
spp. pollen in any of the sections is in the pine zone of

Mile #7 Bog.
The scarcity of Populus pollen in the bog sediments is

probably due to its low preservability, especially in an

alkaline environment, rather than to a low frequency of
This

aspen and balsam poplar in the surrounding vegetation.

situation has been noted by many palynologists, and the
problem was dealt with experimentally by Sangster and Dale

(.1961, l96#). Populus tremuloides pollen was shown to

deteriorate rapidly in various environments, with faster

rates under conditions of higher pH.
Profiles of semi-aquatic and aquatic types in the

Spruce zone show little similarity from bog to bog. Tri-

glochin-Potamogeton—type reaches a major peak of 3# percent
In the other

in the upper part of the zone in Mile #7 Bog.
The per-

bogs it is of rare occurrence at these levels.

c-‘-erl:rtages of Cyperaceae are fairly consistent and average
In Mile

around 20 percent in Moose Bones and Mile 16 Bogs.
47 Bog, Cyperaceae is abundant in the lower layers but

becomes much less so rather abruptly near the surface. A

similar situation is seen in the Jasper Creek Bog profile,
Cyper-

although the decrease occurs earlier in the section.

aceee pollen in Wilson Creek Bog averages around 20 percent,
Pediastrum spp.

but the profile undergoes major fluctuations.
o
ohtinues to occur in moderate numbers in the pine zones of
3933 Bones and Mile l6 Bogs. In the'lowest sample of the

Igae Bones Bog core it was, in fact, much more abundant

188
than all other pollen and spores. This condition was found

in only one other place, the 1.5 to 2 meter level in the

spruce zone of the Mile l6 Bog core. Almost no Pediastrum

colonies were observed in pine zone samples from the three

other bogs .

XII. RADIOCARBON DATING

Seven radiocarbon dates are available to use in estab-

lishing a Holocene chronology for the Atlin valley. Three

samples from Mile #7 Bog, two from Mile l6 Bog, and one each

from Jasper Creek and Wilson Creek Bogs have been dated. In

this section, background information on the dated samples is

Presented, and the dates and certain aspects of their

8ignificance are discussed.
First it is to be noted that there are typically three

mad or sediment types which have been involved in the formation

or the Atlin valley bogs. These are stiff, blue-gray glacial

clay in the bottom portions, marl at intermediate levels,

and sedge-moss peat in the upper parts. Within each of these

tyIDes there is little variation, and the boundaries between

their: are distinct, with little intergrading in most cases.
11 additional type, glacial drift, may occur below these. It

was not possible to tell, with the Davis sampler, the exact

n .
a"‘31—‘az‘e of the underlying, coarser sediments, although they
a.
13Deared to be a stiffer clay, ordinarily with a few sand
I.
3 Q1118 and pebbles. In Mile l6 Bog sampling was stopped at

a.
thick sand layer.

~

189

It is to be noted that there is no correlation between

the boundaries of these three sediment types and the boundaries
<>f the three pollen assemblage zones discussed above. This is

to be expected since changes in sediment type are a function
of hydrarch succession whereas vegetational changes on the

surrounding uplands, and therefore pollen rain, are presumed

to be related to a clisere. Although it is likely that the

climatic and physiographic agents controlling the clisere

have influenced the bogs too, there is no apparent reason

for a direct relationship between bog stratigraphy and forest

d evelopment .
This fundamental clay-marl-peat sequence was recognized

early in bog sampling and it was decided that appropriate

levels for radiocarbon samples would be the boundaries be-

tween these types. Consequently two of the dates are for

the bottommost peat in Mile #7 (Figure 23) and Mile 52 Bogs.

'I'l'le respective levels and dates are l#0 cm: 3,200 1' 160 years
B- P. and 182.5 cm: #,l60 I 180 years B.P. With these data,

Peat accumulation rates could be calculated, and for each

bog a rate of 0.0## cm per year, or #.# cm per 100 years, was

obtained. Although these two bogs are only five miles apart

and their developmental histories have probably been similar,
they. do occupy different local drainage areas, they are of
air rerent sizes, there are notable differences between them
in their extant vegetation, and their peat layers are approxi-
that ely #2.5 cm different in thickness. In view of these dis-
all“illarities, the identical peat accumulation rates in these

¥

190

two bogs suggest that rates may have been similar in other

bOgs in the Atlin valley. Thus, by applying the 0.0## cm

Iaer year rate, the 155 cm level in Jasper Creek Bog is dated

at 3,690 years B.P. This, and other extrapolated dates,

appear on Figures 21 through 25 in parentheses.
A date for the bottom of the Moose Bones Bog core was

not determinable in this manner because the peat here is of

a different nature. Since standing water in the bog is con-

fined almost entirely to the pond for most of the year, dead
organic material, up to the pond's edge, is eXposed more or
less directly to the atmosphere and is therefore more highly

The peat, including that nearest the surface, is

<>Jcidized.
In addition, living vegeta-

fine grained and dark in color.
tion in and near the pond, i.e., in the area of organic accumu-

lation, is not as abundant as in the other bogs, consisting

 

almost entirely of Carex sp. (cf. aquatilis) with little moss.
If this has also been the case in the past, then it is to be
expected that a unit of vertical distance in the core here is

et111:].valent , timewise, to somewhat more than one unit in the

0tI’ler cores. Correlations with the other pollen and spore

profiles supports this and shows, in fact, that organic build-
up takes place at about half the rate in other bogs. It is
be:L3.eved, furthermore, that such correlations, particularly
with the Mile l6 Bog diagram, allow the assigning of meaningful
ages to key levels in the Moose Bones Bog section. Thus , the
spbuce/pine zone boundary, at the 75 cm level, is dated at

3" 900 years B.P., and the bottom of the section, 5,200 years

B-b-

¥

191

In Mile 16 Bog, radiocarbon dates are 2,560 i 140 years
B.P. for a sample covering the 140-163 cm depth range and
6,700 i 300 years B.P. for a sample between the 625-648 cm
levels. The midpoints of the positions in the section of
these samples, 150 and 635 cm, respectively, are used for
calculation purposes, the same also being done for the other
dated sections. On this basis, an average sediment accumu-
lation rate of 0.1171 cm/yr is calcualted for the portion of
the section lying between the two dated levels. Thus the
spruce/pine zone boundary, at 225 cm, is dated at 3,920
years. The extrapolated date for the bottom of the section
is 8,323 years B.P. Taking into account the higher propor-
tion of inorganic sediments in the bottom approximately
75 cm, which probably accumulated at a faster rate than the
organic material, this estimate may be somewhat high. It
seems reasonable to reduce this age estimate to 8,000 years
B.P.

It can be seen that the sediment accumulation rate in
'the Mile l6 Bog section has been at least three times that
in Mbose Bones Bog and well over twice as fast as in the
three southern bogs where, as will be shown, peat accumulation
rates are nearly equal. The sand and silt dilution factor,
mentioned on page 18#, may be at least partially responsible
for this higher rate. The source of such material is obvious
in that this bog, unlike the others, is small, deep and sur-
rounded on three sides by steep, sandy slopes. Figure 22,

in the sediment type column, shows that the proportion of

192

sand and silt is variable. It is suggested that this vari-
ability is related, in part, to the history of forest fires
on these slopes. Severe fires can eXpose the mineral soil
and leave it vulnerable to sheet erosion. Such a situation
exists at present, and vegetation survey data for the 16W
stand (Table 8) show this. Shrubs, herbs, and mosses, along
with live trees, are, in total, of fairly low C-A value.
Soil-holding plants such as Arctostaphylos uva-ursi, Linnaea
borealis, and bryophytes are only now becoming reestablished,
and there is a large amount of bare ground. The influence of
fires on erosion and deposition in the Mile l6 Bog basin
might be coupled, furthermore, with variations in rainfall.
Although the average annual precipitation at Atlin is only
11.3 inches (Table 1), a maximum.of 19 inches was recorded
in 1938 (Canada Department of Transport - Meteorological
Branch, unpublished data). It is likely, on the basis of
the writer's experience, that most of this additional pre-
cipitation came in the form.of heavy and prolonged rains
late in the summer. Such an occurrence, coming within a few
years after a major fire, could wash excess mineral material
into the bog. The sandy layers at 1.9 and 2.h meters, for
example, may be due to such a combination of conditions.
Dates for both organic and inorganic fractions of a marl
sample between 325 and 3fl8 cm.in Mile #7 Bog have been 0b-
tained and are, respectively, 8,600 i 330 and 8,670 i 900
years B.P. Using the difference, 5,h00 years, between the

former date and the date at the base of the peat as the

193

length of time required for the marl to accumulate, along
with the thickness of the marl, 196 cm, an accumulation rate
of 0.036 cm per year, or 3.63 cm per 100 years was calculated.

In Mile 52 Bog, the first marly sediments appear at the
480 cm level. The marl accumulation rate cannot be applied
to date this level, however, because clay, in varying pro-
portions, continues as a major admixture up to 358 cm. From
here up to the peat, at 183 cm, the nature of the marl
appears quite similar to that of Mile 47 Bog. Applying the
rate to the 358 cm level, therefore, gives an extrapolated
date of 9,038 years B.P. It appears that marl deposition
began considerably more than 400 years earlier in Mile 52
Bog than in Mile 4? Bog.

In Wilson Creek Bog a radiocarbon date of 8,000 I 350
years B.P. was obtained for a sample centering on the 335
cm.level, at the base of the peat (Fig. 25). With these data,
a peat accumulation rate of 0.042 cm/yr was calculated, a
rate very close to the 0.044 cm/yr obtained for both Mile 47
and Mile 52 Bogs.

By using the marl accumulation rate of 0.036 cm/yr
calculated for the Mile 47 Bog section, it is possible to
extrapolate down from the dated level in Wilson Creek Bog
to an age of 10,200 years B.P. for the bottommost marl a few
on up from the bottom of the section.

.A tentative chronology may be applied to the Jasper
Creek Bog diagram (Fig. 24) by correlations with the Wilson
Creek Bog diagram. In the latter, the shrub/spruce zone

194

boundary is estimated, by extrapolation from the dated level,
to be 8,860 years. It is believed that this date can rea-
sonably be applied to the corresponding level in Jasper Creek
Bog diagram.because the two bogs are only a few miles apart
and the major vegetational changes represented by this zonal
boundary probably were contemporaneous around each bog. By
doing this, and then extrapolating down to the base of the
marl in Jasper Creek Bog, an age estimate of 11,050 years is

obtained.

XIII. COMPARISONS OF SURFACE POLLEN ASSEMBLAGES
WITH VEGETATION

In this section an attempt is made to determine the
extent to which surface pollen assemblages from the bogs
reflect the nature of the general Atlin valley vegetation
and local vegetation in the vicinity of each bog. Compari-
sons of pollen percentages with basal area percentages and
with qualitative assessments of vegetation composition,
particularly as discussed in the section on bog vegetation,
are involved. The discussion deals largely with the four
imain tree species, white spruce, lodgep01e pine, alpine fir,
and aspen, because these are the predominant components of
the Atlin valley vegetation. Three of these produce a large
Share of the airborne‘pollen. For purposes of this type of
81budy, basal area is considered an appropriate measure of
time prevalence of a tree species in terms of pollen produc-

tion (Hansen, 1949a; Davis and Goodlett, 1960).

195

Regional comparisons

That regional vegetation, i.e., vegetation within at
least several tens of miles of the deposition site, deter-
mines the composition of a pollen assemblage is shown by
studies of Carroll (1943), Hansen (1949a), Davis and Goodlett
(1960), and Terasmae and Mbtt (1964, 1965). Major factors
involved are characteristics of pollen grains which make it
possible for them to be carried considerable distances by
the wind, the mixing of pollen types in the atmosphere,
especially in mountainous areas where there is turbulence,
and the location of deposition sites in open areas away
from the edge of the forest. Ritchie and Lichti-Federovich
(1963) and Lichti-Federovich and Ritchie (1965) analyze
pollen rain-vegetation relationships from the standpoint of
landformrvegetation regions and show that the latter may be
recognized through characteristic pollen assemblages.
Terasmae and Mott (1964, 1965) show that the basic vegetation
type of the area from which a pollen sample was obtained can
be distinguished, in the pollen spectrum, from the total,
regional pollen rain produced by several major vegetation
types. The effects of long distance dispersal, particularly
with regard to the introduction of exotic types, are shown
by these authors and by Ritchie and LichtiLFederovich (1966),
JBartley (1967), and Terasmae (1967).

The major concern at present is to establish a reliable
,measure of the total Atlin valley vegetation in terms of the

Surface pollen samples, with the hope that this measure will

196

make it possible to develOp reasonable ideas, by studying
fossil pollen assemblages, as to what the total vegetation
has been like at different times in the past. It is be-
lieved that the effects of climate and climatic changes can
only be interpreted from vegetation at the regional level,
where the continuously varying local edaphic and historical
factors, producing what is in reality a mosaic of vegetation
types across the landscape, are smoothed out and the vege-
tation is looked upon as a composite, climatically respon-
sive (i.e. climactic) whole. The studies cited above, and
others, indicate that a reasonable correlation between sur-
face pollen assemblages from the six Atlin valley bogs and
the regional vegetation in the valley can be established
with the data at hand. In addition, the possibility of
local correlations, i.e. with vegetation within a few miles
of the bogs, can be explored. Although a major local in-
fluence is exerted by plants of the ASB group, it is seen
that some differences in surface assemblages from.bog to
bog can be attributed to peculiarities of the local upland
vegetation too. 4

Figure 26 shows the pollen and spore spectra for the
81x bog surface samples. Table 22 compares the average
Pollen percentages for the four major tree species in each
sample with the percent of total basal area for the species.
Time pollen percentages do not total 100 because they are
CELlculated on the basis of total NEB types. R values (Davis,
19N53) are given in the right hand column. Although the

197

meaningfulness of these is dependent on several factors, as
Davis (1963) and Lichti-Federovich and Ritchie (1965) point
out, they are considered useful here in giving a general
impression of the degree of representation of the present
species on a regional scale. The R values show that spruce,
at 0.43, is somewhat over twice as prevalent in the vegetation
as its pollen percentage indicates, and pine, with a value of
2.3, less than half. Both fir and Pepulus spp. are very
underrepresented. 0n the basis of discussion in the section
on vegetation, it can be concluded that fir may be much more
prevalent than its pollen record would indicate. This is
especially so at Jasper Creek Bog where the fir pollen per-
centage is less than two, but the tree is abundant in the
adjacent mixed coniferous forest west of the bog. In addi-
tion, it occurs in pure stands approximately one mile to the
north (Table 18 and Fig. 27). With regard to aspen, the
pollen record, to the extent that it has been developed
here, permits no conclusions regarding its status in the
vegetation except, perhaps, in extreme local cases. In the
latter regard, Figure 28 shows a relatively high pollen per-
centage of about five in the Mile 47 Bog sample, along with
a significantly higher prevalence of aspen in the vegetation
‘rithin two miles to the north and south. The findings pre-
Esented here regarding representation of these four species
exampare with information given by Faegri and Iversen (1964),
DEIvis and Goodlett (1960), and MeAndrews (1966).

O

198

oN oaamaa

>u._._<> z_..:( 3: z. mQOm o Sow... mm4m§<m uvazm z. mwOS—Zwumua 5.0mm OZ< Zu...0a

o . . . c . I =
. . i . . . _ .

000 xwmmo ZOW£>>
00m xwwmo mwawi.
00m mm mi}
00m nv w._=2
00m 9 mi}
00m wszm meOI

 

wwa>k 00m OC<DO<
n.2ww OZ< U_h<DO<

199

Table 22. Basal areas and pollen representation of the
four major tree species in the Atlin valley.

 

 

 

Pollen %
mean of Total B.A. %

Species samples) (in2) Total B.A. R
Picea glauca 23.8 81,952 55-5 0.43
Iflnus contorta 58.3 37,067 25.2 2.3
.Abies lasiocarpa 0.3 3,202 2.2 0.14
JPOEulus Bpp. 1.0 25,182 17.1 0.058

83.4 147,403 100.0

 

 

200

Figure 27. Basal area distribution of the four main
tree species along the Atlin road.

Total basal area in square inches at each site is plotted
against site position along the first six miles of the west-
southwest-east-northeast trending Carcross road and the north-
south trending Atlin road. The two roads intersect at mile
one. Sites are at every milepost, except south of Atlin
where they are at two-mile intervals.

The locations of five of the six bogs discussed in the
text are shown. The tree survey was not extended as far as
Wilson Creek Bog.

201

 

2!:>

     

WHITE SPRUCE

+ + + + 4»
Al PINE FIR

 

17 T ‘1' I I V V Ti ‘1

0 IOOO 2000 3000 4000
IIAN‘I Alt! l IIN' r

BASM ARLA msrmsunom or WHHL SPRU(L

lODGLPOLL PINE. ASPEN/POPLAR. AND ALPIN! HR
ALONG TH. (AM ROSS/ARIN ROAD IRANSH I

Figure 27

202

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

PINE‘
SPRUCE-
EL s1 a
T
i
FIR+
._ . . . J
POPLARJ
.14. * all-Jill a.
12 34 345 345 345 34 3
m NOSE MILE 16 MILE 47 MILESZ JASPER WILSM
m5 BOG soc ”G CESEK CtchK

WC

 

 

WSONS N SlRFACE SAMPLE POLLEN PERCENTAGES WITH TREE BASAL

t MLEN PEKENTAGE. AVEmE G 5!! MG SLRFACE SAMPLES.
ON SIRVEV TOTAL. 3. POLLEN PERCENTAGE IN soc.

TO TWO MILES SOJTH 0F soc.

Figure 28

A. BASAL AREA PERCENTAGE.
s. BASAL AREA PERCENTAGE. mow soc TO FIVE MILES soum.
g/t = LESS mm TWO PERCENT.

MM '9"

I007.

AREA PERCENTAGES.

2. BASIL AKA PERCENTAGE BASED
TWO MILES NWT"

203

Local comparisons

Figure 28 shows that most of the entities vary consid-
erably from one bog to another, and it is because of this
that at least five cores from the valley are considered
necessary for developing a palynological record. An attempt
is made now to assess the individual spectra in relation to
local vegetation, using local basal area data and qualitative
observations, along with regional R values for comparison
(Figures 27 and 28; Table 22).

Figure 28 gives, as bars numbered "4", the basal area
percentages of the four major tree species for sites at a
distance of two miles and less north and south of the bogs.
In addition, the same type of data is presented, as bars
numbered "5", for tree survey sites located up to five miles
south of the bogs. The former data are taken as a sample
of local arboreal vegetation all around the bog. The latter
are given for comparison and for the purpose of testing the
hypothesis that the major influence on the pollen rain is
from.the south, due to prevailing winds from the south during
the flowering season (Figure 6). Because of the way the tree
survey was conducted, data of the number 4 type are not
available for Wilson Creek Bog, and number 5 type data are
:not available for this nor for Mbose Bones and JaSper Creek
IBogs.

Mbose Bones Bog. By comparing "3" in the Moose Bones
130g column of Figure 28 with "1" it can be seen that, for

izhe four trees, the pollen spectrum here more nearly resembles

204

the regional average than in any other bog. However, the
local vegetation relationships here also closely resemble

the regional situation, as can be seen by comparing "4" and
"2". Therefore it is difficult to make a distinction between
local and regional influences with these data.

It is suggested that M005e Bones Bog receives pollen
from a broader area than the other bogs because of its loca-
tion in the northwest end of the valley. Here, low, rela-
tively level terrain extends for a considerable distance
around the bog, particularly to the west, and winds blowing
north out of the Taku Arm and Tagish Lake areas, as well as
the Atlin valley, could bring pollen to the bog. If so,
the pollen rain here, originating from a larger and more
diverse area, would be more representative of the regional
vegetation than in the other bogs.

The two fir grains found in the Moose Bones Bog surface
sample could have blown north from higher elevations on
Jubilee Mountain. In general, the minor occurrences of fir
in bogs where no fir trees were found within several miles
around can be eXplained on the basis of this Species' pre-
valence at elevations above approximately 3,000 feet through-
out the valley.

(Salix and Betula percentages reflect the importance of
these genera in the shrub zone of the bog and in nearby
Places (Table 21).

The Alngg value, as in other bogs, is more difficult to

irlterpret in terms of its role in the vegetation. No alders

205

were found in any bog, and very few were found during the
general vegetation and tree surveys. General observations
in the Atlin valley indicate that alder is a pioneer on
abandoned rocky stream beds and flood plains. A major
occurrence of this kind is along lower Pine Creek about two
miles southeast of Atlin village. Sites of this nature are
not common at the present time, but it is recognized that
alder is ordinarily overrepresented in a pollen rain and
therefore of less importance than its pollen percentages
indicate (Faegri and Iversen, 1964). Furthermore, alder
habitat.was not specifically searched out during the field
work, and it may be more prevalent in local areas than is
realized.

The grass pollen percentage is notably higher in Meose
Bones Bog than in any other. This is explained by the

presence here of the Calamagrostis neglects, Deschampsia

 

 

caespitosa, and Poa palustris zones. At the other bogs

 

there are no grass zones of this type, and grasses are
ordinarily only scattered in the surrounding upland vege-
tation. Hansen (1953) notes the scarcity of grass pollen
in bogs along the Alaska Highway.

Only two CaryOphyllaceae grains were counted, in spite

 

 

of the abundance of Stellaria sp. in the Calamagrostis
neglects zone.
Cyperaceae pollen is abundant in the Moose Bones Bog

sample, a reflection of the Carex sp. (cf. aquatilis) zone.

 

Similar relationships are seen elsewhere, except at Mile 47

206

and Wilson Creek Bogs where, although there are sedge-moss
zones, these are less extensive, and Carex spp. are rela-
tively less important than mosses, Juncus spp., and Luzula
spp. ‘

Mile 16 Bog. Pine and spruce pollen percentages in the

 

surface sample from this bog are similar to the regional
averages, but fir and aspen grains were not found (Figure 28).

Spruce is uncommon in the vicinity of the bog, with
pine nearly the exclusive arboreal species. However, spruce
pollen is about 16 percent, and pine pollen, at 60 percent,
is not as prevalent as might be expected from basal area
data. Alder and birch pollen are as important here as in
any of the surface samples (Figure 26), even though neither
of these were seen in the bog nor on the sandy slopes around
the bog. '

In view of the fact that Mile 16 Bog is small in area
and was, before the 1958 fire, nearly surrounded by pine
forest, it could be expected that the sample consist of al-
most no grains besides pine, except for those produced by
plants in the bog. This view is based on a model of pollen
dispersal presented by Tauber (1967). Because pine pollen
is not exclusive here, it is assumed that the material of
the surface sample, a clump of mostly living Drepanocladus
aduncus moss, accumulated subsequent to the 1958 fire. The
fire, of course, considerably reduced the pine pollen source,
although a few living, mature pines, in flower, were seen

near the bog when it was visited in 1968 (Fig. 14). The

207

reduction of pine pollen would have caused the percentages
of spruce, alder, and birch to be higher with no change in
their actual numbers. Alder and birch, however, probably
were deposited in greater quantities following the fire be-
cause of elimination of forest cover, possibly a barrier to
pollen diSpersal, between the bog and the Snafu Creek area
somewhat over one-tenth of a mile to the south. The pollen
and spore diagram for Mile l6 Bog (Figure 22) shows that
between 12 and 42 cm, the position in the column of the
second sample5, the pine percentage is higher, and spruce,
alder, and birch percentages are lower.

The finding of only three Salix grains reflects the
scarcity of willows in the bog. The few Juniperus, grass,

and Artemisia grains reflect the existence of a large area

 

of herb-heath vegetation (Table 15) on slopes above the bog

to the east. The two Epilobium grains, a unique occurrence

 

among the surface samples, may be attributed to the small
enclave of several living species at the northwest edge of
the bog. It is also possible that these grains were produced
by Epilobium angustifolium, the common fireweed, which is
widespread in the burned pine forest around Mile l6 Bog, but
less frequent in upland vegetation around other bogs. Cyper-
aceae pollen grains are most prevalent in the present sample,
a reflection of the importance 0f.§EEE§ aquatilis ssp.

aquatilis in the sedge zone.

 

The spruce situation at Mile 16 Bog tends to deny the
hypothesis that the major pollen source is south of the bog.

208

In part "5" of the Mile l6 Bog column of Figure 28, no basal
area percentage is shown for spruce within five miles south
of the bog. Instead, the spruce that does occur in the
vicinity of the bog is shown, by part "4", to be within two
miles to the north. Table 18 and Figure 27 show a prevalence
of spruce within several miles to the north of the bog and

its near absence up to nine miles south.

 

Mile 47 Bog. Figure 28 shows that pine is considerably
overrepresented here, that Spruce is moderately underrepre-
sented, and that aspen, as usual, is very underrepresented
in the pollen rain. The highest aspen count was, however,
obtained from this sample, and this may reflect the higher
abundance of the species in the vicinity, particularly north
of the bog. In the general vegetation survey (Table 18),
several mature, old growth aspen stands were encountered
at miles 42, 44, and 46.

Aspen is less important to the south than to the north,
and the general situation for this species tends to deny
the hypothesis thatthe major pollen source is in the area
south of the bog. It could be argued that the five percent
of aspen pollen was actually blown north to the bog from the
trees south of it, and that pollen produced by the aSpen
stands to the north is usually blown further in that direction.
It is to be noted, however, that at Mile 52 Bog five percent
more aspen, in terms of basal area, occur within five miles
to the south (Fig. 28), and only negligible aspen pollen

was encountered in the surface sample there. Differential

209

preservation between the two bogs could be invoked to ex-
plain this if it were not for the fact that the upper sedi-
ments and chemistry of each appear to be similar. In any
case, the actual number of aSpen pollen preserved is likely
to be a small fraction of the amount originally deposited.

The spruce situation at Mile 47 Bog lends support to
the hypothesis. This species is represented in the pollen
assemblage to a greater degree than in the other bogs. Figure
27 shows the preponderance of spruce up to seven miles south
of the bog and its low to intermediate importance up to ten
miles north.

A single Eagix grain was seen in the Mile 47 Bog surface
sample, probably the result of long distance transport. The
nearest occurrence 0f.EEEE§.t° the Atlin area is to the east
(Hultén, 1968), indicating that southerly winds during the
flowering season are not particularly important in pollen
dispersal. However, this is only one grain; the $5253 grain
encountered in the Wilson Creek Bog sample could well have
blown up from the Taku River area to the south.

The eight percent 0f.§El£§ in the Mile 47 Bog surface
sample, the second highest among the surface samples, may
reflect, in part, the bog's shrub zone. This zone is fairly
well deve10ped in some places, though not near the sample
site. The chief influence, however, may be the tree willow

forest adjacent to the bog on the northwest, as described

on page 153.

210

The Triglochin-Potamogeton-type pollen is significant
here, as well as in the Mile 52 Bog sample. _It is probable
that the pollen belongs mostly to Triglochin maritimum,

 

since Potamogeton was not observed in the Mile 47 Bog pond,

 

and Triglochin, as a calciphile, is common in both of these
bogs close to the sampling sites.

The low value for Cyperaceae pollen is not explainable
at this time. Although the sampling site is some distance
away from the sedge-moss zone, it lies adjacent to the bul-

rush (Scirpus validus) zone and the pollen rain would be

 

expected to have been influenced by this vegetation. No
evidence has been found in the literature that Cyperaceae
pollen does not preserve well in calcareous environments. In
the Mile 52 Bog surface sample, where chemical conditions
were similar, Cyperaceae pollen is of relatively high occur-
rence (Fig. 26). Finally, no evidence is at hand to indicate
that Scigpus pollen is less resistant to destruction than
that of §E£E§°

Mile 52 Bog. The spruce and pine pollen percentages

 

here are similar to those of Mile 47 Bog and reflect the
similarities in distribution of these two species around
the two bogs (Fig. 27, 28). Betula pollen reflects the

common occurrence of B. glandulosa in the bog. The several

 

grains from grasses and herbaceous dicots can be related to
vegetation in a local, nearly mesic microhabitat near the

edge of the pond on the east side.

211

Jasper Creek Bog. 0n the basis of pollen percentages
and tree survey data, pine and spruce are both somewhat more
highly represented here than on the regional average (Fig.
28). This is due to the presence of a forest comprising
large and mature pines around the eastern approximately one-
half of the bog and a mixed coniferous forest of mature
spruce, along with pine and alpine fir, around the western
half. These mature forests surrounding the bog have no
doubt contributed greater amounts of spruce and pine pollen
to the bog than would be expected from basal area data
alone. The latter were obtained at sites approximately one
mile north and south of the bog (Fig. 27).

It is mentioned above (p. 161) that alpine fir is an
important component of the mixed coniferous forest adjacent
to the bog on the west. Despite this, only two fir pollen
grains were encountered in the surface sample. An explana-
tion is suggested on grounds on screening of fir pollen by
a narrow zone consisting predominantly of spruce along the
west edge of the bog, possibly coupled with prevailing winds
blowing north-northwestward through the area in which the
bog is located. It is noted above that Spruce is more fre-
quent nearest the bog and that fir increases in proportion
to spruce and pine some distance away. These spruce are
mature, 40 to 50 feet tall, and closely spaced. There is
also a narrow shrub zone at the forest-bog transition. Even
if winds were from the west and down the slope upon which

this forest occurs, most of the pollen from within the

212

forest would be blocked by this barrier. With regard to fir
pollen lifted into the air above the forest, Tauber's (1967)
model of pollen dispersal indicates that relatively few of
the grains would be deposited at the sampling site in the
bog, which lies only about 100 feet from the forest edge. It
is likely, in any event, that most of this pollen is dis-
persed to the northwest by prevailing winds, rather than
eastward and into the bog.

Willows are common around the bog, although the shrub
zone is narrow, and more Salix pollen might be expected
(Fig. 26). 'Algus and Betula were not encountered in the
bog nor in upland vegetation for several miles around.

Agycopodium is common in the mixed coniferous forest, a pro—

 

bable source of the two microspores counted, and grasses
are scattered in the pine forest.

Wilson Creek Bog. Although no quantitative vegetation

 

observations were made within several miles of this bog,
general observations discussed on page 161 ff. provide a
basis for understanding the pollen rain here. Pine and
spruce both are important in the forest, but pine seems to
lead in dominance, and large trees were seen at the bog's
edge in several places. This preponderance of mature pines,
coupled with a high rate of pollen production and deposition
near the forest's edge (Buell, 1947), seems to account for
the high proportion of pine pollen relative to spruce.
Betula is scarcely represented in the pollen rain

despite its presence at places in the bog and surrounding

213

forest. Sedges also are underrepresented compared to their
importance in the bog vegetation.

S 5y. Taken together the surface sample pollen data
(Figure 26) provide an indication of the relative importance
of some of the dominant Species in the regional upland vege-
tation on the basis of the relationships developed above.

In addition, a few conclusions are possible, on the basis
of surface spectra, regarding the nature of the local vege-
tation, both within and around the bogs.

Lodgepole pine generally appears over twice as important
in the pollen rain as it actually is in the vegetation.
Spruce should be interpreted, from its relative importance
in the pollen spectra, to be approximately twice as preva-
lent in the regional vegetation. With regard to alpine fir,
the presence of one or a few grains may be taken to indicate
that the species is present, if not important, somewhere in
the general vicinity of the bog. Single grains of Tguga and
.EEEEE probably result from dispersal from distant regions.

Juniperus grains in the three northern bogs reflect the pre-

 

sence in this part of the valley of the upland, dry sites
bearing the herb-heath type of vegetation. Populus is so
poorly represented that nothing can be said of its vegeta-
tional status except, perhaps, in extreme cases, as at Mile
47 Bog, where it reaches four percent of the pollen total.
Tree willows of the forests in general are probably not
represented, although the relatively high Salix percentage
in Mile 47 Bog may reflect the presence of a nearby stand of

214

almost pure tree willow vegetation. Except for such occur-
rences as this, which would be difficult to distinguish in
fossil spectra (unless particular Species of willow pollen
can be recognized), the importance of willow shrubs in non-
aquatic parts of the bogs can be reasonably determined from
the percentages of willow pollen. (Alggg is considerably
overrepresented, and where its pollen is encountered in any
amount, the indication seems to be that the plant is impor-
tant as a pioneering shrub in local, relatively fresh, stream
deposits somewhere not more than a few miles from the bog.
Betula is also overrepresented, but not as much as alder.
In general, the presence of this pollen type may be taken to
indicate that shrub birch is common in and near the bog.
lgpopodium.microspores are found in bogs with mature,
old growth spruce or mixed coniferous forest nearby. Grass
is underrepresented, particularly in Moose Bones Bog where
several species occur near the deposition site and in Mile
l6 Bog where the herb-heath vegetation type occurs on the
slopes above the bog on the east. Fpilobium.pollen appeared

 

only in Mile l6 Bog where the spebies was prevalent near the
deposition site. Artemisia, appearing sparingly in the

 

surface samples of Moose Bones and Mile l6 Bogs, gives,
along with Juniperus, an indication of the nearby herb-
heath vegetation on dry slopes.

With regard to representation of ASB vegetation, 23$:
glochin-Potamogeton-type pollen indicates a high amount of

 

calcium carbonate in the sediments at the time of deposition.

215

A relatively high proportion of Cyperaceae pollen, i.e. 20
percent or more, seems to correlate with predominance of the

large sedge Carex aquatilis ssp. aquatilis in a standing

 

water environment, as at Meose Bones and Mile l6 Bogs.
Lesser quantities do not correlate as well with the status
of sedge species in the bog, although even a moderate per-
centage, i.e. 12 percent or so, may indicate an abundance
of sedge in a wet habitat, as at Jasper Creek Bog. The im-
portance of Scirpus validus in Mile 47 Bog was not, for some
unknown reason, reflected in the surface sample.

Pediastrum was not identified to Species, but since
nothing is known of the ecology of this alga in the Atlin
region anyway, no interpretation can be made now regarding
its appearance in the palynological record.

There is some evidence that pollen assemblages are
biased toward vegetation located within a few miles to the
south of the bogs due to prevailing southerly winds during
the flowering season. But there is just as much evidence to
refute this, wherein particular pollen percentages compare
better with the composition of the vegetation to the north.
It can be concluded, therefore, that a considerable amount
of atmospheric maxing of pollen occurs, probably because of
turbulence over the generally irregular topography and because
of the heterogeneity of the vegetation. This is an indica-
tion that the average pollen rain, as determined in the five

key bogs, bears a characteristic relationship to the

216

vegetation of the Atlin valley and that similar relationships
existed in the past.

XIV. HOLOCENE ENVIRONMENTS AND CHRONOLOGY

Previous work
In his palynological investigation of a series of bogs
along the Alaska Highway, including two in the head of the
Atlin valley at Mileposts 859 and 872 (see map, Fig. l),
Hansen (1950, 1953) found "little or no evidence for climatic
trends in the pollen profiles, except perhaps a general
amelioration throughout the time represented." Hansen con-
sidered the major evidence for climatic amelioration to be
the general increase in pine pollen upward in the sections.
He concluded, on the basis of the early appearance of its
pollen in most sections, that pine, along with spruce and
other forest elements, persisted during the Wisconsinan Age
in refugia in west-central Yukon Territory and in northeastern
British Columbia and western Alberta and, following deglacia-
tion, Spread southeastward and northwestward, respectively,
from each refugium to revegetate the area between.
Unfortunately, Hansen's work involved, for the most part,
only the upper, more abundantly polleniferous organic sedi-
ments; his diagrams lack an absolute chronology from radio-
carbon dating; and the Yukon and British Columbia diagrams
contain profiles for only pine, spruce, fir, and grass.
Heusser (1967a) reviewed Hansen's Alaska Highway profiles

and pointed out that spruce pollen actually reached the

217

milepost 872 bog site some time before pine and that, on the
other hand, pollen of the latter was much more abundant than
spruce pollen in the earliest sediments of a relatively

deep section farther to the southeast at milepost 647. On
this basis, Heusser reasoned that the major source of spruce
was the westcentral Yukon refugium and, furthermore, that
pine migrated into the deglaciated area, not from the Yukon,
but from the refugium in northeastern British Columbia and
western Alberta.

With regard to late Quaternary environments in south-
eastern Alaska and north-coastal British Columbia, Heusser
(1960, 1965, 1966, 1967b) assembled a large amount of flor-
istic, ecological, and climatological information in con-
junction with his analysis and interpretation of several
muskeg and bog sections from this North Pacific maritime
strip. His five-part geobotanical chronology, shown here
as Figure 29, can be compared with the Atlin valley chronology
presented as Figure 32.

Terasmae and Hughes (1966) deve10ped two pollen and
Spore diagrams for sites in the Ogilvie M0untains about 420
miles north-northwest of Atlin. Their record dates back
about 13,870 years at which time an herbaceous, sedge and
grass tundra, comparable to modern vegetation at Barrow,
Alaska, prevailed. A second pollen assemblage zone, begin-
ning about 12,500 years B.P., represents continuing herb-
aceous tundra conditions and reflects, in addition, a

significant admixture of birch (Betula glandulosa?) and

218

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

YEARS B. P. FEAT STRATIGRAPHY CLIMATIC 2
X 1,000 AND VEGETATION lNTERPRETATION INTERVAL
_’ 0 - l 4
Muskeg regeneration and
1 W invasion of coast forest
Western h 10 k , COOL Sub-Atlantic
2 4 em c maleum HUMID
-l.5 - 0.25
Lodgepole pine
3 a
4 WARM Sub-Boreal
‘ ligneous peat Coast forest DRY
predominance 0.25 - 2.0
A
E ”’ 5
H § Western hemlock
g; WARM Atlantic
9. sedge peat Sitka spruce HUMID
£23 6 1 u - 2.25
a.
>4
m :
E5" 7 4
WARM
ligneous peat DRY hurt-.1]
-2.U - 2.0
_ 8
9 ‘ Lodgepole pine forest
CUUL Pro-”()rcnl
HUMID
10"b——-—-———-—-———«-——-. 4.5-4.0
11 Lodgepole pine parkland Younger Dryas
q
,- .1 Alleri'u]
12 a
13 .
Older hryus
14 a
15 d r _ — _ — d
Figure 29. Genhotanical chronology for southeastern Alaska and

north-coastal British Columbia (after Heusser, 1966, l967h).

l . .
Including estimated range of temperature departures from prCSUnL
July means in OC.

2 Applicable to North Pacific North America in general.

218-A

lesser amounts of willow and alder in the regional vegetation.
A third zone begins about 9,000 years B.P. with major rises
in Spruce and alder percentages. Although these authors
evidently feel that evidence is insufficient for a climatic
interpretation other than the statement that "the magnitude
of the postglacial climatic changes appears to have been
smaller than in the more southerly regions," the sequence

of vegetation described seems to indicate a general amelio-
ration of climate during the Holocene Epoch.

Pine pollen is not significant in the Ogilvie Mbuntains
diagrams, and Terasmae and Hughes (1966) provide no evidence
for the hypothesis that pine migrated into their area from
the adjacent unglaciated part of Yukon Territory. Instead,
pine seems to have arrived in relatively recent times from
more distant sources. Evidence is provided, on the other
hand, for the west-central Yukon refugium's having been the
source of spruce, birch, alder, and willow.

Borns and Goldthwaite (1966) and Denton and Stuiver
(1966) have worked out the major features of a glacio-
climatological chronology covering the past 12,500 years
for the Kaskawulsh Glacier region of the St. Elias Mountains
in southwestern Yukon Territory on the basis of glacial
geologic and geobotanical studies. About 12,500 years B.P.
the glaciers of this region commenced to retreat from their
.maximum "classical" Wisconsinan (Kluane Glaciation) positions
and continued receding until about 9,000 years B.P. when

their termini reached positions a considerable distance

219

upvalley. The glaciers remained in a retracted state during
the ensuing Hypsithermal (Thermal Maximum) interval. Palyno-
logical evidence indicates that a climate wetter than today's
prevailed during at least the latter portion of Hypsithermal
time. A temperature decrease, apparently accompanied by a
decrease in humidity, initiated a Neoglacial advance about
2,700 years B.P. Terminus positions during the Neoglacial
were all downvalley from any since the end of the Wisconsinan
with the greatest post-Wisconsinan advance culminating about
300 years ago. These glaciers began to recede to their pre-
sent positions a short distance upvalley from their maximum
Neoglacial stands 100 to 150 years ago. Denton and Stuiver
(1966) Show, through correlations in other areas, that Neo-
glacial climatic changes were essentially synchronous, at
least in alpine regions, in the Northern Hemisphere.

A brief review of Quaternary paleoecological problems
in the Yukon Territory and adjacent regions was published
by Terasmae (1967). He pointed out that, whereas post-
glacial climatie changes in this area may well have been
comparable to those in temperate latitudes in magnitude and
time, they may be more difficult to detect by palynological
means because of greater ecological amplitudes of the arctic
or subarctic Species involved. ‘

Hampton (1969) studied the Quaternary glaciologieal,
vegetational, and climatic history of the Snag-Klutlan area
about 275 miles northwest of Atlin. His geobotanical

chronology, beginning approximately 40,000 years B.P., is

220

of particular significance to the present study. On page
186 he writes:

The oldest sediments . . . represent a cold
climate, with the landscape covered by fell
field. . . . A short time before 37,700 B.P.,
the climate ameliorated and shrub tundra, domi-
nated by Shrub birch, invaded the area. Shrub
tundra then dominated until 31,500 B.P. Fol-
lowing 31,500 B.P., the climate again cooled
and the landscape was covered by sedge-moss
tundra until shortly before 10,000 B.P. At
13,500 B.P., a slight change in the climatic or
limnologic conditions occurred, and an aquatic
vegetation developed. . . ; sedges also in-
creased in importance relative to grasses.
Shortly before 10,000 B.P. the climate ameli-
orated and the landscape was reinvaded by
shrub tundra. Further warming allowed a spruce
woodland to cover the landscape by 8,000 B.P.
Since 6,000 B.P., the vegetation and climate
has been similar to those prevailing today.
Precipitation has been generally higher during
warm.intervals than during cold intervals; it
also seems to have increased during the last
600 years.

Logs from above the present tree line in—
dicate that tree line and summer temperatures
have been higher than gresent at least three
times during the last 000 years. A tree ring
chronology from trees near tree line indicate(s)
that summer temperatures have been generally
cooler during the last 250 years than at pre-
sent.

With regard to mean July temperatures, Rampton (1969)
concluded that they were approximately 120 F lower between
13,500 and 10,000 years B.P., and approximately 80 F lower
between 10,000 and 8,000 years B.P. than the present level
of 57° at Snag. (The mean July temperature at Atlin for the
1906-1946 record period was 540 F.) Furthermore, Rampton
(1969, p. iv) states:

Logs from above the present tree line émply

that summer temperatures fluctuated .4O - 2 F
above the present values between 600 B.P. and

221

1220 B.P. Neoglacial ice advances suggest that

the climate has been periodically more severe

than present since 3250 B. P., and that the 500

years receding 1940 was the coolest part of the

last 000 years. Tree- -ring studies indicate

that othe last 200 years preceding 1940 were up

to 2° F cooler than present.

Local interpretations

In Chapter IX the extant vegetation in and around Moose
Bones, Mile 16, Mile 47, Mile 52, Jasper Creek, and Wilson
Creek Bogs was described and discussed. Palynological
stratigraphy and other sedimentological aspects of sections
from all but Mile 52 Bog were covered in Chapter XI. Here,
diagrams of these sections were described in terms of three
major zones, characterized, in turn, by pollen assemblages
in which shrubs, spruce, and pine were dominant. In Chapter
XII radiocarbon dating and the establishment of a basis for
an absolute Holocene chronology was discussed. Chapter XIII
dealt with comparisons of modern pollen spectra and vegeta-
tion composition and set forth some guidelines for inter-
preting fossil pollen and spore assemblages.

In this chapter, interpretations will be made of the
palynological record from each bog in turn, based on the
background provided in these earlier chapters, in conjunction
with autecological information from the literature. The
possible nature of the postglacial environment in which each
bog developed will be discussed. At several points it will
be necessary to provide further discussion on the extrapola-

tion and correlation of sections on the basis of a few radio-

carbon dates, and additional autecological and synecological

222

information, particularly with respect to the climatic
indicator value of major vegetation types, will be brought
forth. Where apprOpriate, aspects of phytogeography, glacial
geology, and climatic change will be explored in some detail.
Following this, an interpretation of regional vegetation and
climatic conditions during Holocene time will be deve10ped

on the basis of a composite palynological record from the

Atlin valley bogs.

Moose Bones Bog

The Meose Bones Bog section begins in the upper part of
the spruce pollen assemblage zone (Fig. 21). The Spruce/pine
zone boundary in this section is set at the 75 cm level (not
marked in Figure 21). A tentative date of 3,900 years B.P.
for this level is suggested on the basis of correlation with
the spruce/pine zone boundary in the Mile l6 Bog section
where such a date is obtained by extrapolation from a radio-
carbon dated level a short distance above. By extrapolation
downward in the Moose Bones Bog section, a tentative age of
5,200 years B.P. is obtained for the bottommost sediments
at 100 cm.

It is believed that by 5,200 years B.P. the Moose Bones
Bog area had been free of glacial ice for at least 5,000
years (see below), that physiographic conditions had become
stabilized, and that vegetation had been adjusted to the
prevailing climate and various edaphic situations for a long
time. The high percentage value of spruce and low value

for lodgepole pine at the bottom of the section may reflect

 

223

the occurrence on nearly all upland sites of a closed spruce
forest comprising stands of both the feather moss and shrub-
herb faciations of the white Spruce association. Pine is
not believed to have immigrated to the area by this time,
and pine pollen percentage values are low enough to be
ascribed to long distance transport.

The rapid rise of pine pollen percentages at about the
50 cm.level, approximately 2,600 years B.P., is attributed
to the appearance of at least a few pine trees on certain
Sites in the vicinity of the bog. It was shown earlier that
pine is considerably overrepresented in pollen assemblages
in the Atlin valley, and other investigators have also noted
the high pollen productivity of pines and the tendency for
wide pollen dissemination (e.g. Buell, 1947; Faegri and
Iversen, 1964; Terasmae, 1967). In view of this, pine need
not have become an important element in the vegetation at
the time of the beginning of the increase noted here as long
as there were a few trees favorably situated with respect to
winds during flowering season and the location of the depo-
sition site. Spruce may have remained nearly as abundant as
before, at least during the period of initial pine pollen
rise, with its relative pollen percentages becoming reduced
by increasing amounts of pine pollen.

Heusser (1967a) has shown, on the basis of Hansen's
(1953) work, that pine probably migrated into northwestern
British Columbia and southern Yukon Territory from an un-

glaciated corridor in northeastern British Columbia and

224

western Alberta, rather than from the west-central Yukon
refugium. The more recent work of others (Terasmae and
Hughes, 1966; Rampton, 1969) has demonstrated the impro-
bability of pine's having persisted in the Yukon area
during the Wisconsinan Age. With this being the case, pine
would not be expected to have appeared in the Atlin valley
until relatively recently, after migrating westward across
the northern Rocky and Cassiar Mountains, a distance con-
siderably greater than the distance between the Yukon
refugium and the Atlin valley.

An alternate possibility is that pine migrated into
the Atlin valley from the southwest. Heusser (1960, 1965)
Shows that lodgepole pine was an early pioneer invader of
deglaciated terrain in southeastern Alaska, immigrating from
nearby refugia along the southeastern Alaska/northwestern
British Columbia coast and islands. If it had migrated
across the Coast Mountains via the various trans-range
river valleys, including that of the Taku River, by some
time early in the Holocene, it might have moved thence
northward through the interior valleys.

Critchfield (1957) shows that both a coastal subspecies

(Pinus contorta ssp. contorta) and an interior subspecies

 

 

(g. contorta ssp. latifolia) of lodgepole pine are distin-

 

 

guishable. If the present Atlin valley pine population is
derived from one or more coastal refugium.populations, it
should be recognizable as the former subSpecies. Although

no detailed study has been made, it appears from the few

225

collections examined to date that only the interior subspecies
occurs in the Atlin valley.

An additional consideration is that pine persisted in
unglaciated parts of British Columbia and Alberta lying to
the south or southeast of the Atlin valley during the Wis-
consinan Age. However, in view of the fact that most of the
Rocky Mbuntain, Interior Plateau and valley, and Coast Moun-
tain portions of British Columbia were covered by ice during
this time, it is unlikely that a suitable refugium existed
anywhere north of the southern glacial limit in Washington,
Idaho, and Montana. Two important exceptions are, of course,
between the Cordilleran and Keewatin ice sheets in north-
eastern British Columbia and western Alberta and the extensive
unglaciated area northwest of the Atlin valley (Johnston,
1926; Kerr, 1934; Armstrong and Tipper, 1948). In this
regard, the greater proximity of the northeastern British
Columbia-western Alberta refugium to the Atlin valley, in
conjunction with the evidence of Hansen (1953) and Heusser
(1967a), precludes the need to hypothesize the Holocene
origin of Atlin valley pines as south of the glacial limit.

In view of the relatively recent date that pine appeared
in the Atlin valley (see Figs. 21-25 plus further discussion
below) and the fact that the trees here apparently belong
to the interior subspecies, in conjunction with glacial
geological evidence, it is concluded that the present pine
population derives from one which occupied the northeastern
British Columbia-western Alberta refugium.during the Wiscon-
sinan Age.

226

After reaching the vicinity of Moose Bones Bog, the
continued expansion of lodgepole pine, as reflected in its
pollen profile in the pine zone, to its present level in
the vegetation may have been promoted by increasing dryness
of the climate. The influence need not have been a direct
one. Instead, with summers of lower rainfall, forest fires
may have been more frequent, allowing pine, a fire species,
to spread to additional sites throughout the area (Hansen,
1950. 1953; Lutz, 1955)-

The origin, at higher elevations to the south, of the
infrequent alpine fir grains in the Moose Bones Bog surface
sample is discussed on page 204. A similar origin is likely
for the few grains occurring in samples from other levels
in the section. Therefore, the alpine fir profile in Moose
Bones Bog is not particularly meaningful with respect to
local environmental conditions, although fir profiles in
other sections discussed below appear to have indicator
value.

Alder pollen (Algus crispa (Ait.) Pursh subspp. and A.
incana (L.) Moench) occurs at levels of over ten percent
through the lower approximately three-fourths of the profile,
undergoing a moderate decline in the upper two-thirds of the
pine zone. In the other Atlin valley sections, initial
abundances of alder pollen could have been produced by
early successional vegetation on the recently deglaciated
valley floor. By the time the Moose Bones Bog section

began, primary succession would already have led to a

227

generally stable vegetation. Changes in the status of alder
at this time, therefore, would have been more directly under
the influence of changing climate. An alder increase may be
brought about both by moderating temperatures and increasing
moisture (Livingston, 1955; Colinvaux, 1964). In view of
its apparent early postglacial abundances in the Atlin valley
(see below), when temperatures were probably lower than at
other times during the Holocene, it is concluded that the
temperature factor has remained favorable for alder and that
the plant is primarily a moisture indicator here. Firsthand
evidence for this is presented in Table 5 and on page 82
where it is explained that minor amounts of alder occur at
present in moist locations within stands of the feather moss
faciation of the white spruce association. Also, alder was
found to be relatively abundant in a few gravelly stream.
bank situations at several places in the Atlin valley. Some
sites near timberline, where precipitation would be higher
than at lower elevations, were found to contain significant
quantities of alder. It is important both in forests and on
proglacial terrain near the Llewellyn Glacier at the south
end of the valley where, under the influence of incursions
of maritime air more or less directly across the Coast Moun-
tains, conditions are more humid. The moist habitat affini-
ties of alder have been noted by other workers, including
Lutz (1956), Mckay and Terasmae (1963), and LaRoi (1967).

In view of these considerations, the decline in alder pollen
percentages in the upper pine zone (above the 50 cm level)

228

of the Moose Bones Bog section is believed to be an indication
of increasing dryness during the past approximately 2,600
years. This would corroborate the similar conclusion
reached on the basis of the Spruce and pine profiles, and
it would, furthermore, be in accordance with findings of
Borns and Goldthwaite (1966) in the Kaskawulsh Glacier area
in the eastern St. Elias Mountains.

It is recognized that the usefulness of alder as a
climatic indicator is limited by the fact that the genus
is a prolific producer of airborne pollen and tends to be
overrepresented in most assemblages. Local ecological con-
ditions favoring the occurrence of a few alder bushes can
have a major influence on the pollen rain (Terasmae, 1958).
Because of this possibility in the Moose Bones Bog area, the
relatively modest decline in alder pollen percentages in the
upper pine zone might be meaningless from a climatic stand-
point. There are two considerations, however, which lend
support to the conclusion reached above. First, the alder
pollen profile is relatively smooth throughout, indicating
a gradual and long-term change in the status of alder in the
vegetation. This change could have been related to a de-
crease in white spruce forest, with which alder tends to be
associated, under the influence of more frequent fires and
a concomitant eXpansion of lodgepole pine (Lutz, 1956; LaRoi,
1967; Rampton, 1969). If the pollen production represented
were the result of local occurrence of alder, say on the

gravelly bank of a stream somewhere in the area, more erratic

229

pollen productivity through time would be expected because
of the temporary nature of such habitats and the periodic
decimation of alder stands with shifting stream channels or
replacement of the stands by vegetation of later successional
stages. Secondly, the alder profile in Moose Bones Bog is
similar to those of the other four bogs where similar inter-
pretations appear reasonable.

The rising birch pollen percentages, from the bottom
of the section to the level of the spruce/pine zone boundary,
may reflect higher humidity during late spruce zone time
than during the subsequent pine zone time. They may also
indicate the expansion outward and into the surrounding
forest of the relatively moist shrub zone. This is based
on the fact that the vegetation of the shrub zone today con-

sists primarily of Betula glandulosa and some willow and may

 

have consisted of similar vegetation in the past. The drop
in the birch profile in the lower pine zone might reflect

the closing in again of the forest around the bog under a
dryer climate. The decrease in willow percentages just prior
to the time of the birch (and alder) peak might have resulted
from the fact that willows, as plants ordinarily poorly
represented in the pollen rain because of low pollen pro-
ductivity and/or transportability, were forced farther away
from.the deposition site with the increase in diameter of the
herbaceous zones inside the shrub zone. Such a zonal dis-
placement would not have affected the representation of birch

since it is ordinarily well represented in the pollen rain

230

at sites located some distance from.the source. In this con-
nection it is noted that willow is abundant in a large stand
of depression shrub vegetation beginning about 100 m to the
south and southeast of Mbose Bones Bog and extending to the
head of Little Atlin Lake (p. 141-142). Although this is

in the direction of prevailing spring and summer winds

(Fig. 6), willow pollen grains are not numerous in the modern
spectrum from the bog (Fig. 26).

At present the four herbaceous zones surrounding the
pond and sample site in Moose Bones Bog are dominated by
sedges and grasses (Table 21). If these zones were occupied
by simular vegetation in the past, and if they did increase
in size under the influence of a more humid climate, more
sedge and grass pollen should have been deposited. Contemp-
oraneous peaks in both grass and sedge profiles occur in
the lower half of the diagram. Although these peaks do not
represent major fluctuations and are based on only two
samples, separated by a sample containing relatively lower
proportions of grass and sedge pollen, they do provide some
support for the interpretation made on the basis of the
willow and birch profiles.

Additional, albeit minimal support for the hypothesis
of a change from relatively humid to dryer conditions in
pine zone times comes from.the occurrence in the lower part
of the diagram of several grains of miscellaneous aquatic
or semi-aquatic types and, in the upper portion, of pollen
of Juniperus and Compositae, plants ordinarily occupying

 

dry sites (see below).

231

In terms of the conifer profiles, the Moose Bones Bog
diagram is very similar to those of Hansen (1953) for bogs
at mileposts 858 and 872 and at other points on the Alaska
Highway. By correlation with these diagrams, which gener-
ally begin just prior to the major changes in shape of the
spruce and pine profiles, it is seen that Hansen's record
also begins approximately 5,200 years B.P. Hansen's (1953,
p. 539) suggestion, then, of "perhaps a general amelioration
(of climate) throughout the time represented" refers to only
the latter approximately one-half of "postglacial" time.
This interpretation may not conflict with the more detailed
Helocene chronology developed in this dissertation provided
increasing dryness is considered an aspect of "amelioration."
0n the other hand, the hypothesis presented here of a
gradual temperature decrease during the past two to three
thousand years does not agree with Hansen's interpretation.
It is recognized, however, that the three profiles he con-
sidered have, by themselves, little, if any temperature
indicator value in the Atlin region for this interval
(Terasmae, 1967).

Mile l6 Bog

The Mile 16 Bog section begins at a depth of 8.25 m, in
the lower part of the spruce pollen assemblage zone (Fig. 22).
USing a sediment accumulation rate of 0.1171 cm/yr, calcu-
lated for the portion of the section between the 1.50 and
6.35 m levels which are radiocarbon dated at 2,560 I 140 and
6,700 i 300 years B.P., respectively, it is possible to

232

extrapolate downward and obtain a tentative age of 8,320 years
B.P. for the bottom of the section. Since the lower approxi-
mately 0.75 m contains a relatively large amount of sand and
silt, which probably accumulated faster than the organic
material, it seems appropriate to reduce the age estimate
somewhat. An age of 8,000 years B.P. for the beginning of
this section is suggested.

In view of the fact that spruce pollen was already being
produced in moderate quantities at the time the first Mile 16
Bog section sediments were deposited, it is concluded that
spruce trees had become established in the vicinity of the
bog by at least 8,000 years B.P. Pine, on the other hand,
had not yet reached the area, and the few pine grains which
occur at most levels in the lower two-thirds of the spruce
zone can be readily accounted for by long distance transport.

In the lower approximately 1 m.of the section, where
spruce undergoes an increase, alder and birch pollen per-
centages are at relatively high levels, and willow pollen is
also present in significant quantities. There is, in addi-
tion, a moderate amount of sedge pollen. Earlier it was
explained that Mile 16 Bog has developed in a glacial kettle
located in a kame terrace. In early developmental stages,
before the formation of a bog mat, there was probably little,
if any semi-aquatic or more mesic terrain between the pond,
presumably larger than at present, and the surrounding, dry
sandy slopes of the kettle. This means that shrub vegetation

would have been scarce or non-existant in the bog proper

233

because of the lack of suitable peripheral habitat zones.
Pollen from shrubs would have to have originated either in
other bogs having the required edaphic conditions or in
upland areas. Field observations show that few other bogs
have existed in the vicinity of Mile 16 Bog, and upland
sites are believed, therefore, to have been the major source
of these pollen types. Sedge is to be included here, as
this plant could not have been very abundant in the bog in
the absence of a bog mat or other semi-aquatic terrain sur-
rounding the kettle pond.

Alder pollen could have blown into the bog from many
sites along streams on the main valley floor a kilometer or
so away or from sites on the banks of nearby Snafu Creek.
Willow, birch, and sedge pollen is believed to have been
produced, along with spruce pollen, by a Spruce woodland
type of vegetation occupying the majority of upland Sites
at this time. Such a vegetation type may have been transi-
tional between an earlier shrub tundra, in which willow,
birch, and sedge were prominent components, and a subsequent
white spruce forest. At the time of the beginning of the
Mile 16 Bog section, white spruce is believed to have only
recently migrated into the area, under the influence of
a warming postglacial climate, from the west-central Yukon
refugium to the northwest. Spruce trees may have existed
as scattered groves and clumps as they do at timberline in
the Atlin valley today (Fig. 30). Mean July temperatures
were probably a few degrees lower than at present (see

further climatic discussion below).

234

By the time of deposition of sediments at the 7 m level
spruce forest had become established in the vicinity of the
bog and the spruce woodland and shrub tundra zones had been
displaced to higher elevations. This is indicated, in part,
by a decline in birch pollen values. That this upland, sedge-
bearing vegetation type existed at an increasing distance
from the bog is indicated by a drop in sedge pollen per-
centages just below the 6.5 m level. Soon afterwards, the
initial development of a bog mat could have given rise to
autochthonous sedge pollen which then increased to relatively
high levels within the time represented by the accumulation
of another meter of sediments. The willow pollen profile is
seen to behave in a similar manner, but with the rebound in
percentages occurring higher than that for sedge, reflecting
the time necessary for centripetal growth of the bog mat and
the appearance, in the peripheral portion of the bog, of the
less wet conditions favorable to willow growth.

The peak in willow pollen at the 5.5 m level cannot be
taken seriously since it is based on only one sample. It
could, for example, represent the chance existence, for a
relatively short time period, of a clump of willows on a
drier swell close to the sampling site.

The spruce forest surrounding Mile l6 Bog, having
thoroughly replaced the earlier Spruce woodland by approxi-
mately 7,000 years B.P., was either of the shrub-herb
faciation type, or it may have been, in the absence of pine,

which might otherwise have invaded, an open and dry spruce

235

woodland type which is rare in the Atlin region at present.
The latter suggestion is based on the occurrence throughout
the area of the bog of a very well-drained sandy and gravelly
glacial drift, a substratum which is not well suited to

white spruce growth. Further evidence is seen in the occur-
rence of a wide variety of shrub and herb pollen types.

The Juniperus profile reaches fairly high values, up to

 

about 16 percent, in the spruce zone. Such values are not
particularly reliable here because most of the grains counted
as juniper were corroded or badly distorted and difficult to
identify. Juniper pollen does not preserve well in moss
polsters (Faegri and Iversen, 1964) and may have undergone

a certain amount of destruction in Mile 16 Bog sediments.
Nevertheless, there seems to have been quite a bit more
juniper around Mile 16 Bog in spruce zone times than at
present. Field observations and the general vegetation survey

show that juniper, including Juniperus communis L. and par-

 

ticularly .g. horizontalis Moench is an important element in

 

the herb-heath association (Table 15). This vegetation type
is, in general, characteristic of the driest and most well-
drained sites, and it occurs at present near Mile 16 Bog

in stand 16E. Faegri and Iversen (1964) state that juniper
is a plant of arid woodland and grassland habitats. Terasmae
and Mott (1965) found it on open, rocky and gravelly slopes,
but also in some bogs. Ritchie (1969) found juniper to be

a plant of upland, xeric sites.

236

The evidence suggests that juniper occurred in greater
abundance in the vicinity of Mile 16 Bog during spruce zone
times in response to a drier climate, an interpretation.which
conflicts with the interpretation of the Moose Bones Bog
record. Alternatively, the climate may have been more moist
but may also have been warmer, in which case potential
evapo-transpiration would have been higher (Sanderson, 1948).
A higher potential evapo-transpiration may have offset any
moisture gain from higher precipitation, creating, in con-
junction with the highly pervious substrate of the Mile 16
Bog area, a greater water need, with reSpect to plant growth,
during the summer months. Plants adapted to xeric habitats,
therefore, would have been favored. This interpretation,
i.e. higher temperatures and precipitation than during sub-
sequent pine zone times, is accepted here. Additional evi-
dence is presented below.

Shepherdia canadensis pollen occurs throughout the
section. This species, although adapted to a wide range of
habitats (LaRoi, 1967), is particularly abundant on recent
mineral soils or glacial deposits (Ritchie, 1967) and well-
drained alluvial soils (Mckay and Terasmae, 1963). In the
general vegetation survey, Shepherdia reached its highest
importance values in the lodgepole pine, aspen, and mixed-
wood forest associations (Tables 6, 11, and 12), stands of
which ordinarily occupy well-drained sites. The species is
entomophilous (McAndrews, 1966) and grossly underrepresented
in fossil pollen spectra (Ritchie and Lichti-Federovich,

237

1968). The occurrence, therefore, of even a few grains in
most samples would indicate the continuing abundance of
Shepherdia and, therefore, of relatively dry and open sites.

 

There are several additional indications in the pollen
record of dry Site vegetation in the vicinity of Mile l6
Bog during spruce zone time. Ericales pollen, possibly of
Arctostap los uva-ursi, an inhabitant of dry, sandy places

 

 

(Hultén, 1968), occurs in several samples. This species
was found to be one of the few widespread members of the
Ericales in the Atlin valley, reaching high importance
values in stands of the lodgepole pine brfilé and the aspen
and herb-heath associations (Tables 8, 11, and 15) as well
as in other stands of open vegetation on dry sites.
Gramineae pollen is consistent throughout in low quan-
tities, and Saxifragaceae pollen occurs at various levels.

The latter can reasonably be attributed to Saxifragra tri-

 

cuspidata, the only saxifrage which is abundant at the pre-
sent time in the Atlin region, always on dry, rocky or sandy

sites. Rosaceae, Artemisia, and other Compositae pollen, all

 

produced by plants of habitat affinities Similar to those
mentioned above, is frequently encountered in Mile 16 Bog
samples. In addition, the relative abundance of pollen
produced by a wide variety of other sun-loving herbaceous
dicots indicates the open nature of the forest surrounding
the bog.

The possibility of recurring forest fires and destruc-

tion of the ground cover, followed by sheet wash of the

 

238

relatively steep upper slopes of the kettle in which Mile

16 Bog is located, has been discussed. Three lines of
palynological evidence are available to support this explana-
tion. (1) The spruce pollen profile is quite erratic. Sig-
nificant profile fluctuations are to be expected because of
variability in pollen production related to the effects of
short-term.climatic changes and other factors affecting
deposition and preservation of the pollen. However, the
fluctuations here seem to be unusually large. It is sug-
gested that they are the result of periodic decimation of the
forest vegetation by fire. It is noted that dips in the
spruce profile occur at levels where inorganic sediments are
most abundant (Fig. 22). In view of these considerations,
the interpretation of higher precipitation levels during
spruce zone times gains some support in that the sheet wash
proposed here would have been more effective at higher pre-
cipitation levels, possibly higher than at present. The
latter possibility is indicated by the absence of inorganic
admixtures in the upper approximately 1.75 m of the section,
even after the establishment of pine forest, presumably under
the influence of continuing periodic forest fires.

(2) There are a number of occurrences of Lycopodium

 

spores in the spruce zone. In the general vegetation survey,

chopodium.was found to be important in stands of the shrub-

 

herb faciation of the white spruce association at mile 813
where there was evidence of fire perhaps 50 years ago.

Elsewhere, Lycopodium is rare in the Atlin valley except for

 

239

occurrences in stand 30E of the feather moss faciation of
the white spruce association, and the mixed coniferous forest
west of Jasper Creek Bog (Fig. 18). In this connection,

A. T. Cross (personal oral communication 1970) states that

Iyeopodium.may be characteristic of old burns in the middle

 

Appalachians. In addition to these considerations of poss-
ible old burn affinities of Lycopodium, it is suggested that

 

there may have been a greater tendency for such relationships
in the past when climatic conditions, namely higher tempera-
tures and precipitation, were different from the present.

(3) Pollen of Epilobium, a genus containing typical

 

fire species, was encountered in a number of samples. Since

species of Epilobium produce a bulky, non-anemophilous pollen

 

grain, plants would have to have been frequently abundant
close to the bog to have become so well represented in the
pollen record. It should be mentioned, however, that at

present a small enclave of several species of Epilobium

 

occurs adjacent to the bog. If this existed in the past it
could have been the major pollen source.

Toward the upper boundary of the spruce pollen assemblage
zone alpine fir pollen becomes slightly more frequent. A
wetter climate at this time may have caused a spread of fir
onto additional sites in the Atlin valley, including some
closer to Mile 16 Bog. As was discussed earlier, fir appears
to be limited, in part, in its present occurrence in the
valley, as is alder, by low moisture conditions, being found

primarily in areas believed to receive higher amounts of

240

precipitation. It is not likely that fir became established
on the calcareous, well-drained kame terrace deposits in

the immediate vicinity of Mile l6 Bog, but higher terrain,
lacking a mantle of glacial material, located a Short dis-
tance to the east and northeast from the bog, may have been
favorable for fir growth under the more humid conditions of
spruce zone times.

Although evidence for dry site vegetation around Mile
l6 Bog during spruce zone time is abundant, the palynological
record shows that moisture was not a limiting factor for
aquatic and semi-aquatic vegetation in the bog. Since Mile
l6 Bog existed in a closed basin into which there was no
stream drainage, precipitation would have to have remained
at significant levels. Particularly, the profiles for the
aquatics, including Isoétes-type, Sparganium, Nymphaeaceae,
Hippuris, and Pediastrum.are indicative (Fig. 22).

 

The woody chunks shown in the sediment type column are
probably pieces of water lily rhizome and not ligneous
material as was found in the recurrence horizons of south-
eastern Alaska muskegs by Heusser (1960, 1965), interpreted
there as indicative of forest invasion of the muskeg in
response to a drier climate.

In the pine pollen assemblage zone of the Mile 16 Bog
section, the increase in pine percentages is particularly
pronounced, with Spruce percentages correspondingly lower
than in any other section at most levels. This relationship

may indicate a return to drier climatic conditions for the

241

reasons discussed in connection with the Moose Bones Bog
section. Other palynological evidence of increased dryness
during this time is lacking, however, probably because of
the condition of low moisture availability which seems to
have prevailed throughout the preceding spruce zone time
interval. Uhder these circumstances, the vegetation, for
the most part, would not have been as sensitive to a gen-
eral change to a drier climate as at other sites.

Figure 22 Shows that pine pollen first appears in sig-
nificant quantities (i.e. approximately 15 percent) around
4,200 years B.P. Equivalent percentages are not registered
in Moose Bones Bog until around 2,600 years B.P., and pine
does not seem to have become an important element of the
vegetation around Mile 47 Bog until only about 2,000 years
B.P. (Fig. 23). In Jasper Creek Bog (Fig. 24), pine pollen
percentages reach significant levels around 2,300 years B.P.
In Wilson Creek Bog (Fig. 25), an initial peak of 12 percent
is seen at approximately the 6,700 year level, but the first
significant percentages in the sustained pine pollen profile
appear around 3,800 years B.P.

0n the average, these dates are believed to reflect the
time required for pine to migrate into the Atlin valley from
the east following deglaciation of the general northern
British Columbia and southern Yukon Territory region. Al-
though deglaciation has not been precisely dated throughout
most of this region, it is probably safe to say that, except
for higher elevation areas, it was complete by 8,000 years

242

B.P. Even with this conservative estimate, it can be seen
that the westward migration of pine, from the refugium in
northeastern British Columbia, across a distance of perhaps
450 miles, required on the order of 4,000 years.

The variability of the dates of first Significant pine
pollen appearances from bog to bog may provide a more de-
tailed insight into the nature of the migration pattern. As
is noted, the earliest appearances are in the Mile 16 and
Wilson Creek Bog sections, and the more recent ones are at
Mile 47 and Jasper Creek Bogs, lying between the former two
(Fig. 1). .Mile 16 is in alignment with a broad, relatively
low area extending eastward into the northwest-southeast
trending Teslin valley and lowlands. Wilson Creek Bog is
situated in the valley of the O'Donnel and Pike Rivers which
also extends, via the upper Nakina River valley, to the Teslin
lowlands. Following establishment of pine in the Teslin area,
westward movements of pine seeds may have occurred compari-
tively easily through these low elevation routes into the
Atlin valley. Mile 47 Bog (also Mile 52 Bog), on the other
hand, is blocked from such movements by the local mountain
ranges lying directly east of the central portion of the
Atlin valley (Fig. 1). Moose Bones Bog is somewhat separated
also from the northern Teslin area by mountains lying immed-
iately to the east.

After reaching the Mile l6 Bog area, the advancing pine
front may have split, with migrations both to the north, to
the Moose Bones Bog area, and south to Mile 47 Bog. The

243

amount of time for the spread of pine into these latter two
areas from Mile l6 Bog, approximately 1,600 and 2,200 years,
respectively, is probably greater than would be required under
ideal circumstances. Although no conclusive explanation for
these slow rates is available at this time, site conditions
and the presence of stable vegetation, in which it might have
been difficult for a newcomer arboreal species to become
established, may have been involved. In this connection the
discussion of possible environmental conditions around Mile
16 Bog in spruce zone times is relevant. Here, with a dry,
well-drained substrate and perhaps a relatively sparse spruce
forest, pine may have become readily established as the first
seeds reached the area. In addition, fire, a factor also
promoting pine establishment, may have been more prevalent
here.

The apparent delay in the establishment of pine around
Jasper Creek Bog after its entering the Wilson Creek Bog
area only a few miles to the east is not explainable at this
time. Presumably site conditions were unfavorable, but
this is not too plausible in view of the extensive sandy
hillside lying immediately east of the bog whereupon lodge-
pole pine is dominant at present (Fig. 19).

Mile 47 Bog. The time scale for the lower approximately
135 cm of the Mile 47 Bog section is somewhat uncertain be-
cause the rate of deposition of the sedimentary material
here is difficult to determine. This material, a viscous

and sticky, fine-grained substance, was referred to above

244

(p. 188 ff.) as blue-gray glacial lake clay. Although no
particle size analysis was made, the material is probably a
fine-grained silt or "rock flour" of the type carried by
glacial streams into proglacial lakes where it slowly settles.
The silt originates from scouring of bedrock by the over-
riding ice mass with its bedload of rock debris (Flint, 1957)
and may be carried directly to a lake for deposition. In
other cases it may be incorporated in till deposits and re-
moved and recycled later by meltwater and redeposited in
lakes (Fulton, 1965).

The rate of glacial lake clay (silt) deposition would
appear to depend on physiographic conditions around the
deposition site, including proximity of the ice front, rate
of melt, courses of meltwater stream channels, and the com-
position and distribution of glacial deposits. A study of
existing glacial deposits can provide some knowledge of these
factors. From reconnaisance observations it is known that
Mile 47 Bog is surrounded by glacial drift, but the compo-
sition and extent of this material has not been determined.

Although there is not enough information at hand to
estimate the rate of silt deposition in Mile 47 Bog, it may
be reasonable to assume that at least a few hundred years,
perhaps up to a thousand, were required for the approximately
135 cm.to accumulate (Fig. 23). On this basis, and on the
basis of the radiocarbon date of 8,600 i 330 years B.P. at
the base of the overlying marl section, it is concluded that
the Mile 47 Bog record goes back at least 1,400 years farther

245

than the 8,000-year Mile l6 Bog record, to about 9,400 or
9,500 years B.P.

Pollen and spore counts for samples deposited during
the first 300 to 400 years, up to about the 4 m level, are
so low that only tentative interpretations are possible. It
appears, primarily on the basis of the willow, alder, ngag,
Artemisia, and Compositae profiles, that succession on pro-
glacial terrain in the vicinity of the bog was well underway
at this time, but little can be inferred regarding vegetation
on the lower valley walls some distance away. Sites here
would have been available to colonization by plants earlier
because ice would have melted below their level before dis-
appearing from the valley floor. Some evidence for an
herbaceous tundra vegetation at these sites is provided by
the occurrence of significant quantities of sedge pollen
near the bottom of the section. It is possible that at

least some of the relatively large amounts of Artemisia and

 

Compositae pollen also originated in such a vegetation type.
Additional evidence for the existence of some form.of
tundra vegetation on the lower valley walls is provided by
the Egygg_peak at the bottom of the section. On Vancouver
Island, Terasmae and Fyles (1959) found leaves, tentatively
identified as nggg drummondii, associated with pollen and

 

spore assemblages in 12,000-year-old samples which indicated
a climate substantially colder than at present, perhaps
similar to climates in certain present-day arctic areas.

The writer has observed extensive patches of Egyas sp. on

246

outwash within several miles of the terminus of the Dusty
Glacier in the eastern St. Elias Mountains. Although no
meteorological records are available for this area, shrub
tundra occupying the lower valley walls above this portion
of the Dusty Glacier valley floor indicates that mean summer
temperatures are lower than in the Atlin valley at present.
0n the valley walls above the Dusty Glacier, upvalley from
the terminus, the vegetation grades into an herbaceous
tundra, and a short distance downvalley from the terminus
the shrub tundra grades into a spruce woodland type of
vegetation on the valley walls.

Since Egyas is probably not anemophilous (J. Terasmae,
personal oral communication 1969), it must have been fairly
abundant in the area of Mile 47 Bog to be so well repre-
sented at the bottom of the section. It can be seen from
the preceding evidence that such a ngas abundance may have
been related to climatic conditions associated today with
an herbaceous or Shrub tundra vegetation type. The ngas
occurrence indicated here might as well have been associated
with a spruce woodland type of vegetation as in the Dusty
Glacier area downvalley from the terminus,but the absence of
spruce pollen from the samples in question precludes such
an interpretation.

Although a more exact inference as to the vegetation on
the valley walls in the vicinity of Mile 47 Bog around 9,400
years B.P. cannot be made because of the low total pollen

counts in the lowest samples, it appears fairly certain

247

that a shrub tundra had developed by about 9,000 years B.P.
This is indicated primarily by the appearance of significant
quantities of birch pollen and, to a lesser degree, by de-

creases in Dryas, Artemisia, Compositae, and Cyperaceae

 

pollen. Such a vegetation change would indicate an amelio-
ration of the climate, a Situation to be expected during a
period of deglaciation. As is discussed above, shrub tundra
is also believed to have existed in the Mile 16 Bog area some
time prior to the beginning of the record there at 8,000
years B.P. The fact that spruce had become established in
the Mile l6 Bog area by this time, creating what is believed
to have been a Spruce woodland vegetation, a type which may
be considered transitional between Shrub tundra and spruce
forest, also indicates ameliorating climatic conditions,
particularly with respect to temperature.

The spruce pollen profile shows that Spruce forests
did not become established in the Mile 47 Bog area until
about 7,200 years B.P. Spruce pollen deposited before this
time, back to around 8,000 years B.P., was in low quantity
and may have been delivered to the site by long distance
tranSport. If the Mile 47 Bog record is a reliable indi-
cator, it is probable that spruce was completely absent from
the vicinity of the bog prior to about 8,400 years B.P. since
no spruce grains were found in the samples deposited then.
The lack of spruce pollen cannot be attributed to conditions
unfavorable for deposition or preservation because counts of

up to 300 other types were obtained.

248

In order to confirm the apparent absence of spruce from
the Mile 47 Bog area of the Atlin valley prior to around
8,400 years B.P., samples estimated to be of comparable
age from nearby Mile 52 Bog (see Chapter XII) were examined
in a cursory way for spruce pollen content. A number of
traverses were made of eaah slide and a subjective estimate
made of the preportion of spruce grains. At the estimated
7,200 year level, spruce pollen was encountered frequently.
Downward from here, however, the amount of spruce pollen
relative to other types decreased noticeably until, in
samples from approximately the 8,000 year level, spruce
grains were only rarely encountered. In a sample at the
8,400 year level only two or three grains were seen in at
least a dozen traverses of the slide, and at the 8,700 year
level, no grains were encountered in at least 30 traverses
of two slides.

The Mile 52 Bog record for spruce appears, therefore,
to parallel the Mile 47 Bog record. The few spruce grains
deposited in Mile 52 Bog between 8,400 and around 7,500
years B.P. can be accounted for by long distance transport,
as in Mile 47 Bog. In both places spruce pollen may have
come from farther north, from the advancing spruce woodland
there, or it may have blown into the Mile 47-Mile 52 Bog area
from the south. It will presently be shown that Spruce
forests had become established in the Jasper Creek-Wilson
Creek Bog area by about 9,000 years B.P. During the flower-
ing season, prevailing winds in the Atlin region are south-

erly and southeasterly (Fig. 6) and, if this was the case

249

in early Holocene times too, there could be an important
southern element in the record.

The early Mile 47 Bog record, coupled with that of
Mile l6 Bog, provides evidence that mean July temperatures
in the Atlin valley were less than 50° F prior to at least
8,000 years B.P. in the north and until about 7,500 years
B.P. in the mid-latitude portion of the valley. This is
based on the apparent nature of spruce migration into the
vicinities of Mile 16, Mile 47, and Mile 52 Bogs. The
northern limit of white spruce forests in Canada has been
correlated with the 10° c (500 F) July isotherm by Griggs
(1937), Halliday and Brown (1943), and others. The assump-
tion is made that ecological requirements of white spruce
were similar in the past and that its distribution was
similarly limited by mean July temperatures of less than
50° F. Had the mean July temperature been higher than this,
it is believed that white spruce would have migrated into
the Atlin valley from the north-central Yukon refugium
earlier and that its pollen would appear, therefore, lower
in the Mile 47 and Mile 52 Bog sections. White spruce is
considered an aggressive or opportunist species, capable of
rapidly immigrating into recently deglaciated areas and
colonizing all but the coarser grained of fresh mineral
soils (Ritchie, 1964, 1967). Given these attributes, Spruce
migration into the northern part of the Atlin valley should
have followed closely upon the receding ice front had cli-

matic conditions been favorable. Even if it had not been

9

250

able to invade proglacial terrain on the valley floor until
several hundred years of plant succession had taken place,
the adjacent lower valley walls would have been available
for colonization at an earlier time. It is suggested that,
had climate not been inhibiting, spruce would have been
growing on the lower valley side slepes near the Mile 47
and Mile 52 Bog Sites by the time sediments and pollen had
begun to accumulate. The fact that no Spruce pollen was
found in the lower samples is an indication that spruce had
not entered the area.

In the absence of spruce woodland or spruce forest, a
shrub tundra appears to have developed on the exposed portions
of the valley walls at lower elevations and perhaps also to
some extent on the more physiographically stable parts of the
valley floor in the north. Rampton (1969) cites evidence
that shrub tundra in the Snag-Klutlan area existed when the
mean July temperature was around 48° F, or 6° lower than at
present in the Atlin village area (Table 1; Fig. 5). At pre-
sent, a shrub tundra vegetation type dominated by Betula
glandulosa, Salix spp., and‘Vaccinium spp. exists at higher

 

 

elevations. In proceding upslope in many areas, timberline
is encountered around 4,000 to 4,200 ft. Here a zone of
shrub tundra begins and extends up the elevation gradient
several hundred feet farther. In broad, subalpine valleys
lying above approximately 4,200 feet, such as the upper
Ruby Creek valley north of Surprise Lake (Fig. l, 30), shrub

tundra occurs over rather extensive areas. No meteorological

251

data are available for shrub tundra areas in the Atlin region.
It is certain, however, that summer temperatures are several
degrees lower in such areas than at lower elevations because
of the summer lapse rate. There are no data for the Atlin
or other weather stations in the region which would make
possible the computation of this factor, but a summer lapse
rate of 3.8° F/l,000 ft was determined by Rampton (1969) for
the Snag-Klutlan area where climatic conditions are generally
similar. Applying this rate to the Atlin region, it can be
seen that summer temperatures at the 4,200 foot level would
be at least 7° F lower than at the elevation of Atlin Lake,
about 2,200 ft. On this basis it is concluded that early
Holocene summer temperatures just above the present elevation
of Atlin Lake, where a shrub tundra appears to have existed
on the lower valley walls, may have averaged around 47 or
48° F.

If, as is suggested above, an herbaceous tundra vege-
tation type persisted in the vicinity of Mile 47 Beg prior
to about 9,000 years B.P., summer temperatures may have been
as much as 10° F lower than at present, or around 44° F.
Rampton (1969) shows this vegetation type (his "sedge-moss
tundra") to be associated with such temperatures. In addition,
a tentative summer lapse rate analysis can be applied, as was
done above, to obtain a similar estimate of temperature con-
ditions. At present an herbaceous tundra vegetation occupies

sites lying above approximately 5,000 ft in the Atlin region.

252

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253

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254

The question should be raised as to how spruce could
have been prevented from entering the northern part of the
Atlin valley by unfavorable temperature conditions in early
IHolocene times while existing in abundance farther to the
:northwest, in the west-central Yukon refugium, not only in
the early Holocene, but also during the preceding Wisconsinan
.Age. It might be assumed that temperatures would have been
even lower in the latter place. Mean annual temperatures
‘probably were lower there than in the Atlin valley where, as
'was explained in Chapter IV, there is somewhat of a moderating
maritime climatic influence. It is just this influence,
Zhowever, which.may have conditioned the summer temperatures,
causing them to be lower than in more continental regions.

It would, presumably, also have caused winter temperatures
to be higher, so that the mean annual temperature in the
Atlin valley would have been higher than in regions deeper
in the continental interior. The Yukon refugium is a con-
tinental area and would not have experienced as much of a
Pacific maritime influence. This area is farther from the
sea than the Atlin region and is outside the zone of the
shifting storm tracks which bring cooler temperatures in the
summer as well as increased precipitation. Furthermore,
this area is protected from incursions of Pacific maritime
air by the St. Elias Mountains which are higher and more
extensive than the Northern Boundary Range which lies between
the Atlin region and the sea. Summer temperatures would,

therefore, have been higher, and winter temperatures lower,

 

 

255

presumably low enough that the mean annual temperature would
have been lower than in the Atlin region.

Meteorological data Show that such relationships exist
in northwestern Canada at present. Figure 5 shows that at
Whitehorse, lying some distance southeast of the west-central
Yukon refugium, summer temperatures are significantly higher
than at Atlin. At both Whitehorse and Carcross, winter 4i
temperatures, in most cases, are lower than at Atlin. An
examination of temperature conditions at stations lying well
within the Yukon refugium area shows this situation even more
clearly. For example, at Dawson, mean temperatures for
June, July, and August are 56.9, 59.8, and 54.50 F, respect-
ively, and for November, December, and January they are,
respectively, 2.5, —21.9, and -l7.6o F (Canada Dept. of Trans-
port — Meteorological Branch, 1967). The reader may compare
these figures with the Atlin data in Figure 5 and note the
considerably greater yearly range of temperatures at Dawson.
In addition, the mean annual temperature at Dawson is 23.60 F,
compared with 32° F at Atlin (Table 1).

The two peaks in Is05tes-type Spores in the shrub zone
portion of the Mile 47 Bog diagram would be difficult to
reconcile with the low temperature conditions hypothesized
here if these Spores are really of Isoétes spp. Isoétes
is a plant of temperate to north-temperate climates. It
occurs today in south-coastal Alaskan regions, and its north-
ward advance in mid-Holocene time, as far as the Brooks

Range, is considered an indicator of Thermal Maximum climatic

 

256

conditions (Livingston, 1955; Heusser, 1967). In view of
the uncertainty as to the identity of these spores, however,
the hypothesis cannot be nullified in view of this information.
There is no apparent basis for further discussion of the
Isoétes-type Spore profile at this point.

The major increase of Cyperaceae pollen percentages
around the 9,000 year level may indicate the development of
a bog mat around the edge of the Mile 47 Bog pond, a body of
'water which would have been considerably larger at this time,i.e.
during the early stages of organic accumulation.

The several samples from the upper part of the shrub
zone in the Mile 47 Bog section containing high proportions
of $2222 pollen, deposited between approximately 8,600 and
7,000 years B.P., are puzzling in view of the environmental
interpretations being developed (Fig. 23). Jansen (1967)
states that 21222 sp. indicates high pH and a high base con-
tent of the soil. It is significant that the plant appears
to have become established in Mile 47 Bog around the time
of initiation of marl deposition, when, with dissolved calcium
carbonate being brought into the bog in increased quantities,
the pH would have been higher than previously. It cannot be
said with certainty why $2222 did not remain in the bog any
longer than is indicated by its pollen record, nor why it
did not appear in any of the other bogs. Possible factors
include a change to less favorable, i.e. lower pH levels,
increasing competition from other plants on the developing

bog mat, or a change to less favorable climatic conditions.

257

Typha is considered a plant of temperate affinities (Ritchie
and de Vries, 1964), but it is doubtful that the climate was

more temperate during the time that Typha appears to have

grown in the Mile 47 Bog than at other times. Sangster and

Dale (1961, 1964) have shown the low preservability of M
pollen in various kinds of sediments, suggesting that the
answer to the present problem is lack of representation at
all but certain levels where unusual chemical conditions
prevail in the sedimentary environment.

At approximately the 7 ,200 year level in the Mile 47 Bog
diagram a major rise in spruce pollen percentages occurs,

indicating that the transitional spruce woodland vegetation,

represented by lower pollen percentages, was relatively

Short-lived and that spruce forests were developing, pro-
bably over most of the valley floor as well as upon increas-

ingly large areas of the valley walls as the climatically

controlled timberline receded upslope. Accompanying this

rise is a decrease in willow, birch, and Artemisia percentages,

indicating that the shrub tundra vegetation zone was being
displaced upslope to sites more distant from the deposition

By this time temperatures probably had risen to around

site.
A concomitant increase in dryness is

the present levels.
indicated by a drop in the alder and a significant rise in

the grass profiles. Accompanying this is the appearance of

r. few grains of juniper pollen and a somewhat higher frequency

1f Shepherdia pollen in several samples from this part of the

 

action. Both of these plants occur more commonly on dry

Ltes.

 

258

At approximately the 5 ,200 year level a major decline in
spruce pollen percentages occurs, accompanied by a moderate

increase in alder and a slight increase in birch percentages

(Fig. 23). Because of the notable drawback of the method of
plotting relative percentages of pollen, wherein a change in

the numerical abundance of one type in a series of samples
automatically influences the percentages and apparent abun-

dances of other types, even though the actual, numerical

abundances of the latter remain unchanged, it is not possible

to say whether only spruce, only alder, or whether both
varied in importance in the vegetation-around Mile 47 Bog.

It is possible, nevertheless, that alder became somewhat
Spruce impor-

more important in the vegetation at this time.
AS has

tance may or may not have declined concomitantly.
been shown, one type of habitat for alder at present is wet

sites in stands of the feather moss faciation of the white

spruce association. By invading such Sites, alder may have

increased with no corresponding decrease in spruce, a change
which might have resulted from the onset of a period of higher

precipitation. The moisture indicator value of alder is dis-
cussed in connection with the Moose Bones and Mile l6 Bog

records. The discussion of the birch profile in the Moose
Bones Bog record may also be applied here as support for the

interpretation of a return to a wetter climate.

The Cyperaceae profile may be significant at this point.

Figure 23 shows that Cyperaceae percentages decrease consid-

erably, beginning some time prior to the decrease in spruce

rag-:2-

259

percentages, and remain low during the period of lower spruce

and higher alder percentages. Keeping in mind the method

of construction of the diagram (Chapter XI), it can be seen

that the profiles for spruce, alder, etc., are independent

 

of the Cyperaceae profile insofar as the mechanics of diagram

construction are concerned. All of these profiles may be N

related, however, in reflecting the influence on all plant 1|

types of changes in environmental conditions. In the present “5

case, an increase in precipitation may not only have promoted
a return of alder to greater importance in the upland vege-
tation, but may also have raised the water table in the bog.

This may have caused flooding of the bog mat, thereby re-
ducing the amount of semi—aquatic Carex and/or Scirpus habi-

tat. With the areal extent of this vegetation reduced, in

conjunction with its displacement to a greater distance from

the deposition site, Cyperaceae pollen deposition at the site

would have dropped to lower levels. (See Figure 31 and dis-

cussion in Wilson Creek Bog section.)

At approximately the 2,500 year level in the Mile 47
Bog section pine pollen makes an appearance and, in general,
anreases upwards to the surface as in the other bogs. The
.ignificance of this increase is believed to be related, as
n Moose Bones and Mile l6 Bogs, to increasing dryness of
he climate during the time represented. '

Further evidence for such a climatic trend is provided

' the Cyperaceae profile. As was explained above, the

duction in Cyperaceae pollen percentages through spruce

 

260

zone times is believed to be related to increased precipita-

tion and a rise of the mean water level in the bog. If pre-

cipitation began to decrease around 3,000 years B.P., then
the water level may have begun to fall, bringing about a

corresponding increase in Size of the sedge zone, or the

bulrush zone, as the case may have been (Fig. 15). This

could have caused the major increase in supply of Cyperaceae

pollen indicated by the rise in the profile around the

spruce/pine zone boundary.
It is suggested that as dryness increased, the bog

water table continued to fall, bringing about a reduction

again in size of the sedge zone. In this case, however, the

encroachment upon this zone was from the periphery, as the

shrub zone increased centripetally, rather than from the
inside, as when the water table rises and there is flooding

(Fig. 31). If this process actually occurred, then an

increase in shrub pollen would be eXpected to correspond

with the decrease in sedge. It is seen (Fig. 23) that

willow pollen percentages do, in fact, increase in samples

from the uppermost levels. At present there are no alder

or birch in the shrub willow zone of the bog and, if this

were also true in the past, only willow percentages would

be eacpected to rise here. It can be seen that alder and

birch percentages remain at low values in approaching the

surface.
Although evidence from the Mile 47 Bog section pre-

sented so far indicates a return to drier conditions by

 

l

 

261

upper spruce zone time, the alpine fir profile indicates
rather strongly that conditions remained moist, perhaps

becoming more so by the end of spruce zone time around 2,500
years B.P. (Fig. 23). Such an interpretation has been
developed already for the Moose Bones and Mile l6 Bog

records. At present, alpine fir in the Atlin valley
appears to grow in places of higher precipitation, i.e. in

the southern part of the valley and at higher elevations in

northern areas. Thus as a moisture indicator the appearance

of alpine fir pollen in later Spruce zone times would sup-
Infrequent

port the hypothesis of increased precipitation.

earlier occurrences, back to the 7,100 year level, may be
explained by long distance transport. During earlier, drier

times, fir would probably have existed only at higher ele-
vations at the latitude of Mile 47 Bog. Since alpine fir

tends to be quite underrepresented in pollen spectra (Fig.
28), it is difficult to estimate its actual vegetational

It is fairly certain, however, that by late Spruce

status.
zone times the species had become established as a fairly

important member of the vegetation at lower elevations.

its status appears, by virtue of less frequent pollen

Later,
occurrence, to have declined somewhat during pine zone times

when, as is suggested above, precipitation probably also

fecreased.
There is no evidence in the alpine fir profile, in the

arm of a re-increase in pollen percentages, of a return to

atter conditions during the last several hundred years, a

 

 

262

hypothesis which will be developed presently on the basis

of the willow and Cyperaceae profiles. However, this does

not negate the hypothesis because it would probably take fir

longer to respond to such a change, i.e. to invade certain

sites at lower elevations in significant quantities and grow

to pollen producing age, than it would willow and sedge in p

the bog. FE
Such considerations as this may be important with regard L'

to the question of why alpine fir did not appear earlier in

the record, i.e. around 5,200 years B.P. when, as is dis-

cussed above, the climate is believed first to have become

wetter. There may be a lag time for fir establishment after

climatic conditions change to favor its occurrence in an

area because of difficulty in invading an already stable

vegetation. The palynological record shows that this vege-

tation was probably white spruce forest (Fig. 23).
The drop in the willow profile near the top of the

section indicates that precipitation may have increased

again during the past several hundred years. Evidence for

this was first presented in the discussion of Mile 52 Bog

vegetation. Here it was suggested that a stand of dead

spruce trees near the northeastern edge of the pond may have

been killed by a recent rise of the water table. Several

dead white spruce trees have also been encountered in Mile

47 Bog, primarily in the sedge-moss zone (Fig. 15) and a

number of small dead spruce occur in the sedge zone of

Jasper Creek Bog. These can be seen in Figure 18 toward the

 

263

left Side of the photo in the area between the two ponds.
In addition, Lietzke (1970) in his study of the soil in stand
59W, suggested that a recent trend to a more moist climate

may be responsible for increased deposition of lime near the

surface there.

 

‘.

Contrary to expectation, confirmation of the present _
interpretation of the upper willow profile in Mile 47 Bog Fr
is not found in the Cyperaceae profile, which generally con- 21
tinues to decline toward the surface. The anomalously low '
proportion of Cyperaceae pollen in the Mile 47 Bog surface

sample, in Spite of the abundance nearby of Scirpus validus,

is discussed on page 210. Although no explanation is avail-

able it can be reasonably assumed that the low Cyperaceae

percentages are not related to climate, but instead to some

problem in pollen productivity or preservation in recent

times. Scirpus validus is obviously present in abundance in

a relatively extensive, semi-aquatic zone (Fig. 15). There

is no evidence, other than lack of Cyperaceae pollen in the

record, that this zone has not increased in size during the

past few hundred years. Thus, the hypothesis cannot be

nullified on this count.

The appearance and rapid rise to considerable percentage

levels of the Triglochin-Potamogeton pollen type during the

time interval in question probably relates to these low

Cyperaceae pollen values. Since percentages for Triglochin- {
\

Potamogeton.type and Cyperaceae are calculated on the basis

 

of the same total, i.e. the total pollen and spore count

 

264

 

exclusive of Pediastrum, a major increase in the former would
obviously influence the relative abundance of the latter

pollen type, thereby partially explaining its low values.
If the pollen type in question here is Potamogeton, its

abundance in the upper levels of the section would support

the hypothesis of increased precipitation during the time [F

represented. With an increase in the bog water table, there

would have been an enlargement of the area of open pond water,

and therefore of Potamogeton habitat. This, of course, leaves

open the question of why Potamogeton did not appear during

earlier times of higher precipitation. A temperature control

cannot be invoked in this case, as Potamogeton, a low arctic
species (Porsild, 1964), could probably have existed under

the range of temperatures proposed here for Holocene time.

 

In view of this, and in view of the fact that Potamogeton
does not occur at present in the Mile 47 Bog pond, whereas

Triglochin was found to be common in the bog, the pollen pro-
Because of

 

file here is probably that of the latter genus.
the broad geographic distribution of both Triglochin mari-

timum and _T. palustris, these species have little climatic

indicator value .

Jasper Creek Bog
In many ways the Jasper Creek Bog record is Similar to

that of Mile 47 Bog and, in the upper part, to the records

of Mile l6 and Moose Bones Bogs (Fig. 21-24). However, there

are a few important differences which must be discussed.

265

Additional significance lies in the fact that the record

from Jasper Creek Bog appears to go back farther than in the

other bogs.
There are no radiocarbon dates for the Jasper Creek Bog

section, but dates from Mile 47 and Wilson Creek Bogs permit

the application of a tentative chronology. As was shown in

Chapter XII, the peat accumulation rate in Mile 47 and Mile

52 Bogs has been 0.044 cm/yr, on the average, and the Wilson
Creek Bog rate has averaged 0.042 cm/yr, a very similar

value. It seems reasonable to assume that the peat accumu-
lation rate for Jasper Creek Bog has been of the same order

of magnitude. Since Jasper Creek Bog is closer to Wilson
Creek Bog, the rate from the latter is used to calculate a

tentative age of 3,690 years B.P. for the base of the peat.
Extrapolating upward from.this level, the Spruce/pine zone

boundary is set at 2,500 years B.P. (Fig. 24).

The only available marl accumulation rate is the one

for the Mile 47 Bog section of 0.036 cm/yr. Applying this

to the Jasper Creek Bog section gives a date of 11,050 years
B.P. for the beginning of marl deposition. This estimate

is probably too great because of the likelihood that marl
has accumulated at a faster rate here than in Mile 47 Bog

due to proximity of an extensive source of calcium carbonate

(p. .18; Fig. 18). The age of this level Should therefore

be reduced somewhat.
An indication of the amount of reduction required may

be obtained from the Wilson Creek Bog record (Fig. 25).

.4:
.1

 

266

There, peat accumulated over a much longer period of time, the
base of the peat being radiocarbon dated at 8,000 f 350 years
B.P. The base of the peat there lies only a short distance
above the shrub/spruce zone boundary, a reasonable age esti-
mate for which may be obtained by applying the aforementioned
Mile 47 Bog marl accumulation rate. Since the thickness of

marl between the shrub/spruce zone boundary and the base of

 

the peat is relatively small, any error in extrapolation
should be correspondingly small. In addition, Wilson Creek
Bog is not so directly influenced by drainage from nearby
extensive areas of carbonate rocks as is Jasper Creek Bog.
Thus the marl accumulation rate may have been somewhat less
than in the latter bog, perhaps more nearly the rate in Mile
47 Bog. Applying this rate, 0.036 cm/yr, in extrapolating
downward from the 8,000 year level in the Wilson Creek Bog
section gives a date of 8,860 years B.P. for the shrub/spruce
zone boundary. To be conservative, and to account for the
probability that the marl accumulated at least a little
faster here than in Mile 47 Bog, this estimate is reduced
to 8,500 years B.P.

Wilson Creek and JaSper Creek Bogs are only about six
miles apart and lie at the same latitude (Fig. 1). Therefore
major vegetation changes on the uplands around each of them,
of the type reflected in the pollen profiles across the
shrub/spruce zone boundary, were probably contemporaneous.

On this assumption it is believed that the Jasper Creek and

Wilson Creek Bog diagrams correlate closely and that the

267

estimated shrub/spruce zone boundary age of 8,500 years B.P.
in Wilson Creek Bog may reliably be extended to the Jasper
Creek Bog section. This provides a date for a level only a
short distance from the base of the marl in the latter.
Extrapolating to the base of the marl, and taking the pre-
cautions discussed above, it can be seen that the age of the
first marl deposits in Jasper Creek Bog is, at most, 10,000
years, and probably considerably less. An age of 9,500
years is suggested.

The problem of establishing a time scale for the blue-
gray clay portion of the section is the same as for the
Mile 47 Bog section as discussed on pages 243-245. It is
possible that only a few hundred years are represented here,
or perhaps one or two thousand. By correlation with the
Wilson Creek Bog diagram, the outstanding spruce pollen peak
at the 4.7 m level appears to have occurred around 10,200
years B.P. In Wilson Creek Bog, this peak may be more
accurately dated because of a radiocarbon date within the
section (Fig. 25).

The earliest pollen assemblages from Jasper Creek Bog,
‘below the 4.9 m level (Fig. 24), reflect a tundra vegetation
consisting of elements of both herbaceous tundra and shrub
tundra vegetation types. Indicative of the herbaceous tundra
are Cyperaceae, Gramineae, Artemisia, Compositae, and poss-
ibly the undifferentiated types, believed to consist primarily
of herb pollen. Shrub tundra is indicated by willow, alder,

and, particularly, birch pollen.

 

 

 

 

268

The exceptionally high alder percentages in this case
are not believed to represent a moist climate so much as the
proximity of glacial outwash terrain upon which alder may
have been relatively abundant as a pioneer species. Since
alder is favored by a somewhat warmer climate than is gen-
erally associated with herbaceous tundra, it is concluded

that the area in the immediate vicinity of Jasper Creek Bog

P'- I‘L... .

was occupied primarily by shrub tundra and that herbaceous
tundra occurred somewhat farther away at higher elevations
on slopes of the nearby Johnson Range (Fig. 19).

The lower Egyag pollen peak, probably produced by plants
colonizing the surrounding, then recently deglaciated terrain,
may, in conjunction with the tundra types, reflect a signifi-
cantly cooler climate than at present. 0n the basis of these
vegetation interpretations and other evidence presented
earlier, the mean July temperature at this time may have been
on the order of 47-48° F.

A striking feature of the Jasper Creek Bog record is
the high spruce peak centered on the 4.7 m level, a level
dated, as eXplained above, at 10,200 years B.P. Since a
similar peak occurs at the bottom of the Wilson Creek Bog
diagram, at what is probably a comparable level in time,
it appears that a major change in the vegetation occurred
in.the vicinity of these two bogs and that a spruce-rich
flora dominated the scene for at least a few hundred years.
Such a peak as this might be attributed to reworking and
redeposition of older deposits containing high proportions

269

of Spruce pollen. In view of the fact that the two bogs
involved are located in different local drainage basins,
this explanation does not appear reasonable.

In attempting to explain these early, isolated spruce
pollen peaks, consideration must be given to the possibility

that a temporary invasion of Sitka spruce was responsible.

An important indication of this is the fact that the average

IP'J'

size of the spruce pollen grains in the samples in question
from both Jasper Creek and Wilson Creek Bogs is significantly
less than the average for white spruce. In the Wilson Creek
Bog diagram the frequency of spruce grains measuring less
than 96’” between the tips of the bladders are plotted in a
separate column (Fig. 25). In Jasper Creek Bog, all five of
the spruce grains encountered at the 4.75 m level were of
this size category, and at the 4.70 level, about one-half of
the 91 spruce grains counted were less than 96‘“ in size.

It has been shown by several investigators that the mean
measure between the tips of the bladders of white spruce
grains is somewhat greater than 100‘”, and for black spruce,
less than 100,H- A statistical study made by the writer
indicates that 96 iiis probably a more appropriate measure
for distinguishing the two species in this region. The pro-
bability, however, that the spruce grains in the below 96‘”.
size category in the Jasper Creek and Wilson Creek Bog samples
are of black spruce is low in view of the fact that this
species is not known to occur in the Atlin valley at present,

and there is no reason to believe that conditions, namely an

270

acid substrate, were more favorable for it in this area in
the past. 0n the other hand, Heusser (1960) shows that
Sitka spruce grains are also smaller, on the average, than
those of white spruce.

At present the environment of Sitka Spruce is charac-
terized by fairly high precipitation and humidity and mean
July temperatures ranging from around 52 to 640 F (Heusser,
1960). The species is believed to have occupied a refugium
in the northern Queen Charlotte Islands during the Wiscon-
sinan (Heusser, 1960). Summer temperatures in the southern
part of the Atlin valley might have risen rather sharply
around 10,400 to 10,500 years B.P. Similar changes may
have occurred in the general region between the valley and
the Taku River and within this valley and others even
farther south where they transect the Coast Mountains. This
temperature change, in conjunction with higher precipitation
levels, may have promoted the migration of Sitka spruce
through one or more of the trans-range valleys and into or
near the southern part of the Atlin valley.

A return to cooler conditions within a few hundred
years might have brought about the demise of the Sitka spruce
p0pulation in this area and a return to a shrub tundra vege-
tation type, evidence for which is well shown in both dia-
grams just below the shrub/spruce zone boundary (Fig. 24, 25).
It is to be noted that the proposed mean July temperature
decrease need not have been of the same magnitude as the in-

crease, from the level of perhaps 47° F suggested above for

271

the time prior to spruce immigration, to the 52° F or more
which would have been necessary to bring this immigration
about. A decrease to just below 52° F may have been suffi-
cient for removal of the Sitka spruce pOpulation. Although
the temperature regime may then have remained favorable for
white spruce, i.e. mean July temperature greater than 50° F,
this species, if it migrated into the region from the north,
would not yet have reached the Jasper Creek Bog area. As was
explained earlier, it apparently did not reach the Mile 47-
Mile 52 Bog area until around 8,000 years B.P. (p. 247-250).
The shrub-Spruce zone boundary, as discussed above, is
set at the 8,500 year level in Jasper Creek Bog. At this
level spruce pollen becomes very abundant again, a condition
'which is maintained through the remainder of the section.
If the record of white spruce migration into the Atlin valley,
as interpreted earlier and reiterated above, is reliable,
then this species could not have reached the JaSper Creek
Bog area until at least 7,500 years B.P. In view of this,
the first thousand years or so of continuous spruce occur-
rence in the area may have involved a return of Sitka spruce
under the influence, again, of higher summer temperatures
and rainfall. Then, if the climate had gradually become
drier during early Spruce zone times, Sitka spruce would
again have died out. But by this time white spruce, having
finally migrated into the southern part of the valley, could
have replaced Sitka spruce in the upland vegetation. Given

that this replacement occurred gradually and continuously,

272

there need not appear any break in the pollen record to mark
the event, save for a shift to slightly higher mean pollen
size. Such a shift was observed.
unfortunately the evidence against the migration of
Sitka spruce into the southern Atlin valley area in early
Holocene times is rather strong, and the temperature con- .
ditions which would have been necessary conflict with the F-
low summer temperature interpretation developed earlier for '
the pre-spruce period in the northern part of the valley
(p. 249-251).
In the first place, the summer temperature increases
which this hypothesis prOposes, including a mean July in-
crease of at least 5° F, are not likely to have occurred
within a space of only two or three hundred years.
Secondly, a return of summer temperatures, around
8,500 years B.P., to levels favoring a return of Sitka spruce
would most likely have been accompanied by comparable, and
perhaps, in view of the more continental location, even
higher temperatures in the northern part of the valley.
Uhder such circumstances the rate of southward migration
of white Spruce would have been greater, and spruce pollen
‘would be expected to appear considerably earlier in the Mile
47 and.Mile 52 Bog sections than it does.
If 22225 is as good an indicator of a cooler climate as
has been discussed earlier, then the occurrence of a second
[Egyag pollen peak within a short time of the spruce peak in
Jasper Creek Bog would tend to nullify the hypothesis.

273

A fourth consideration involves precipitation. The
minimum mean annual precipitation within the present range
of Sitka Spruce is around 32 inches, and at most stations
it is considerably higher (Heusser, 1960). The mean annual
precipitation at Atlin is approximately 11 inches (Table 1),
and it is probably several inches higher than this in the
southern part of the valley at present. Although the pre-

_'_

cipitation may have been higher yet in this area prior to

If-

the first spruce pollen peak, a possibility indicated by the
high alder pollen percentages, it is difficult to see how

it could have been greater than around 20 inches. In the
Snag-Klutlan area Rampton (1969) associates the shrub tundra
vegetation type with mean annual precipitation levels of
only eight to ten inches, and the herbaceous tundra there

is believed to have existed under an even scantier regime.
However, alder pollen is of low percentage value or absent
from the record in shrub and herbaceous tundra times there.
Nevertheless, alder in the Atlin valley may thrive at pre-
cipitation levels considerably lower than 32 inches per year.
It appears that a more than plausible precipitation increase,
as well as a major temperature increase, would have been
necessary for Sitka spruce to enter the southern part of the
.Atlin valley.

If, in spite of all this, Sitka spruce did migrate from
the northern Queen Charlotte Islands into the southern part
of the Atlin valley by 10,200 years B.P., significant quan-
tities of spruce pollen should be found in samples of

27a

comparable age from bogs in the southern portion of the
southeastern Alaska panhandle and in north—coastal British
Columbia. These areas would have lain across the hypo-
thetical migration route. However, Heusser's (1960) investi-
gations Show that Sitka Spruce did not become established
here until around 8,000 years B.P., the time of beginning of
the Thermal Maximum.

Finally, it is not likely that Sitka spruce, or any L.
other non-alpine species, could have migrated through any 2
of the more northerly of the trans-range river valleys, such
as that of the Taku, prior to around 8,000 years B.P. Before
this time the valleys were still occupied, at lower eleva-
tions, by ice of the dwindling cordilleran glacier complex
(Heusser, 1954a).

The pros and cons of the hypothesis of a Sitka spruce
migration into the southern part of the Atlin valley during
early Holocene time, or perhaps during late Pleistocene
Allerod time, have been explored because without it, or a
similar hypotheSis, an explanation of the prominence of
spruce in the lower part of the profiles in both the Jasper
Creek and Wilson Creek Bog sections becomes very difficult.

Additional information is required to settle the problem.
Particularly, several sections are needed from'bogs south
of the Atlin valley in areas adjacent to the eastern flanks
of the Coast Mbuntains and in the vicinity of the Taku River
valley. Besides the radiocarbon dating of these sections,
careful identifications will have to be made of the spruce

L

275

pollen grains in an attempt to differentiate between white
spruce, Sitka spruce, and perhaps also black spruce which
may have occupied some of the areas involved.

In spite of the present phytogeographic problem, some
useful conclusions can be drawn on the basis of the infor-
mation at hand. In view of the occurrence at approximately

the 10,200 year level of considerable quantities of spruce

. h. anti

pollen of one species or another in both the Jasper Creek .l
and Wilson Creek Bog sections, it is clear that the local
vegetation contained at least a few spruce trees. It is
concluded that the mean July temperature, accordingly, was
at least 50° F, the minimum for white spruce, if not 52° F,
the approximate minimum for Sitka spruce.

This short, warmer interval appears similar to the
Aller5d or Two Creeks of other areas and the Late Glacial
II of Heusser (1960, 1965) for the Olympic Peninsula. Al-
though the Two Creeks interval had ended by at least 11,000
'years B.P. (Broecker and Farrand, 1963; Heusser, 1966), the
present interval appears not to have begun until about 500
years later. unfortunately the latter age estimate is deter-
mined by extrapolation and correlation from too few radio-
carbon dates. Uhtil more dates for the Jasper Creek and Wil-
son Creek Bog sections, or comparable sections from nearby
areas, are available, the true magnitude of the time differ-
ential, if any, between the early warm interval (Zone VIII,
Fig. 32) of the Atlin valley and the Two Creeks of mid-
Continental Nerth America, or the AllerBd of Europe, cannot

be known.

276

On pages 26-32 the Holocene glaciation and glacial
geology of the Atlin valley and adjacent areas is discussed
and some preliminary interpretations with respect to climatic
oscillations are made. It appears that the lower sediments
of the Jasper Creek and Wilson Creek Bog sections were

deposited while ice still occupied the main Atlin valley

'3

and the glacial features discussed earlier, including pitted

Tr .t-._ n.
1..-

outwash, knob and kettle topography, and gravel terraces,
were being formed in the northernmost part of the valley.

The Jasper Creek and Wilson Creek Bog sites are situated in
the O'Donnel-Pike River transection valley, which opens into
the main Atlin valley. These sites were covered by a dis-
tributary from the main ice stream flowing northward out of
the Northern Boundary Range (Aitken, 1959; Fig. l). The
distributary ice would have been thinner in the O'Donnel—
Pike River valley and over the bog sites than in the main
valley because these sites lie at a higher elevation than
the floor of the main valley, i.e. the bottom of Atlin Lake.
Because of being thinner here, ice would have disappeared
from.the bog sites earlier. Thus bog succession and the
development of a pollen record could have been underway while
ice still occupied the main Atlin valley, including the Meose
Bones and Mile l6 Bog areas.

It is suggested that the early climatic oscillation
represented by the first Spruce peaks in the records from
Jasper Creek and Wilson Creek Bogs (Figs. 24, 25) is related
‘to a period of fairly rapid retreat of the glacier terminus

277

in the northern part of the valley. Specifically, the
gravel terraces and knob and kettle topography located
northeast of White MOuntain and the pitted outwash in the
Mbose Bones Bog area (Denny, 1952; Wheeler, 1961: Fig. l ;
p. 27) were formed during a time of stagnation correlated
with the lowest portion of the Jasper Creek Bog record.
This provides a date for the origin of these features of

1m
!
5

around 10,400 years B.P.

During the next few hundred years, under a temporarily
warmer climate, the ice melted out of the Little Atlin
Creek valley north of White Mbuntain and the Little Atlin
Lake portion of the main valley.

It is suggested that after this, with a return to
cooler conditions around 10,000 years B.P., stillstand of
the ice front again occurred, bringing about the formation
of the kame terrace in which Mile l6 Bog is located (p. 143).

As the climate became warmer again, about 9,000 years
B.P., a more continuous retreat of the main ice stream from
the Atlin valley appears to have begun. Although another
period of slower retreat, with periodic halts of the ice
front, probably was responsible for the series of closely
spaced recessional moraines at the head of Atlin Lake
(p. 28), this is not reflected in the records from Jasper
Creek and Wilson Creek Bogs.

Continuing upward in the Jasper Creek Bog diagram
(Fig. 24), interpretations comparable to those developed for
the Moose Bones, Mile l6, and Mile 47 Bog sections seem

 

278

reasonable. A transitional spruce woodland vegetation type

is indicated by the moderate, although increasing, spruce

pollen percentages and the declining birch percentages at

the shrub/Spruce zone boundary. The mean July temperature

at this time was, again, at least 50° F, and probably con-

tinued to rise through early spruce zone times. A peak ‘
in juniper pollen at the boundary, followed by another a [P

short distance above, indicates that conditions were drier ‘

F?‘

than before. The drop in Cyperaceae percentages, following
a peak in the upper shrub zone which probably reflects the
development of a bog mat, may also indicate drier conditions.
In this case, a lowering of the bog water table may have
brought about the destruction of sedge habitat (see p. 281-
284 and Fig. 31).

The willow and birch profiles may reflect the occurrence
. of these plants in a large moist, but not wet, zone around
the bog pond in early spruce zone times, a zone which in-
creased in size as the water level fell. This interpretation
seems reasonable in view of the fact that willow pollen is
scarce in the surface and near-surface samples from the bog,
in spite of the fact that at present a few willow shrubs
occur around the periphery of the bog. In order to have had
even the moderate willow representation shown for early
spruce zone times (Fig. 24), willow habitat must have been
more extensive than now.

That precipitation increased again in later spruce zone

time is indicated first by the alder pollen percentage rise

279

beginning at about the 2.45 m level. The extrapolated date
for this level is 5,400 years B.P. Although the alder pro-
file drops to quite low levels at approximately 1.75 m,
significant proportions of alpine fir pollen occur here, and
this, as was argued earlier, may indicate continuing moist-
ness in upland areas. In addition, the rise to a consider-
able percentage of the Cyperaceae percentage just below the
spruce/pine zone boundary may be related to a redeveIOpment
of sedge brought about by a rise in the bog water table.

A return to drier conditions in pine zone time is
indicated by the notable expansion of the lodgepole pine
profile and the decreases of fir, alder, and sedge percen-
tages (Fig. 24). Although it may be a little too early in
the profile, the Gramineae pollen observed across the zonal
boundary may also be related to such conditions.

As is discussed elsewhere (p. 258-260, 281—284), the
slight rise in the Cyperaceae profile at the top of the
section is an indication of a return to wetter conditions

‘within the past few hundred years.

Wilson Creek Bog

Because dating and important profile features of the
Wilson Creek Bog section have been discussed earlier, par-
ticularly with respect to establishing a chronology for the
JaSper Creek Bog section and in working out the Holocene
phytogeography of spruce and lodgepole pine, only a brief
review of the record and of local environmental interpreta-

tions need be made here.

280

The record is believed to begin at least 10,200 years
B.P. (Fig. 25). At this time the spruce profile appears to
be undergoing a decline from what may have been an even
greater peak, comparable to the one in Jasper Creek Bog
(Fig. 24), in response to an interval of notably warmer
climate. At this time values are quite low for willow and
particularly birch, indicating that the earlier shrub tundra
vegetation, occurring at lower elevations in the vicinity
of the bog, had been largely replaced by spruce forest. High
alder values at this time may indicate that, while warm,
the climate was also somewhat more moist. Much of the alder
may have grown as an early colonizer of nearby meltwater
stream.bars, but the moist climate interpretation is given
some additional support by the appearance of a few Umbelli-
ferae grains near the bottom of the section along with
Spores of Polypodiaceae and Selaginella and high values of
Cyperaceae pollen. In addition, pollen of plants which
often indicate dry conditions, such as juniper, grass, and
Artemisia, are infrequent.

Following closely upon this interval, approximately
10,000 years B.P., a return to cooler conditions is indicated
by the near disappearance of spruce pollen and the increase
of willow and birch. That it may also have been drier is
indicated by the drop in alder and sedge percentages and the
rise of Artemisia and Compositae. At this time the major

vegetation surrounding the bog was probably a shrub tundra.

281

The mean July temperature may have been around 48° F, and pre-
cipitation probably was low.

By about 9,000 years B.P. spruce entered the area again
and a spruce woodland appears to have occupied most upland
sites until around 8,500 years B.P. By this time stands of

closed spruce forest may have become established on many

‘ 3

sites (See Figure 30.)

A)...

Except for low values of alder and the appearance of a L,
few juniper, grass, and Thaligtgum grains, evidence for dry-
ness in early spruce zone times, unlike the other sections,
is lacking. The occurrence of significant quantities of
Selaginella spores and of high Cyperaceae pollen percentages

 

would seem to indicate more moist conditions. Hewever, these
latter two observations might be reconciled with increased
dryness. Selaginella, i.e.g§. selaginoides, is a plant of
wet or damp places (Colinvaux, 1964; Hultén, 1968) and may
therefore have been limited to the bog, in which case there
would be no relationship with dry, upland terrain. With
regard to the Cyperaceae profile, it has been suggested that
a lowering of the bog water level in response to a lower
precipitation regime could bring about an increase in amount
of habitat suitable for sedge growth in an area where the
water had previously been too deep.

It is recognized that this is contrary to the mechanism
suggested for changes in amount of sedge habitat in Jasper
Creek Bog (p. 279): although comparable with the suggested
Mile 47 Bog situation (p. 259). These arguments need not

282

conflict. It is believed that the size of the bog basin and
the configuration of its floor, or of the surface of the
overlying sediments in which plants take root, determine the
environmental effects of changes in water level. Figure 31
illustrates two hypothetical cases. In A, under the condi-
tions of water level 1, the sedge zone, a zone observed in
the Atlin valley to occur where the water table is ordinarily (F-
at or just above the ground surface, is larger than under
conditions of water level 2. In case A the water is too deep
for sedge growth in the former sedge zone (1), and there is
little terrain where the new water level (2) bears the appro-
priate relationship to the ground surface for sedge growth.
In B, the reverse situation is illustrated. In this case a
rise in the water table causes a major increase in sedge
habitat. It is also to be noted that sedge zone 2 may have
been a shrub willow zone during the time of lower water level.
It can be seen that, depending on the physiography of
Mile 47, Jasper Creek, and Wilson Creek Bog basins, lowering
of their respective water tables might bring about the sug-
gested results. Mile 47 and Wilson Creek Bogs may be exemp-
lified by case A, whereas B is intended to Show what may be
the Jasper Creek Bog situation. Further field work in these
‘bogs will be necessary to confirm or disprove this hypothetical
mechanism, although it is doubtful that any meaningful con-
clusion about the mechanism, as it may have operated in the
past, can ever be drawn because of the impossibility of know-

ing the surface configuration of the sediments in the bogs in

283

 

——SEDGE ZONE 1 ———-

 

 

 

 

 

 

 

 

 

 

‘\\-~.___,—fla///’//’ ——— SEDGE ZONE 2—__~Mm-
B 603 ZONE 1

Figure 31. Hypothetical effects of changes in levels of
bog water tables on sizes of sedge vegetation zones.

(See text.)

284

the past. In addition it is believed possible that, as sedi-
ments of different types accumulated at different rates in
different parts of a bog, the overall surface configuration
may have changed in such a manner that the effects of fluc-
tuations in the water level may also have changed.

Continuing upward in the Wilson Creek Bog diagram (Fig.
25), somewhat more moist conditions are indicated by a

slight rise, beginning around 2.75 m, of the alder profile,

i
it,“

followed by a rather significant rise in the fir profile at
1.4 m. Above the spruce/pine zone boundary, beginning about
2,600 years B.P., conditions again appear to have become
drier. This is indicated by the continuing increase in pine,
the declining fir and alder profiles, and perhaps also by
the continuation of the Gyperaceae profile at moderate to
high levels.

For reasons discussed above the prominent decrease in
the cyperaceae profile within the upper approximately 25 cm
of the section may indicate a return to more moist conditions

during the past several hundred years.

Regional interpretations

The analysis of the extant vegetation and environments
in the Atlin valley presented in the first part of this
dissertation, in conjunction with interpretations and dis-
cussions of the five sections constituting the general
palynological record for the valley presented in this chapter,
make it clear that conditions have not been the same in all

areas during the Holocene. Because of minor maritime climatic

 

285

influences the southern part of the valley has been, and
remains, different from.the northern, more continental part.
The Jasper Creek and Wilson Creek Bog records indicate
higher precipitation levels than at Mile 47, Mile l6, and
Mbose Bones Bogs. There seems also to be evidence in the
palynological record of differences in summer temperatures,
the southern part of the valley being, on the average, T
somewhat cooler than the northern part. It is emphasized E
that these precipitation and temperature differences, and
corresponding vegetation differences, are not considered to
have been large, nor are they at present. The Atlin region
is distinctly continental throughout and cannot be considered
as lying along a major maritime-continental climatic gra-
dient. Furthermore, the present study can only provide some
indication of the qualitative nature of the differences.
To estimate the true magnitude of present and past climatic
differences in different parts of the Atlin valley and in
the region as a whole, meteorological data will have to be
Obtained from several new stations, and additional palyno-
logical studies will have to be made. Particularly, the
determination of absolute rates of pollen deposition in bogs,
rather than of percentage frequencies of pollen occurrence
in bog samples which represent variable periods of deposi-
tion, may provide a more accurate indication of past vegeta-
tion types and associated environmental conditions.

Different rates and patterns of migration of certain
species into the Atlin region under early postglacial

286

 

 

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

YEARS B.P. ZONE MAJOR VEGETATION AT mg CLIMATIC GLACIAL
X 1.000 LOWER ELEVATIONS a; CHARACTERIZATION ACTIVITY
SPRUCE FOREST wm PINE ' ______
- ' MINOR CHANGES IL 8065 1: ill/I WARM WET Neoglacial
1. I {2 ’ advances
2": u SPRUCE EORESI wum PM. i‘ ; l COOL DRY Coigt
EL (Mountains
3, III SPRUCE FOREST wum FIR i “‘1 WARM WET
_. ' 'I
I
:5 4. I
g _ IV SPRUCE FOREST wnu ALDER i WARMER WETTER
2 I
z 5‘ I general
_I ‘ retreat
< l
E 6* I
u: a
I - a
I- V SPRUCE FOREST : WARM WET
7‘ ..
u I. ----- —4
8 ' i ter ittent
I, n m
- v| SPRUCE woooumo ”a COOL DRY I retreatJ
9 ’ ' £111 r. d'
ammsnmuu .v s s an
‘ VII (HERBACEOUS TUWA IN NORTH) ': COOLER DR'ER (readvance?)
‘ . I _j
0 VIII SPRUCE WOODLAND ’; COOL DRY 1 retreat ]
4" r fi*
"will---.51R‘EJTTL---.UCI __L.I-C_°9L.EB-.°‘3_'E_'3-2511135692.
50 54
q

 

* at: late Wisconsinan maximum

A tentative Holocene geobotanical chronology tor the Atlin region

Figure

32

I?

 

 

envi
ence

mor'

pro
dev
Atl

gen

key
enc
rep:
con:
ShOI
brie
the:
from
back
fUtu

to h:
termE
and d
defin;
MM

”00d1

286-A

environmental conditions were also responsible for differ—
ences in vegetation in various parts of the region until
more recent times.

An attempt has been made to synthesize the information
provided in the records from each of the five bogs and to
develop a composite Holocene geobotanical chronology for the
Atlin valley and, by inference, for the Atlin region in

_ “.-...‘_.

general. The results of this synthesis are depicted in
Figure 32. Here the differences in time of occurrence of
key indicator species, such as spruce and pine, and differ-
ences in the extent to which major vegetation types are
represented are averaged, as it were, for the purpose of
constructing the general record. A nine-zone chronology is
shown, and each zone, beginning with the oldest, No. IX, is
briefly discussed below. Although many palynologists number
their zones from the bottom up, the zones here are numbered
from the top down in anticipation of extending the record
back in time, with the establishment of additional zones, as
future work is conducted in the Atlin region.

In order to characterize the climate which is believed
to have prevailed during the time of each zone, the relative
terms "cooler, cool, warm, and warmer" and "wetter, wet, dry,
and drier" are used. There is little basis for quantitative
definitions of these terms at this point, except that "cooler"
may be associated with shrub tundra, "cool", with spruce

woodland, "warm” with spruce forest, as at present, and

 

 

0f
Vic;

beg,

tWee;

287

"warmer" with vegetation which existed when summer tempera-
tures were somewhat higher than at present.

Whereas the present climate of the Atlin region is con-
sidered "warm” on the temperature scale, it is also desig-
nated "wet". However "wet" in the absolute sense is not
implied. Instead the climate is considered wet relative to
what it was at various times in the past when precipitation

W I a" -.

levels appear to have been substantially lower than at
present. In general, cooler times tend to be associated
'with lower precipitation, and higher precipitation tends to
occur when growing season temperatures, on the average, are
higher.

Zone IX. Only the JaSper Creek record extends back
into this interval of time (Fig. 1, 24, 32). AS has been
discussed, the lower time boundary of the zone cannot be
determined with certainty because radiocarbon dates at appro-
priate levels in the section are lacking, and the sedimen-
tation rate is too uncertain for accurate correlation and
extrapolation. The upper time boundary may be set at 10,500
years B.P. on the basis of correlation of the isolated spruce
pollen peak with a similar one, more accurately dated, at the
bottom.af the Wilson Creek Bog diagram (Fig. 25).

It is possible that vegetation and climate characteristic
of the Zone IX time interval was already prevalent in the
vicinity of the bog at the time the Jasper Creek record
began (Fig. 24). In view of the thickness of sediments be-
tween the tentatively dated 10,200 year level and the bottom

of
It
fi
be

Atl
Ju5'
term

Olin

 

Stil
daril

24, 25

bGCauS I

 

288

of the section, this may have been about 11,000 years B.P.

It may have been about this time that late Wisconsinan ice
first retreated from the site, leaving behind a water—filled
basin in which the present bog has developed. By the time of
this retreat, a Shrub tundra vegetation had become established
on sites exposed earlier at somewhat higher elevations, giving
rise to the various pollen types shown. Alder appears to

have begun colonizing sites around the new basin only shortly
after the terrain was available.

Because of the nature of the vegetation it is believed,
for reasons discussed earlier, that the mean July temperature
during Zone IX time was around 47 or 48° F, some 6 or 7° F
below the 1906-1946 mean at Atlin (Table l). Precipitation
‘was probably less at this time, averaging perhaps 8 or 9
inches per year. Zone IX climate is characterized as cooler
(i.e. substantially lower temperatures than at present) and
drier. The late Wisconsinan advance (i.e. valders) of the
Atlin valley glacier is believed to have culminated during or
just prior to zone IX time. The northernmost position of the
terminus was in the Mbose Bones Bog-White Mbuntain area. These
climatic conditions appear to have been responsible for a
stillstand or even stagnation of the terminus in this area
during the latter part of the interval.

Zone VIII. This interval, indicated by the Jasper Creek

 

Bog record and, in part, by the Wilson Creek record (Fig.
24, 25, 32), is interpreted as warmer than in zone IX time

because of the temporary appearance, in the southern part

 

 

 

 

of

th:
phi
er
wc
CC

1C

gr

81'

by

deI
f1]
moi
(N
the
tin.
new
a f.
c111

MOun
“5.101
than
1‘ 5111.

01Mt

289

of the valley, of spruce. In view of an earlier discussion,
(p. 269-275) it appears more likely that white spruce, rather
than Sitka spruce, was involved, even though this leaves a
phytogeographic enigma. With white spruce, mean July temp-
eratures would have been at least 500 F. AS the climate
would have to have been favorable before spruce immigration
could take place, the beginning of the interval is set at
10,500 years B.P., approximately 300 years before the spruce
pollen peak at the 4.7 m level in the Jasper Creek Bog dia-
gram (Fig. 24). Shortly after the time of this peak temp-
eratures decreased again, bringing an end to zone VIII time
by 10,000 years B.P.

Precipitation levels in zone VIII time are not easy to
determine from the general record, as changes among the pro-
files of types which can often be used as indicators of
moisture levels are not contemporaneous in Jasper Creek Bog
(Fig. 24). In Wilson Creek Bog there is some indication
that conditions were more moiSt than in subsequent zone VII
time. This, in connection with the fact that spruce forest
‘usually occurs where mean annual precipitation is at least
a few inches higher than where tundra occurs, indicates the
climate was relatively moist.

With higher temperatures the freezing level in the Coast
Mbuntains, particularly during the spring and fall when the
:major storms occur, would have been at a higher elevation
than before. This may have changed the annual balance in
rain- and snowfall so that, in Spite of higher overall pre-

cipitation, critical névé areas east of the crest of the

 

 

Coast
less
the t

place

again
summe
to z«
cool
tion
sion
time
Atli

the
won]
for
aDDJ
Vali

OCC‘

 

290

Coast Range feeding Atlin region glaciers would have received
less snow and more rain. It is suggested that a retreat of
the terminus of the Atlin and Taku Arm valley glaciers took
place under these conditions during zone VIII time.

Zone VII. Around 10,000 years B.P. the landscape was
again covered by shrub tundra in response to a decrease in
summer temperatures and precipitation to levels comparable
to zone IX time. The zone VII climate is characterized as
cooler and drier. It is suggested that theSe climatic condi-
tions caused a halt in the overall pattern of glacial reces-
sion, resulting again in stillstand of the terminus, this
time in the area of the kame terrace between Little Atlin and
Atlin Lakes.

During the zone VII interval ice probably receded for
the first time from the Mile 47 Bog site. Hewever, the bog
would have remained in close proximity to the glacier margin
for some time. With the terminus in the Mile l6 Bog area,
approximately 30 miles to the north, a large portion of the
valley just west of Mile 47 Bog would still have been
occupied by ice.

The record at Mile 47 Bog appears to have begun about
the midpoint of zone VII time, and from this it appears that
an herbaceous tundra existed in the vicinity of the bog con-
temporaneously with shrub tundra in the Jasper Creek-Wilson
Creek Bog area. Such vegetational differences in these two
areas may be explained by differences in microclimates. In
the Mile 47 Bog area local climatic conditions were probably

 

st:
hi:
Cr
va
ai

ti

SI
re
SE
EE
cc
8:1

Ce

De;
48,};
the

We

291

strongly influenced by downglacial drainage of cold air from
higher elevations to the south and southwest. The Jasper
Creek-Wilson Creek Bog area, located away from the main
valley, would not have been directly affected by such cold
air movements (Fig. l). A vegetation type adapted to rela-
tively colder conditions would therefore have persisted
longer in the Mile 47 Bog area than in the latter area where
warmer conditions would have existed earlier.

This local climatic influence may not only explain the
lag in appearance of shrub tundra around Mile 47 Bog, but
may also be a factor in the relatively late appearance of
spruce there. Be that as it may, it is difficult to see
how white Spruce could have reached the JaSper Creek-Wilson
Creek Bog area without having migrated southward through the
Atlin valley. Having done so, Spruce pollen, at least in
small quantities, should appear earlier in the Mile 47 Bog
record than it does. In its absence at lower levels in the
section (Fig. 23) the problem of the early Holocene phyto-
geography of white spruce in the valley remains. The present
considerations do, however, suggest the possibility that
spruce migrated southward through the valley during the pre-
ceding, warmer, zone VIII interval, an interval not contained
by the Mile 47 Bog record, hence giving rise to the zone VIII
peaks in Jasper Creek and Wilson Creek Bogs. Spruce may then
have disappeared from.mid-latitude parts of the valley during
the relatively cooler zone VII time. To account for the re-

appearance of spruce in the southern part of the valley in

 

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292

zone VI time at least 500 years before its appearance in
the Mile 47 Bog record, it might be hypothesized that spruce
survived the cooler, zone VII interval some place south of
the Jasper Creek-Wilson Creek Bog area. Additional palyno-
logical studies will be required to test this hypothesis.

Zone‘VI. The beginning of this zone, 9,000 years B.P.
(Fig. 32), is marked by pollen assemblages from Jasper Creek
and Wilson Creek Bogs which suggest the establishment of
spruce woodland and the return of the climate to a somewhat
less cool and less dry condition. Again, areas to the north,
as around Mile 47 Bog (Fig. 23), appear to have lagged behind
in the development of a corresponding vegetation type.
Because temperatures had increased, and apparently continued
to increase into the following zone V interval, instead of
turning downward again as during the spruce woodland times
of zone VIII, glacial recession resumed, to continue until
at least mid-Holocene time. This may have been caused, as
before, by changes in the seasonal distribution of rain and
snow at critical elevations in the Northern Boundary Range
where the Atlin valley ice originated. Recession during
zone VI time appears, on the basis of glacial deposits at
the north end of Atlin Lake (p. 28), to have been inter-
mittent due to minor climatic oscillations which are not
reflected by the general palynological record.

Zone V. By 8,000 years B.P. Spruce forest had become
widespread in the southern part of the valley and spruce

woodland was succeeding to spruce forest in the Mile 47 and

293

Mile l6 Bog areas (Fig. 22-25, 32). Temperatures were con-
tinuing to rise, and they probably reached present day levels
around the beginning of zone V time. As such this may be
considered the beginning of the Thermal Maximum in the Atlin
valley. Precipitation levels are also considered to have
increased so that the climate now may be characterized as
warm and wet. under these conditions of higher temperatures
and precipitation glacial accumulation areas probably re-
ceived a greater prOportion of rain than before. Thus glacial
retreat gained momentum. By the end of zone V time at 5,500
years B.P. glaciers may have shrunken to near their post-
Wisconsinan minima. Also, with the disappearance of ice
from the Atlin valley, the effect of downglacier movements

of cold air on vegetation around Mile 47, Mile l6, and Mbose
Bones Bogs no longer was important. Therefore major vegeta-
tion changes among the five bogs appear to have become more
nearly synchronous,more nearly reflecting regional climatic
changes during the remainder of Holocene time.

Zone IV. Zone IV is marked by pollen assemblages in-
dicating temperature and precipitation levels higher than at
present. Thus the climate can be characterized as warmer
and wetter (Fig. 32). It is Speculated that temperature and
precipitation may have reached their Holocene maximum levels
and then begun to decrease somewhat toward the end of zone IV
time, although there is no real evidence of this in the

palynological record.

294

Zone III. It appears that by some time prior to 3,000
years B.P. the climate began to deteriorate from the condi-
tions of maximum warmth and moisture of zone IV times.
During the zone III interval climatic conditions are be-
lieved to have been, as in zone V time, more like the pre-
sent. The zone IV/zone III boundary is defined as the time
when temperature and precipitation had decreased to present
levels. This is believed to have occurred approximately
2,500 years B.P. As such, this also marks the end of the
Thermal Maximum.in the Atlin region.

Zone II. As was discussed at various points in inter-
preting the individual records from the five Atlin valley
bogs, temperature and precipitation in the region appear to
have been decreasing by about 2,500 years B.P. It is be-
lieved that after this point in time conditions were both
cooler and drier than at present and remained so until only
several hundred years ago. The climate is therefore char-
acterized as relatively cool and dry.

Such conditions may have been responsible for a lowering
of the freezing level and a redistribution in the annual
balance of rain and snowfall in accumulation areas east of
the crest of the northern Boundary Range. With an increase
here of snowfall, Neoglacial advance of the Llewellyn and
Williston Glaciers could have begun during zone II time.

Although the climatic conditions reSponsible for this
advance are characterized in the same manner as the climates

of zone VIII and zone VI times (i.e. cool and dry), when ice

295

in the northern part of the Atlin valley is believed to have
been receding (Fig. 32), the present interpretation does not
necessarily conflict with these earlier interpretations.
Levels of accumulation during the Neoglacial, following a
long Thermal Maximum interval of maximum glacial retreat,
even if sustained indefinitely, would probably not have
brought about an advance of the Llewellyn Glacier of more
than a few miles into the main Atlin valley. Here, under
the prevailing "cool and dry" climate, there would have been
significant downwastage in the terminal zone. AA balance
between accumulation and wastage would have maintained a
certain optimum terminus position at some point in the
southern part of the valley (Fig. 1). Given, then, a maximum
extension of the glacier to a point well northwest of the
valley during the Wisconsinan, under climatic conditions
substantially more glacial, the relatively warmer climatic
conditions of zone VIII and of zone VI times, even though
comparable to Neo-glacial conditions, could have brought
about the earlier suggested periods of recession into and
through the northern part of the valley.

Zone I. This zone is believed to have begun within the
past several hundred years. The lower boundary of the zone
in Figure 32 is set somewhat arbitrarily at the 750 year
level. The zone is characterized by changes in bog vegeta-
tion which indicate a general rise in water level, hence of
precipitation, subsequent to zone II time. Increased lime

accumulation in the upper few inches of the soil profile

296

studied in vegetation survey stand 59W also indicates in-
creased precipitation in recent times. Although no evidence
of a concomitant rise in summer temperatures is discernable
in the general palynological record, glacial geological
considerations, in conjunction with the parallel relation-
ship of temperature and precipitation changes Shown for the
majority of the present chronological scheme, indicate that
summer temperatures have also undergone a moderate increase
to present levels during zone I time. Such changes appear
to be related to a general, though moderate, post-Neoglacial
retreat of glaciers in many areas.

A complex and well documented history of lesser glacial
fluctuations during the past few hundred years, including
the Llewellyn Glacier and others of the Northern Boundary
Range, (see citations in Chapter III), is believed to have
been caused by lesser climatic oscillations which are not
reflected in the palynological record. Generally, climati-
cally controlled vegetation changes are so slow that the
palynological method is insensitive to such Short term cli-
matic changes of lesser magnitude, especially in northern
interior regions where the number of indicator Species is

small and their ecological tolerances are broad.

XV. SUMMARY AND CONCLUSIONS

A study of plant communities and of Holocene vegetation

and climatic history in the Atlin region has been made.

297

.Specific emphasis has been placed on the Atlin Lake valley
(Atlin valley) where the bulk of the field work was done.

The term "Hblocene" is used to designate the interval
between the present and the time in the past when certain
climatic changes initiated world-wide retreat of the latest
substage of Wisconsinan glacial ice. In a nine-zone geo-
botanical chronology developed for the Atlin region the lower
Helocene boundary is tentatively placed at the 10,500 year
level, the beginning of the zone VIII time interval.

The Atlin region centers on Atlin Lake and Little Atlin
Lake in northwestern British Columbia and south-central Yukon
Territory. Secondary roads, including the Atlin road, con-
structed in conjunction with past mining operations, have
been important to the work reported here. The Atlin road
begins at mile 866 on the Alaska Highway and runs approxi-
mately 82 miles south and southeast through the Atlin valley
serving as a transect of the vegetation at lower elevations.
Atlin village (latitude 59°54' N; longitude 133°42' w;
elevation 2,200 ft), located at mile 60, mid-way on the east
shore of Atlin lake, is the only pOpulated place in the
region and served as the base of operations for most of the
field work.

At the time the study was initiated in the summer of
1966 little knowledge of the glacial geology, soils, flora,
plant communities, nor of the geObotanical history of the
region was available. In an attempt to remedy this situation

plant collections have been made and upland plant communities

298

analyzed and defined using techniques based, in part, on the
methods of the Braun-Blanquet school. A quantitative tree
survey has been conducted using the point-quarter method, and
bog vegetation has been studied and described in general
terms. Several bogs have been sampled for pollen analysis,
and the results of such analyses have been used as the basis
for a geobotanical chronology for the region.

The plant collections have made possible the appending
to this dissertation of a preliminary catalog of vascular
and non-vascular plants of the Atlin region (Appendix F).
This catalog contains 11 lichen, l4 bryophyte and hepatic,
and 237 gymnosperm and angiosperm species.

To Obtain information about upland plant communities
a general vegetation survey was conducted. At two-mile
intervals along the Atlin road transect two stands of vege-
tation were selected within a radius of about 300 feet around
the mileposts. USing the Domin cover-abundance scale as a
measure of Species importance, relevés were drawn up for
30-ft-square quadrats laid out in the stands. The releves
were later assembled on a general asSociation table. After
inspection of this table, relevés of stands Showing simi-
larities in cover and abundance of dominant species, usually
in the arboreal stratum, were regrouped into community asso-
ciation tables.

The major vegetational unit recognized here is the asso-
ciation, represented by a community association table. Where

the relevés of a community association table Show major

299

differences in composition and/Or importance of lower strata,
two or more subdivisions of the association, termed facia-
tions, are recognized. A third category, the associes, is
applied to vegetation still in early stages of succession,
usually following fire . A

Twelve community association tables, representing nine
associations, one of which is divided into two faciations,
and two associes, are presented. The composition and struc-
ture of each of these community types, certain aspects of
their physical environments, and their importance in terms
of frequency of stands and species diversity are discussed.
These communities are listed here in descending order of
importance:

(1) Mixedwood forest association. Dominated by white
spruce and aspen and sometimes also by balsam.pOplar, tree
willow, and lodgepole pine; contains diverse and usually
dense shrub and herb strata, the latter being the most dense
of any community type; lichen and moss stratum unimportant.
Fire history and proximity of a variety of seed sources are
considered instrumental inthe development of this community

type. Associated soils are Boralfic Cryorthods.

(2) White spruce association/Shrub-herb faciation.
Dominated by white spruce; minor admixtures of other species
variable from stand to stand; two faciation subdivisions con-
sidered: an herb phase and a shrub-herb-moss phase, the

former characterized by greater importance of the herb stratum

300

and the latter, by high importance of the shrub, herb, and
moss strata together.

(3) Aspen association. Dominated by aspen, usually
with an admixture of tree willow and sometimes of balsam
poplar.and white Spruce; a mixed broadleaf forest phase is
recognized in stands where aspen, balsam.poplar, and tree
'willow are approximately equal in importance; shrub stratum.
usually denser than in coniferous forests; herb stratum.
usually quite full; lichen and moss stratum insignificant.
Mbst of the stands of this association lacked signs of
former fires.

(4) White spruce association/feather moss faciation.
Dominated by white spruce, typically forming a dense canopy;
shrubs and herbs scarce; large patches of feather mosses on
forest floor. Frozen ground was encountered beneath the
moss carpet in two stands. This association is considered
the climatic climax on mesic sites in the Atlin valley.

(5) Lodgepole pine brule (associes). Abundant fire-
killed pine trees present; pine seedlings, and often aspen
seedlings abundant. The frequency of this vegetation type
indicates the importance of fire in the ecology of the Atlin
region.

(6) White spruce-lodgepole pine association. Dominated
by white spruce and lodgepole pine. Canopy density and im-
portance of shrub and herb layers variable; some stands

approach the feather moss condition.

301

(7) Lodgepole pine association. Middle-aged or older
lodgepole pine trees may dominate; pure, old-growth lodgepole
pine forests are rare; shrub and herb strata of low to
moderate importance; lichen and moss stratum insignificant
to quite dense, particularly where reindeer lichens occur.

A soil, classified as a Typic Cryopsamment, was studied in
one stand.

(8) Herb-heath association. Arboreal stratum lacking;
subshrub and herb strata predominant; occupies exposed, wind-
swept sites where frequent, intense fires may be a major
perpetuating factor.

(9) White spruce brfile (associes). Stands contained
evidence of older burning only; white spruce generally slow
in becoming reestablished; composition and physiognomy of
this community type quite variable, probably a result of
major differences in fire intensity and degree of burning
over short distances, coupled with variable seed sources.

(10) Depression shrub association. Arboreal stratum
lacking; shrub stratum dominant; herb stratum.diverse but
light; moss stratum.thick. Characteristic of poorly drained,
moist, but not necessarily saturated areas; associated soil
a Terrie Cryosaprist.

(11) Mixed woodland association. Dominated by widely
spaced white spruce, lodgepole pine, and one or more of the
broad-leaved species in an open and sunny, parklike aspect;
shrubs and herbs only scattered; much of the ground covered

by reindeer lichens.

302

(12) Alpine fir association. Dominated by alpine fir,
often forming a dense canopy; shrub stratum.sparse or dense
depending on openness of canOpy; herb stratum sparse; lichen
and moss stratum dense. This vegetation type is believed
to occur largely in response to higher moisture levels and
is therefore found more commonly in the southern portion of
the Atlin valley and at higher elevations, outside the range
of the general vegetation survey.

Two of the 86 stands studied are unclassified, repre-
senting transitional, or ecotonal vegetation. General obser-
vations show that ecotonal conditions are of considerable
areal importance in the Atlin valley. The survey was de-
signed to exclude stands containing vegetation of this type
and therefore the results do not portray the true status of
it.

Two other community types which were observed but not
measured in the general vegetation survey are the lodgepole
pine woodland, characterized by widely spaced, mature pine
trees and a dense reindeer lichen ground cover, and the
mixed coniferous forest, wherein white spruce, alpine fir,
and lodgepole pine share dominance. A more detailed analysis
of general vegetation survey data is provided on pages 106-126.

In the tree survey, point-quarter transects were run at
one-mile intervals along most of the Atlin road. Trees in
a zone about 1,000 feet wide, centering on the road, were
included. The survey has resulted in the following infor-

mation:

303

(1) Almost half (47 percent) of the trees in the Atlin
valley are white spruce. With a frequency of 37 percent,
this Species occupies over a third of the landscape within
range of the survey. With respect to basal area, it is more
important than all other species combined.

(2) Lodgepole pine, although slightly less important
than aspen in terms of numbers and land area occupied, is
second only to spruce in basal area. Even so, it has less
than half the basal area of spruce.

(3) Dead (fire-killed) lodgepole pine is quite important
in terms of numbers and amount of occupied terrain, being
fourth in both respects. The data indicate that over eight
percent of the valley area has been recently burned. Obser-
vations along the Alaska Highway and elsewhere indicate that
this may be a conservative measure of the effect of fire.

(4) Aspen is the second most abundant tree in the valley
and occupies slightly more land area than pine (disregarding
dead pine trees). It is considerably less important in terms
of basal area, however.

(5) Tree willow is common as an admixture of most for-
est types.

(6) Alpine fir appears to be quite unimportant compared
to Spruce, pine, aspen, and tree willow. As discussed above,
however, it is believed to be an important component of the
total valley forest, growing primarily at higher elevations.

(7) Balsam poplar is relatively unimportant, although it

is widespread.

304

(8) Alder is insignificant as a tree Species in the
Atlin valley.

(9) A comparison of tree survey and general vegetation
survey data shows a high degree of correlation with regard
to the frequency, abundance, and dominance of the forest
tree species.

(10) Eighty-three percent of the 5,840 quadrants ob-
served contained trees.

Bog vegetation was studied in six bogs which were also
sampled for palynological purposes. From.north to south in
the Atlin valley these are: Moose Bones, Mile 16, Mile 47,
Mile 52, Jasper Creek, and Wilson Creek Bogs. Although
these bogs are quite variable, several general, more or less
concentric vegetation zones, occurring along a moisture
gradient, can be recognized. No one bog contains all of
these.

(1) Sedge-moss zone. Dominated by gaggx aquatilis ssp.
aquatilis and Drepanocladus aduncus. water table ordinarily
above the surface. (2) Sedge zone. Dominated by 9222!
aquatilis, with few other plants present. water table at or
below the surface. (3) Bulrush zone. Dominated by Scigpus
validus, with few other species present. water table above
surface. (4) Shrub willow zone. Dominated by Salix_spp.,
sometimes with an admixture of Betula_glandulosa. (5) Grass

 

zone. Dominated by various species of Gramineae. Subdivided

into Calamagrostis neglects, Deschampsia caespitosa, and Fee

305

Apalustris zones. (6) Dog spruce zone. Dominated by white
spruce, shrub willows, and a variety of herbs and mosses.

Ericaceous plants and Sphagnum.spp. were rare, reflecting,

 

along with other, positive indicator species, such as 23;;
glochin.maritimum, the generally alkaline growing conditions
in Atlin valley bogs.

A circumnavigation of Mile 47 Bog, with a description
of the upland vegetation in eight sectors up to a distance of
approximately 200 feet from the bog, Shows the typical hetero-
geneity and variability over short distances of upland vege-
tation adjacent to the bog and in the Atlin valley in general.

A palynological record, in the form of five pollen and
spore diagrams, is presented. Seven radiocarbon dates have
permitted the application of an absolute chronology to the
diagrams, beginning approximately 11,000 years B.P. in the
Jasper Creek Bog record. Some extrapolations and interpola-
tions, using calculated sediment accumulation rates, have had
to be made.

Palynomorphs whose percentage frequencies are plotted
on the pollen and spore diagrams are separated into two
categories: (1) aquatic and semi-aquatic bog (ASB) types
and (2) non-aquatic bog and extra-bog (NEE) types. The pollen
diagrams are divided into three major pollen assemblage zones
for purposes of description and discussion. These include,
from bottom to top, the shrub, spruce, and pine zones. In

most cases the zonal boundaries are not contemporaneous from

306

bog to bog, showing that major vegetation changes occurred
at different times in different parts of the Atlin valley.

As background for interpreting the palynological record,
a comparison of surface pollen spectra and data from the
tree survey was made. Consideration is made of the extent
to which both the regional vegetation and the local vegeta-
tion, i.e. within a few miles of the bogs, is reflected by
the spectra.

Lodgepole pine generally appears over twice as important
in the pollen rain as it actually is in the vegetation.
Spruce should be interpreted, from its relative importance
in the pollen Spectra, to be approximately twice as prevalent
in the regional vegetation. With regard to alpine fir, the
presence of one or a few grains may be taken to indicate that
the species is present, if not important, somewhere in the
general vicinity of the bog. Single grains of Tsugg and
.Lagix probably result from diSpersal from.distant regions.
Juniperus grains in the three northern bogs reflect the pre-
sence in this part of the valley of the upland, dry sites
bearing the herb-heath type of vegetation. Populus is so
poorly represented that nothing can be said of its vegeta-
tional status except, perhaps, in extreme cases, as at Mile
47 Bog, where it reaches four percent of the pollen total.

Tree willows of the forests in general are probably not
represented, although the relatively high Salix percentage
in Mile 47 Bog probably reflects the presence of a nearby

stand of almost pure tree willow vegetation. Except for such

307

occurrences as this, which would be difficult to distinguish
in fossil spectra (unless individual species of willow pollen
could be recognized), the importance of willow shrubs in non-
aquatic parts of the bogs can be reasonably determined from
the percentages of willow pollen, Algus is considerably
overrepresented, and where its pollen is encountered in large
quantities the indication seems to be that the plant is
important as a pioneering shrub in local, relatively fresh
stream deposits somewhere not more than a few miles from the
bog. Betula is also overrepresented, but not as much as
alder. In general the presence of this pollen type may be
taken to indicate that shrub birch is common in and near the
bog.

'gycopodium.microspores are found in bogs with mature,

 

old-growth spruce or mixed coniferous forest nearby. Grass
is underrepresented, particularly in Moose Bones Bog where
several species occur near the deposition site and in Mile l6
Bog where the herb-heath vegetation type occurs on the slopes
above the bog on the east. Epilobium.pollen appeared only
in Mile l6 Bog where the species was prevalent near the depo-
sition site. Artemisia, appearing sparingly in the surface
samples of Moose Bones and Mile l6 Bogs, gives, along with

Juniperus, an indication of the nearby herb-heath vegetation

 

on dry SIOpes.

There is some evidence that pollen assemblages are
biased toward vegetation located within a few miles to the
south of the bogs due to prevailing southerly winds during

308

the flowering season. But there is just as much evidence

to refute this, wherein particular pollen percentages compare
better with the composition of the vegetation to the north.

It is concluded, therefore, that a considerable amount of
atmospheric mixing of pollen occurs, probably because of
turbulence over the generally irregular tOpography and because
of the heterogeneity of the vegetation. This is an indication
that the average pollen rain, as determined in the five bogs,
bears a characteristic relationship to the vegetation of the
Atlin valley and that similar relationships may have existed
in the past.

The palynological record sheds light on the Holocene
phytogeography of white spruce and lodgepole pine. White
spruce appears to have migrated southwestward from.the west-
central Yukon refugium and to have reached the northern part
of the Atlin valley by at least 10,500 years B.P. During a
warmer interval, from approximately 10,500-10,000 years B.P.,
'it may have migrated southward through the valley and into
the Jasper Creek-Wilson Creek Bog area. _During a subsequent
interval lasting approximately 1,000 years, when temperatures
were too low for spruce, it retreated both to the northwest
and south from the valley. With the return of warmer condi-
tions approximately 9,000 years B.P. white spruce reentered
the valley from each of these directions. By around 7,200
years the two spruce migration fronts met somewhere in the
mid-latitude region of the valley. Thus the Holocene affor-
estation of the valley was complete.

309

Lodgepole pine is believed to have migrated from a
refugium.in northeastern British Columbia and western Alberta.
It became established first around 4,000 years B.P. in the
Mile 16 and Wilson Creek Bog areas. These areas were more
directly accessible to the westward migrating pine than
were intervening areas because they are in line with low
terrain extending eastward to the Teslin depression. Later
pine migrated north and south from.the Mile l6 Bog area to
the vicinities of Moose Bones and Mile 47 Bogs. Direct west-
ward migration of pine into the latter areas is believed to
have been blocked by mountains lying east of them.

The knowledge which has been deve10ped thus far of the
extant Atlin valley vegetation, in conjunction with the
observed relationships between the vegetation and the modern
pollen rain, provide a basis for a broad interpretation of
past vegetation types from the palynological record. Addi-
tional Observations of the distribution and climatic condi-
tions associated with vegetation types not occurring in the
Atlin valley at present, but at higher elevations in the
region, along with vegetation-climate relationships discussed
in the literature, allow certain conclusions regarding past
environments to be made.

The time sequence of Helocene environments as interpreted
for the Atlin region is represented by a provisional geobotan-
ical chronology comprising nine discrete intervals or time

201188 e

310

Zone IX. le,000-lO,500 years B.P. During this interval
the main Atlin valley was still occupied by a lengthy glacier,
the surface of which was relatively level and averaged about
3,000 feet in elevation, or 800 feet above the present level of
Atlin Lake. The glacier sloped gently to a terminus in the
northernmost part of the valley and was characterized by a
more or less equilibrium regime tending toward downwasting
and stagnation. It is believed that the terminus at this time
still lay close to its maximum late Wisconsinan position. The
pitted outwash in the Moose Bones Bog area and the knob and
kettle topography and associated gravel terraces in the White
Mountain-Squanga Lake region were formed at this time. The
Mile 16, Mile 47, and Mile 52 Bog sites were still covered by
ice, but the Wilson Creek and Jasper Creek Bog sites had re-
cently become exposed by the glacial thinning Subsequent to
the late Wisconsinan maximum. Vegetation in the vicinity of
the latter bogs was a shrub tundra, indicative of mean July
temperatures of 46-48° F and of mean annual precipitation of
6-8 inches. Zone IX climate is characterized as relatively
cooler and drier than any subsequent climatic interval,
except possibly zone VII as discussed below. Presumably
these conditions were contemporaneous with cooler and wetter
(more maritime) conditions along the Alaskan coast. On this
basis it is suggested that the Arctic Front, or line of de-
marcation between the generally anticyclonic continental
weather conditions of the Atlin area and the normal cyclonic,
oceanic conditions of the coast, lay near or partly within

the southwestern portion of the Atlin region.

311

The zone IX interval is believed to represent approxi-
mately the last 500 years of the Wisconsinan Age of the
Pleistocene Epoch in the Atlin region. AS such it is pro-
bably comparable to the Valders maximum.of the American
mid-continent chronology and to the YOunger Dryas in other
regions. This would make it contemporaneous with the Late
Glacial III phase outlined by Heusser in his palynological
studies in the overall Nerth Pacific maritime region.

Zone VIII. 10,500-10,000 years B.P. Uhder the influence
of a warmer climate the Atlin.valley glacier terminus under-
went a retreat of 10-15 miles from.its zone IX position.
vegetation in the Jasper Creek-Wilson Creek Bog area changed
to a spruce woodland type, similar to, but drier than the pre-
sent vegetation lying between approximately 4,200 and 4,500
feet in the Atlin region. Mean July temperatures were some-
what above the 50° F level, and annual precipitation may have
risen to perhaps 8-10 inches. Though slightly warmer than
zone IX time, the climate is still characterized as cool and
dry. Presumably the mean position of the Arctic Front was
farther toward the coast than in zone IX time, i.e. well south
and west of the Atlin region.

Zone VIII is recognized as the first distinct Subdivision
of the Helocene Epoch in the Atlin region. Thus the lower
Holocene boundary is set at 10,500 years. This represents the
beginning of the Pre-Boreal or the Early POstglacial interval

as recognized by Heusser in southeastern Alaska.

 

 

 

 

312

Zone VII. 10,000-9,000 years B.P. A return to cooler
conditions caused a halt in the retreat of the Atlin valley
glacier ice front. This resulted in a stillstand or possibly
even a slight readvance. The large kame terrace lying along
the valley side slope between Little Atlin and Atlin Lakes
provides the clue to this interpretation.

vegetation in the Jasper Creek-Wilson Creek Bog area
during this interval was a shrub tundra. Summer temperatures
and precipitation may have been as low as during zone IX time,
with the mean position of the Arctic Front again shifted in-
land, closer to the Atlin region.

The zone VII interval is considered a part of Pre-Boreal
or Early Postglacial time, and represents a climatic oscil-
lation not generally delineated in other areas. It may cor-
relate with the Sumas Stade of southwestern British Columbia,
and possibly the valders II stillstand (or readvance) in the
mid-continent chronology.

Zone‘VI. 9,000-8,000 years B.P. An intermittent retreat
of the Atlin.valley glacier seems to have occurred during this
interval, resulting in the formation of the series of closely
Spaced recessional moraines in the vicinity of the northern
end of Atlin Lake. Recession probably continued to gain
momentum throughout this interval and into zone V time under
the influence of a generally ameliorating climate. The Mile
47-Mile 52 Bog area was first exposed during zone VI time.
The Mile l6 Bog site was probably also exposed, but the ice
block buried there had not yet melted out to create the

kettle in which the bog subsequently developed.

313

A spruce woodland vegetation again developed in the
vicinity of Jasper Creek and Wilson Creek Bogs. A shrub tundra
may have persisted around Mile 47 Bog because spruce had not
yet re-migrated to this area. The proximity of the Mile 47
Bog site to the margin of the glacier, whose terminus was
still 20-25 miles farther north, and the effects of cold,
downglacier winds may also have delayed the development of a
warmer-habitat vegetation.

This interval is considered a third and final subdivision
of a period comparable to the Pre-Boreal in other regions or
the contemporaneous Early Postglacial recognized by Heusser
in southeastern Alaska.

It is suggested that during zone VI time the mean position
of the Arctic Front was again Shifted coastward through the
dominance of the continental high pressure anticyclone. This
resulted in the cool-dry conditions believed to have existed
in the Atlin region as Opposed to the contemporaneous cool-
humid conditions previously described by Heusser for the
coastal areas of Alaska.

Zone‘V. 8,000-5,500 years B.P. By the beginning of zone
V time temperatures in the Atlin valley had more or less
reached present levels. As such this marks the beginning of
the Thermal Maximum interval which, including its waxing and
waning phases, was to last for upwards of 5,000 years. At
the beginning of this time precipitation was at least as great
as at present, i.e. 11-12 inches per year. The zone V climate

is generally characterized as warm and wet. Again the term

314

"wet" is used not in an absolute sense, but to designate a
precipitation regime which was wet relative to the much drier
and more continental conditions associated with earlier tundra
vegetation.

The Atlin valley was occupied primarily by white spruce
forest during zone V time. The glacier continued to oscillate,
but the general trend now was downwastage and recession. By
the end of the interval the terminus may have reached a posi-
tion not far from the present Llewellyn Glacier terminus.

Zone‘V corresponds to the Boreal of other areas. In the
Atlin region this warmpwet interval begins at the same time
as the warmpdry Boreal of southeastern AlaSka as determined
by Heusser. Therefore the mean position of the Arctic Front
during this interval may be assumed to have been shifted even
farther toward the coast. Furthermore, regional temperatures,
higher than in any previous interval, including zone'VIII,
probably resulted in increasing storminess and hence an in-
creasing wetness, particularly during the summer months,
reaching its maximum.in the subsequent zone IV interval.

Zone IV. 5,500-3,250 years B.P. During this interval
Helocene temperatures and precipitation attained their maxi-
mum levels. It is suggested that mean July temperatures may
have been as high as 56° F and that precipitation was several
inches higher than at present. Thus the zone IV climate is
characterized as (relatively) warmer and wetter. At this time
glaciers are believed to have shrunken to their post-Wiscon-
sinan minima. The main Atlin.valley glacier terminus is

315

presumed to have receded well into the Boundary Range source
valley of the present Llewellyn Glacier, and in fact some
distance upvalley from its 20th century terminus. This, of
course, would represent the ultimate retreat of the main
Atlin valley ice that began about 7,000 years earlier, i.e.
in zone IX time.

vegetation in the Atlin valley under these conditions
may have been more luxuriant than at present. It may have
resembled the present vegetation of the southwestern part of
the region where the maritime climatic influence is greater.
In particular, alder is believed to have been abundant as an
inhabitant of wet sites in old-growth Spruce forests, such
sites being significantly more widespread than at present.

Zone Iv may be comparable to the Atlantic period of other
areas and to the middle Hypsithermal as recognized by Heusser
in southeastern Alaska, although its time boundaries appear
to be later than in the latter area.

As for the general position of the Arctic Front during
this time, it still lay farther toward the coast. In fact it
is believed to have been sufficiently withdrawn from the
Juneau Icefield itself that even the strongly maritime Taku
Glacier receded some dozen miles north of its subsequent Neo-
glacial positions (M; M. Miller, personal oral communication,
1970). As in the case of zone V time the increased tempera-
tures in zone IV accompanied increased atmospheric turbulence
and storminess which in turn resulted in continuing wetter

conditions.

316

Zone III. 3,250-2,500 years B.P. The appearance of

 

alpine fir in the Atlin valley spruce forests is considered
an indication of continuing high precipitation levels but of
decreasing temperatures. By the end of this interval mean
July temperatures are believed to have decreased to the pre-
sent level of about 54° F. The time this temperature level
was attained is designated the end of the Thermal Maximum.

The zone III interval is considered comparable to the
Sub-Boreal of other areas. It appears to have ended about
1,000 years later in the Atlin region than as reported by
Heusser with respect to southeastern Alaska. 0n the other
hand, it is nearly contemporaneous with the end of Sub-Boreal
(and of Thermal Maximum) time in more southerly regions. AS
for the position of the Arctic Front, it began to shift in-
land during this time, as climatic conditions more closely
approached those characterizing Neoglacial time. With this
return to generally colder conditions, there was generally
less storminess in the Atlin area, hence less precipitation
during the growing season.

Zone II. 2,500-c 750 years B.P. During this interval
climate was somewhat cooler as well as drier than at present.
New the Arctic Front and storm tracks were apparently shifted
inland with increased dominance of the maritime pressure cell.
Consequently there was decreased storminess and precipitation
in the Atlin region. Neoglacial advances of mountain and
valley glaciers in the northern Boundary Range reflect these
conditions of lower temperature and increased maritimity in

317

that sector; but decreased storminess is reflected by the
increase in dry climate vegetation in the interior Atlin
region as shown by the palynological record. In this regard
it is noted that a greater proportion of pine in the Atlin
valley forests reflects a higher frequency of forest fires
resulting from the generally drier conditions. The Atlin
valley climate is thus characterized as cool and dry and
therefore out of phase with that over the Alaska coast. It
is believed to have been similar to climatic conditions in
zones VI and VIII.

Zone I. c 750 years B.P. to present. The palynological
record does not indicate the complex, short-term climatic
oscillations which may have occurred in the Atlin region
during late Neoglacial (Little Ice Age) time. Further
studies in dendrochronology, lichenometry, glacial geology,
and perhaps more detailed palynological analyses of recent
bog sediments and of lake bottom.sediments will be necessary
to work out this pattern. It appears that there has been a
general, minor warming trend to present temperature levels
during the past several hundred years. There is evidence in
the bogs, furthermore,-of an increase in precipitation during
this time. In the existing glaciers of the Boundary Range
and along the Alaskan Coast there has been a much more sensi-
tive fluctuational response to late Neoglacial climatic pul-
sations. This further supports the contention that the Arctic
Front in Holocene time generally shifted back and forth in a

318

linear belt paralleling either side of the axis of the
Boundary Range somewhat south and west of the Atlin valley.

The sequence of biogeochronological subdivisions of the
Hblocene Epoch in the Atlin region is Similar to sequences
which have been worked out by others in many different re-
gions. In some cases subdivision boundaries are contempor-
aneous. In particular, such synchroneity appears to exist
in chronologies of the maritime regions west and southwest
of the Coast Mountains and the interior Atlin region lying
to the northeast. A contribution to understanding the nature
of these complex relationships is given by the palynological
evidence discussed in this dissertation. The key to broad
regional interpretations lies in recognizing that cool and
moist conditions in the Alaskan coastal zone have been
approximately contemporaneous with cool and dry climatic
conditions in the northern British Columbia-Yukon interior,
and that warm and relatively dry coastal climatic conditions
appear to have prevailed at times when the interior exper-
ienced a warm.and wet climate. \The explanation of these
seemingly opposite secular trends appears to relate to the
delicately shifting position of the Arctic Front in and near
the Atlin region at least in the late Pleistocene, and on
through the Helocene Epoch.

FOOTNOTES

FOOTNOTES

1Moose Bones Bog: an informal, unofficial name for the
bog lgcated northwest of the Jakes Corner-Carcross road at
mile .5.

The other bogs are named for their locations along the
Atlin road or for nearby creeks which appear on maps of the
National Topographic Series published by the Surveys and
Mapping Branch, Canada Department of Mines and Technical
Surveys , Ottawa.

2A complete set of the Atlin region vascular plant col-
lections through 1968 is housed in the Beal-Darlington
Herbarium of Michigan State university. Nearly complete
duplicate sets are to be given to the herbarium.of the Na-
tional Museum of Natural Sciences in Ottawa and to the
herbarium.of the university of Alaska. A fourth set may be
given to the herbarium.of Queen's university in Kingston,
Ontario. Additional collections from the Atlin region will
be deposited primarily in these four herbaria.

A set of the cryptogams has been given to the Crypto-
gamic Herbarium.of Michigan State university, and a second
set remains in the writer's private collection.

VOucher specimens for the pollen reference sample pre-
parations (Appendix E) are housed in the Beal-Darlington
Herbarium.of Michigan State university.

3Brfilé. This term is French and applies to areas burned
over within approximately 30 years prior to investigation and
whose vegetation is still in early stages of secondary suc-
cession. ~

uThe writer's pacelength on smooth and level terrain is
approximately 38 inches.

5This sample, like the uppermost "surface" sample in
Jasper Creek Bog, was loose, coarsely fibrous, and watery.
It was not considered feasible to sample it at close inter-
vals because of the likelihood of settling, or differential
settling of pollen and spores in this portion of the column.

319

LITERATURE CITED

LITERATURE CITED

Aitken, J. D. 1959. Atlin map-area, British Columbia.
Geological Survey of Canada Memoir 307. 89 p.

north central British Columbia. American Journal of
Science 246: 283-310.

Bartley, D. D. 1967. Pollen analysis of surface samples of
vegetation from arctic Quebec. Pellen et Spores 9:
101-105. I

Bilsland, W. W. 1952. Atlin, 1898-1910: The story of a
gold 380m. British Columbia Historical Quarterly 26:
121-1 .

Borns, H. W., Jr. and R. P. Goldthwait. 1966. Late-Pleisto-
cene fluctuations of Kaskawulsh Glacier, southwestern
Yukon Territory, Canada. American JOurnal of Science
264: 600-619.

Bostock, H. S. 1948. Physiography of the Canadian cordil-
lera, with special reference to the area north of the

558h parallel. Geological Survey of Canada Memoir 247.
10 p.

Boughner, C. 0., R. W. Longley, and M. K. Thomas. 1956.
Climatic summaries for selected meteorological stations
in Canada. velume III. Frost data. Department of
Transport, Meteorological Division. Toronto. 94 p.

Boughner, C. C. and M. K. Thomas. 1967. The climate of
Canada. Meteorological Branch, Air Services, Department
of Transport, Toronto. 74 p.

Broecker, W. S. and W. R. Farrand. 1963. Radiocarbon age of
the Two Creeks forest bed, Wisconsin. Geological
Society of America Bulletin 74: 795-802.

Buell, M. F. 1947. Mass dissemination of pine pollen. JOur-
n21 of the Elisha Mitchell Scientific Society 63: 163-
1 7.

Cairnes, D. D. 1913. Portions of the Atlin district, British
Columbia. Geological Survey of Canada Memoir 37.

320

320-A

Carroll, G. 1943. The use of bryophytic polsters and mat in
the study of recent ollen deposition. American Journal
of Botany 30: 361-3 . '

Chapman, J. D. and D. B. Turner (ed.). 1956. British Colume
bia atlas of resources. Climatic maps p. 14-22.
British Columbia National Resources Conference, 1956.

Christie, R. L. 1957. Bennett, Cassiar District, British
Columbia. Geological Survey of Canada, Map 19-1957.

Cockfield, W. E. 1925. Silver-lead deposits in the Atlin
district, British Columbia. Geological Survey of Canada
Summary Report, 1925: 15A-24A.

Cohee, George V. 1968. Holocene replaces recent in nomen-
clature usage of the U. 8. Geological Survey. American
Association of Petroleum Geologists Bulletin 52.

Colinvaux, P. A. 1964. The environment of the Bering Land
Bridge. Ecological Monographs 34: 297-329.

Critchfield, W. B. 1957. Geographic variation in Pinus
contorta. Maria Moors cabot Foundation PublicatIon No.
3. *Harvard university, Oombridge.

Curtis, J. T. 1959. The vegetation of Wisconsin: An ordi-
nation of plant communities. The university of Wisconsin
Press, Madison. 655 p.

0118111118, E. J. and He E. wright, Jr. (6d.). 1967. water-
nary Paleoecology. Yale university Press, New Haven and
London. 433 p.

Daubenmire, R. 1968. Plant communities: A textbook of
plant synecology. Harper and Row, New York. 300 p.

Davis, M. B. 1963. On the theory of pollen analysis. Amer-
ican JOurnal of Science 261: 897-912.

Davis,.M. B. 1969. Palynology and environmental history
during the Quaternary Period. American Scientist 57:

317-332-

Davis, M; B. and J. C. Goodlett. 1960. Comparison of the
present vegetation with pollen Spectra in surface
s les from Brownington Pond, Vermont. Ecology 41:

34 357.

Deevey, E. 3., Jr. and R. F. Flint. 1957. Postglacial Hypsi-
thermal interval. Science 125: 182-184.

 

 

 

 

320-B

Denny, C. S. 1952. Late Quaternary geology and frost
phenomena along the Alaska Highway, northern British
Columbia and southeastern Yukon. Geological Society
of America Bulletin 63: 883-922.

Denton, G. H. anan. Stuiver. 1966. Neoglacial chronology,
northeastern St. Elias MOuntains, Canada. American
JOurnal of Science 264: 577-599.

Faegri, K. and J. Iversen. 1964. Textbook of pollen analy-
sis. Hafner Publishing Co., Inc., New Yerk. 237 p.

Flint, R. F. 1957. Glacial and Pleistocene geology. Jehn
Wiley a Sons, Inc., New York. 553 P.

Frey, D. G. 1951. Pollen succession in the sediments of
Singletary Lake, North Carolina. Ecology 32: 518-533.

Fulton, R. J. 1965. Silt deposition in late-glacial lakes
of southern British Columbia. American Journal of
Science 263: 553-570.

Griggs, R. F. 1934. The problem of arctic vegetation. Jour-
nal of the Washington Academy of Science 24: 153-175.

Griggs, R. F. 1937. Timberlines as indicators of climatic
trends. Science 85: 251-255.

Gwillim, J. C. 1901. Atlin mining district. Geological
Survey of Canada Annual Report 1899 12: B5-48.

Halliday, W. E. D. 1937. A forest classification for Canada.
Canada Department of Mines and Natural Resources, Forest
Service Bulletin 89: 1-50.

Halliday, w. E. D. and A. w. A. Brown. 1943. The distribu-
tion of some important forest trees in Canada. Ecology

24: 353-374.

Hansen, H. P. 1949a. Pollen content of moss polsters in
relation to forest composition. American Midland
Naturalist 42: 473-479.

Hansen, H. P. 1949b. Postglacial forests in west central
Alberta Canada. Bulletin of the Torrey Botanical Club

Hansen, H. P. 1950. Postglacial forests along the Alaska
Highway in British Columbia. Proceedings of the American
Philosophical Society 94: 411-421.

Hansen, H. P. 1953. Postglacial forests in the Yukon Terri-
tfiry and Alaska. American JOurnal of Science 251: 505-
5 2.

320-0

Hegg, K. M. 1967. A photo identification guide for the land
and forest types of interior Alaska. U. S. Forest Ser-
vice Research Paper NOR-3. 55 P.

Heusser, C. J. 1954. Alpine fir at Taku Glacier, Alaska,
with notes on its postglacial migration to the territory.
Bulletin of the Torrey Botanical Club 81: 83-86.

Heusser, C. J. 1960. Late-Pleistocene environments of Nerth
Pacific Nerth America. American Geographical Society
Special Publication No. 35. 308 p.

Heusser, C. J. 1965. A Pleistocene phytogeo raphical sketch
of the Pacific Northwest and Alaska, . 69-483. 2_|Z_n_
H. E. Wright, Jr. and D. G. Frey ed. . The Quaternary
of the united States. Princeton versity Press,
Princeton. 922 p.

Heusser, C. J. 1966. Pleistocene climatic variations in the
‘western united States, p. 9-36. .gn Pleistocene and post-
Pleistocene climatic variations in the Pacific area.
Bishop Museum.Press, Honolulu.

Heusser, C. J. 1967a. Pleistocene and postglacial vegetation
of Alaska and the Yukon Territory, p. 131-151. Ig’H. P.
Hansen ed.) Arctic Biology. Oregon State university
Press, orvallis. 318 p. 2nd ed.

Heusser, C. J. 1967b. Polar hemispheric correlation:
Palynological evidence from.Chile and the Pacific Nerth-
west of America, p. 124-141. In J. S. Sawyer ed.).
Proceedings of the InternationEI Symposium on orld
Climate, ,000 to O B. C. Royal Meteorological Society,
London. 229 p.

Helland, S. S. 1964. Landforms of British Columbia, a
physiographic outline. British Columbia artment of
Mines and Petroleum Resources Bulletin No. 8. 138 p.

Horton, K. W. 1956. The ecology of lodgepole pine in
Alberta and its role in forest succession. Canada
Department of Northern Affairs and Natural Resources,
Forestry Branch, Forest Research Division, Technical
Nete No. 45. 29 p.

Hultén, E. 1940. History of botanical exploration in Alaska
and Yukon Territories from the time of their discovery
to 1940. Botaniska Netiser 1940: 289-346.

Hultén, E. 1968. Flora of Alaska and neighboring territories.
Stanford university Press, Stanford. 1008 p.

Janssen, C. R. 1967. A floristic study of forests and bog
vegetation, northwestern Minnesota. Ecology 48: 751-765.

321

Jeffrey, W. W. 1961. Netes on plant occurrence along lower
Liard River, Nerthwest Territories. National Museum of
Canada Bulletin 171: 32-115.

Johnston, W. A. 1926. The Pleistocene of Cariboo and
Cassiar districts, British Columbia, Canada. Transac-
tions of the Royal Society of Canada Ser. 3, vol. 20,
Sec. 4: 137-147.

Kendrew, W. G. and D. P. Kerr. 1955. The climate of British
Columbia and the Yukon Territory. Edmund Cloutier,
Ottawa. 222 p.

Kerr, F. A. 1934. Glaciation in northern British Columbia.
Transactions of the Royal Society of Canada 28: 17-31.

Kerr, F. A. 1936. Quaternary glaciation in the Coast Range,
northern British Columbia and Alaska. Journal of
Geology 44: 681-700.

Kershaw, X. A. 1964. Quantitative and dynamic ecology.
Edward Arnold, Ltd., London. 183 p.

La Roi, G. H. 1967. Ecological studies in the boreal spruce-
fir forests of the Nerth American taiga. I. Analysis
of the vascular flora. Ecological Monographs 37: 229-

253.

Leahey, A. 1949. Factors affecting the extent of arable
lands and the nature of the soils in the Yukon Territory.
Pgoceedings of the 7th Pacific Science Congress 6:

l “'20.

Leopold, E. B. 196 . Late-Cenozoic patterns of plant extinc-
(ed. Pleistocene effinctions, the search for a cause.
ale university Press, New Haven. 453 p.

Lichti-Federovich, S. and J. C. Ritchie. 1965. Contemporary
pollen spectra in central Canada. II. The forest-
rassland transition in ManitOba. Pollen et Spores 7:

3-88.

Lietzke, D. A. 1969. Soils and soil-vegetation relationships
in the Atlin valley, British Columbia, Canada. Unpub-
lished manuscript. Department of Soil Science, Michigan
State university, East Lansing. 21 p.

Livingston, D. A. 1955. Some ollen profiles from arctic
Alaska. Ecology 36: 587- 00.

Lutz, H. J. 1956. Ecological effects of forest fires in the
interior of Alaska. U. S. Dept. of Agriculture Tech-
nical Bulletin No. 1133. 121 pp.

 

 

 

322

Mackay, J. R. and J. Terasme. 1963. Pollen diagrams in the
Mackenzie Delta area, N.W.T. Arctic 16: 228-238.

MbAndrews, J. H. 1966. Postglacial history of prairie,
savanna, and forest in northwestern Minnesota. Memoirs
of the Torrey Botanical Club 22(1): 1-72.

McTaggart-Cowan, I. 1941. Fossil and subfossil mammals
from the Quaternary of British Columbia. Transactions
of the Royal Society of Canada 35. Section IV: 39-50.

‘Miller, C. D. 1969. Chronology of neoglacial moraines in
the Dome Peak area, north Cascade Range, washington.
Arctic and Alpine Research 1: 49-66.

Miller, M. M. 1961. A distribution study of abandoned
cirques in the Alaska-Canada Boundary Range, p. 833-
847. ‘Itheology of the Arctic, vo1. II. university of
Toronto Press.

Miller, M. M. 1963. Taku Glacier evaluation study. State
of Alaska Department of Highways (mimeo.) 200 p. plus
appendices.

Miller, M. M. 1964a. Inventory of terminal position changes
in Alaskan coastal glaciers since the 1750's. Proceed-
ings of the American Philosophical Society 108: 257-273.

Miller, M;.M. 1964b. Morphogenetic classification of Pleisto-
cene glaciations in the Alaska-Canada Boundary Range.
giocgegings of the American Philosophical Society 108:

7- 5 .

Miller, M. M. 1967. Alaska's mi ty rivers of ice. National
Geographic Magazine 131: 1 -217.

Miller, M. M., C. P. Egan, and R. E. Beschel. 1968. Neo-
glacial climatic chronology from recent radiocarbon and
dendrochronological dates in the Alaskan Panhandle,

No. 16. In Science in the NOrth. Glaciological and
Arctic Sciences Institute, Michigan State university,
East Lansing. (mimeo.) (abstr.)

Miller, N. G. 1969. Late- and postglacial vegetation change
in southwestern New Ybrk state. Ph. D. Thesis, Michigan
State university, East Lansing. 325 p.

Monger, J. W. H. 1968. Late Paleozoic rocks of northwestern
British Columbia and south-central Yukon: A progress
report, p. 49-50. 'In Program.and Abstracts, 19th Alaskan
Science conference. Alaska Division, American Association
for the Advancement of Science, Whitehorse. 72 p.

 

 

 

 

 

 

 

323

Moss, E. H. 1953a. Forest communities in northwestern
Alberta. Canadian JOurnal of Botany 31: 212-252.

Moss, E. H. 1953b. Marsh and bog vegetation in northwestern
Alberta. Canadian Journal of Botany 31: 448-470.

Mulligan, R. 1963. Geology of Teslin map-area, Yukon Terri-
tory. Geological Survey of Canada Memoir 326. 96 p.

Neustadt, M. I. 1967. The lower Hblocene boundary, p. 415-
425. ‘13 E. J. Cushing and H. E. Wright, Jr. (ed.).
Quaternary Paleoecology. Yale University Press, New
Haven. 433 p.

Oberle, M. 1969. Forest fires: Sup ression policy has its
ecological drawbacks. Science 1 : 568-571.

Petterssen, S. 1958. Introduction to meteorology. MbGraw-
Hill Book Co., Inc., New Ybrk. 327 p. 2nd ed.

Péwé, T. L. 1967. Permafrost and its effect on life in the
NOrth, p. 27-65. ‘;§_H. P. Hansen (ed.) Arctic Biology.
Oregon State university Press, Corvallis. 318 p.
2nd ed.

Pollock, J. B. 1918. Blue-green algae as agents in the
deposition of marl in Michigan lakes. 20th Michigan
Academy of Science Report, 1918: 247-262.

Poore, M. E. D. 1955. The use of phytosociological methods
in ecological investigations. I. The Braun-Blanquet
system. II. Practical issues involved in an attempt
to apply the Braun-Blanquet system. III. Practical
Eggléggtion. JOurnal of Ecology 43: 226-244; 245-269;

Poore, M. E. D. 1956. The use of phytosociological methods
in ecological investigations. IV. General discussion
05 phytosociological problems. Journal of Ecology 44:
2 “500

Porsild, A. E. 1951. Botany of southeastern Yukon adjacent
to the Canol road. National Museum.of Canada Bulletin
NO 0 121 : l-ll-OO o

Porsild, A. E. 1964. Illustrated flora of the Canadian
Arctic Archipelago. National Museum.of Canada Bulletin
146: 1-218, 2nd ed., revised.

Porsild, A. E. and H. A. Crum. 1961. The vascular flora of
Liard HOtsprings, B. C., with notes on some bryophytes.
National.Museum.of Canada Bulletin 171: 131-197.

 

324

Potzger, J. E. 1956. Pollen profiles as indicators in the
history of lake filling and bog formation. Ecology 37:

476-483.

Rampton, V. N. 1969. Pleistocene geology of the Snag-
Klutlan area, southwestern Yukon Territory, Canada.
Ph. D. Thesis, university of Minnesota, Minneapolis.

237 P-

Raup, H. M. 1934. Phytogeographic studies in the Peace and
upper Liard River regions, Canada, with a catalogue of
the vascular plants. Contributions from.the Arnold
Arboretum of Harvard university VI. 230 p.-

Raup, H. M. 1941. Botanical problems in boreal America.
I and II. The Botanical Review 7: 147-248.

Raup, H. M. 1945. Forests and gardens alon the Alaska
Highway. Geographical Review 35: 22-4 . ‘

Raup, H. M. 1947. The botany of southwestern MacKenzie.
Sargentia. A continuation of the Contributions from
the Arnold Arboretum of Harvard University'VI. 275 p.

Ritchie, J. C. 1964. Contributions to the HOlocene paleo-
ecology of westcentral Canada. I. The Riding Mountain
area. Canadian Journal of Botany 42: 181-19 .

Ritchie, J. C. 1967. Ho1ocene vegetation of the north-
western precincts of the glacial Lake Aggassiz basin,
p. 217-229. .Ig W. J. Mayer-Cakes (ed.) Life land and
water. Univ. of Manitoba Press, Winnipeg. 414 p.

Ritchie, J. C. 1969. Absolute pollen frequencies and
carbon-l4 age of a section of Holocene Lake sediment
from the Riding Mountain area of Manitoba. Canadian
Journal of Botany 47: 1345-1349.

Ritchie, J. c. and B. de Vries. 1964. Contributions to the
HOlocene paleoecology of west-central Canada: a late-
glacial deposit from the Missouri Coteau. Canadian
JOurnal of Botany 42: 677-692.

Ritchie, J. C. and S. Lichti-Federovich. 1963. Contemporary
pollen spectra in central Canada. I. Atmospheric
samplfis at Winnipeg, ManitOba. Pollen et Spores 5:
95-11 0

Ritchie, J. C. and S. Lichti-Federovich.. 1967. Pollen dis-
persal phenomena in arctic-subarctic Canada. Review of
Paledbotany and Palynology 3: 255-266.

 

 

 

 

325

Ritchie, J. C. and S. Lichti-Federovich. 1968. Holocene
pollen assemblages from the Tiger Hills Manitoba.
Canadian Journal of Earth Sciences 5: 873-880.

Rowe, J. S. 1959. Forest regions of Canada. Dept. of
NOrthern Affairs and Natural Resources, Forestry Branch
Bulletin 123: 1-71.

Sanderson, M. 1948. The climates of Canada according to the
ngw Thornthwaite classification. Scientific Agriculture

Sangster, A. G. and H. M. Dale. 1961. A preliminary study
of differential pollen grain preservation. Canadian
Journal of Botany 39: 35-43.

Sangster, A. G. and H. M. Dale. 1964. Pollen grain pre-
servation of underrepresented species in fossil spectra.
Canadian JOurnal of Botany 42: 437-449. ,

Sears, a. B6 l942.~ Xerothermic theory. Botanical Review 8:
70 -73 .

Shelford, V. E. 1963. The ecology of NOrth America. Uni-
versity of Illinois Press, urbane. 610 p.

Sigafoos, R. S. 1958. Vegetation of northwestern North
America, as an aid in interpretation of geologic data.
U. 3. Geological Survey Bulletin 1061-E: 165-185.

Spiegel, M. R. 1961. Schaumis outline of theory and problems
of statistics. Schaum Publishing Co., New YOrk. 359 P.

Stone, K. H. 1948. Aerial photographic interpretation of
natural vegetation in the Anchorage area, Alaska.
Geographical Review 38: 465-474.

Swarth, H. S. 1936. Mammals of the Atlin region, north-
western British Columbia. Journal of Mammalogy 17:

398-405 .

Tauber, H. 1967. Differential pollen dispersion and fil-
tration, p. 132-141. Ian. J. Cushing and H. E. wright,
Jr. (ed.) Quaternary PEleoecology. Yale university
Press, New Haven. 433 p.

Terasmae, J. 1958. Contributions to Canadian palynology.
Part I. The use of palynological studies in Pleistocene
stratigraphy. Part II. an-glacial deposits in the
St. Lawrence lowlands, Quebec. Part III. an-glacial
deposits along MUssinaibi River, Ontario. Geological
Survey of Canada Bulletin 46: 35 P.

326

Terasmae, J. 1961. Netes on late-Quaternary climatic 1
changes in Canada. Annals of the New Ybrk Academy of
Science 95: 658-675.

Terasmae, J. 1967a. Netes on Quaternary palaeoecological
problems in the Yukon Territory, and adjacent regions.
Geological Survey of Canada Paper 67-46. 12 p.

Terasmae, J. l967b. Postglacial chronology and forest
history in the northern Lake Huron and Lake Superior
regions, p. 45-58. 'Ig Cushing, E. J. and H. E. wright,
Jr. (ed.) Quaternary Paleoecology. Yale University
Press, New Haven. 433 p.

Terasmae, J. l967c. Recent pollen deposition in the north-
eastern District of Mackenzie, NOrthwest Territories,
Canada. Palaeogeography, Palaeoclimatology, and
Palaeoecology 3: 17-27.

Terasmae, J. l967d. A review of Quaternary palaeobotany
and palynology in Canada. Geological survey of Canada
Paper 67-13. 12 p.

Terasmae, J. and J. G. Fyles. 1959. Palaeobotanical study
of late-glacial deposits from‘Vancouver Island, British
Columbia. Canadian JOurnal of Botany 37: 815-817.

Terasmae, J. and O. L. Hughes. 1966. Late-Wisconsinan
chronology and history of vegetation in the Ogilvie
Mbuntains,uYukon Territory, Canada. The Paledbotanist
15: 235-2 2.

Terasmae, J. and R. J. Mott. 1964. Pollen deposition in
lakes and bogs near Ottawa, Canada. Canadian Journal
of Botany 42: 1355-1363.

Terasmae, J. and R. J. Mott. 1965. Modern pollen deposition
in the Nichicun Lake area, Quebec. Canadian Journal of

Botany 43: 393-404.

U. S. Department of Agriculture, Soil Survey Staff. 1967.
Soil classification, a comprehensive system. 7th
approximation and supplements. Soil Survey Staff, Soil
Conservation Service, U. S. Department of Agriculture,
Washington, D. C.

Watson, K. DeP. and W. H. Mathews. 1944. The Tuya-Teslin
area, northern British Columbia. British Columbia
Department of Mines Bulletin 19: 52 p.

Wheeler, J. 0. 1961. Whitehorse map-area, Yukon Territory.
Geological Survey of Canada Memoir 312: 156 p.

APPENDICES

APPENDIX A

SELECTED SOIL PROFILE DESCRIPTIONS

Soil rofile descriptions made by David A. Lietzke in
August, 19 9. (From Lietzke, 1970).

I. Boralfic Cryorthods, coarse loamy, mixed.
(Canada: Bisequal Gray-Wooded.)

Site: West of mile 3, Atlin road. Westerly exposure;
15-20 percent slope.

'Vegetation: Muxedwood forest association.

 

 

DEPTH

HORIZON (inches) DESCRIPTION

01 2-0 Organic root mat.

A1 0-2 Black (lOYR2/1) silt loess. Weak fine
granular structure; very friable. Abrupt
wavy boundary. Mildly alkaline. pH 7.5.

A2 2—4 Light brownish gray (lOYR6/2) silt loess.
Weak fine granular structure; very friable.
Abrupt wavy boundary. Mildly alkaline.
pH 7.0. .

B2lir 4-6 Reddish brown (5YR4/4) silt loess with
sand grains in the lower part (pebble
line). Weak fine granular structure.
‘Very friable. Clear wavy boundary.

Mildl alkaline. pH 7.3 Quick test
(lOYR /3).
IIB22ir 6-8 Dark reddish brown (5YR3/4) gravelly loam.

Weak fine granular structure; very fri-
able. Abrupt wavy boundary. Mildly
alkaline. pH 7.5. Quick Test (lOYR6/3).

327

328

IIA'2 8-14 Yellowish brown (lOYR5/4) loam. Weak
fine granular structure; very friable.
Abrupt wavy boundary. Mildly alkaline.

pH 7.5.

IIB't 14-20 Grayish brown (lOYR5/2) to light olive
brown (2.5Y5/4) fine loam. Weak fine
subangular blocky structure; very fri-
able. Clear wa boundary. Mildly
alkaline. pH 7.

IIC2lca 20-23 Light brownish gray (2.5Y6/2) loam.
Weak fine subangular blocky structure;
very friable. Clear wavy boundary.
Highly effervescent. pH 8.2.

IIC22ca 23-33 Light brownish gray (2.5Y6/2) and brown
(7.5YR4/4) loam. Weak thin platy struc-
ture; very friable. Gradual wavy
boundary. Highly effervescent. pH 8.2.
The entire horizon had a pinkish gray
appearance, the result of many fine root-
lets in this layer.

IIC23ca 33-49 Light olive gray (2.5Y6/2) loam. Weak
fine platy structure; very friable.
Gradual wavy boundary. pH 8.0

IIC3 49-69 Olive gray (5Y6/2 - 5/2) loam. Mederate
fine subangular blocky structure; verg
friable. Gradual wavy boundary. pH .0.

IIC4 69-75 Gray (5Y5/1) loam. Moderate medium.sub-

angglar blocky structure; very friable.
pH .0.

II. Typic Cryochrepts, coarse lo , mixed.
(Canada: Orthic Brown-WOodegT¥

Site: Gravel pit exposure east of Alaska Highway one-
third mile north of milepost 896.

‘Vegetation: Mixed woodland association.

 

 

DEPTH
HORIZON (inches) DESCRIPTION
01 3-0 Organic root mat.
A2 O-l Yellowish brown (lOYR5/4) silt loess.

Weak thin platy structure; very friable.
Abrupt wavy boundary. pH 7.5.

 

 

 

 

 

Entic Cryorthods, coarse loamy

329

Dark reddish brown (5YR3/4) sandy loam
(a combination of loess and sandy under-
lying material). Weak fine granular
structure; very friable. Clear wavy
boundary. pH 7.9. Quick test (lOYR7/3).

Light olive brown (2.5Y5/4) fine and
very fine sands. Single grain. Loose.
Abrupt irregular boundary. pH 7.3.

Gray (lOYR6/l) lacustrine silts. Weak
thin platy structure; very friable.
Abrupt wavy boundary. Highly efferves-
cent in dilute acid.

Gray (lOYR5/l) coarse sand and gravel.
Single grain. Loose. pH 7.8.

mixed.
Orthic Brown-WOoded.)

Moraine at east end of Simpson Lake. Nearly level.

 

B2ir 1-3
IIB'2 3-20
IICca 20-36
IIIC2 36+
III.
(Canada:
Site:
Vegetation:
ciation (?).
DEPTH
HORIZON (inches)
A1 O-l
A2 ---
B211r 0-4
B22ir 4-8
B31 8-15
B32 15-21

White spruce-lodgepole pine forest asso-

DESCRIPTION

 

Dark reddish brown (5YR3/3) loam. Weak
fine granular structure. ‘Very friable.
Abrupt wavy boundary. pH 4.8.

Only a few traces. Not sampled.

Reddish brown (5YR4/3) loam. Weak fine
granular structure. Very friable.
Abrupt wavy boundary. pH 5.0.

Strong brown (7.5YR5/6) sandy loam. Weak
fine subangular blocky structure. Very
friable. Clear wavy boundary. pH 5.7.

Dark brown (7.5YR4/4) sandy loam. Weak
fine subangular blocky structure. Very
friable. Clear wavy boundary. pH 5.9.

Dark yellowish brown (lOYR4/4 sandy

loam. Weak fine subangular b ocky struc-
turg. Very friable. Abrupt wavy boundary.
pH .0

330

1102 21-27 Dark brown (lOYR3/3) sand and loamy sand.
Weak fine granular structure. Very fri-
able. Abrupt wavy boundary. pH 6.1.

IIC3 27-32 Dark yellowish brown (lOYR4/4) stratified
very fine sand and silts. Massive.
Structureless. pH 6.2.

IV. Typic Cryopsamments, sandy mixed.
(Canada: Orthic Regosols.)

Site: Road cut in kame terrace in southwestern end of
Fourth of July Creek valley.

Vegetation: Lodgepole pine association.
DEPTH

 

 

HORIZON (inches) DESCRIPTION

01 0-1 Organic mat.

A1 0-2 Dark grayish brown (lornu/a) sand and
gravel. Weak fine granular structure.
Very friable. Clear wavy boundary.
pH 6.4.

B 2-10 Grayish brown (lOYR5/2) sand and gravel.
No evidence of clay accumulation.
Single grain. Loose. Gradual wavy
boundary. pH 6.4.

Ci 10-28 Grayish brown (2.5Y5/2) sand and gravel.
Single grain. Loose. Gradual wavy
boundary. pH 6.4.

C2 28+ Light brownish gray (2.5Y6/2) sand and

gravel. Single grain. Loose. pH 6.4.

‘V. Boralfic Cryorthods, loamy skeletal, mixed.
(Canada: Bisequal Gray-Wooded.)

Site: West of Atlin road at the Warm.Springs, c 15
miles south of Atlin. (Stand SlSW) Nbrtheasterly exposure;
well-drained.

vegetation: Alpine fir association.

331

 

 

DEPTH
HORIZON (inches) - DESCRIPTION
01 6-2 Organic mat. Identifiable plant re-
mains mostly of acid mosses.
02 2-0 Black (lOYR2/l) well decomposed or-
ganic matter.
A1 0-; Brown (lOYR4/3) sandy loam. Weak fine
granular structure. Dry. Soft. pH 4.8.
Bir 3-5 Brown (7.5m5/4) sandy loam. Weak fine
granular structure. Dry. Soft. pH 5.5.
B'2 5-17 Yellowish brown (lOYR5/6) loam. Weak
fine ranular structure. Dry. Soft.
pH 4. .
B'23 17-22 Olive brown (2.5Y4/4) loam. Weak fine
granular structure. Dry. Soft. pH 5.8.
Ci 22-35 Light olive brown (2.5!5/4) loam. Weak
fine granular structure. Dry. Soft.
pH 7.0.

‘VI. Histic Cryaquepts, coarse loamy, mixed calcareous.

Typic Cryaquepts?)
Canada: Carbonated Humic Gleysol.)

Site: East of Atlin road at mile 52. (Stand 52E) Poor
drainage; 4-6 percent slope; westerly exposure.

Vegetation: White spruce association/Feather moss
faciation.

 

 

DEPTH

HORIZON (inches) DESCRIPTION

01 8-2 Reddish, acid raw peat.

81 2-0 Black (5YR2/1) sapric muck.

Clg 0-23 Light olive gray (5Y6/2 - 5/2) lacustrine
silts and very fine sands. Massive.
Very friable. Calcareous.

C2g 23-36 Same as the Clg horizon except frozen
hard and difficult to auger.

033 36-62 Same as the Clg horizon except drier.

th frozen.

332
'VII. Terric Cryosaprists, euic.
(Canada: Terric Uhic Humisol.)

Site: West of Atlin road at mile 59. (Stand 59W)
Level, depressed area; poorly drained.

'Vegetation: Depression shrub association.

 

 

DEPTH
HORIZON (inches) DESCRIPTION
31 0-8 Recent vegetation remains. Snail
shells on the surface and throughout
the horizon. pH 8.0.
S2 8-18 Black (lOYR2/l) muck. Very wet.
pH 7.2.
S3 18-36 Black (5YR2/1):muck. Fairly dry and
compact. pH 7.0.
IIC 36+ Dark gray (5Y4/l) silt to silt loam.with

a few prominent olive brown (2.5Y4/4)
mottles. Structureless; massive. pH

6.5.

.APPENDIX B

TREE COMMON NAMES USED IN THIS DISSERTATION
AND EQUIVALENT SCIENTIFIC NAMES

Alaska yellow cedar (Alaska cypress). Chamaecyparis noot-
katensis (Lamb.) Spach

Alder. Alnus cris a (Ait.) Pursh subsp. cris a; A. cris a
(AiFTT—Pursfi subsp. sinuata (Regel)‘HfiI¥¥?'afid I.

incana (L.) Mbench suEsp. tenuifolia (Nutt.) BrEitung

 

Alpine fir. Abies lasiocarpa (Hook.) Nutt.*

 

Aspen (Quaking aspen; trembling aspen). Populus tremuloides
Michx.

Balsam poplar (Cottonwood). Populus balsamifera L. subsp.
balsamifera*

Black cottonwood. Po ulus balsamifera L. subsp. trichocarpa
(Torr. & Gray) HfiIt.

 

Black spruce. .Pigga_mariana (Mill.) Britt., Sterns & Pogg.
Douglas fir. Pseudotsuga Menziesii (Mirb.) Franco
Engelmann spruce. Picea Engelmannii (Parry) Digelm.

Jack pine. _P_i_nu_s_ Banksiana Lamb.

Larch (Tamarack). Larix laricina (Du Roi) K. Koch var.
alaskensis (Wight) Raup

Lodgepole pine. Pinus contorta Dougl.‘gx_Loud. subsp.
latifolia (EEEEIE.) Oritchfield*

Mountain hemlock. Tsuga Mertensiana (Bong.) Sarg.
Paper birch. Betula a rifera Marsh. subsp. humdlis (Regel)
I¥era ME

Hult. and E. papyg rsh. var. commutata (Hegel)
Fern.

 

Sitka spruce. Picea sitchensis (Bong.) Carr.

333

334

Tree willow. Salix spp.

Western hemlock. ngga heterophylla (Raf.) Sarg.
Western red cedar. Thugs plicata D. Don

 

White spruce. Picea glauca (Moench) Voss var. albertiana
(S. Brown) Sarg.

* When used in the text the simple names "fir", "poplar",

"pine", and "spruce" refer to the species listed here in
nearly all cases.

 

** It is believed that Picea lauca var. Porsildii Raup also
occurs in the Atlin regIon, pafticularly at intermediate
elevations. The abundance of Porsild's white spruce
relative to Alberta white spruce has not yet been deter-
mined.

 

 

APPENDIX C

THE DOMIN COVER-ABUNDANCE SCALE

(From.Kershaw, 1964: Table 1.5)

Cover about 100 percent

Cover greater than 75 percent
Cover 50-75 percent

Cover 33-50 percent

Cover 25-33 percent

Abundant, cover about 20 percent
Abundant, cover about 5 percent
Scattered, cover small

Very scattered, cover small
Scarce, cover very small

Isolated, cover usually small

* Braun-Blanquet equivalent values

335

|-‘
O

xi-Imwa-mox-Iocxo

5*

 

 

 

 

APPENDIX D

PROCEDURE FOR PREPARATION OF BOG SEDIMENT SAMPLES, INCLUDING

PEATS, MARLS, AND PARTIALLY INORGANIC MATERIALS

Plan to work with as many samples in a set as can be
placed in the centrifuge, usually 6. A vigorous worker
should be able to prepare 2 sets of 6 samples simul-
taneously using 2 centrifuges, etc. This should require
8-10 hours .

Clean and number 6 40 ml round-bottom glass centrifuge
tubes.

Select from each bog sample a chunk of material about the
size of a pebble. The sample does not have to be weighed
nor its volume determined because the procedure is not
meant for determining absolute pollen and spore content
per unit quantity of sediment. As the proportion of in-
organic material in the samples rises, larger chunks
should be selected. If the sample is largely sand or
silt, the amount to be prepared should be approximately
equivalent to a teaspoonful.

As they are selected place the chunks into the tubes.

Fill each tube 1/3 to 1/2 with 5-10% KOH. Place a clean
glass stirring rod in each.

Let the samples sit a few minutes. Stir and break up the
samples as much as possible during this period.

Place tubes in boiling water bath for 5 minutes. Stir
constantly and vigorously. This is the deflocculation
step.

Remove tubes from boiling water bath. Remove stirring
rods, washing them off into tubes with a Jet of distilled
water from.aquirt bottle.

NOTE: For convenience, place the six stirring rods in numer-

ical order on a paper towel near the test tube rack.
Place tubes in rack in the same order each time they are
removed from centrifuge. This way the rods can be used

336

10.

NOTE:

11.

12.

NOTE:

13.

14.

15.

16.

337

over and over without having to be washed between
stirrings. It will be easy to keep track of the rods
so that they can be returned to the same tubes each
time. If there is ever any question as to which rod
goes to which tube, all the rods should be washed.

Wash hot suspensions through No. 80 sieve and into 250
m1 beaker. The amount of water used in washings will
cool the samples and dilute the KOH to inhibit any
further deterioration of palynomorphs. Wash each
residue through the sieve until its beaker is full.
wash the sieve thoroughly between each operation.

Pour beaker contents into 90 ml polyethylene tubes.
Balance the tubes and centrifuge 4 minutes at 1,500 rpm.
At this point the beakers could be allowed to stand

or c 24 hours. The supernatant could then be decanted
directly).

All subsequent centrifugations will involve balancing
the tubes and will be performed at 1,500 rpm.for 3-4
nunmmes.

Repeat until all material is washed from.beakers.
Usually requires 4 repeats.

Wash at least twice more. (Ample washings at all stages
have been found to give better results.)

Always be sure that samples are thoroughly dislodged
from the bottoms of the tubes each time water is added
for another washing. use a spatula and stir, or use a
super mixer. The super mixer probably breaks bisaccate
grains, and its use should therefore be kept to a minimum.

Make a visual inspection of the residue and estimate the
amount of inorganic material. Silt and sand will go to
the bottom first during centrifugation and can be seen
as a light gray layer below the darker organic materials.
Record the approximate amount of inorganics on the pre-
paration schedule, e.g. "a minor amount of silt" or "a
moderate amount of sand", etc.

If there is no inorganic material, or a very minor
amount, delete steps 19 through 23.

If it is determined that the samples contain no cal-
careous material, steps 14-18 may also be omitted.

Fill tube about 1/2 with 10% HCl. Add slowly at first
in case the reaction is vigorous.

Heat in boiling water bath for 5 minutes. Keep well
stirred.

Centrifuge and decant.

338

17. Wash. Wash well, at least 3 times.

18. Prepare)some 50% HF. (To 100 ml of 70% HF add 40 ml

NOTE: When working with HF and when conducting the acetoly-
sis procedure (steps 18-29), use gloves, apron, and
face shield. Perform all of these steps under a venti-
lation hood. No glass implement should be brought near
the HF hood nor come in contact with HF. Use poly-
ethylene or copper containers and stirring rods.
Acetolysis may be performed with glass equipment but
under a different hood.

19. Place samples in 90 m1 polyethylene centrifuge tubes and
add c 20 m1 of 50% HF.

20. Carefully place tubes in boiling water bath. Allow to
heat 3-5 minutes. Stir occasionally.

21. Centrifuge and decant.
22. Wash 3 times with water.

23. Transfer residues back into original (cleaned) 40 ml
tubes.

24. Wash with glacial acetic acid. use c 1/3 tubefull for
.each. Be sure that samples are dislodged and thoroughly
mixed with the acid. Use a glass or copper stirring rod
for this.

NOTE: The purpose of washing the samples with glacial acetic
acid is to dehydrate them. Water should never come in
contact with acetic anhydride nor with the acetolysis
solution because the reaction can be violent. Therefore
all equipment should be dry before using or washed with
glacial acetic acid.

25. Mix acetolysis solution: 1 part concentrated sulfuric
acid to 9 parts acetic anhydride. For six samples, put
54 ml of acetic anhydride into a graduated cylinder.
Slowly, drOp by drop, add 6 ml of sulfuric acid. This
will allow 10 ml of solution for each sample.

26. Add c 10 ml acetolysis solution to each sample and stir
well.

27.- Place tubes into boiling water bath. Allow to heat for
l-lé-minutes and no longer. Stir occasionally.

28. Centrifuge. Decent into a special beaker under the hood.
Set this aside to discard after several days into the
sink.

29.
30.

NOTE:

31.
32.

33.
34.

35.

36.

37-
38.
39-
40.

41.

339

Wash with glacial acetic acid. Centrifuge and decant.
wash with water 3 or 4 times.

If aggregations of the residues form, break them up
with the super mixer or a spatula.

Fill tubes to about 1/2 way to top of taper with water.

Stain with Safranin-O. Ordinarily only a few drops are
required, but the optimum-amount depends on the amount

of residue, the condition of the stain, and the degree

of staining desired.

Add 2 drops of 10% ammonium hydroxide.

Place a clean spatula into each tube and stir. Begin
timing from.the moment of first stirring.

After 3 minutes remove spatulas and fill tubes with
water. Centrifuge and decant.

Wash once. Examine a wet mount of l or more of the
residues to see if staining is adequate. If so, con-
tinue washing until supernatant is clear or only
faintly colored.

Transfer residues into l-dram.vials using a clean bulb
pipette for each.

Allow vials, which will be full of residue suspended in
water after washing out the tubes, to settle for 3 hours
or longer.

Siphon off excess water to concentrate residues.

Add approximately 1/3 by volume of hydroxyethyl cellulose
HEC .

Make permanent microscope slides using Harleco Synthetic
Resin (HSR) as a mounting medium.

APPENDIX E

PLANTS OF THE ATLIN REGION USED IN THE PREPARATION
OF POLLEN REFERENCE SLIDES

The first number following each plant name is its col-
lection number. Numbers with an M are catalog numbers in
the pollen and spore reference collection of the Departments
of Geology and Botany and Plant Pathology, Michigan State
University.

Achillea borealis 295 M797
ASTOPyron BP- ? M820
Agrostis scabra ? M818
Amelanchier alnifolia 261 M790
-Anemone multifida 327 M800
Aquilegia formosa 100, 118, 194 M772
Arabis Holboellii 189 M781
Arctostaphylos uva-ursi 232 M787
Arnica cordifolia 338 M801
Artemisia arctica 267 M793
Aster sibiricus 251-A M789
Astragalus americanus 340 M803
Carex sp. ? M821
CastilleJa unalaschensis 101 M773
Cerastium.arvense 370 M807
Chenopodium.capitatum 55 M768

340

341

Delphinium.glaucum

Erigeron eriocephalus

Erysimum cheiranthoides
Fragaria virginiana subsp. glauca
Galium.borea1e

Gentiana propinqua

Geocaulon lividum
Geum.macr0phyllum.subsp. perincisum
Hordeum Jubatum

Lupinus arcticus

Hummlus guttatus

Moehringia lateriflora
Oxytropis campestris

Parnassia palustris

Pedicularis labradorica

P. sudetica

Penstemon procerus

Phacelia Franklinii
Polemonium.pulcherrimum
Polygonum.aviculare

P. viviparum

Potentilla anserina

P. diversifolia

P. pennsylvanica var. glabrata
Pyrola asarifolia var. purpurea
P. secunda var. secunda

Rubus idaeus subsp. melanolasius

386

239
384

399
136

385 f

157
222

397
276
345
212

69
229
325
396
361
279

53
275
391

95
339
142
191
113

M811
M788 .
M809
M815
M777
M810
M779
M785
M817
M814
M795
M804
M784
M791
M786
M799
M813
M806
M796
M767
M794
M812
M771
M802
M778
W82
M774

342

Saxifraga tricuspidata 171,

Senecio pauperculus

S. triangularis

Solidago multiradiata

Tofieldia glutinosa subsp. brevistyla
Veronica alpina A

Viburnum edule

Zygadenus elegans 61, 82,

228

265

120
122

57
199
320
168

M780
M792
M775
M776
M769

M798
M770

APPENDIX F

PRELIMINARY CATALOG OF THE FLORA OF THE ATLIN REGION

Index ofgrogps and families

Lichens (ll)* . . . . . . . . 344
Mosses and liverworts (14) . . 345
Equisetaceae l . . . . . . . 347
Cupressaceae 1 . . . . . . . 347
Juncaginaceae (2) . . . . . . 347
Gramineae (29) . . . . . . . . 348
cyperaceae £21) . . . . . . . 351
Juncaceae . . . . . . . . 354
Liliaceae 3) . . . . . . . . 355
Orchidaceae (7 . . . . . . . 355
Salicaceae lO . . . . . . . 356
Betulaceae l) . . . . . . . . 358
Santalaceae ( ) . . . . . . . 358
Polygonaceae (3) . . . . . . . 358
Chenopodiaceae (2g . . . . . . 358
Caryophyllaceae ) . . . . . 359
Ranunculaceae (7 . . . . . . 360
Fumariaceae (l . . . . . . . 361
Cruciferae (14 . . . . . . . 361
Crassulaceae ( A . . . . . . . 362
‘Saxifragaceae ( ) . . . . .-. 36
Rosaceae (25) . . . . . . . . 3
Leguminosae (7) . . . . . . . 367
‘Violaceae (l) . . . . . . . . 368
Onagraceae ( ) . . . . . . . . 368
Haloragaceae 1 . . . . . . . 369
Ombelliferae 1 . . . . . . . 369
Pyrolaceae (7) . . . . . . . . 369
Ericaceae ( ) . . . . . . . 370
Primulaceae (1) . . . . . . . 370
Gentianaceae (3% . . . . . . . 371
Polemoniaceae ( ) . . . . . . 371
Hydrophyllaceae (1) . . . . . 372
Boraginaceae (3) . . . . . . . 372
labiatae (l) o o o o o o o o o 372
Scrophulariaceae (10 . . . . 37
Orobanchaceae (1) . . . . . . 37

343

344

Lentibulariaceae 1) . . . . . 374
Plantaginaceae (l . . . . . . 375
Rubiaceae (2) . . . . . . . . 375
Caprifoliaceae (1) . . . . . . 375
valerianaceae l; . . . . . . 375
Campanulaceae l . . . . . . 376
Lobeliaceae (1 . . . . . . . 376
Compositae ( 8 . . . . . . 376

* Number of representatives of group
. or family given in parenthesis.

 

LICHENS

Alectoria ochroleuca (Hoffm.) Mass.

925. NE. vaughan. Tundra vegetation in summit area on
west side of mountain. c 5,700 ft. 20 August 1968.

Cladonia cariosa (Ach.) Spreng.

967. Moose Bones Bog. c 2,350 ft. Mesic site in spruce
forest south of bog. 1 September 1968.

Cladonia chlorophaea (Floerke) Spreng.

985. White spruce forest west of Moose Bones Bog.
c 2,350 ft. 3 September 1968.

Cladonia gracilis (L.) Willd.

818. Mile 47 Bog. c 2,400 ft. Dry summits of swells,
sometimes in dense mats with Peltigera aphthosa. 10 July 1968.

Lecanora epibgyon (Ach.) Ach. '

924. .Mt.'Vaughan. Tundra vegetation in.summit area on
west side of mountain. c 5,700 ft. 20 August 1968.

Parmeliella.praetermissa (Nyl.) P. James

807. Low, mossy swell in Mile 47 Bog. Rare. c 2,400 ft.
10 July 1968.

Peltigera aphthosa (L.) Willd.
816. Mile 47 Bog. c 2,400 ft. Uncommon.

969. Moose Bones Bog. c 2,350 ft. Common in shrub
willow stand southeast of bog. 1 September 1968.

345

Peltigera rufescens (Weiss) Humb.

970. Moose Bones Bog. c 2,350 ft. Shrub willow and
mixed forests around bog. 1 September 1968.

Pertusaria dactylina (Ach.) uyl.

923. Mt. Vaughan. Tundra vegetation in summit area on
west side of mountain. c 5,700 ft. 20 August 1968.

Psoroma hypnorum (Vahl) S. Gray

968. Moose Bones Bog. c 2,350 ft. Mesic site. 1
September 1968.

Xanthoria candelaria (L.) Th. Fr.
820. Mile 47 Bog. c 2,400 ft. A corticolous lichen
on dead white spruce tree in sedge-moss zone. 10 July 1968.
MOSSES AND LIVERWORTS

m pseudotriquetrum (Hedw.) Schwaegr.

803. Mile 47 Bog. In thick mat, associated with Juncus
arcticus subsp. ater. Abundant. Dominant locally. c Wft.

y .
823-0. Mile 47 Bog. c 2,400 ft. Intermixed with 823-A.
10 July 1968.

PEEL“ roellii Phil.

823-D. Mile 47 Bog. c 2,400 ft. Intermixed with 823-A.
10 July 1968.

CatoscOpium nigritum (Hedw.) Brid.

949. Wilson Creek Bog. I c 3,050 ft. Magor moss with
Carex spp. in sedge-moss zone. 23 August 196 .

Ceratodon purpureus (Hedw.) Brid.

908-A. Moose Bones Bog and forest west of hog. c 2350
ft. Abundant from outer herb zone of bog through shrub zone
and into white spruce forest. 3 September 1968.

Cinclidium stygium Sw.

843-3. Mile 47 Bog. c 2,400 ft. Intermixed with Dre-
panocladus vernicosus particularly near edge of open water.

346

Drepanocladus aduncus (Hedw.) Warnst.

823-B. Mile 47 Bog. 0 2,400 ft. Intermixed with
823-A. 10 July 1968.

835. Mile 47 Bog. c 2,400 ft. Common in sedge-moss
zone. 10 July 1968. .

896. Mile 16 Bog. c 2,400 ft. Major associate of
Carex aquatilis subsp. a uatilis in sedge-moss zone. Partly
to mostIy submerged. 2 ugus 968.

979. Moose Bones Bog. c 2,350 ft. Common in moist
bog vegetation zones. Associated with Calamagrostis neglecta
and obscured by dead foliage of this Species in many areas.
Decreasing abundance toward outer herb zone where Ceratodon
purpureus becomes increasingly abundant. 3 Septem er

 

Phleum.commutatum.Gandoger var. americanum.(Fourn.) Hult.

91. Near Atlin. 6 July 1966.
198. Near Atlin road several miles south of Atlin.
8 July 1966.
66 223. wright Creek road south of Surprise Lake. 9 July
19 .
858. Near up er Ruby Creek road, north-northeast of
Ruby Mountain. ,500 ft. 19 August 1968.

Drepanocladus vernicosus (Lindb.) warnst.

836. Jasper Creek Bog. c 2, 400 ft. The dominant moss

of the sedge Carex thygchgp¥ysa)-moss zone. Both.moss and
sedge in stan wa er, mos o moss submerged with greener

parts above water. 11 July 1968
843-A. (Same as 836).

Hylocomium splendens (Hedw.) B.S.G.

847-B. Intermixed with Pleurozium schreberi (847-A).
Relative abundance at site not determined.

Leptobgm pyriforme (Hedw.) Wils.

980-B. Intermixed with Ceratodon purpureus (980-A).
Relative abundance not determined.

Marchantia‘pglymggpga L.

894. Mile l6 Bog. c 2,400 ft. At base of root-soil
mass of blown down tree near edge of hog. Common locally.

21 A at 1968.
“535. (Same as 894).
Mnium affine Bland. var. Eggicum.(Laur.) B.S.G.

823-A. Mile 47 Bog. c 2,400 ft. ‘Very abundant in open
water and muddy depressions. Frequently in thick mats. 10
July 1968.

347

Pleurozium.schreberi (B.S.G.) Mitt.
847-A. Mixed coniferous forest west of Jasper Creek

Bog. c 2,500 ft. Abundant in soft mats over large portions
of forest floor. 11 July 1968.

.§ph§§§Em;capillaceum.(Weiss) Schrank var. tenellum.(Schimp.)
r.

898. Upper west branch of Ruby Creek below Mt. Leonard.
c 4, 800 ft. Wet stream bank. Common locally. 19 August 1968.

Tomenthypnum.nitens (Hedw.) Loeske
814. Mile 47 Bog. c 2,400 ft. Abundant, dominant

locally. 10 July 1%
815. (Samey as 814. )

EQUISETACEAE

Equisetum.scirpoides Michx.
38. Gravel pit on O'Donnel Atlin) road c 20 miles

south of Atlin. c 2,900 ft. ugust 1%5.
808. Mile 47 Bog. Common. 2400 ft. 10 July 1968.
CUPRESSACEAE

Juniperus horizontalis Moench
291. Nerth of Atlin road at mile 6. c 2,400 ft. 11
JUNCAGINACEAE

Triglochin maritimum L.

70. Near Warm Bay c 14.5 miles south of Atlin. Area of
mineral springs and seepage; ground covered by mineral
deposits. c 2,2 0 ft. 27 A st 1965..

821. Mile 7 Bog. c 2, 0 ft. 10 July 1968.

Triglochin palustris L.

96 392. In Mile 52 Bog, Atlin road. c 2,350 ft. 5 July
1 7.

 

348
GRAMINEAE

Hierochloe alpina (Sw.) Roem. & Schult.

915. .Mt.'Vaughan. In alpine tundra zone near summit.
c 5,700 ft. 20 August 1968.

Muhlenbergia Richardsonis (Trin.) Rydb.

976. Moose Bones Bog. Common to locally abundant in
outermost, mesic, herbaceous zone. 3 September 1968.

Phleum.pratense L.

33. Warm Springs, c 15 miles south of Atlin. Open,
moist and grassy. c 300 ft. %27 August 1965.
88. Near Atlin. 26 July 196

Alopecurus acqualis sobol.

954. Moose Bones Bog. uncommon in inner moist,
herbaceous zones. Flowering. 1 September 19668.

Arct rostis latifolia (R. Br.) Griseb. var. arundinacea
(%In. ) Griseb.

812. Mile 47 Bog. On drier swells in turfy or hummocky
sites at edge of spruce forest. Common.Iow cover value.
Scattered. c 2, 400 ft. 10 July 1968.

832. Mile 47 Bog. In 8 ruce zone near edge of bog.
Common on drier swells. 0 2,00 ft. 10 July 1968.

Agrostis stolonifera L.

1968 907. Mile l6 Bog. Near inside edge of bog. 21 August

Agrostis scabra Willd.

31. Gravel pit on O'Donnel (Atlin) road c 20 miles south
of Atlin. c 2 ,900 ft. 24 August 1965.

90. Near Atlin. 6 July 1966.
1966 225. Wright Creek road south of Surprise Lake. 9 July
1966 231. wright Creek road south of Surprise Lake. 9 July

Calamagrostis canadensis (Michx.) Beauv.

905. Mile 16 Bog. Near edge of bog. 21 August 1968.
906. Mile l6 Bog. Near edge of bog. 21 August 1968.

 

 

 

 

 

349

Calamagrostis inexpansa Gray

256. Near outlet of Surprise Lake. c 3,000 ft. 10
July 1966.

Calamagrostis neglects (Ehrh.) Gaertn., Mey. & Schreb.

968 955. Moose Bones Bog. Dominant in zone. 1 September
1 . ’

Calamagrostis purpurascens R. Br.

379. Mile 56 Atlin road, west of road. c 2,450 ft.
3 July 1967.

Deschampsia caespitosa (L.) Beauv.

255. Near outlet of Surprise Lake at water's edge.
c 3,000 ft. 10 July 1966.
68 957. Moose Bones Bog. Dominant in zone. 1 September
19 .

Trisetum spicatum (L.) Richter

3. Ruby Creek road north of Surprise Lake. Nearly level,
bulldozed area next to road; easterly exposure. c 3,800 ft.
23 August 1965.

21. Gravel pit on O'Donnel road c 20 miles south of
Atlin. 0 2,900 ft. 24 August 1965.

22. Dry, open gravel pit on O'Donnel (Atlin road) c 20
miles south of Atlin. c 2 900 ft. 24 August 1965.

101-3. Near Atlin. 6 July 1966.
966 22 . wright Creek road south of Surprise Lake. 9 July

234. Early July 1966.

879. Mt. Leonard, c 4,800 ft. on east side of mountain.
Herbaceous tundra zone. 19 August 1968.

922. Mm. vaughan. In herbaceous tundra zone in summit
area on west side of mountain. c 5,700 ft. 20 August 1968.

1

Trisetum.spicatum.(L.) Richter var. Maidenii (Gand.) Fern.
104. Near the Grotto approx. 16 miles south of Atlin.
c 2,400 ft. 6 July 1966.
153. Several mdles south of Atlin, near road. 8 July
178. Several miles south of Atlin, near road. 8 July
186. Several miles south of Atlin, near road. 8 July

190. Several miles south of Atlin, near road. 8 July

 

4

 

 

350

Danthonia intermedia Vas ey

866. Ruby Creek road. 0n north-northeast side of Ruby
Mountain. c 4,500 ft. 19 August 1968.

Poa alpina L.

23. Gravel pit on O'Donnel road c 20 miles south of
Atlin. c 2,900 ft. 24 August 1965.
8. Near Atlin. 6 July 1966.
9. Near Atlin. 6 July 1966.
966 230. Wright Creek.road south of Surprise Lake. 9 July (
1 .

Poa pratensis L. 4

 

28. Gravel pit on O'Donnel road c 20 miles south of
Atlin. c 2,900 ft. 24 August 1965.

Poa.pa1ustris L.

103. Near the Grotto c 16 miles south of Atlin.
c 2,400 ft. 6 July 1966.

107-00 Near Atlin. 6 July 1966.

185. Several miles south of Atlin. 8 July 1966.

336. Near Mile 52 Bog. 23 June 1967.

375. East of Atlin road at mile 16. Dry, sandy, west-
facing slope. c 2,600 ft. 3 July 1967.

961. Moose Bones Bog. Dominant of zone. 1 September

1968.

Poa lanata Scribn. & Merr.

 

861. Near up er Ruby Creek road, north-northeast of
Ruby Mountain. c ,500 ft. 19 August 1968.

Poa annua L.

29. Gravel pit on O'Donnel road c 20 miles south of
Atlin. c 2,900 ft. 24 August 1965.

Poa leptocoma Trin.

913. .Mt. Vaughan. In tundra zone in summit area on
west side of mountain. c 5,700 ft. 20 August 1968.

Festuca altaica Trin.

257. Near outlet of Surprise Lake. c 3,000 ft. 10

326. Near Mile 52 Bog. 23 June 1967.

349. East of Atlin road at mile 59 in open spruce for-
est. c 2,300 ft. 1 July 1967.

351

813. ‘Mile 47 Bog. Scattered on dry swells. 10 July
1968 .
Festuca ovina L. var. brevifolia (R. Br.) wats.

20. Gravel pit on O'Donnel road c 20 miles south of
Atlin. c 2,900 ft. 24 August 1965.

32. Gravel pit on O'Donnel road c 20 miles south of
Atlin. c 2,900 ft. 24 August 1965.

987. Moose Bones Bog. In outermost, mesic, herbaceous
zone. 6 September 1968.
Bromus inermis Leyss.

130. Several miles south of Atlin. 8 July 1966.

Agropyzon subsecundum.(Link) Hitchc.

293. Near mile 6, Atlin road. c 2,300 ft. 11 July 1966.

Agropyron,pauciflorum.(Schwein.) Hitchc.

105. Near the Grotto approx. 16 miles south of Atlin.
c 2,400 ft. 6 July 1966

107-A. Near Atlin. 6 July 1966.

176. Several miles south of Atlin. 8 July 1966.

1 7. Several miles south of Atlin. 8 July 1966.

l 7. Several miles south of Atlin. 8 July 1966.

960. Moose Bones Bog. Uncommon in outer herbaceous
zone and in shrub and forest zones. 1 September 1968.

Agggpyggg,sp. (possibly X Agroelymus)

128. Near the Grotto approx. 16 miles south of Atlin.
c 2,400 ft.‘ 6 July 1966.

Hordeum.Jubatum.L.

~ 25. Gravel pit on O'Donnel (Atlin) road c 20 miles
south of Atlin. c 2,900 ft. 24 August 1965.

179. Several miles south of Atlin. 8 July 1966.
CYPERACEAE

Eriophorum,angustifolium.Honck.

59. Near warm.Bay, c 14.5 miles south of Atlin, an area
of seepage and mineral Springs. Calcium carbonate crust on
ground.‘ 27 August 1965.

839. Has some characteristics of E. viridi-carinatum

Engelm.) Fern. and may therefore be a Hybrid. Jasper Creek
. In wet moss & sedge zone. Uncommon. c 2,400 ft.
11 July 1968.

_D...) lunar.
l

352

Scirpus validus M.Vahl

834. Mile 47 Bog. Dominant in Scirpus zone, occupying
major portion of bog. c 2,400 ft. 10 July 1968.

Carex nardina E. Fries
805-B. Mile 47 Bog. Common. c 2,400 ft. 10 July 1968.
Carex dioica L. subsp. gynocrates

68 805-A. Mile 47 Bog. c 2,400 ft. Uncommon. 10 July
19 .

Carex scirpoidea Michx.

162. Several miles south of Atlin. Male plant.
8 July 1966.
164. Several miles south of Atlin. 8 July 1966.

Carex diandra Schrank

826. Mile 47 Bog. c 2,400 ft. 10 July 1968.

841-3. Jasper Creek Bog. In Carex (g. rhygchopgysa)
zone. c 2,400 ft. 11 July 1968.
Carex Bebbii Olney

26. Gravel pit on O'Donnel road c 20 miles south of
Atlin. c 2,900 ft. 24 August 1965.

'gargx praticola Rydb.
108. Near Atlin. 6 July 1966.
.Qa£g§.Mackenziei Krecz.
1966 218. Wright Creek road south of Surprise Lake. 9 July

66 227. Wright Creek road south of Surprise Lake. 9 July
19 .

966 240. wright Creek road south of Surprise Lake. 9 July
1 o

Carex Bigelowii Torr.

910. Mb. vaughan. In tundra zone in summit area on
west side of mountain. c 5,700 ft. 20 August 1968.

Carex aquatilis wahlenb. subsp. aquatilis
310. Mile 52 Bog. Dominant in zone. 31 August 1966.

 

353
801. Mile 16 Bog. Dominant bog plant, forming thick
‘gags & tugsocks. Springy close to Open water. c 2,400 ft.
ulg 19 7
24. Mile 47 Bog. Dominant in sedge zone. c 2,400 ft.
10 Ju%x 1968.
2. JaSper Creek Bog. In wet Carex rhynchophysa zone.
Carex aurea Nutt.

163. Several miles south of Atlin. 8 July 1966.
393. Mile 52 Bog. 5 July 1967. L

Carex Rossii Boott

974. In closed spruce forest north of Moose Bones Bog. .
Common. 3 September 1968. ‘ '1

Carex Sartwellii Dewey

971. Moose Bones Bog. Scarce to common locally in
outer herbaceous and shrub zones. 3 September 1968.

Carex limosa L.

841-A. Jasper Creek Bog. In wet Carex rhynchopgysa
zone. 11 July 1968.

Carex petricosa Dew.

882. Mt. Leonard. Moist area near stream c 4,800 ft
on east side of mountain. 19 August 1968.

883. Same as 882).

859. by Creek road. On north-northeast side of Ruby
Mountain. c 4,500 ft.
Carex capillaris L.

161. Several miles south of Atlin. 8 July 1966.
Carex capillaris L. var. magor DreJ.

804. Mile 47 Bog. uncommon. c 2,400 ft. 10 July 1968.
Carex Williamsii Britt.

966 236. wright Creek road south of Surprise Lake. 9 July
1 .

Carex Oederi Retz. subsp. viridula (Michx.) Hult.

938. Wet, north-facing slope above warm Bay, ap rox.
14.5 miles south of Atlin. c 2,300 ft. 25 August 1 8.

 

 

 

 

 

 

   

 

354

Carex rflchopflsa C. A. Mey.

837. Jasper Creek Bog. Dominant sedge of wet sedge
zone. c 2,400 ft. 11 July 1968.

JUNCACEAE

Juncus arcticus Willd.

 

81. Near Atlin. 6 July 1966. (
129. Several miles south of Atlin. 8 July 1966. f
226. wright Creek road south of Surprise Lake. 9 July

 

1966. .
259. Near outlet of Surprise Lake. c 3,000 ft. Speci- 3
men from one large clump in wet soil near water. 10 July 1966. E
959. Moose Bones Bog. Uncommon in drier herbaceous A
zones. 1 September 1968.

Juncus arcticus Willd. subsp. ater (Ryde.) Hult.

 

802. Mile 47 Bog. Abundant. Moist site with moderately
dense to dense moss cover. c 2,400 ft. 10 July 1968.

Juncus Drummondii E. Mey.

884. Mt. Leonard. Moist area near stream. c 4,800
ft on east side of mountain. 19 August 1968.

Juncus falcatus E. Mey.

 

887. Mt. Leonard. Moist area near stream c 4,800 ft on
east side of mountain. 19 August 1968.

Juncus alpinus‘Vill.

60. Near warm Bay c 14.5 miles south of Atlin. Area of
seepage and mineral springs. Calcium carbonate deposits on
ground. Some plants in shallow water. c 2,200 ft. 27 August

1955.
Luzula parviflora (Ehrh.) Desv.

246. Wright Creek road south of Surprise Lake. 9 July
1966.215. Wright Creek road south of Surprise Lake. 9 July
1966. '

Luzula parviflora (Ehrh.) Desv. subsp. parviflora

860. Near up er Ruby Creek road, north-northeast of
Ruby Mountain. c ,500 ft. 19 August 1968.

355

Luzula arcuata (Wahlenb.) Sw.

911. Mt. Vaughan. In herbaceous tundra zone in summit
area on west side of mountain. c 5,700 ft. 20 August 1968.

LILIACEAE

Tofieldia pusilla (Michx.) Pers.

56. Near Warm Bay c 14.5 miles south of Atlin. Area
of mineral Springs and carbonate deposits. Some plants
growing in shallow water. c 2,250 ft. 27 August 1965.

158. Near road south of Atlin. 7 July 1966.

237. Wright Creek valley south of Surprise Lake.

9 July 1966.

wnymw—*rW“V'—'

Tofieldia glutinosa (Michx.) Pers. subsp. brevistyla Hitchc.

 

57. Near Warm Bay c 14.5 miles south of Atlin. Seepage
and mineral springs with carbonate deposits on ground.
c 2,250 ft. 27 August 1965.

gygadenus elegans Pursh

61. Near Warm Bay c 14.5 miles south of Atlin. Moist;
seepage and mineral spri s with carbonate deposits on ground.
c 2, 0 ft. 27 August 1 5.

2. Near Atlin. 6 July 1966.
168. Vicinity of road south of Atlin. 6 July 1966.

ORCHIDACEAE

gripedium passerinum Richards.
159. Several miles south of Atlin. 8 July 1966.
401. Vicinity of Atlin road at mile 4. Shady, moist,

mixed pOplar and spruce stand west of road. c 2,300 ft.
Early July 1967.

Amerorchis rotundifolia (Banks) Hult.

403. In dense, moist, mixed poplar and spruce forest
west of Atlin road at mile 4. c 2,300 ft. Early July 1967.

Platanthera hyperborea (L.) Lindl.

46. Warm Springs c 15 miles south of Atlin. Open,
moist, grassy area. 0 2,300 ft. 27 August 1965.

HA

 

 

 

 

356

64. Near Warm Bay c 14.5 miles south of Atlin. Seepage
and mineral gprings, carbonate deposits on ground. 0 2,250 ft.
27 August 19 5.

90. Mile 52 Bog. Common. 5 July 1 7.
2. Vicinity of Atlin road at mile . In moist,
mixed spruce and poplar forest west of road. c 2,300 ft.
Common. Early July 1967.

Platanthera obtusata (Pursh) Lindl.

160. Vicinity of road several miles south of Atlin.
8 July 1966.

254. Near outlet of Surprise Lake. Damp, mossy Site.

c 3,000 ft. 10 July 1966. (

335. Vicinity of Atlin road at mile 52. c 2,400 ft. 4
23 June 1967. T

357. Vicinity of Atlin road at mile 52. Shady, mossy
spruce forest east of road. c 2,400 ft. 1 July 1967.

404. 'Vicinity of Atlin road at mdle 4. West of road
in moist, dense, mixed spruce and p0plar forest. c 2,300 ft.
Early July 1967.

810. Mile 47 Bog. Rare. c 2,400 ft. 10 July 1968.

 

Spiranthes Romanzoffiana Chem.

934. Wet northerly slope above Warm.Bay, c 14.5 miles
egggh of Atlin. Flowering. Common. c 2,300 ft. 25 August
1 .

Listera borealis Morong

356. In shady, mossy spruce forest east of Atlin road
at mile 52. c 2,400 ft. 1 July 1967.

406. In dense, moist, mixed poplar and spruce stand
west of Atlin road at mile 4. c 2,300 ft. Early July 1967.

Corallorrhiza trifida Chatelain

358. Vicinity of Atlin road at mile 52. Shady, mossy
spruce forest east of road. c 2,450 ft. 1 July 1967.

365. Specimens from sites at miles 24 and 28, Atlin
road. Early July 1967.

405. Vicinity of Atlin road at mile 4. Dense, moist,
mixed poplar and spruce forest west of road. c 2,300 ft.

SALICACEAE
Salix reticulata L.

208. In boggy area near Wright Creek road south of
Surprise Lake. 9 July 1966.

357

886. Mt. Leonard.‘ Moist area near stream c 4,800 ft
on east side of mountain. 19 August 1968.

Salix.arctica Pall. subsp. torulosa (Trautv.) Hult.

 

317. Collected at miles 1, 40, 50, 60, Atlin road.
31 August 1966.

Salix arctophila Cockerell

909. Mt. Vaughan. In tundra zone in summit area on
west side of mountain. c 5,700 ft. 20 August 1968.

Salix Eauca L. subsp. acutifolia (Hook.) Hult.

 

819-B. Mile 47 Bog. Common. In clumps with 819-A.
Appears to be result of introgression between subspp.
acutifolia & labrescens, with a closer resemblance to
acutIfoIia. c 2,400 It. 10 July 1968.

Salix glauca L. subsp. glabrescens (Anderss.) Hult.

819-A. Mile 47 Bog. Growing in clump w 819-B. Common.
c 2,400 ft. 10 July 19 8. '

830. Mile 47 Bog. Common on small hillock in sedge
zone. c 2,400 ft. 10 July 1968.

Salix.myrtillifolia Anders.

71. Near Atlin. 6 July 1966.
. 322. Adjacent to south side of Mile 52 Bog. Dominant.
23 June 1967.
811. Mile 47 Bog. Common. c 2,400 ft. 10 July 1968.
825. Mile 47 Bog. c 2,400 ft. 10 July 1968.

Salix gyrtillifolia Anders. var. pseudomyrsinitis (Anderss.)
"'RBEl

831. PrObably a hybrid form, with S. Barcla i Anderss.
Mile 47 Bog. Common on small embankment near ponH within
sedge zone. c 2,400 ft. 10 July 1968.
Salix Barclayi Anderss.

353-A. Shrub willow and birch thicket west of Atlin
road at mile 54. c 2,400 ft. 1 July 1967.

Salix Chamissonis Anderss.

315. East of Atlin road at mile 50. c 2,400 ft. Young
spruce stand developing after fire. 31 August 1966.

 

 

358
Salix depressa L. subsp. rostrata (Anderss.) Hiitonen
983. Mile 4.5, East Carcross road, across from.Moose

Bones Bog. Abundant. Common roadside shrub willow. 2
September 1968.

BETULACEAE

Betula glandulosa Michx.
817. Mile 47 Bog. Uncommon. c 2,400 ft. 10 July 1968.

SANTALACEAE

Geocaulon lividum.(Richards.) Fern.

 

966 157. Near Atlin. Widespread in spruce forests. 6 July
1 . '
806. Mile 47 Bog. uncommon. c 2,400 ft. 10 July 1968.

POLYGONACEAE

Rumex maritimus L.

964. Moose Bones Bog. Rare in inner, moist, herbaceous
zones. 1 September 1968.
966. (Same as 964).

Polygonum viviparum L.

275. Vicinity of road north of Surprise Lake. c 3,300
ft. 10 July 1966. .

Polygonum.aviculare L.
53. Bulldozed, rocky area near Atlin road at Fourth of
July Creek. c 2,400 ft. Common. 24 August 1965.

184. Edge of road several miles south of Atlin. Common.
6 July 1966.

CHENOPODIACEAE
Chenopodium capitatum (L.) Aschers.

55. .Mile 54, Atlin road. Open, rocky, bulldozed area
adjacent to road on west, c 2,400 ft. Common. 24 August 1965.

359

1966 294. Near Atlin road at mile 6. c 2,300 ft. 11 July

ChenOpodium rubrum L.
963. Moose Bones Bog. In inner, moist herbaceous
zones. 3 September 1968.
CARYOPHYLLACEAE

Stellaria crassifolia Ehrh.

Wright Creek road south of Surprise Lake. c 3,500
ft. 9 July 196

Stellaria monantha Hult.

 

Near road several miles south of Atlin. 7 July 1966.
Cerastium Beeringianum.Cham.& Schlecht.

277. Vicinity of road north of Surprise Lake. c 3,300
ft. 10 July 1966.

Cerastium.arvense L.

126. Near the Grotto c 16 miles south of Atlin.
c 2,400 ft. 7 July 1966.

174. Near road south of Atlin. 8 July 1966.

2 . Mile 6, Atlin road. c 2,300 ft. 11 July 1966.

32 . Vicinity of Atlin road at mile 52. Rocky area
on small hill west of bog. c 2,400 ft. 23 June 1967.

370. ‘Vicinity of Atlin road at mile 16. Open sandy,
west-facing slope. c 2,500 ft. Common. 3 July 1967.

Moehringia lateriflora (L.) Fenzl
172. Near road several miles south of Atlin. 6 July
233. wright Creek road south of Surprise Lake. 9 July
'345. Near Atlin road at mile 52. c 2,350 ft. 23 June
Silene Menziesii Hook. subsp. Williamsii (Britt.) Hult.

CO 0 nov 0

175. Vicinity of road south of Atlin. 8 July 1966.

360
RANUNCULACEAE

Aquilegia formosa Fisch.

100. Near Atlin. 6 July 1966.

118. Near the Grotto c 16 miles south of Atlin.
c 2,400 ft. Dry site. Rare. 6 July 1966.

194. East of Atlin road several miles south of Atlin.
Rocky, exposed site. Rare.l Early July 1966.

Delphinium glaucum S. wats.

4. Ruby Creek road. Open, bulldozed area. c 3,800 ft.
Common. 23 August 1965.

9. Gravel pit on O'Donnel (Atlin) road c 20 miles south
of Atlin. c 2,900 ft. 24 August 1965.

127. Near the Grotto c 16 miles south of Atlin.
c 2,400 ft. 7 July 1966.

386. Mile 8.9, Atlin road, at Haunka Creek. c 2,300 ft.
Gravelly, bulldozed area. 6 July 1966.

Anemone parviflora Michx.

66 155. Near road several miles south of Atlin. 7 July
19 .

350. West of Atlin road at mile 59. c 2,300 ft.
30 June 1967.

Anemone multifida Poir.

83. Near Atlin. 6 July 1966.
109. Near the Grotto c 16 miles south of Atlin.
c 2,400 ft. 6 July 1966.
12 . Near Atlin. 7 July 1966.
13 . Near Atlin. 7 July 1965.
302. Mile 6, Atlin road. c 2,300 ft. 11 July 1966.
327. Mile 52, Atlin road. c 2,350 ft. 23 June 1957.

Pulsatilla patens (L.) Mill. subsp. multifida (Pritz.) Zamels

332. Near summit of low rocky hill west of Mile 52
Bog. c 2,500 ft. 23 June 1967. Setting seed.

Thalictrum.a1pinum.L.

943. Wilson Creek Bog. Common in thick moss of sedge
zone. 25 August 1968.

361
FUMARIACEAE
Corydalis aurea Willd.
169. Several miles south of Atlin. Early July 1966.
Flowering.
CRUCIFERAE
Barbarea orthoceras Ledeb.

260. Vicinity of outlet of Surprise Lake. c 3,000 ft.
10 July 1966.

 

Rorippa.nasturtiumtaquaticum.(L.) Hayek E

51. In water in warm.Springs area c 15 miles south of
Atlin. c 2,300 ft. Abundant. Flowering. 27 August 1965.

Rorippa hispida (Desv.) Britt. var. barbareaefolia (DC.) Hult.
953. Moose Bones Bog. Common in inner herbaceous zones.
Cardamine oligosperma Nutt.

242. Vicinity of road in wright Creek valley south of
Surprise Lake. wet moss cushion. 9 July 1966.

Capsella bursa-pastoris (L.) Medic.

117. Near the Grotto c 16 miles south of Atlin, c 2,400
ft. 6 July 1966.

Draba borealis DC.

119. Near the Grotto c 16 miles south of Atlin. c 2,400
ft. 6 July 1966.

Draba aurea vahl

266. Vicinity of road north of Surprise Lake. c 3,400 ft.
10 July 1966.

Draba lanceolata Royle

1. Ruby Creek road. Bulldozed area next to road
c 3,800 ft. Easterly e osure. 22 August 1965.

102. Near Atlin. July 196 .

110. Near the Grotto c 16 miles south of Atlin.
c 2,400 ft. 6 July 1966.

362

Descurainia sophioides (Fisch.) 0. E. Schulz

173. Several miles south of Atlin. 8 July 1966.
Arabis arenicola (Richards.) Gelert

337. Near mile 52, Atlin road. In shrub willow stand
south of bog near edge of Spruce forest. Semi-Open and dry.
c 2,350 ft. 23 June 1967.
Arabis lyrata L. subsp. kamchatica (Fisch.) Hult.

274. Near road north of Surprise Lake. c 3,400 ft.
10 July 1966.

Arabis Drummondii Gray
15. Gravel pit on O'Donnel (Atlin) road c 20 miles

south of Atlin. c 2,900 ft. 24 August 1965.
94. Near Atlin. 6 July 1966.

W‘h“. ... -..”,—

Arabis Ho1boellii Hernem. var. retrofracta (Graham) Rydb.

966 189. Near road several miles south of Atlin. 8 July
1 .

309. Snafu Lake. Open, sandy hillside east of camping
area. c 2,500 ft. 11 July 1966.

376. East of Atlin road at mile 16. Unforested, sandy
hillside. c 2,600 ft. 3 July 1967.

Erysimum.cheiranthoides L.

50. Warm.Springs area c 15 miles south of Atlin. Open,
moist site. c 2 300 ft. 27 August 1965.

384. Mile 8.9, Atlin road, at Haunka Creek. Bulldozed,
gravelly site. c 2,300 ft. 6 July 1967.

933. Warm Springs c 15 miles south of Atlin. Abundant
locally. 2,300 ft. 22 August 1968.

CRASSULACEAE

Sedum lanceolatum.Torr.

135. South Of Atlin. 7 July 1965.
170. Near road several miles south of Atlin. 8 July

1966.
304. Snafu Lake. On dry, sandy hillside east of
camping are. c 2,500 ft. 11 July 1966.

Sedum rosea (L.) Scop.

344. Opening in spruce and aspen stand on low hill west
of Mile 52 Bog. c 2,400 ft. 23 June 1967.

363
SAXIFRAGACEAE

Saxifraga tricuspidata Rottb.

966 171. Near road several miles south of Atlin. 6 July
1 .
228. wright Creek road south of Surprise Lake. In
clump on sandy creek bank near old mine. c 3,700 ft.
9 JUly 1966.

278. ‘Vicinity of road north of Surprise Lake. c 3,300
ft. 10 Ju1y 1966.

Saxifraga punctata L. subsp. insularis Hult.

 

196. Several miles south of Atlin. 8 July 1966.
202. wright Creek road south of Surprise Lake. c 3,800
ft. 9 July 19 6.

Chrysosplenium tetrandrum (Lund) T. Fries

243. wright Creek road south of Surprise Lake. Mossy,
wet area in broad valley. c 3,800 ft. 9 July 1966.

939. Growing in mats on en water on wet, north-facing
slope above warm.Bay, approx. 1 .5 miles south of Atlin.
c 2,300 ft. 25 August 1968.

Parnassia palustris L.

69. Near warm.Bay c 14.5 miles south of Atlin. Area
of seepage and mineral springs. Calcium carbonate deposits.
c 2,250 ft. 27 August 1965.

Parnassia palustris L. subsp. neogaea (Fern.) Hult.

263. ‘Vicinity of road north of Surprise Lake. c 3,200
ft. 10 July 1966.

Parnassia palustris L. var. montanensis (Fern. & Rydb.)
Hitcfie.

394. Mile 52 Bog. 5 July 1967.'
Parnassia Kotzebuei Cham,& Schlecht.

79. Near Atlin. 6 July 1966.

201. Center of wright Creek road south of Surprise Lake
at old mine. c 3,900 ft. 9 July 1966.

347. In damp shrub birch and willow stand west of Atlin
road at mile 59. c 2,300 ft. 1 July 1967.
Ribes triste Pall.

314. Spruce forest near mile 30, Atlin road. c 2,400
ft. 31 August 1966.

364

Aconitum delphinifolium DC.

6. Ruby Creek road. Bulldozed area next to road,
easterly exposure. c 3,800 ft. 23 August 1965.

206. Wright Creek road south of rise Lake. Dry,
spruce-pine forest. uncommon. 9 July 1 6.

ROSACEAE

Amelanchier alnifolia (Nutt.) Nutt.

134. East of Atlin road c 12 miles south of Atlin.
Open, sandy slope. 7 July 1966.

261. Near outlet of Surprise Lake, c 3,000 ft. Steep
barren embankment below road, just above water. 10 July 196 .

Rubus arcticus L. subsp. acaulis (Michx.) Focke

203. Wright Creek road south of Surprise Lake, in
vicinity of old mine. c 3,700 ft. 9 July 1966.
409. Early July 1967.

Rubus arcticus L. subsp. stellatus (Sm.) Boiv. emend. Hult.

145. 7 July 1966.
Rubus idaeus L. subsp. melanolasius (Dieck) Focke

113. Near the Grotto, c 16 miles south of Atlin.
c 2,400 ft. 6 July 1966.
96 182. Near road several miles south of Atlin. 6 July
17.

Fragaria virginiana Duchesne subsp. glauca (S. wats.) Staudt
144-A. Near road several miles south of Atlin. 7 July

1966.

252. Near outlet of Surprise Lake on dry hillside in
lodgepole pine forest. c 3,000 ft. Common. 10 July 1966.

369. ‘Vicinity of Atlin road at mile 32. c 2,600 ft.
3 July 1967.

399. In dense, young aspen stand east of Atlin road
at mdle 12. c 2,550 ft. 6 July 1967.

Potentilla palustris (L.) Scop.

844. Jasper Creek Bog. In wet sedge zone. uncommon.
c 2,400 ft. Flowers in pre-anthesis condition. 11 July 1968.

Potentilla uniflora Ledeb. A

917. Mt. Va han. In tundra zone in summit area on
west side. c 5,70 ft. 20 August 1968.

.fi“l.:hfif4'a

"I." i

355

921. Mt.‘Vaughan. In tundra zone in summit area on
west side. c 5,700 ft. 20 August 1968.

Potentilla norvegica L. subsp. monspeliensis (L.) Aschers. &
rae n.

 

18. Gravel pit on O'Donnel road c 20 miles south of
Atlin. c 2,900 ft. 24 August 1965.

72. Near Atlin. 6 July 1966.

262. Near outlet of Surprise Lake. c 3,000 ft. 10
July 1965.
Potentilla nivea L. var. tomentosa Nilsson-Ehle lo

152. Several miles south of Atlin. 7 July 1966. 4
Potentilla Reokeriana Lehm. subsp. HOokeriana

381. Mile 16 Atlin road. Dry, sandy, west-facing slope g
east of road. c 2,600 ft. 3 July 1967,

Potentilla multifida L.

330. Vicinity of Atlin road at mile 52. c 2,400 ft.
23 June 1967.

Potentilla arguta Pursh subsp. convallaria (Rydb.) Keck
133. Open, sandy slope east of road c 12 miles south
of Atlin. 7 July 1966.
150.' Near road several miles south of Atlin. 7 July
1966.
Potentilla pennsylvanica L.

382. East of Atlin road at mile 16. Unforested, sandy,
west-facing slope. c 2,600 ft. 3 July 1967.

Potentilla pennsylvanica L. var. strigosa Pursh.
851. Near Atlin in dry, gravelly area.
Potentilla pennsylvanica L. var. glabrata S. Wats.

339. ‘Vicinity of Atlin road at mile 52. c 2,400 ft.
23 June 1967.

Potentilla gracilis Dougl.

852. In Atlin. Abundant in open, gravelly area around
old outpost hospital bldg. c 2,200 ft. 15 August 1968.

366

Potentilla diversifolia Lehm.

95. Near Atlin. 6 July 1966. A

217. wright Creek road south of Surprise Lake. On
bank above road. 9 July 1966. A
Potentilla diversifolia Lehm. var. glaucophylla Lehm.

132. Near road several miles south of Atlin. 7 July

1966.
249. wright Creek road south of Surprise Lake. 9 July

1966
Potentilla anserina L.

391. Mile 52 Bog. Open, moist area. Rare, in a local
patch. 5 July 1967.

Potentilla Egedii WOrmsk. subsp. yukonensis (Hult.) Hult.

 

207. Sandy soil near inside edge of dried up pond near
wright Creek road south of Surprise Lake. c 3,500 ft. 9
July 1966.

Chamaerhodos erecta (L.) Bunge subsp. Nutallii (Torr. & Gray)
‘HfiIt.

 

389. ‘Vicinity of Atlin road at mile 16. Dry, sandy,
unforested, west-facing slope. c 2,600 ft. 6 July 1967.

Geum.macrgphy11um.Willd. subsp. perincisum.(Rydb.) Hult.

66 222. wright Creek road south of Surprise Lake. 9 July
19 .

.23! g integrifolia M. vahl

354. ‘Vicinity of Atlin road at mile 59. Dry, open
spruce forest east of road. c 2,300 ft. Rare. 1 July 1967.

Prunus Sp. (cf. melanocarpa (A. Nels.) Shafer.)

311. Near mile 30, Atlin road. In closed Spruce forest.
c 2,400 ft. 31 August 1966.

Rosa acicularis Lindl.

316. Collected at miles 1, 10, 20, and 40, Atlin road.
Widespread. 31 August 1966.

367
LEGUMINOSAE

Lupinus arcticus S. wats.

2. Ruby Creek road. c 3,800 ft. 23 August 1965.

74. Near Atlin. 6 July 1966. a

97. Near Atlin. 6 July 1966.

204. wright Creek road south of Surprise Lake. Sandy
23%% in dry, spruce and pine forest. c 3,600 ft. 9 July

397. In dense, young aspen stand east of Atlin road
at mile 12. c 2,550 ft. 3 July 1967.

Medicago lgpulina L.

47. warm Springs area near road c 15 miles south of
Atlin. Open, moist, grassy. c 2,300 ft. 27 August 1965.

Astragalus americanus (HOok.) M. E. Jones

146. Near road south of Atlin. 7 July 1966.
253. Near outlet of Surprise Lake. c 3,000 ft.

10 Jul 19%
340. Near Atlin road at mile 52. 23 June 1967.
371. Near Atlin road at mile 56(7). 3 July 1967.

Astragalus alpinus L.

80. Near Atlin. 6 July 1966.
121. Near the Grotto c 16 miles south of Atlin.
c 2,400 ft. 6 July 1966.
1966 235. wright Creek road south of Surprise Lake. 9 July
298. Nbrth of Atlin road at mile 6.11 July 1966.
. gung aspen forest east of Atlin road at mile
12. c 2,550fi July 1 %7.

Oxytrgpig,Maydelliana Trautv.

66 140. Near road several miles south of Atlin. 7 July
19 .

QEIEESEEE campestris (L.) DC. subsp. gracilis (Nels.) Hult.

212. wright Creek road south of rise Lake. Embank-
ment above road. c 3,200 ft. 9 July 19 .

290. Mile 6, Atlin road. c 2 ,300 ft. 11 July 1966.

323. Near Mile 52 Bog. c 2,400 ft. 23 June 1967.

372. Mile 56,At11n road. c 2,450 ft. 3 July 1967.

377. East of Atlin road at mile 16. Sandy, west-facing
slope. c 2,600 ft. 3 July 1967.

Tm.“ ‘ - . -—--__.. yaw
' a 5'
d‘m—~ I"

.0.

368

Hegysarum.alpinum.L. subsp. americanum.(Michx.) Fedtsch.
112. Near the Grotto c 16 miles south of Atlin.
c 2,400 ft. 6 July 1966.

300. NOrth of Atlin road at mile 6. c 2,400 ft.
11 July 1966.

VIOLACEAE

Viola adunca Sm.

972. Moose Bones Bog. Common in outermost, mesic,
herbaceous zone and in shrub zone. 3 September 1968.

ONAGRACEAE

Epilobium.angustifolium.L.

l7. Gravel pit on O'Donnel Atlin) road c 20 miles
south of Atlin. c 2,900 ft. ugust 19 65.

68. Near warm Bay c 14. 5 2miles south of Atlin.
c 2,250 ft. Seepage and mineral springs. Ca1cium.carbonate
crust on ground. 27 August 1965.

Epilobium,1atifolium.L.
93. Near Atlin. 6 July 1966.
139. Several miles south of Atlin. Early July 1966.
66 213. wright Creek road south of Surprise Lake. 9 July
19 .
220. wright Creek road south of Surprise Lake. 9 July

248. wright Creek road south of Surprise Lake. 9 July

Epilobium palustre L.
822. Mile 47 Bog. In dense moss, rooting in the moss,

of locomium type. Locally abundant. c 2,400 ft. 10 July I

1 .
{Epilobium.HOrnemannii Rchb.

l9. Gravel pit on O'Donnel (Atlin) road 0 20 miles
south of Atlin. c 2 ,900 ft. 24 August 1965.

 

369
HALORAGACEAE

Hippurus vulgaris L.

883. Mile 47 Bog. Sparse in open mud near edge of
water & in Scirpus zone. c 2,400 ft. 10 July 1968.

UMBELLIFERAE

Heracleum lanatum Michx.

42. warm.Springs area c 15 miles south of Atlin. Open,
moist, grassy area. Growing in open water of mineral springs.
c 2 ,300 ft. 27 August 1965.

PYROLACEAE

Pyrola asarifolia Michx.

966 167. Near road several miles south of Atlin. 6 July
1 o

Pyrola asarifolia (Michx.) var. purpurea (Bunge) Fern.

66 142. Near road several miles south of Atlin. 7 July
19 .
348. Vicinity of Atlin road at mile 59. 1 July 1967.
359. Shady, mossy spruce forest east of Atlin road at
mile 52 c 2, 450 ft. 1 July 1967.
366. Vicinity of Atlin road at mile 32. c 2,600 ft.
3 Ju1%.196 7.
09 Mile 47 Bog. Rare. c 2,400 ft. 10 July 1968.

Pyrola chlorantha Sw.

166. Several miles south of Atlin. 8 Ju1%01966.
368. East of Atlin road at mdle 32. .

3 July 1967.
girola minor L.
149. Several miles south of Atlin. 7 July 1966.
Pyrola secunda L. subsp. secunda
1966 191. Near road several miles south of Atlin. 6 July

367. Vicinity of Atlin road at mile 32. c 2,600 ft.
3 July 1967.

370

Pyrola secunda L. subsp. obtusta (Turcz.) Hult.

116. Near the Grotto c 16 miles south of Atlin.
c 2,400 ft. 6 July 1966.

Moneses uniflora (L.) Gray

156. Vicinity of road several miles south of Atlin._
8 July 1966.
66 238. wright Creek road south of Surprise Lake. 9 July
19 .

407. Shady, mossy spruce forest east of Atlin road
at mile 52. 0 2,400 ft. 5 July 1967.

ERICACEAE

Ledum.palustre L. subsp. groenlandicum (Oeder) Hult.
73. Near Atlin. 6 July 1966.

Arctostab los uva-ursi (L.) Spreng. var. adenotricha Fern.&
‘Macor.

 

 

 

66 232. Wright Creek road south of Surprise Lake. 9 July
19 .

vaccinium.vitis-idaea L. subsp. minus (Lodd.) Hult.

 

85. Near Atlin. 6 July 1966.

271. ‘Vicinity of road north of Surprise Lake.
c 3,300 ft. 10 July 1966.
vaccinium caespitosum.Michx.

86. Near Atlin. 6 July 1966.

Oxycoccus microcarpus Turcz.

214. Wright Creek road south of Surprise Lake. Boulder-
strewn area covered with moss. c 3,200 ft. 9 July 1966.

845. Jasper Creek Bog. Locall abundant on moss
hummocks in shrub willow zone. c 2, 00 ft. 11 July 1968.

PRIMULACEAE

Androsace septentrionalis L.

 

269. Near road north of Surprise Lake. c 3,400 ft.
10 July 1966.

371

270. (Same as 269).
284. orth of Atl n road at mile 6. c 2,400 ft.
11 Ju1 1966.
1967 3 3. Near Atlin road at mile 52. c 2,350 ft. 23 June
373. East of Atlin road at mile 16. c 2,600 ft. Dry,
sandy, west-facing slope. 3 July 1967.
395. East side of Atlin road at mile 8. c 2,500 ft.
Late June 1967.

GENTIANACEAE

Gentiana amarella L. subsp. acuta (Michx.) Hult.

l6. Gravel pit on O'Donnel (Atlin) road c 20 miles
south of Atlin. c 2,900 ft. 24 August 1965.

Gentiana propinqua Richards.

282. Vicinity of road north of Surprise Lake. c 3,400
ft. 10 July 1966.

285. Vicinity of Atlin road at mile 6. c 2,300 ft.
11 July 1966.

3 5. Mile 8.9, Atlin road, at Haunka Creek. c 2,300
ft. Bulldozed, gravelly site. 6 July 1967.

Megyanthes trifoliata L.

840. Jasper Creek Bog. Common at ed e of open water.
Fruits developed. c 2,400 ft. 11 July 1968.

POLEMONIACEAE

Polemonium.acutiflorum Willd.

966 245. Wright Creek road south of Surprise Lake. 9 July
1 .

331. Moss, shad spruce forest in vicinity of Atlin
road at mile 52, c 2, 0 ft.

408. Early July 1967.

Polemonium,pulcherrimum.Hook.

l4. Gravel pit on O'Donnel (Atlin) road c 20 miles
south of Atlin. c 2,900 ft. 24 August 1965.

84. Near Atlin. 6 July 1966.

99. Near Atlin. 6 July 1966.

183. Vicinity of road several miles south of Atlin.
6 July 1966.

372

1966 221. wright Creek road south of Surprise Lake. 9 July
279. Vicinity of road north of Surprise Lake.

c 3,300 ft. 10 July 1966.
301. Mile 6, Atlin road. c 2,300 ft. 11 July 1966.

HYDROPHYLLACEAE

Phacelia Franklinii (R. Br.) Gray

 

361. East of Atlin road at mile 16. Steep,_sandy,
west-facing Slope. c 2,600 ft. Rare. 3 July 1967.

388. Mile 8.9, Atlin road, at Haunka Creek. Bulldozed,
gravelly area. c 2,300 ft. 6 July 1967.

BORAGINACEAE

Lappula myosotis Moench

292. NOrth of Atlin road at mile 6. c 2,400 ft.
11 Jul 1966.

3 7. Mile 8.9, Atlin road, at Haunka Creek. c 2,300
ft. Bulldozed, gravelly site. 6 July 1967.
;Myosotis alpestris F. W. Schmidt subsp. asiatica Vestergr.

197. wright Creek road south of Surprise Lake.
0 3,700 ft. 9 July 1966.

Mertensia paniculata (Ait.) G. Don
75. Near Atlin. 6 July 1966.

96. (Same as 75).
LABIATAE

Dracocephalum.parviflorum.Nutt.

888. Near summit of ridge east of mile 16, Atlin road.
c 2,700 ft. Burned lodgepole pine stand. 21 August 1968.
uncommon.

373

SCROPHULARIACEAE

Penstemon Gormani Greene

287. Vicinity of Atlin road north of mile 6. c 2,300
ft. 11 JUly 1966.

305. Snafu Lake. Dry, sandy hillside east of camping
area. c 2,500 ft. 11 July 1966.

374. East of Atlin road at mile 16. Open, sandy, west-
facing hillside. c 2,600 ft. Common. 3 July 1967.

Penstemon procerus Dougl.

66 141. Near road several miles south of Atlin. 7 July
19 .
66 193. Near road several miles south of Atlin. 8 July

19 Q

205. wright Creek road south of Surprise Lake. Open
spruce and6pine stand on dry, sandy soil. c 3,400 ft.
9 July 196 .

281. Vicinity of road north of Surprise Lake. c 3,300
ft. 10 July 1966.

296. Mile 6, Atlin road. c 2,300 ft. 11 July 1966.

396. Unforested, well-drained, grassy area, east of
Atlin road at mile 8. c 2,500 ft. 6 July 1967.

Mimulus guttatus DC.

48. Warm Springs c 15 miles south of Atlin. c 2,300 ft.
Growing in or next to stream of mineral water. Abundant.
27 August 1965.

276. ‘Vicinity of road north of Surprise Lake. c 3,400
ft. Moist. 10 July 1966.

veronica WOrmskjoldii Roem. & Schult.

199. wright Creek valley south of Surprise Lake. Wet
shrub stand. c 3,700 ft. 9 July 1966.

273. ‘Vicinity of road north of Surprise Lake. c 3,300
ft. 10 July 1966.

Castilleja unalaschcensis (Cham. & Schlecht.) Malte

101. Near Atlin. 6 July 1966.
211. wright Creek road, south of Surprise Lake. Uh-
forested bank above road. c 3,200 ft. 9 July 1966.

Castilleja caudata (Pennell) Rebr.

66. Near warm.Bay c 14.5 miles south of Atlin. Seepage
and mineral springs. Calcium carbonate crust on ground.
c 2,250 ft. 27 August 1965.

148. Vicinity of road south of Atlin. 7 July 1966.

I” ‘

 

 

 

 

374

869. Ruby Creek Road. c 4,500 ft on north-northeast
side of Ruby Mountain.

Rhinanthus minor L. subsp. borealis (Sterneck) Love

 

853. In Atlin. Abundant in open, gravelly area around
old outpost hospital bldg. c 2,200 ft. 15 August 1968.

Pedicularis ornithorhyncha Benth.

914. Mt.‘Vaughan. In tundra zone in summit area on
west side. c 5,700 ft. 20 August 1968.

Pedicularis labradorica‘Wirsing

66 229. Wright Creek road south of Surprise Lake. 9 July
19 .
334. Mile 52, Atlin road. 0 2,400 ft. 23 June 1967.
355. Shady, mossy spruce forest east of road at mile
52. c 2,400 ft. Common. 1 July 1967. _

398. Dense, young aspen stand east of Atlin road at
mile 12. c 2,550 ft. 6 July 1967.

Pedicularis sudetica Willd.

264. ‘Vicinity of road north of Surprise Lake. c 3,300
ft. 10 July 1966.

325. Shrub willow stand west of Atlin road at mile 52.
c 2,400 ft. 23 June 1967.

352. Moist shrub birch and willow stand west of Atlin
road at mile 59. c 2,300 ft. Common. 30 June 1967.

OROBANCHACEAE

Orobanche fasciculata Nutt.
889. Open, rocky, southwesterly slope above mile 16,

Atlin road. c 2,700 ft. Parasitic on Artemisia frigida.
21 August 1968. Common.

LENTIBULARIACEAE
Utricularia intermedia Hayne

838. Jasper Creek Bog. Common in wet sedge zone.
c 2,400 ft. 11 July 1968.

 

375
PLANTAGINACEAE

Plantago eriopoda Torr.

973. Moose Bones Bog. Common in patches in outermost,
mesic, herbaceous zone. 3 September 1968.

RUBIACEAE

Galium boreale L.

13. Gravel pit on O'Donnel (Atlin) road c 20 miles
south of Atlin. c 2,900 ft. 24 August 1965.

131. Near the Grotto c 16 miles south of Atlin.
c 2,400 ft. 7 July 1966.

136. Open, sandy slope above road several miles south
of Atlin. 7 July 1966.

Galium trifidum L. subsp. trifidum

829. Mile 47 Bog. Growing abundantly on small moss
hummock in open mud of sedge zone near edge of pond.
c 2,400 ft. 10 July 1968.

CAPRIFOLIACEAE

Viburnum edule (Michx.) Raf.

115. Near the Grotto c 16 miles south of Atlin.
c 2,400 ft. 6 July 1966.

312. Vicinity of Atlin road at mile 1. c 2,400 ft.
31 August 1966.

320. Spruce and aspen stand southwest of Mile 52 Bog,
Atlin road. c 2,400 ft. Common. 23 June 1967.

VALERIANACEAE

Veleriana dioica L. subsp. sylvatica (Soland.) F. G. Meyer

 

268. Vicinity of road north of Surprise Lake.
c 3,300 ft. 10 July 1966.

376
CAMPANULACEAE

Campanula lasiocarpa Cham. subsp. lasiocarpa

857. Upfier Ruby Creek road north-northeast of Ruby
Mountain. c ,500 ft. 19 August 1968.

LOBELIACEAE

Lobelia kalmii L.

936. Common in wet sedge meadow on north-facing lepe
above warm.Bay, approx. 14.5 miles south of Atlin. c 2,300
ft. In flower. 25 August 1968.

COMPOSITAE

Solidago multiradiata Ait.

45. warm Springs area c 15 miles south of Atlin,
c 2,300 ft. Shady, moist, and grassy. 27 August 1965.

63. Near warm.Bay c 14.5 miles south of Atlin, c 2,250
ft. Seepage and mineral springs with carbonate crust on
ground. 27 August 1965.

122. Near the Grotto c 16 miles south of Atlin.

c 2,400 ft. 7 July 1966.
66 216. Wright Creek road south of Surprise Lake. 9 July
19 . 7

272. ‘Vicinity of road north of Surprise Lake. 0 3,300

ft. 10 July 1966.

Solidago decumbens Greene var. oreophila (Rydb.) Fern.

288. ‘Vicinity of Atlin road north of mile 6. c 2,400
ft. 11 July 1966.

362. East of Atlin road at mile 16. _Steep, sandy,
west-facing Slope. c 2,600 ft. 3 July 1967.

Solidagglepida DC.

43. warm.Springs area c 15 miles south of Atlin.
c 2,300 ft. Open, moist, and grassy. 27 August 1965.

Aster sibiricus L.

383. Mile 8.9, Atlin road, at Haunka Creek. Bulldozed,
gravelly area next to road. c 2,300 ft. Abundant. 6 July

1957.

377

251. Near outlet of Surprise Lake. c 3 000 ft.
10 Jul 1966. ’

2 0. Near road north of Surprise Lake. c 3,400 ft.
10 July 1966.

Aster laevis L.

49. warm Springs area c 15 miles south of Atlin.
Open, moist, and grassy. c 2,300 ft. 27 August 1965.

62. Near warm.Bay c 14.5 miles south of Atlin. Seepage
and mineral springs. Calcium carbonate crust on ground.
Some plants in shallow water. c 2,250 ft. 27 August 1965.

Erigeron compositus Pursh var. glabratus Macoun

341. 'Vicinit of Atlin road at mile 52. On low hill
west of bog. c 2, 0 ft. 23 June 1967.

363. Vicinity of Atlin road at mile 16. Sandy, west-
facing hillside. c 2,600 ft. 3 July 1967.

Erigeron eriocephalus J. vahl

239. wright Creek road south of Surprise Lake.
9 July 1966.

Erigeron elatus Greene

$32. ‘Vicinity of road south of Atlin. 8 July 1966.
68 8. Jasper Creek Bog. Rare. c 2,400 ft. 11 July
19 .

944. In gravel pit on O'Donnel road a prox. 20 miles
south of Atlin. c 2,900 ft. 25 August 196 .
958. Moose Bones Bog. 3 September 1968.

Antennaria rosea Greene

124. Near'the Grotto c 16 miles south of Atlin.
c 2,400 ft. 7 July 1966.

286. NOrth of Atlin road at mile 6. c 2,400 ft.
unforested, well-drained site. 11 July 1966.

308. Snafu Lake. Dry hillside east of camping area.
c 2,500 ft. 11 July 1966.

333. Vicinity of Atlin road at mile 52. Unforested,
well-drained area near summit of low hill west of bog.
c 2,400 ft. 23 June 1967.

342. Vicinity of Atlin road at mile 52. unforested,
well-drained area near summit of low hill west of hog.
c 2,400 ft. 23 June 1967.

Antennaria rosea Greene var. nitida (Greene) Breitung

5. Ruby Creek road. Bulldozed area next to road,
easterly exposure. c 3,800 ft. 23 August 1965.

 

375

329. Near Atlin road at mile 52. Southwest of bog.
c 2,400 ft. 23 June 1967.

380. East of Atlin road at mile 16. Open, sandy
west-facing hillside. c 2,600 ft. Common. 3 July 1967.

Achillea borealis Bong.

7. Ruby Creek road. Bulldozed area near road, easterly
exposure. c 3,800 ft. Abundant. 23 August 1965.

10. Gravel pit on O'Donnel road c 20 miles south of
Atlin. c 2,900 ft. 24 August 1965.

58. Near Warm.Bay c 14.5 miles south of Atlin. c 2,250
ft. Unforested, wet area of springs and calcium carbonate
crusts on ground. 27 August 1965.

295. North of Atlin road at mile 6. c 2,400 ft.

11 July 1967.

Matricaria matricarioides (Less.) Porter

54. Open, rocky, bulldozed area next to Atlin road
near Fourth of July Creek. c 2,400 ft. 24 August 1965.

856. Moist depression in gravel pit on Fourth of Jul
Creek road, near MeDonald Lks. c 3,100 ft. 18 August 196 .
Artemisiafrigida Willd.

303. North of Atlin road at mile 6. c 2,300 ft.
11 July 1966.

360. East of Atlin road at mile 16. Unforested, sandy,
west-facing hillside. c 2,600 ft. 3 July 1967.
Artemisia alaskana Rydb.

307. Snafu Lake. unforested, dry, sandy hillside east
of camping area. c 2,600 ft. 11 July 1966.

Artemisia arctica Less.

267. Near road north of Surprise Lake. c 3,400 ft.
10 July 1966.

306. Snafu Lake. unforested, sandy hillside east of
camping area. 0 2,500 ft. 11 July 1966.
Artemisia borealis Pall.

378. Dry, sandy, west-facing hillside above Atlin road
at mile 16. c 2,600 ft. Common. 3 July 1967.

Petasites sagittatus (Banks) Gray

321. Moist shrub willow thicket west of Atlin road at
mile 52. c 2,400 ft. 23 June 1967.

 

379

Arnica frigida C. A. Mey.

44. warm Springs area c 15 miles south of Atlin.
c 2,300 ft. Open, moist, and grassy site. 27 August 1965.

Arnica cordifolia Hook.

76. Near Atlin. 6 July 1966.

98. (Same as 76) -

144-B. EXposed, roc slope above road several miles
south of Atlin. 7 July 1 6.

283. Near road north of Surprise Lake. c 3,400 ft.
10 July 1966.

297. Mile 6, Atlin road. c 2,300 ft. 11 July 1966.

338. Vicinity of Atlin road at mile 52. In spruce-
aspen forest southwest of bog. c 2,400 ft. Common.
23 June 1967.

Arnica Chemissonis Less. subsp. foliolosa (Nutt.) Maguire

854. In Atlin. Common in open gravelly area near old
outpost hospital bldg. 0 2,200 ft. 15 August 1968.

Senecio gymbalarioides Nutt.

289. Vicinity of Atlin road north of mile 6. c 2,400
ft. 11 July 1966.

Senecio pauperculus Michx.

65. Near warm.Bay c 14.5 miles south of Atlin. Seepage
and mineral spri s with carbonate crust on ground. c 2,250
ft. 27 August 1 5.
1966 195. Near road several miles south of Atlin. 8 July
265. Near road north of Surprise Lake. c 3,300 ft.
10 July 1966.

Senecio triangularis Hook.

12o.' Near the Grotto c 16 miles south of Atlin.
c 2,400 ft. 6 July 1966.

874. Ruby Creek road. Gravelly alluvium on north-
northeast side of Ruby Mountain. c 5,000 ft. 19 August
1968.

Senecio lugens Richards.

147. Several miles south of Atlin. 7 July 1966.

Agoseris glauca (Pursh) Raf.

945. In gravel pit on O'Donnel roadgggprox. 20 miles
south of Atlin. c 2,900 ft. 25 August 1 .

 

380

lggoseris aurantiaca (Hook.) Greene

868. Ruby Creek road. Gravelly alluvium on north-
northeast side of Ruby Mountain. c 5 ,000 ft. 19 August

1968.
Crepis nana Richards. var. nana

, 946. On bulldozed and stream-cut gravels and sand near
mine on Spruce Creek. c 3,100 ft. 28 August 1968.

Hieracium grac ile Hook.

878. Mt. Leonard. Moist area near stream c 4,800 ft
on east side of mountain. 19 August 1968.

“Amy-.10“;—
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