INFORMATION TO USERS
The most advanced technology has been used to photo­
graph and reproduce this manuscript from the microfilm
master. UMI films the text directly from the original or
copy submitted. Thus, some thesis and dissertation copies
are in typewriter face, while others may be from any type
of computer printer.
The quality of this reproduction is dependent upon the
quality of the copy submitted. Broken or indistinct print,
colored or poor quality illustrations and photographs,
print bleedthrough, substandard margins, and improper
alignment can adversely affect reproduction.
In the unlikely event that the author did not send UMI a
complete manuscript and there are missing pages, these
will be noted. Also, if unauthorized copyright material
had to be removed, a note will indicate the deletion.
Oversize materials (e.g., maps, drawings, charts) are re­
produced by sectioning the original, beginning at the
upper left-hand comer and continuing from left to right in
equal sections with small overlaps. Each original is also
photographed in one exposure and is included in reduced
form at the back of the book. These are also available as
one exposure on a standard 35mm slide or as a 17" x 23"
black and white photographic print for an additional
charge.
Photographs included in the original manuscript have
been reproduced xerographically in this copy. Higher
quality 6" x 9" black and white photographic prints are
available for any photographs or illustrations appearing
in this copy for an additional charge. Contact UMI directly
to order.

University Microfilms International
A Bell & Howell Information C om pany
3 0 0 North Z e eb Road, Ann Arbor, Ml 4 8 1 0 6 -1 3 4 6 USA
3 1 3 /7 6 1 -4 7 0 0 8 0 0 /5 2 1 -0 6 0 0

Order Number 8912540

T he relationship o f site factors and th e incidence o f cytospora
and septoria cankers and poplar and w illow borer in hybrid
poplar plan tation s in M ason and M anistee counties, M ichigan
Abebe, Gashawbeza, Ph.D.
Michigan State University, 1988

UMI

300 N. Zeeb Rd.
Ann Arbor, MI 48106

THE RELATIONSHIP OF SITE FACTORS AND THE INCIDENCE OF
CYTOSPORA AND SEPTORIA CANKERS AND POPLAR AND WILLOW BORER
IN HYBRID POPLAR PLANTATIONS IN MASON AND MANISTEE COUNTIES,
MICHIGAN.

By
Gashawbeza Abebe

A DISSERTATION

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of
DOCTOR OF PHILOSOPHY

Department of Forestry and
Department of Botany and Plant Pathology
1988

ABSTRACT

THE RELATIONSHIP OF SITE FACTORS AND THE INCIDENCE OF
CYTOSPORA AND SEPTORIA CANKERS AND POPLAR AND WILLOW BORER
IN HYBRID POPLAR PLANTATIONS IN MASON AND MANISTEE COUNTIES,
MICHIGAN.

By
Gashawbeza Abebe
Two hybrid poplar plantations in the northwestern part
of Lower Michigan were surveyed (1984-87)
of

poplar

and

willow

Septoria cankers.
water

potentials,

clonal

damage,

Tree heights,
root

differences

conditions.

borer

root

development,

were

for the incidence

and

starch

disease

measured

Cytospora

to

and

levels,

leaf

incidence

and

determine

stand

Soil samples were analyzed for physical and

chemical properties.
At the Manistee site cytospora canker was prevalent,
while at

the Mason site,

Septoria canker,

and poplar

and

willow borer were predominant. The incidence of Septoria
canker

was

highly

correlated

to

tree

height

and

borer

damage.
A discontinuous ortstein layer was present at both study
sites.

Eventhough

there was no significant difference

the beginning of the ortstein layer;

for

the maximum depth and

thickness of the ortstein layer were significantly different
between the two study sites. Tree root development and stem
height were significantly reduced by the presence of the

Gashawbeza Abebe

ortstein layer.
Except for N and Ca, the two study sites were different
in their soil nutrient contents. The Mason site had more P,
K and Mg than the Manistee site, while the reverse was true
for Fe, Mn and A 1 . Soil nutrients and tree height were the
two factors which correlated most closely with the pest
problems in the two plantations. Cytospora canker increased
as Fe and A1
Septoria

levels

canker

increased and as K levels decreased.

incidence,

however,

increased

with

increasing levels of P, K and Mg, and as Fe and A1 levels
decreased.

Poplar and willow borer damage was

found

to

increase with increasing P and K levels.
Using discriminant and stepwise regression analyses,
equations accounting for more than 80* of the variation in
the

incidence of cankers and borer were developed.

An

interaction model between pest incidence, and soil and stand
factors was developed.

DEDICATION

This dissertation is dedicated to my son Abiye G.
Abebe; my sister Jerusalem K. Afework and her husband Hailu
Afework, the two persons who have always been supportive of
my education.

Whatever

I achieve

you. May God bless you.

iv

in my

life

I owe

it

to

ACKNOWLEDGEMENTS

I

thank

and

express

a

deep

gratitude

to

my

major

professor, Dr. John H. Hart for his support in every aspect
of this study, from study site selection to data collection
and financial support.

Dr.

Hart was very understanding of

the day to day dilemma of being a foreign graduate student.
He never lost confidence in me and his timely encouragement
when

things

were

appreciated.

Most

down,
of all

will

always

be

remembered

and

I am indebted to his untiring

review and editing of this dissertation.
I also

thank my graduate

Charles E. Cress,
Hart

Jr.,

for

Dr.

their

committee members,

Donald I. Dickmann and Dr.
interest

in

my

program,

Dr.

James B.
valuable

suggetions and for reading and reviewing this dissertation.
I also

appreciate the assistances I got from my friends,

Tesfai Mebrahtu, Nancy Johnson and the late Kahsu Girmay, in
the field data collection.
Special thanks are also due to Dr. Neil W. Macdonald for
his help

in determining soil aluminum

level and to Dr.

Raymond 0. Miller for his advice and help with the computer
work.

v

TABLE OF CONTENTS

LIST OF TABLES ......................................

viii

LIST OF FIGURES .....................................

x

GENERAL INTRODUCTION ................................
Study sites description ...........................
Poplars ............................................
Objectives ........................................

1
1
2
4

LITERATURE CITED ....................................

6

THE INCIDENCE OF SEPTORIA CANKER, CYTOSPORA CANKER
AND POPLAR AND WILLOW BORER IN TWO HYBRID POPLAR
PLANTATIONS IN NORTHWESTERN MICHIGAN ...............

8

INTRODUCTION ........................................
Cytospora canker ..................................
Septoria canker ...................................
Poplar and willow borer ...........................

9
9
11
12

MATERIALS AND METHODS ...............................
Tree mortality ....................................
Tree height ........................................
Disease rating ....................................

14
14
14
14

RESULTS AND DISCUSSION ..............................
Tree mortality ....................................
Tree height ........................................
Disease rating ....................................

15
15
17
18

LITERATURE CITED ....................................

25

TREE VIGOR AND PLANTATION CONDITION .................

29

INTRODUCTION .........................................
Root starch level .................................
Leaf water potential ..............................

30
30
31

MATERIALS AND METHODS ...............................
Root starch level .................................
Leaf water potentials .............................

33
33
34

RESULTS AND DISCUSSION ..............................
Root starch levels ................................
Leaf water potentials .............................

38
38
38

LITERATURE CITED ....................................

41

vi

SOIL CHARACTERISTICS AMD THEIR RELATIONSHIP WITH
THE INCIDENCE OF SEPTORIA CANKER, CYTOSPORA CANKER
AND POPLAR AND WILLOW BORER .........................

44

INTRODUCTION .........................................
Stress factors and predisposition to pests .......
Soil characteristics and hybrid poplars ..........

45
45
47

MATERIALS AMD METHODS ...............................
Ortstein layer ....................................
Soil nutrient levels ..............................
Methodology to assess relationship between soil
characters and pest problems ......................
Ortstein layer ...................................
Soil nutrient levels .............................

50
50
51

RESULTS AND DISCUSSION ..............................
Ortstein layer ....................................
Soil nutrient levels ..............................
Relationship between soil characters and pest
problems ...........................................
Ortstein layer ...................................
Soil nutrient levels .............................

54
54
58

D I S S C U S S I O N ..........................................

90

LITERATURE CITED ....................................

96

APPENDIX A ...........................................
APPENDIX B ...........................................

100
102

vii

53
53
53

65
65
83

LIST OF TABLES

Table
1. Summary

of mortality of

trees

by

Page
study sites .. 16

2. Summary of clone mortality between 1984 and 1987 .. 17
3. Tree heights in 1984 by clone and by study site ... 18
4. Comparison of canker and borer ratings of NE 47
between the Mason and Manistee plantations .......

19

5. Canker and borer rating by clone in 1986 at the
Mason plantation ...................................

22

6. Canker and borer rating in 1986 of NE 47 at the
Manistee plantation ...............................

24

7. Root starch level ratingssummary ..................

39

8. Leaf water potential means in - bars at Mason
plantation ......................................... 39
9. Summary of ortstein layer distribution and depth
in cm at Mason plantation.. ........................ 55
10. Summary of ortstein layer distribution and depth
in cm at Manistee plantation ......................

56

11. Ortstein layer depth and thickness comparison
between the two study sites .......................

58

12. Average soil nutrient contents (kg/ha) at Mason
sampled from ten profiles (one m deep) with 32
horizons ...........................................

59

13.

Average soil nutrient contents (kg/ha) at
Manistee sampled from seven profiles (one m deep)
with 20 horizons ..................................

60

14. Comparison of soil nutrient means (kg/ha) between
the study sites ...................................

61

15. Variation in soil nutrient levels at the Mason
plantation ......................................... 62
16. Variation in soil nutrient levels at the Manistee
plantation ......................................... 63

viii

Table
Page
17. Means of soil nutrients by horizon at the Manistee
plantation ........................................ 63
18. Means of soil nutrients by horizon at the Mason
plantation ........................................

64

19. Correlation coefficients between soil nutrient
levels by horizon and disease ratings at Mason .... 85
20 r~ Correlation coefficients between soil nutrient
levels by horizon and Cytospora canker incidence
on NE 47 at Manistee ..............................

86

21. Means of soilnutrients grouped by pest ratings ... 87

ix

LIST OP FIGURES

Figure
Page
1. Field layout of samples taken for ortstein
layer, soil nutrients and roots at Mason .......... 36
2. Field layout of samples taken for ortstein
layer , soil nutrients and roots at Manistee ......

37

3. The conglomerate characterstics of an ortstein
layer, sample from the Mason plantation ...........

57

4. Relationship between soil depth to the ortstein
layer and tree height at the Manistee plantation .. 67
5. Relationship between soil depth to the ortstein
layer and tree height at the Mason plantation .....

68

6. Root development and pattern at a place where
the ortstien layer was absent at Mason .........

69

7. Root development and pattern at a place where
the ortstein layer was present at Mason ...........

70

8. Relationship between soil depth to the ortstein
layer and Cytospora canker rating at the Mason
plantation .........................................

71

9. Relationship between soil depth to the ortstein
layer and Septoria canker rating at the Mason
plantation .........................................

72

10. Relationship between soil depth to the ortstein
layer and poplar and willow borer damage rating
at the Mason plantation ............................

73

11. Relationship between soil depth to the ortstein
layer and Cytospora canker rating at the Manistee
plantation .........................................

74

12. Relationship between soil depth to the ortstein
layer and Septoria canker rating at the Manistee
plantation .........................................

75

13. Relationship between soil depth to the ortstein
layer and poplar and willow borer damage rating
at the Manistee plantation ......................... 76
14. Relationship between tree height and
Cytospora
canker rating at the Mason plantation .............

x

77

Figure
Page
15. Relationship between tree height and Septoria
canker rating at the
Mason plantation ......... 78
16.

Relationship between tree height and poplar
and willow borer damage rating at the Mason
plantation .........................................

79

17. Relationship between tree height and Cytospora
canker rating at the
Manistee plantation ......

80

18. Relationship between tree height and Septoria
canker rating at the
Manistee plantation ......

81

19. Relationship between tree height and poplar and
willow borer damage rating at the Manistee
plantation .........................................

82

20. An interaction model between site factors and
pests incidence on hybrid polar clones at the
Mason and Manistee plantations ....................

91

xi

6EHERAL IMTRODPCTIOW
Study Sites Description
The study sites were located
Township,

Section

Township,

29,

T23N,

Section 3, T18N,

in Manistee

R14W)

R16W)

and

counties

(Maple Grove

Mason

(Custer

in Michigan,

on

plantations established by Packaging Corporation of America
(PCA).

Between 1969 and 1981 PCA established about

hectares

of hybrid poplar plantations

1,000

in the northwestern

part of Lower Michigan for its mill near Filer City.

The

mill makes a corrugated medium pulp and paper board.
The Manistee plantation was established in the spring of
1978.

The plantation was a mixed stand of two hybrid poplar

clones : NE 47 and NE 235.
berolinesis) cv. Oxford]

NE 47 [P. maximowiczii X (P. X
is a cross between the Japanese

poplar and the natural hybrid Berlin poplar (P. laurifolia X
P. nigra).

NE 235 (P. deltoides X P. nigra Incrassata) is a

hybrid between eastern cottonwood and black poplar (Dickraann
and Stuart, 1983; Woods,1984). Previous to planting the site
was an abandoned field. Before planting, the land was plowed
and cuttings were machine planted with 2.4 by 3 m spacing.
Herbicides were applied the second year

for weed control.

This study site was

and was

about

1.2 hectares

planted with about 1605 cuttings in 23 rows.

initially

The soil was

somewhat poorly to poorly drained, and the land had 0 to 2%
slope.

The water table was within 1.25 m from the surface

and soil profiles were highly mottled.

A cemented layer of

ortstein was sometimes observed.

The plow layer was sandy

and the soil taxon is Aerie haplaquod of the Pinch soil
series (Woods, 1984).
The Mason plantation (1.8 hectares)

was established in

the spring of 1979 with a mixture of cuttings of clones NE
47, NE 235 and NE 308. NE 308 (P. nigra var Charkowiensis x
P.

nigra

Incrassata)

varieties

is a cross between

(Ministry of Natural Resources,

two black poplar
1983).

The field

was under cultivaton prior to planting with hybrid poplars.
The site was plowed and herbicides applied before cuttings
were machine planted with an average spacing of 2.4 by 3 m.
Additional herbicides were applied the second year for weed
control.

Originally 2655 cuttings in 34 rows were planted.

The soil was moderately well drained and the land had 0 to
slope.

A discontinuous cemented layer of ortstein was

observed.

The plow layer was sandy loam and the soil taxon

2%

is Typic haplaquod of the Ogemaw series.
In 1984 both plantations had conspicuous gaps and open
spaces where the trees had died.
Poplars
The

genus

Populus

is

in

the

Salicaceae

family

and

consists of nearly 30 species, which are widely distributed
in the Northern Hemisphere

(Rehder,

1954;

Dickmann and

Stuart, 1983). Poplar culture began in the United States in
1784 when Lombardy poplar,

Populus nigra L.

was first introduced into the country (Rehder,
then

poplars

have

been

planted

for

cv.

"Italica"

1954). Since

shelter

belts,

ornamentals

and pulpwood

production.

hybridization of poplars

The

first

artificial

in the United States was done

the spring of 1924 (Stout, Mckee and Schreiner,

in

1927; Stout

and Schreiner, 1933).
Since the early 1950's the genus Populus has been the
major single source of pulpwood in the Lake States (French,
1976).

Intensive poplar plantations were being developed in

the North Central Region of the U.S. to produce wood biomass
in order to meet future demands for fiber and energy (Ostry,
1981).

Poplars were also widely planted for sheltering

orchards, fields and farms in Michigan and the Great Plains
(Walters,et a l ., 1982)

and Prairie

Provinces

of Canada

(Hocking, 1970).
Populus hybrids are potentially useful trees in a short
rotation fiber production system.
low
and

initial mortality,
high

weight

rapid diameter and height growth,

yields

(Bowersox and Ward. 1976).
suggested

that

the

Their ease of planting,

are

a

few

of

their

advantages

Lees and Anderson (1980) further

genus

Populus

might

offer

more

possibilities for genetic improvement than any other genus
of forest trees.

However, to utilize their full potential,

proper clone and site selections are very important.
planted off site
pests

and

If

the trees are susceptible to a number of

the expected yields

are

not

achieved.

This

phenomenon was observed in the Packaging Corporation of
America

(PCA) hybrid poplar plantations

in northwestern

Lower Michigan, where growth rate was reduced, mortality was

high, and canker diseases and insect borers were prevalent.
Poplars require high levels of moisture and nutrients and
hence their growth is affected by site factors.

Soil depth,

soil fertility, soil pH, soil moisture and soil aeration are
some of the site factors that should be considered before
poplar plantation establishment

(Dickmann and Stuart,1983).

The presence and size of sweet fern

(Comptonia

peregina)

and bracken fern (Pteridium aquilinum) are good indicators
of site quality for poplar
1963).

(Graham,

Areas with a heavy growth of reeds

c o mmunis),

reed grass

(Phalaris

(Carex paludosa) are unsuitable
the best
where

Harrison and Westell,

sites are

root

hardpans or gravel

is

layers

Brit. For. Commission,
layer within 30 cm

arundinacea) or

(Peace,

those with deep,

penetration

not

(Phragmites

1952).

medium

Generally

textured soil

interrupted

by

(Dickmann and Stuart,

1923).

sedges

bedrock,
1983;

Gt.

Areas with an impermeable

of the surface are poor sites as a

stagnant water table may develop (Graham et a l ., 1963).

In

addition, when surface layers of such areas become dry,
there is no opportunity for water replacement from below or
for

the

roots

to

penetrate

deep

into moisture

bearing

strata.

OBJECTIVES
The objectives of this study were:
1.

To determine if the incidence of Septoria canker,

Cytospora canker and poplar and
influenced by site factors.

willow borer

damage was

5
2.

To determine

if there was

a spatial

relationship

between soil physical and chemical characteristics and the
incidence of cankers in the hybrid poplar stands.
3.

Based on the above

relationships,

to develop

the

"best" predictive equation(s) for Septoria canker, Cytospora
canker,

and poplar and willow borer damage to the three

Populus hybrid clones in the study sites.

LITERATURE CITED

Bowersox, T.W. and W.W. Ward. 1976. Short-rotation,
fiber
production
system
for
hybrid
poplar.
Pennsylvania State University.
School of Forestry
Research Briefs 10(1):1-4.
Dickmann, D.I. and K.W. Stuart. 1983.
The Culture of
Poplars in Eastern N. Am e r i c a . Dept, of Forestry,
Michigan State University, East Lansing. PP. 168.
French, J.R. 1976.
Screening aspen for resistance to
Hypoxylon canker.
Ph.D. Dissertation, Michigan State
University, East Lansing. PP. 66.
Graham, A.S., Harrison, R.P. and C.E. Westell. 1963.
Aspens, Phoenix Trees of the Great Lakes Region. Ann
Arbor, University of Michigan Press. PP. 272.
Gt. Brit. For. Commission.
PP. 55.

1932.

Poplars.

Bull. No. 5.

Hocking, D. 1970.
Semesan fungicidal dip controls
canker disease of poplar cuttings in Alberta. Tree
Planters Notes.
21(3):18-20.
Lees, J.C. and H.W. Anderson. 1980.
Intensive management
of hybrid Populus. For. Chronicle 56:171-173.
Ministry of Natural Resources.
Ontario.
Hybrid P o p l a r .
series, Volume 1. PP. 336.

1983. New Forests in
Science
and
Technology

Ostry, M.E. 1981. Important diseases of intensively grown
poplars in the North Central Region . Phytopathology,
71(2) -.247.
Peace, T.R. 1952. Poplars. Forestry Commission Bulletin
19. PP.50.
Rehder, A. 1954.
Manual of Cultivated Trees and
Shrubs. Second Ed. Rev. The Macmillan Company.
PP. 996.

N.Y.

Stout, A.B., R.H. Mckee and E.J. Schreiner.
1927.
The
breeding of forest trees for pulpwood.
Bot. Gard.
28:49-63.
Stout, A.B. and E.J. Schreiner.
1933.
Results of a
project in hybridizing poplars. J. Hered. 24:216-229.

6

7
Walters, J.W., T.E. Hinds, D.W. Johnson and J. Beatty.
1982.
Effects
of partial
cutting
on diseases,
mortality and regeneration of Rocky Mountain aspen
stands.Rocky Mountain For. and Range Exp. Sta., USDA,
For. Serv. Res. Paper. RM-240. PP. 12.
Woods, R.F.
1984.
Effect of site on growth of hybrid
poplar clones planted on commercial scale.
Ph.D.
Disser., Michigan State University, East Lansing.
PP.94.

THE INCIDENCE OF SEPTORIA CANKER, CYTOSPORA
CANKER AND POPLAR AND WILLOW BORER IN TWO
HYBRID POPLAR PLANTATIONS IN NORTHWESTERN MICHIGAN.

8

INTRODUCTION
Cytospora canker
Over 50 Cytospora species were reported on hardwood
hosts

in

North

America

chrysosperma (Pers.)Fr.
one

of

the most

(Spielman,

1985).

(teleomorph:Valsa sordida Nits.) is

common

bark

inhabiting

fungi

indigenous and introduced Populus species
1940;

Hinds,

1976).

Cytospora

found

on

(Christensen,

It was first described by Long from

southwestern U.S. in 1918 (Schreiner, 1931).
Cytospora canker on poplars caused by C. chrysosperma is
widely distributed in the temperate zone of all continents
except Africa (Browne,
the

U.S.A.

In

a

1968).

disease

study

Cytospora canker was one of
(Hinds and Laurent,
isolated
forest

It is widely distributed in
conducted

in

the common diseases

1978).

In Wyoming,

frequently in aspen stands
nursery in North Dakota, C.

(Ross,

Alaska,
of

aspen

the fungus was
1975)

chrysosperma

and in a
destroyed

more than 50fc of the production of salable plants

(Walters

et al_^_, 1982) .
Cytospora canker is generally distinguished by black
pycnidia
exudes

in the dead bark of cankered stems.
allanoid,

hyaline

conidia

in

yellow

mucilaginous tendrils during moist weather
Biggs and Davis

(1983)

inoculation occurs

fungus
to

(Hepting,

red

1971).

reported that colonization after

by mechanical

ramification

wedges of large hyphae in the periderm,
tissues.

The

dense

cortex and phloem

The cells behind are colonized

9

of

both

inter-

and

10
intra-cellularly by smaller hyphae.

The cankers are

long

and narrow and the inner bark rapidly turns dark as the
underlying sapwood is stained light brown.

Generally dead

bark remains attached to the tree for two to three years and
then

falls

off

in large

pieces

exposing

the

sapwood.

Girdled or partially girdled stems

often put out vigorous

sprouts below the canker.

symptoms

Other

include dead

cambium with discolored, watery and smelly wood.
1971).

According

to

Bloomberg

(1962),

canker

(Hepting,
development

increased proportionally with temperature and inversely with
soil moisture

content.

Filer

(1967)

reported

that

the

optimum temperature for growth of the fungus as 25°C.
C .chrysosperma is not an aggresive parasite and attacks
trees when their resistance is lowered by adverse conditions
like severe

pruning,

unfavorable

environment,

fire

injury

(Povah, 1922), other diseases (Hocking, 1970), winter injury
(Kuntz and Ricker,
Anderson,

1979).

1949) or insects (Anderson, Ostry and

Many researchers

including Broadfoot and

Farmer (1969), Schoeneweiss (1975, 1978,

1981), Bertrand et

a l ., (1976), Bloomberg (1962), Bloomberg and Farris
Christensen

(1940),

Filer

(1967),

Juzwick,

(1963),

Nishijma and

Hinds (1978), Graham et a l . (1963), Hinds (1976), Biggs and
Davis
(1971)

(1981,

1983), Zsuffa

have reported that

(1975), Moss

(1922) and Hepting

trees need

to be predisposed

before attack by C. chrysosperma.

11
Septoria canker
Septoria canker is caused by the fungus Septoria musiva
Peck

(teleomorph:

Mycosphaerella populorum G.E.

Thompson).

The fungus is indigenous to North America (Waterman,
It was

first described by C.H.

Peck in 1882

1946).

from Populus

deltoides leaves at Albany, New York (Peck, 1884).
S.

musiva produces leaf spots,

branch and stem cankers

of both native and introduced poplars (Palmer, Schipper and
Ostry,
as

the

1980).

Moore and Wilson (1983) considered S. musiva

worst

pathogen

of

poplars

plantations in Michigan and Wisconsin.
necrotic zones of depressed,
(Long, Bowersox and Merril,

in

nurseries

and

Septoria cankers are

cracked and blackened tissues
1986), which can be flat faced

or can have marginal callus (Walla and Conway, 1986).

Stem

dieback and breakage are commonly observed in poplar stands
infected with S. m u s i v a .

The incidence and severity of

Septoria canker varies by location within a region,
clone,

tree and seed sources

(Zalasky,

1978;

and by

Ostry and

McNabb, Jr., 1985). Hybrid poplar clones derived from P.
trichocarpa. P.

laurifolia

or P.

maximowiczii

are very

susceptible to S. musiva (Ostry and McNabb, Jr., 1986; Walla
and Conway,

1986).

density compared

Stems with cankers had a higher wood

to non-cankered stems

(McNabb Jr.,

1981),

but the wood produced low quality fiber for pulping as it
contained more lignin than healthy wood (Ostry and McNabb,
Jr., 1983).
S.

musiva overwinters in fallen infected leaves and in

stem and branch cankers.

In spring ascospores and conidia

12
from

fallen

leaves

and

conidia

released during wet weather.

from

stem

stipules,

are

Spores are spread by wind or

washed by rain to infect stems and leaves.
through

cankers

petioles,

buds

Infection occurs

and

borer

wounds.

Secondary infections are caused by conidia from pycnidia
from leaf spots.
humidity

Warm temperatures and long periods of high

favor disease

development

(Riffle and Wysong,

1986).
Conidia are hyaline, cylinderic, straight or curved with
one

to four septa and

are

20-50

pm by

3-4 pm

in size.

Ascospores are hyaline with one septum and are 16-28 urn long
and 4.5-6.0 urn wide

(Riffle and Wysong,

1986;

Spielman,

Hubbes and Lin, 1986; Waterman, 1954; Thompson, 1941).
Poplar and willow borer
Poplar

and willow borer

(Coleoptera: Curculionidae)

(Cryptorhvnchus

attacks willows,

and birch (Harris and Goppel, 1967; Matheson,
native

to Europe and Asia

but was

lapathi

(L.),

poplars,

alder

1917).

It is

introduced

America in New York City in 1882 (Furniss, 1972).

to North
It is now

well distributed throughout southern Canada and the northern
half of the United States (Harris and Goppel, 1967).
and willow borer
Europe.

is also an

important pest

Poplar

to poplars

in

It is reported as the most serious insect pest of

poplar plantations in Quebec Province of Canada and in the
Lake States

of the U.S.

Wilson (1983) respectively.

by Morris

(1981)

and Moore and

13
The poplar and willow borer takes one to three years to
complete its life cycle depending on latitude.
takes one year while in British Columbia,

In France it
Canada,

years are needed to complete its life cycle
Goppel,

three

(Harris and

1967). In northwest Michigan C .lapathi takes one to

two years to complete the life cycle depending on local
weather conditions (Moore, 1984).
Adult poplar and willow borer weevils feed on young,
succulent one year old shoots.

After mating adult females

cut small holes at lenticels, branch bases or at the edge of
damaged bark.

One egg

is usually

with fine wood particles.

oviposited and

covered

Hatching occurs 18-21 days later

and the larvae begin enlarging their holes immediately.
Fine brown chips ejected from the holes by the larvae are
the first evidence of damage to poplar trees.

Initially,

mining and feeding are usually round the trunk or branch.
Later,

larvae start mining inwards and upwards towards the

heartwood of the tree and more frass is pushed out through
small openings as the larvae grow.

After pupation emerging

adults leave the mines through the openings made by the
larvae.

The adult

is black and white

or

grayish,

robust,

oval and about 1 cm long. Although winged, adults usually do
not fly long distances
1966).

(Moore,

1984; Matheson,

1917; Doom,

14

MATERIALS AMD METHODS
Tree mortality
Tree
1984,

mortalities

from

planting

(1978

or

1979)

to

from 1984 to 1986 and during the summer of 1987 were

calculated based on the original planting space of 2.4 X 3 m.
Open spaces and dead snags were combined to tally for dead
trees.
Tree height
Height of every tree at both locations was measured in
the summer of 1984 using a telescopic measuring pole.

Each

tree was identified by clone either as NE 47, XE 235 or NE
308.

A

t-test was

conducted to determine if there was a

significant difference in mean of tree heights by study
site.
Disease rating
In the summer of

1984

individual

trees

at

both

study

sites were checked for the presence or absence of Cytospora
canker.

In

the

summer

of

1986

trees

were

individually

examined and rated for Septoria canker and poplar and willow
borer

in

addition

to

Cytospora

canker.

In

the

1986

observation both cankers and borer damage were rated using
the following scoring scheme:

15
Septoria and
Cytospora Cankers

Poplar and
willow borer

1

Absence

No

2

Cankers on branches

Frass on the lower
1/3 of tree

3

Cankers on main stems

Frass on the lower
2/3 of tree

Main stem dieback,
tree dead or dying

Frass on the lower
2/3
and
the upper
1/3 of tree

Rating

Chi-square

of canker

apparent injury

2

(X ) values were calculated for cankers and

borer rating classes to check for independence of site or
clone.

Further analysis

of variance was

carried

out

to

determine clone and site interaction.

RESULTS AMD DISCUSSION
Tree mortality
Between 1978-1984, 44% of the trees died at the Manistee
plantation while 16% died at the Mason Plantation (Table 1).
A

second

inventory

in

the

summer

of

1986

showed

an

additional mortality of 8% and 3% since the summer of 1984
at the Manistee and Mason study sites, respectively.

By the

summer

of

of

1987,

60% at Manistee and

original planted trees were dead.

23% at Mason

In a Chi-square

the
test

comparison of tree mortality by year and study sites showed
a significant interaction (P < 0.05).

16
Table 1.

Summary of mortality

of trees by study sites.

Mason
No. of
trees
dead

Manistee

% Mortality
of original
cuttings
planted

% Mortality
of original
cuttings
planted

No. of
trees
dead

Dead by 1984

415

15.6

705

43.9

Dead by 1986

495

18.6

837

52.1

Dead by 1987

611

23.0

968

60.3

The original planting at the Mason site was a mixture of
clones,

where

the

proportions

or

the

total

cuttings planted for each clone was unknown.

number

Thus,

of

it was

not possible to determine mortality rates by clone prior to
the 1984 inventory.

However, between 1984 and 1987 at the

Mason site mortality was 14%, 9% and 7% for clones NE 47, NE
235, and NE 308, respectively based on 1984 live trees of
each clone

(Table 2).

Similar data were not available from

the Manistee site as 98% of the trees were NE 47. However,
NE 47 showed 29% mortality in 1987 based on 1984 residual
live trees.

These results suggest that location influenced

mortality;

the Mason site was a better site in terms of

survival than the Manistee site.

17
Table 2. Summary of clone mortality between 1984 and 1987

Mason

Manistee

No. of live trees
Clone

No. of live trees

*
mortality

*
mortality

1984

1987

47

288

248

13.9

884

623

29.5

NE 235

944

862

8.7

16

14

12.5

NE 308

1008

933

7.4

NOT

PLANTED

Total

2240

2044

8.8

NE

1984

900

1987

29.2

637

Tree height
Average
study

tree heights

sites

are

shown

for the three clones
in Table

3.

at

Although

the

the

two

Mason

plantation was one year younger, its trees were taller than
those of the Manistee plantation.

A t-test of average tree

height in 1984 by location showed that trees at the Mason
site were

significantly

Manistee site

(3.1 m)

taller

(4.6 m)

(P < 0.01).

Pennsylvania and Maryland,

than

trees

In a clonal

at

study

the
in

NE 308 was ranked in the upper

12.5 percentile group after four years growth

(Demeritt

Jr., 1981). In this study NE 235 grew better than NE 308 at
the Mason plantation.

18
Table 3. Tree heights in 1984 by clone and study site

Clone

Site

N o . of
trees

Ave. h t .
in m

Std.err<

Mason

288

4.5

0.1

Manistee

884

3.1

0.1

Mason

944

4.9

0.1

16

4.2

0.3

1008

4.4

0.1

NE 47

NE 235
Manistee
Mason
NE 308
Manistee

NOT

PLANTED

Disease rating
Since all three clones were not planted at both study
sites it was not possible to compare the effect of site on
all

clones. However, since NE 47 was planted at both study

sites it was used as a basis
difference

in pest

to check if there was any

incidences between the two study sites

(Table 4).
At both study sites Cytospora canker was more prevalent
on branches than on the main stem of NE 47.

However,

more

stem diebacks (27%) were observed on the trees at Manistee
as compared to Mason (2%)

(Table 4).

A Chi-square test

showed significant difference of Cytospora canker incidence
between the two study sites

(P < 0.01).

Trees at Manistee

were growing slower (Table 3), were more stressed than trees

Table 4. Comparison of cankers and borer ratings of NE 47
between the Mason and Manistee plantations.

Poplar and
willow borer
Mason
Rating*
1

No.of
trees

Cytospora canker

Manistee
%

194 78. 2

Mason

No.of
trees%
608 98.1

Manistee

No.of
trees $

168 67 .7

393 63.3

8

3.2

9

1.5

16

6.5

6

1.0

211 85.1

2

0.3

1.1

3

33 13.3

3

0.5

0

0.0

2

0.3

4

1.6

Septoria and
Cytospora Cankers

1
2

Absence of ceinker
Cankers on branches

3

Cankers on main stems

4

Main stem dieback,
tree dead or dying

No.of
trees %

5.2

7

‘
Rating

No.of
trees %
13

7.7

0.8

No.of
trees %

Manistee

62 10.0

19

2

Mason

76 30.6

2

4

Septoria canker

1

0.2

164 26.5

Poplar and
willow borer
No apparent injury
Frass on the lower
1/3 of tree
Frass on the lower
2/3 of tree
Frass on the lower
2/3
and
the upper
1/3 of tree

602 97.2

20
at the Mason site, and hence were more suceptible to C.
chrysosperma.
Septoria canker on NE 47 was more prevalent at the Mason
site than at the Manistee site.

At the Manistee site only

3% of the trees showed symptoms of Septoria canker while at
Mason 95% of the trees had symptoms

by the summer of 1987

(Table 4).
Poplar and willow borer damage on NE 47 was more severe
at the Mason stand (22%) than at Manistee (2%)

(Table 4).

A

Chi-square test showed significant difference (P < 0.01)

in

poplar and willow borer damage between the two study sites.
At Mason 22%,
235

trees,

Ontario,

68% and 97% of the NE 47, NE 308 and NE

respectively,

were attacked by

the

borer.

In

Canada-three-year old NE 47 plantations showed no

infestation by poplar
infested

31 to 51 %

and willow borer,

while

(Morris,1981) . Septoria

NE

308 was

canker and

poplar and willow borer damage to NE 235 and NE 308 at the
Mason plantation were very closely related

(Table 5).

The

insect wound was probably serving as a good infection point
for Septoria muslva (Moore, 1984).
At Mason absence of apparent
varied by clone;
308,

Cytospora canker

injury

31%, 88% and 98% of NE 47, NE 235 and NE

respectively,

were

free of Cytospora

canker

symptoms

(Table 5).
At Mason 81% of NE 308 trees had Septoria canker as
compared to 95% and 97% for NE 47 and NE 235, respectively.
Stem canker and main stem dieback was observed in 92% of NE

21
47 trees,

94% of NE 235

trees and 70% of NE 308 trees.

Unlike Cytospora canker, however, Septoria canker was found
on the main stem as well as on the branches.

Ostry

reported that many hybrid poplar plantations

in the North

Central

S.

United

Generally,

States

have

severity of

canker at Mason,

failed

cankers,

due

to

muslva.

especially of

Septoria

increased during the study period.

the three clones at Mason,

(1987)

Among

the fastest growing NE 235 was

attacked more by S. musiva than NE 47 or NE 308.

As S.

musiva

1939)

it

(Table

3)

is an

aggressive

pathogen

(Bier,

probably preferred the fast growing trees
Mason.

In addition the wounds

caused by the poplar

at
and

willow borer were serving as infection points for S. musiva.
The canker and borer ratings at the Manistee plantation
are shown in Table 6. Since NE 235 comprised less than 2% of
the plantation, ratings for NE 47 only are reported. At the
Manistee plantation Cytospora canker was more prevalent than
Septoria canker and poplar willow borer damage. The slow
growing

(Table

plantation

were

3)

and

more

stressed

trees

susceptible

to

at
the

the

Manistee

nonaggressive

facultative parasite Cytospora chrvsosperma than to the
aggressive Septoria musiva which prefers vigorously growing
trees.

The stressing site factors which predisposed the

trees are discussed in the last part of this study.
As in other places where hybrid poplars are intensively
planted,

pathogens and

insects were severely

quality and productivity of the plantations.

limiting

the

22
TABLE 5. Canker and borer rating by clone in 1986 at the
Mason plantation.

Poplar iand willow borer
NE 47
Borer No. of
rating trees
1
2
3
4
Total

%

194 78.2
19
7.7
33 13.3
2
0.8
248 100.0

NE 235

NE 308

No. of
trees %

N o .of
trees %

26
3.0
36
4.2
770 89.3
30
3.5
862 100.0

298 31.9
97 10.4
374 40.1
164 17.6
933 100.0

Cytospora canker
NE 47
Canker No .of
rating trees %
1
2
3
4
Total

76
168
0
4
248

NE 308

NE 235

30.6
67.7
0.0
1.6
99.9

N o .of
trees

%

754 87.5
102 11.8
2
0.2
4
0.5
862 100.0

No. of
trees %
913 97.9
18
1.9
1
0.1
1
0.1
933 100.0

23
TABLE 5. (cont'd).

Septoria canker

Canker
rating
1
2
3
4
Total

*

Rating

NE 47

NE 235

NE 308

No.of
trees %

No.of
trees %

No.of
trees %

13
5.2
8
3.2
6.5
16
211 85.1
248 100.0

2.8
24
2.7
23
34
3.9
781 90.6
862 100.0

Septoria and
Cytospora Cankers

1
2

Absence of canker
Cankers on branches

3

Cankers on main stems

4

Main stem dieback,
tree dead or dying

179 19.2
105 11.3
575 61.6
74
7.9
933 100.0

Poplar and
willow borer
No apparent injury
Frass on the lower
1/3 of tree
Frass on the lower
2/3 of tree
Frass on the lower
2/3
and
the upper
1/3 of tree

24
TABLE 6. Canker and borer rating in 1986 of NE 47 at the
Manistee plantation

Poplar and
willow borer
Pest
N o .of
rating trees
1
2
3
4
Total

*
Rating

608
7
3
2

Cytospora
canker

%

N o .Of
trees

98. 1
1 .1
0.5
0.3

62
393
1
164

620 100.0

Septoria and
Cytospora Cankers

1
2

Absence of canker
Cankers on branches

3

Cankers on main stems

4

Main stem dieback,
tree dead or dying

Septoria
canker
N o .of
trees

$
10.0
63.3
0.2
26.5

620 100.0

602
9
6
2

%

97.2
1.5
1.0
0.3

619 100.0

Poplar and
willow borer
No apparent injury
Frass on the lower
1/3 of tree
Frass on the lower
2/3 of tree
Frass on the lower
2/3
and
the upper
1/3 of tree

LITERATURE CITED
Anderson, N.A., M.E. Ostry and G.W. Anderson. 1979.
Insect wounds as Infection sites for Hypoxylon
mammaturn on trembling aspen.
Phytopathology, 69
(5):476-479.
Bertrand, P.R., H. English, K. Uriu and F.J. Schick.
1976.
Late season water deficits and development of
Cytospora canker in French prune.
Phytopathology,
66:1318-1320.
Bier, J.E. 1939. Septoria canker of introduced and naive
hybrid poplars. Can. J. Research, Vol.17, Sec. C.
Biggs, A.R. and D.D. Davis. 1981.
The enlargement of
Cytospora canker of hybrid poplar and associated
water relations. Phytopathology, 71(5):558.
Biggs, A.R. and D.D. Davis. 1983.
Histopathology of
bcankers on Populus caused by Cytospora chrysosperma.
Can. J. Bot. 61:563-574.
Bloomberg, W.J. 1962.
Cytospora canker of poplars:
Factors influencing the development of the disease.
Can. J. Bot. 40(10):1271-1280.
Bloomberg, W.J. and S.H. Farris. 1963. Cytospora canker
of poplars: Bark wounding in relation to canker
development.
Can. J. Bot. 41:303-310.
Broadfoot, W.M. and R.E. Farmer, Jr. 1969.
Genotype
and moisture supply influence nutrient content of
eastern cottonwood foliage For. Sci. 15(l):46-48.
Browne, F.G. 1968.
Pests and Diseases of Forest
Plantation Trees. Clarendon Press, Oxford. PP. 1330.
Christensen, C.M.
1940.
Studies on
Valsa
sordida
and
Cytospora
Phytopathology 30(6):459-475.

the biology of
chrysosperma.

Doom, D. 1966. The biology, damage and control of the
poplar and willow borer, Cryptorrhynchus lapathi.
Neth. J. PI. Path. 72:233-240.
Demeritt, Jr. M.E. 1981. Growth of hybrid poplars in
Pennsylvania and Maryland clonal tests. USDA, For.
Serv. RES. Note. NE-302. PP. 2.
Filer, Jr. T.H. 1967.
Pathogenicity of C ytospora,
Phomopsis and Hypomvces on Populus delt o i d e s .
Phytopathology 57:978-980.

25

26
Furniss, M.M. 1972.
Poplar and willow borer.
For. Ser.f Forest Pest Leaflet 121. PP. 5.

USDA.

Graham, A.S., Harrison, R.P. and C.E. Westell. 1963.
Aspens, Phoenix Trees of the Great Lakes Region. Ann
Arbor, University of Michgan Press. PP.272.
Harris, J.W.E. and H.C. Goppel. 1967.
The poplar-andwillow borer, Sternochetus (=Cryptorhynchus) lapathi
(Coleoptera:Curculionidae), in British Columbia. Can.
Ent. 99:411-418.
Hepting, G.H. 1971. Diseases of Forest and Shade Trees
of the U.S. USDA., For. Serv., Agriculture Handbook
No. 386. PP. 658.
Hinds, T.E. 1976.
Diseases of western aspen.
Utilization and marketing as tools for aspen
management in the Rocky Mountains.
Proc. of the
Symposium.
USDA., For. Serv. General Technical
Report RM-29.
Hinds, T.E. and T.H. Laurent. 1978.
Common aspen
diseases found in Alaska.
Plant Dis. Reptr. 62:972975.
Hocking, D. 1970.
Semesan fungicidal dip controls
canker disease of poplar cuttings in Alberta.
Tree
Planters Notes.
21(3):18-20.
Juzwik, J . , W.T. Nishijma and T.E. Hinds.
1978.
of aspen cankers in Colorado.
Plant Dis.
62(10):906-910.

Survey
Reptr.

Kuntz, J.E. and A.J. Ricker. 1949. Winter injury versus
disease
in
Wisconsin
poplar
plantings.
Phytopathology 39:12.
Long, R. , T.W. Bowersox and W. Merrill.
1986.
Artificial inoculation of Populus hybrids with
Septoria musiva.
Can. J. For. Res. 16:405-407.
Matheson, R. 1917.
The poplar and willow borer.
Cornell Agrl. Exp. Stn. Bull. No. 388:455-483.
McNabb, Jr. H.S. 1981. Septoria disease plot - Iowa 4-H
Camp. Unpublished Manuscript.
Moore, L.M. and L.F. Wilson.
1983. Recent advances in
research of some pest problems of hybrid Populus in
Michigan and Wisconsin, P. 94-101.
IN: Hansen, E.A.,
Comp.
Intensive
plantation
culture:
12
years
research.
USDA, For. Serv., North Central For. Exp.
Stn., Gen. Tech.
Rep. NC-91.

27
Moore, L.M.
1984.
The major Insects and diseases
affecting intensively grown hybrid poplars on
Packaging Corporation of America (PCA) lands in
central Lower Michigan. Ph.D. Dissertation, Michigan
State University., East Lansing. PP 155.
Morris, R.C. 1981.
The poplar-and willow borer of
hybrid poplars in Ontario.
Cryptorhynchus lapathi
(L.) Pest Control
Sec. Min. Nat. Res. Ontario. Pest
Control Report No. 12. PP. 7.
Moss, E.H. 1922.
Observations on two poplar cankers
in Ontario. Phytopathology. Vol. 12:425-427.
Ostry, M.E. and H.S. McNabb, Jr.
1983.
Diseases of
intensively cultured hybrid poplars:
A summary of
recent research in the North Central region, P. 102109, IN: Hansen, E.A., Comp. Intensive plantation
culture: 12 years research. USDA, For. Serv., North
Central For. Exp. Stn., Gen. Tech. Rep. NC-91.
Ostry, M.E. and H.S. McNabb Jr. 1985. Suceptibility of
Populus species and hybrids to disease in North
Central United States. PI. Disease. 69(9): 755-757.
Ostry, M.E. and H.S. McNabb Jr. 1986. Populus species
and hybrid clones resistant to Melampsora, Marssonina
and
Sep t o r i a . USDA, For.Serv. North Central Exp.
Stn. Res. Paper.NC-272: PP.7
Ostry, M.E.
1987. Biology of Septoria musiva and
Marssonina brunnea in hybrid Populus plantations and
control of Septoria cnaker in nurseries. Eur. J. For.
Path. 17:158-165.
Palmer, M.A., A.L. Schipper, Jr. and M.E. Ostry.
1980.
How to identify and control Septoria leaf spot and
canker of poplar.
USDA, For. Serv. North Central
For. Exp.
Stan.
Peck, C.H. 1884. Ann. Rept. New York State Botanist.
35:138
Povah, A.H.W. 1921.
An attack of poplar canker
following fire injury. Phytopathology 11(4):157-165.
Riffle, J.W. and D.S. Wysong. 1986. Septoria canker of
cottonwood and hybrid poplars, P. 50-51.
IN:
Diseases of trees in the Great Plains.
USDA, For.
Serv. Rocky Mountain For. and Range Exp. Stn. Gen.
Tech. Rep. RM-129.
Ross. W.D. 1975.
Fungi associated with root diseases
of aspen in Wyoming.
Can. J. Bot. 54:734-744.

28
Schoeneweiss, D.F. 1975. Predisposition, stress and
plant disease.
Annual Review of Phytopathology
13:193-211.
Schoeneweiss, D.F. 1978.
Water stress and a
predisposing factor in plant disease. Water Deficits
and Plant Growth. T.T. Kozlowiski (Ed.) Vol V:61-99.
Schoeneweiss, D.F. 1981.
The role of environmental
stress in diseases of woody plants.
Plant Disease
65(4):308-314.
Schreiner, E.J. 1931. The role of disease
growing of poplar. J. For. 29:79-82.
Spielman, L.J. 1985.

in

the

Unpublished manuscript.

Spielman, L.J., M. Hubbes, and D. Lin.
1986.
Septoria
musiva on hybrid poplar in southern Ontario.
Plant
Disease 70:968-971.
Thompson, G.E.
1941.
Leaf-spot disease of poplars
caused by Septoria musiva and S. populicola.
Phytopathology, 31:241-254.
Walla, J.A. and K.E. Conway. 1986. Cytospora canker of
cottonwoods and willows, p. 48-49.
IN:
Diseases of
trees in the Great Plains USDA, For. Serv. Rocky
Mountain For. and Range Exp. Stn. Gen. Tech. Rep. RM129.
Walters, J.W., T.E. Hinds, D.W. Johnson and J. Beatty.
1982.
Effects of partial cutting on diseases,
mortality and regeneration of Rocky Mountain aspen
stands.
Rocky Mountain For. and Range Exp. S t a . ,
USDA, For. Serv. Res. Paper RM-240. PP.12.
Waterman, A.M.
1946.
Canker of hybrid poplar clones
in the United States, caused by Septoria m u s i v a .
Phytopathology 36(2):148-156.
Waterman, A.M.
1954.
Septoria canker of poplars in
the United States USDA Circular 947. PP. 24.
Zalasky, H.
1978.
Stem and leaf spot infections
caused by Septoria musiva and S. populicola on poplar
seedlings. Phytoprotection, 59(l):43-50.
Zsuffa, L. 1975.
Some problems of hybrid poplar
selection and management in Ontario.
For. Chronicle,
51:240-242.

TREE VIGOR AND PLANTATION CONDITION

29

INTRODUCTION

Root starch level
Tree

vigor

is

defined

as

"an

individual

tree's

physiological condition that results from its physiological
performance within a particular environment"
Tree

vigor

partially

determines

a

(Wargo,

tree's

stresses or attacks by insects and pathogens.

1978).

tolerance

to

One way of

measuring tree vigor is to determine the starch content in
the roots.

In most deciduous trees starch is stored in high

concentrations in the roots.
carbohydrate

reserve

capacity of the plant.

and

Thus, root starch is the major
reflects

Wargo

(1976)

the

photosynthetic

reported that starch

content in the roots was related to root diameter and varied
by season.

The maximum root starch level in sugar maple was

in late fall, with a minimum in spring (Wargo, 1971). Starch
levels in roots are either determined by chemical analysis
(Hassid and Neufeld,
(Wargo, 1975).

1964) or are estimated histochemically

These two methods showed similar results in

root starch content of black oak, white oak and sugar maple.
Thus, Wargo (1981) reported that the histochemical method is
faster and gives an equally accurate estimate of starch
levels in deciduous tree roots.

30

31
Leaf water potential

The water balance in plants influences the initiation and
development
water

of diseases

stress

predisposing
Laemmlen,

is

considered

blue

1981),

(Schoeneweiss,
as

1978).

the

Drought

or

major

factor

in
and

spruce

(Schoeneweiss,

1983;

Kamiri

poplars

(Schoeneweiss,

1978)

and

French

prune (Bertrand et a l ., 1976) to Cytospora canker.
Although the results are contradictory,
experiments have been

conducted

predisposes

Cytospora

suggested

trees
that

differences

these

To minimize

results,

should be measured

on how moisture
canker.

contradictions

in methodology,

inoculation.
consistent

to

Kramer
in terms

a number of

Bier

could

inoculum potential
these

suggested

(1964)

be

due

to

or

time

of

contradictions

(1963)

stress

and

that

of water stress

for

drought

in the plant

rather than in terms of soil water stress.
Plant

water

balance

in

poplar

generally

varies

diurnally, seasonally, and by clone (Pallardy and Kozlowski,
1981)

. Water potential normally reached a minimum late in

the morning.

Slow growing Populus clones showed longer

periods of low leaf water potential compared to that of fast
growing clones.
the

size

positively

of

In another study
Cytospora

cankers

correlated with

bark

(Biggs and Davis,
on

hybrid

relative

poplar

was

turgidity

and

negatively correlated with bark water potential.
stems

subjected

to

-20

to

-30

bars,

1981),

developed

Spruce
cankers

32
whereas no cankers were
bars (Schoeneweiss,
inoculations

with

observed on the

1983).
C.

controls

at

-2.5

Filer (1967) reported that July

chrysosperma

produced

significantly

more stem cankers among 25 cottonwood clones than November
inoculations,
and moisture.

demonstrating
Thus,

the

importance

drought

stress

of

could

temperature
be

the

main

predisposing factor for disease development in both hybrid
poplars and in spruce.
Although many studies have been conducted on the effects
of drought or water stress on woody species,

comparatively

few studies have been conducted on the effect of excess soil
moisture.

Excess soil

sites in Michigan

water may be a problem on certain

(Robertson et a l ., 1979a) . The type and

level of injury caused by excess water differs with species,
soil

type and

decreased

growth

transpiration,
abscission,

flooding
rate

leaf

of

Symptoms
shoot

chlorosis,

of

accumulation,

and pathogens

oxygen
and

from

the

indirectly

products (Gill, 1970; Broadfoot,
are favored by wet
(1975)

and

injury

root,

leaf

Excess water predisposes

exclusion

of

include

increased

epinasty,

leaf

death of roots and increased susceptibility to

attack by predators
1940).

time.

(Gill,
trees

root
by

1970;

directly by

system

or

accumulation

1967).

Kramer,

by
of

the
COg

toxic

Most root diseases

soils but according

to Schoeneweiss

the role of host predisposition in the majority of

cases is not known.

Robertson et a l . (1979a),

however,

reported that adequately drained soil contains more air than
poorly drained soil. Oxygen, the important component of air

33
in the soil,

diffuses approximately 10,000 times faster

through large well drained pore spaces in the soil than
through water logged pore spaces.

Robertson, Kidder and

Mokma (1979b) further recommended surface drainage in order
to reduce the

level

of soluble metals such as iron and

manganese which are toxic in poorly drained and, especially,
acidic

soils.

Season

of

flooding

predisposing trees to pathogens.

is

important

in

Generally winter flooding

is of little significance while excess water during the
growing season is detrimental (Hall and Smith, 1955).

MATERIALS AND METHODS
Root starch level
On October 25,

1986;

54 roots were collected for root

starch analysis. At the Manistee site 14 roots from 7 trees
of NE 47 were sampled. At the Mason site 40 roots (20 roots
from 10 trees of NE 235 and 20 roots from 10 trees of NE 308
) were collected. Root samples were taken f r o m t r e e s n e a r e s t
to the points where soil samples for nutrient analysis were
taken (Figures 1 and 2). Root samples were about one cm in
diameter

and

30

cm

in

length.

They

were

placed

in

a

polyethylene bag and kept on ice for transporting to East
Lansing. The samples were then kept at -20°C until they were
analyzed
potassium

for starch.
iodide

(KI)

Starch

level

solution

was

determined using

following

described by Wargo (1975)(Appendix A).

the

procedure

After the staining,

each cross section was examined under a light microscope at

34
100X magnification and photographed using Ektachrome color
film. Roots were rated as depleted,

low or medium in starch

level based on the relative amount of staining.
Leaf water potentials
On

June

17,

18

and

July

29,

30,

1986

leaf

water

potentials (xylem water potential) of 62 trees were measured
at the Mason plantation, using a Scholander's pressure bomb
(Tyree and Hammel,

1972; Scholander et. a l . , 1965; Tyree,

Dainty and Hunter,

1974;

and Hinckley,

1971).

June measurements,
July.

Two

small

Waring and Cleary,

1967;

Ritchie

The 62 trees were tagged during the
hence the same trees were measured in

branches

(5

to

10 mm

in

diameter)

of

approximately equal size from the same tree were taken 1.5
to 1.7 m above ground from the unshaded side of the tree.
Measurements were taken between 10 A.M.

and 1 P.M. with

sunny skies. A weather station at Ludington,
16 km

southwest
„

ueiiipeiature or

June

14

and

of

_o_

the

plantation,

.

recorded

.

. .

a minimum
o

.

o u ana a maximum temperature or 23 C between

18.

The

minimum

and

maximum

recorded for the July 26 to 29 period were
respectively.

located about

temperatures
14°C and

29°C

No precipitation was recorded for three days

before or while leaf water potential measurements were taken
on June 17 and

18.

for the three

days

A total of 9 mm of rainfall was recorded
(July 26, 27and 28)

before leaf water

potential measurements were taken. However,
precipitation on July 29 and 30.

Clone NE

there was no

235 and NE 308

were sampled equally throughout the stand. These trees were

35
randomly sampled from the better microsites
were growing

vigorosly)

and

(where trees

stressing microsites

(where

trees were short and open spaces were present in the stand
) . Leaf water potential mean differences for NE 235 and NE
308 were compared by month of measurements and microsites
using a t -

test.

36

u
I I V - Cu tlH lH f a t S ilt
S u l Sm

iMi

U |M l

■ S a i l p i t l i k i i l M I t u t t d U |f!
> Soil p u l ( t ailk n m e i t U |tf
S oil n u t r l o n t s &

•

Root ( t o r c h lovot
N

t

r

Figure 1.

irn n II it I
M*

Field
layout
ortstein layer,
Mason.

of
soil

samples
nutrients

taken
for
and roots at

37

K f ' f

Li

ISSPsH .•.I
*

it t
V

t»
14
IS
IS
11
10

in K t w C . llip l. C m . l .n

f t|f

•

Sail S ia n ln ^

■

• Soil profile mlkout ortvtem Ijyti

T

> SoHprofile

a ilb o r t u r m layer

S oli n u tria n U t
R ooi s t o r c h la v a !

•

•
•
4
SS'.. »
> t
K

mX

Figure 2.

f ■<
\* I i

H

7

9

11

■ft I

II

IS

7

19

21

23

2S

Field layout of samples taken for ortstein
layer, soil nutrients and roots at Manistee.

38
RESULTS AND DISCUSSION
Root starch levels
In general

root

starch

levels

as

measured

with

KI

solution were low . Consequently, starch levels were grouped
as depleted (0 to 1%) , low (2 to 5%) or medium (6 to 10%).
Root starch levels by clone and by study sites are shown in
Table

7. When tree heights were compared by

groupings,

a

one

way

analysis

of

starch

variance

level

showed

no

significant difference in mean tree heights with starch
levels

(P > 0.05).

A Chi-square test showed no significant

differences when starch levels were compared by study sites
(P > 0.05) or between clones (P > 0.05). Furthermore, a Chisquare test between starch levels and ratings for Septoria
canker (P > 0.05) or Cytospora canker (P > 0.05) and poplar
and willow borer damage

(P > 0.05)

showed no

significant

differences at Mason.
Leaf water potentials
Summary of leaf water potential means are shown in Table
8.

No significant differences were observed between NE 235

and NE 306 trees on measurements taken on June 17 and 18 (P
> 0.05) or July 29 and 30 (P > 0.05)

.

Within the stand,

when leaf water potential means of NE 235 and NE 308 were
compared

separately

or

together

by

microsites,

no

significant differences were observed at the 5% level of
probability.

39
Table 7. Root starch level ratings summary

Manistee*

Mason**

NE 47

NE 235

NE 308

Starch level

n

n

%

n

%

n

%

Depleted (0-1%)

0

0

3

30

4

40

7

26

Low (2-5%)

5

71

7

70

5

50

17

63

Medium (6-10%)

2

29

0

0

1

10

3

11

%

TOTAL

*

as 98% of the stand was NE 47 the other clones
were not found at the sampling points
** NE 47 was not sampled at this site
n = number of trees

Table 8. Leaf water potentials means in - bars at Mason
plantation

July 29 & 30, 1986

June 17 & 18, 1986
Better
microsite

Stressing
microsite
Total

n

lwp

n

8.5

Better
lUiOlUsite

Stressing
UI4V1 v/

site

n

lwp

n

12 8.6

32

8.5

20 10.4

12 11.4

32 10.8

NE 308 19 10.7

12 9.5

31 10.2

19 12.4

11 12.2

30 12.3

9.6

24 9.1

63

39 11.4

23 11.8

62 11.5

Clone

NE 235 20

Total

39

lwp

9.3

n = no. of trees
lwp = leaf water potential

lwp

n

lwp

Total
n

lwp

40
Plantation vigor could be estimated by combining the
ratings of the sample trees in the stand

(Wargo,

1978).

Thus, the overall low root starch levels

(2 to 5% staining

of

iodide

root

cross-section

indicated

that

physiologically

with

trees

in

vigorous

potassium
both

and

plantations

probably

were

solution)
were

under

not

stress.

Lack of differences in pests incidence or tree height among
root starch level groupings suggested that the trees had
similar vigor.
For Botryosphaeria d o t h i d e a . a common pathogen which
forms

stem

cankers

predisposed by stress,
for

canker

on

a

the

wide

of

woody

leaf water potential

development

(Schoeneweiss, 1981).

range

was

-12

to

plants

threshold
-13

bars

In French prune orchards canker sizes

caused by Cytospora leucostoma increased with increased
water

stress

significant

(Bertrand

et

differences

in

between NE 235 and NE 308
similarly stressed at Mason.

a l .,
leaf

1976).
water

The
potential

lack

of

means

indicated that both clones were

LITERATURE CITED

Bertrand,P.E., H. English, K. Uriu and F.J. Schick. 1976.
Late season water deficits and development of
Cytospora canker in French prune. Phytopathology,
66:1318-1320.
Bier, J.E. 1964.
The relation of some bark factors to
canker susceptibility.
Phytopathology, 54:250-261.
Biggs, A.R.and D.D.
Davis. 1981.
The enlargement of
cytospora canker of hybrid poplar and associated
water relations. Phytopathology 71(5):558.
Broadfoot, W.M. 1967.
Shallow-water impoundment
increases soil moisture and growth of hardwoods.
Soil. Sci. Soc. Amer. Proc. 31:562-564.
Filer, Jr. T.H. 1967. Pathogenecity of Cytospora,
Phomopsis and Hypomyces on Populus d e l t o i d e s .
Pytopathology 57:978-980.
Gill, C.J.
species.
671-688.

1970.
The flooding tolerance of woody
A review. Forestry Abstract. Vol. 3(4):

Hall, T.F. and G.E. Smith. 1955. Effects of flooding on
woody plants, West sandy dewatering project, Kentucky
reservoir.
J. of For. 53:281-285.
Hassid, W.Z., and E.F. Neufeld.
1964.
Quantitative
determination of starch in plant tissues.
p 33-36.
I N : R .I . Whistler [Ed.] Methods in carbohydrate
chemistry, Vol. IV Starch. Academic Press, New York.
Kamiri, L.K. and F.F. Laemmlen. 1981. Effect of droughtstress and wounding on Cytospora canker development
on Colorado blue spruce. J. of Arboriculture 7(5):113116.
Kramer, P.J. 1940.
Causes of decreased absorption of
water by plants in poorly aerated meida.
Am. J. of
Bot. 27:216-220.
Kramer, P.J. 1963.
Water stress and plant growth.
Agronomy J., 55:31-35.
Pallardy, S.G. and T.T. Kozlowski. 1981.
Water
relations of Populus clones. Ecology 62(1):159-169.

41

42
Ritchie, G.A. and T.M. Hinckley. 1971.
Evidence for
error in pressure-bomb estimates of stem xylem
potentials.
Ecology 52(3):534-536.
Robertson, L.S., E.H. Kidder, A.E. Erickson, and D.L.
Mokma.
1979a.
Tile drainage for improved crop
production.
Coop. Ext. Serv.
Michigan State
University, East Lansing, E-909. PP. 11.
Robertson, L.S., E.H. Kidder and D.L. Mokma. 1979b.
Surface drainage for improved crop production.
Coop.
Ext. Serv.
Michigan State University, East Lansing.
E-1295. PP. 8.
Schoeneweiss, D.F.
plant disease.
13:193-211.

1975.
Predisposition, stress and
Annual Review of Phytopathology

Schoeneweiss, D.F. 1975.
A method for controlling
plant water potentials for studies on the influence
of water stress on disease susceptibility.
Can. J.
Bot. 53:647-652.
Schoeneweiss, D.F. 1978. Water stress as a predisposing
factor in plant disease.
Water Deficits and Plant
Growth. T.T. Kozlowiski (Ed.) Vol. V:61-99.
Schoeneweiss, D.F. 1981. The role of enviromental strees
in diseases of woody plants. Plant Disease 65(4):308314.
Schoeneweiss, D.F. 1983.
Drought predisposition to
Cytospora canker in blue spruce.
Plant Disease
67(4):383-385.
Scholander, P.F., H.T. Hammel, E.D. Bradstreet and E.A.
Hemmingsen. 1965.
Sap-pressure in vascular plants.
Negative hydrostatic pressure can be measured in
plants.
Science, 148:339-346.
Tyree, M.T. and H.T. Hammel.
1972.
The measurement of
the turgor pressure and the water relations of plants
by the pressure bomb technique.
J. Experimental
Botany.
23(74):267-282.
Tyree, M.T., J. Dainty and D.M. Hunter.
1974.
The
water relations of hemlock (Tsuqa canadensis). IV.
The dependence of the balance pressure on temperature
as measured by the pressure-bomb technique.
Can. J.
Bot. 52:973-978.
Wargo, P.M. 1971.
Seasonal changes in carbohydrate
levels in roots of sugar maple.
USDA, For. Serv.
Northeastern For. Exp. Stn. Res. Paper NE-213. PP. 8.

43
Wargo, P.M. 1975.
Estimating starch content in roots
of deciduous trees. A visual technique.
USDA, For.
Serv. Northeastern For. Exp. Stn. Res. Paper. NE-313,
PP. 9.
Wargo, P.M. 1976.
Variation of starch content among
and within roots of red and white oak trees.
Forest
Science.
22(3):468-471.
Wargo, P.M. 1978. Judging vigor of deciduous hardwoods.
USDA, Combined forest pest research and development
program. Agric. Information Bull. No. 418. PP. 15.
Wargo, P.M. 1981.
Measuring response of trees to
defoliation stress. p. 248-267.
IN: Doan, C.C. and
M .L . McMnaus(Eds.) The Gypsy Moth: Research Toward
Integrated Pest M a n a g e m e n t . USDA, Expanded Gypsy
Moth Research and Development Program, Technical
Bulletin 1584.
Waring, R.H. and B.D. Cleary. 1967.
Plant moisture
stress:
Evaluation
by
pressure
bomb.
Science
155:1248-1255.

SOIL CHARACTERISTICS AND THEIR RELATIONSHIP WITH
THE INCIDENCE OF SEPTORIA CANKER, CYTOSPORA CANKER
AND POPLAR AND WILLOW BORER

44

INTRODUCTION
Stress factors and predisposition to pests
In general most species of higher plants are either
immune

or

resistant

microorganisms

with

(Schoeneweiss,

to

attack

which

1975).

by

they

the
come

Microorganisms

however,

in

enter

susceptible hosts with equal frequency.
a disease condition,

majority

of

contact

resistant

and

The development of

depends on the influence of

environmental factors on the genetically controlled response
of

the

host

plant

to

the

pathogen

or

its

metabolites

(Schoeneweiss, 1975).
Plant pathologists have long recognized the influence of
environment

on

(Schoeneweiss,
fungicides

attention.

availability

stress

control,

and

numerous

however,

use

of

the

diseases

importance

predisposition
with

contamination
and

of

But with the advent and wide use of

disease

Now,

environmental

epidemiology

1981).

in

environmental

the

and

received

less

concern

over

public

restrictions

fungicides,

of

along

on

the

with

the

development of the Integrated Pest Management (IPM) concept,
there is a renewed interest

in the study of environmental

stresses as predisposing factors in disease development.
Environmental stress is defined as,

"any factor capable

of producing a potentially injurious strain;

stress exerts

the most pronounced effect

in predisposing plants

greater

to

susceptibility

particularly

weak

or

towards

facultative

parasites,

non-aggressive

parasites"

45

46
(Schoeneweiss,

1975).

Nonaggressive

facultative

parasites

like Cytospora chrvsosperma. commonly enter host plants but
remain latent or non-pathogenic until the host is stressed.
Predisposition

is defined by Schoeneweiss

(1975)

as

"the

tendency of non-genetic factors, acting prior to infection,
to affect the susceptibility of plants

to disease".

Thus,

predisposition implies an effect on the host rather than on
the pathogen.

Proneness or disposition of the host

to

disease prior to infection may influence the subsequent
establishment and development of a pathogen

(Schoeneweiss,

1978).
Generally,
stable

resistance to a given plant disease

character

and

has

its

composition of the host plant.

basis

in

the

is a

genetic

But the expression of the

genes may be modified by environmental factors (Barnett,
1959).
water,

These environmental
soil

resistance

conditions,
either

by

factors

(water stress,

temperature,

direct

effect

etc.)

on

the

excess

may

modify

pathogen

or

indirectly through host metabolism.
C.

chrvsosperma

attacks

predisposed by stress as it

weakened

plants

or

those

is a non-aggressive pathogen.

It enters plants through wounds but does not cause disease
damage as long as the host vigor is high
1981).
pathogen

On the contrary,
(Bier,

1939)

(Schoeneweiss,

Septoria musiva is an aggressive

which causes

reduces growth and predisposes

premature

susceptible

defoliation,

trees

to

other

pathogens and environmental stresses (Ostry and McNabb, Jr.
1983).

Cryptorhyncus

l apathi, a stem
**r.

boring

insect,

47
however, prefers trees that are weakened or are under stress
(Wilson, 1976).

Soil characteristics and hybrid poplars
The soil environment
whether

trees

suppressed

survive

and

die.

is a major
and

grow

Roots

factor
or

respond

in determining

whether
to

they

changes

are

in

the

physical and chemical properties of soil depending upon the
tree species and soil type (Rurark, Mader and Tattar, 1982).
Soil

chemical

cation

characteristics,

exchange

characteristics

capacity

e.g.

(CEC),

like soil texture,

nutrient
etc.,

levels,

and

pH,

physical

structure,

drainage,

compaction, etc., influence tree vigor and the productivity
of the site.

Unfortunately, there is lack of detailed soil

chemical and physical characteristics data related to forest
productivity as compared
(1984)

reported

to agricultural

detailed

soil

lands.

Woods

descriptions

and

class ificat ions of the PCA hyhrid poplar sites ^

Vet,- the

report

chemical

contained

limited

information

on

the

composition of the soil.
In establishing hybrid poplar plantations, Dickmann and
Stuart

(1983)

suggested that soil

fertility,

moisture content and aeration be considered.

pH,

depth,

Furthermore,

due to the moderately deep rooting system of hybrid poplars,
the nutrient

content

of

the upper

B horizon

should

be

considered in addition to the A layer in site selections for
hybrid poplar plantations (Roberts and Khalil, 1980).

In a

48
study of soil nutrients in hybrid poplar plantations

in

central Pennsylvania; Ca, N and P were found to be important
factors

influencing

tree

(Bowersox and Ward,
revealed

that N,

height

1977).

and

stem

wood

yield

Studies with birch seedlings

K and P levels

decreased gradually with

increasing uptake of Al while levels of Ca and Mg decreased
rapidly,

showing

differential

the seedlings to A1

level

nutrient

uptake

response

(Goransson and Eldhuest,

by

1987).

Poplar plantation sites in Mason county, Michigan were found
to be very deficient in P by Woods et a l . (1982).
Hybrid poplar clones respond differently to nutrient
levels.

Clones derived entirely from crosses between P.

deltoides and P. nigra were found to be more sensitive to Al
than

clones

derived

in

part

from

m a x i m o w i c z i i , P. balsamifera or P.
Barbour

and

McCormick,

P.

tr ichocarpa, P.

laurifolia

(Steiner,

1984).

Soil compaction is a soil physical property that affects
root

development.

Soil

compaction

alters

the

physical

properties of the soil resulting in localized increases in
soil bulk density which in turn affects soil air, water and
temperature regimes (Rurark
can

be

caused

by

farm

et a l ., 1982).
equipment

or

Soil compaction
animals

destroying the soil's original structure
Bonner, 1966).
density

of

cottonwood
extension

1

thereby

(Broadfoot and

When sandy loam soil was compacted to a bulk
.6 , the

cuttings
was

below

root

and

was

retarded

normal

and

shoot

growth

of

planted

considerably.

hence

shoot

Root

growth was

49
reduced. Broadfoot and Bonner (1966) concluded that soil
compaction decreases the percentage of large pores with
consequent decrease in aeration,

moisture infiltration and

movement of nutrients.
Soil

compaction and cementation could also arise

"hardpans".

Although several types of hardpans,

in origin are known,
ortsteins.
horizon

Ortstein occurs when "all or part of the spodic

is at

least weakly

(U.S.D.A.,

favored

differing

this study was concerned only with

cemented when

massive horizon that is present
pedon"

from

under

accumulation.

1975).

Thus,

into

a

in more than half of each

Spodosol

vegetation

moist

cover

soil
with

development
acid

is

litter

spodosols occur under a wide range of

trees including Tsuga, Picea, Pinus, Larix, Thuja, Populus,
Quercus, and Betula (Buol, Hole and Mccracken, 1980).
According to Simonson (1968),
first

person

to

recognize

substances had accumulated.

the

in 1887 Muller was the
layer

in

which

mobile

Muller called these cemented or

p a r t i a u y cejiieii teu 5 horizons; Ortsteins.

Thus the term

ortstein refers to the B horizon and is derived

from two

German words meaning "stone in place" (Winters and Simonson,
1951).
Simonson

(1968)

reported that ortsteins affect

tree

growth adversely and are troublesome when the soils are
cultivated.

Ortsteins

occur

in

coarse

textured

soil

material such as sands, coarse sands, gravels or mixture of
these (Winters and Simonson,

1951). Generally the ortsteins

in the northern U.S., as well as those in Europe, resemble a

50
conglomerate or concrete in general structure,

with the

coarse particles cemented together by iron oxides
hardpan layers (Winters and Simonson, 1951).

to form

In addition to

iron, ortsteins are also rich in aluminum and manganese and
are not homogenous in chemical composition (Polskiy,
In addition to the chemical

heterogeneity,

1961).

the morphology

and color change with different degrees of waterlogging and
with the length of time of excessive wetness
1968).

Franzmeier

and

Whiteside

(1963a,

b)

(Oglenznev,
studied

a

10,000-year-long chronosequence of spodosols in Michigan and
concluded that between 3,000 and 8,000 years were required
for the formation of a spodosol soil. Generally ortstein
layers occur from 20 to 70 cm below the ground surface and
their depth is not related to relief of the site

(Muir,

1961).

MATERIALS AMD METHODS
Ortstein layer
In the summer of 1984 intensive soil sampling was done
to determine the distribution,

depth and

ortstein layer in the two study areas.
meter deep on transects

10

thickness of the
Soil borings one

m apart were made using a soil

augur. The first soil sample was taken 5 m inwards from the
first tree between rows one and two.

Thereafter,

samples

were taken 10 m apart for 150 m for a total of 15 samples
per row.
row of

Subsequent samples were taken between every third

trees

.

Each soil

sample was

checked

for

color,

mottling and for presence or absence of a cemented ortstein

51
layer.

When an ortstein layer was encountered,

its depth

from the surface and Its thickness were noted. Following the
above sampling procedure,
holes was

dug at

respectively

a total of 180 and

the Mason and Manistee

(Figures

1 and 2).

1 2 0

sample

study

sites,

The minimum depth

(the

distance between the soil surface and the beginning of the
ortstein layer) the maximum depth (the distance between the
soil surface and the end of the ortstein layer)
thickness
depths)

and its

(the difference between the maximum and minimum

were compared within a study site and between the

two study sites.
Soil nutrient levels
In the summer of 1986 soil samples were taken from both
study sites for nutrient content determination.
use of a soil augur,

With the

10 holes at the Mason site and 7 holes

at the Manistee site were dug one meter deep.
size and chape of the study sites,
pattern was used at Mason

Due to the

a v-shaped

sampling

(Figure 1) while samples were

taken diagonally from the SE corner to the NW corner at the
Manistee plantation (Figure 2). Soil horizons in a profile
were differentiated by soil color or texture change as the
plow

layer

(Ap) ,

zone

of

eluviation

(E)

or

zone

of

illuviation (B). The B horizon was further grouped as Bhs or
as Bs based on the accumulation of organic matter

(h) and

sesguioxides of iron and aluminum

(s). Each horizon depth,

thickness and color were recorded.

Color was for moist soil

52
conditions.

Using Munsell soil color charts, gray or light

gray horizons below the plow layer with hue of 7.5YR, 5YR or
2.5YR and a value of greater than or equal to four and a
chroma of less than or equal

to two were

considered as E

horizons. Horizons with 7.5YR or redder (5YR or 2.5YR) hue,
with a value and chroma of <3/3 and >4/4 were grouped as Bhs
and Bs horizons respectively. Soil samples from each horizon
were tested for pH, nitrate nitrogen
phosphorus
potassium

(P),
(K),

exchangeable

magnesium

(NO3 -N),

cations:

(Mg);

and

extractable

calcium

exchangeable

(Ca),

manganese

(Mn), iron (Fe) and aluminum (Al). Soil pH was determined by
the

Glass

Electrode

nitrogen was
Systems,

pH

Meter

determined using

1987),

while

the

(Mclean,

Quickchem method

Bray

P-l

test

determine extractable P level (Knudsen,

K

(Knudsen,

exchangeable

Ca

and

Mg

Peterson

(Lanyon

(Quickchem

was

used

to

(Whitney,

1980).

Pratt,

1982),

and

and

Nitrate

1980). Exchangeable

Mn and Fe were extracted using 0.1N HC1
Exchangeable

1980).

Heald,

1982)

were

determined using neutral IN ammonium acetate (IN NH 4 OAC)
extraction

procedures.

These

nutrients

and

pH

were

determined by the Michigan State University Soil Testing
Laboratory in East Lansing, Michigan.

Exchangeable aluminum

(Al+++) level was determined in the Forest Soil Laboratory,
Michigan

State

spectrophotometer
B) •

University,
(Barnhisel

using
and

the

Bertsch,

DC-Argon
1982)

plasma

(Appendix

53
Soil nutrient

levels between study sites and within a

study site were investigated.
nutrient

levels

between

In addition,

horizons

were

differences in
compared.

Soil

nutrient levels and disease ratings data from the two study
sites were combined for comparison of soil nutrient with
pest incidence ratings.
Methodology to assess relationship between soil
characters and pest problems
Ortstein layer
Nine trees around each ortstein sampling point were
identified to clone (Figure 1 and 2). Trees were grouped by
the presence or absence of ortstein layer.

Average tree

height and percent mortality were compared between the two
groups. The relationship between depth to the ortstein layer
and tree height,

canker incidence,

and insect borer damage

ratings were investigated.
CJri A
4 A
1

4-

**
tiWt W A

Twenty

4 a n 4-». ^
1w

trees

1c
—

around

each

soil

sampling

point

for

nutrient level tests were identified to clone (Figures 1 and
2).

Possible

correlations with soil nutrient levels

and

tree heights, canker incidence and, insect borer ratings
were determined. Correlations between nutrient levels in the
different horizons and disease ratings in a study site were
determined. Using the S t a t i s t i c a l P a c k a g e f o r t h e S o c i a l
Sciences

test

was

(SPSS)

used

(Niel et al., 1975),Scheffes
to

test

multiplerange

for significant differences

in

54
nutrient

level

means

between

profiles

in

between
a

horizons

study

in a profile

site.

All

or

significant

differences were indicated at the 0.05 level

(Steel and

Torrie, 1980).
Using the N u m b e r
(Hintze,

Cruncher

Statistical

System

(NCSS)

1987) multivariate analyses were conducted by the

stepwise regression method to determine how disease ratings
were

related

to site

factors and tree heights.

"Best"

multiple sets were selected on the basis that the partial
correlation coefficients of the included variables were
significant

and

the

included

variable

substantially

contributed to the explained variation.

RESULTS AMD DISCUSSION
Ortstein layer
At the Mason study site 71 {39%) of the 180 borings and
at the Manistee site 52 (43%) of the 120 borings showed an
ortstein layer.

The distribution of the ortstein layer was

discontinuous in both sites. A one way analysis of variance
for

areas

with

ortstein

showed

that

there

were

not

significant differences in the minimum depth, maximum depth
or thickness of the ortstein layer for the Manistee or Mason
sites at P = 0.05. Comparison between the two sites showed
that there was no significant difference
(minimum depth)

of

the ortstein

layer

in the beginning
(P > 0.05),

while

significant differences were found in the maximum depth of
the ortstein

layer

(P < 0.05)

and

the

ortstein

layer

55
thickness

(P < 0 . 0 5 ) .

The minimum,

maximum and average

depths of the ortstein layer are shown in Tables 9,10 and 11
for the Mason and Manistee sites and the comparison between
the

two

sites

respectively.

The

color

of

the

ortstein

layer,in a profile, varied from dark brown or reddish brown
to pale yellow.

Generally the darker ortstein layers were

harder and more difficult to bore with a soil augur than the
lighter colored layers. The pale yellow ortstein layer was
more common at the Manistee site, where the water table was
closer to the ground surface and soil mottling was observed,
than

at

Mason.

The

conglomerate

characteristic

of

an

ortstein layer is shown in Figure 3.
Table 9. Summary of ortstein layer distribution and depth in
cm at Mason plantation.

MIN.DEPTH
Prof.
with
Std.
Transect ort. Mean error

10

8

11

7

12

6

13
14
15

3
7
5

32.5
44.0
33.0
32.5
38.5
31.7
24.8
27.8
30.0
39.0
31.1
49.7
40.3
30.3
39.8

71

34.8

1

2

2

2

3
4
5

3

6

7
8

9

Total 180

2

4
7
4
4
7

7.5
14.0
4.5
7.5
9.2
6.9
3.8
3.3
5.8

MAX.DEPTH
Mean
O i

. J

ORT.THICKNESS

Std.
error
A

tS

Mean

e

4.0
9.5

7.7
2.9
14.2
7.0
4.3
2.1

5.6
7.8
17.4
5.0
7.1

7.3
9.5
6.4
7.9
8.4
4.1
9.2
6.9
8.9
9.0
13.3
7.5
8 . 0

26.0
34.7
33.0
30.8
46.7
37.5
43.3
47.6
34.5
47.9
30.8
36.7
50.3
37.0

1.9

75.4

2.2

40.6

6 . 0

rs

e e
a
W W i V

70.0
67.7
65.5
69.2
78.4
62.2
71.0
77.6
73.5
79.0
80.5
77.0
80.3
76.8

1 0 . 0

Std.
error

2 . 0

9.2
6 . 6

7.9
7.0
9.2
6 . 6

56

Table 10. Summary of ortstein layer distribution and depth in
cm at Manistee plantation.

MIN.DEPTH
Prof.
with
Transect ort. Mean

3
4
5

3
5
3
5
7

2

36.0
36.0
28.7
40. 6
31.4
25.0
28.5
26. 3
35.2
36.0
28.8
20.5
52.5
31.0
35.0

6

2

7

Total 120 52

33 .1

1
2

11

4
3
5
4
4

12

2

13
14
15

2

8

9
10

1

Std.
error
4.7
6.5
5.9
9.5

MAX.DEPTH

Mean

1 0 . 0

74.0
72.0
64.7
61.0
77.7
43.0
62.2
42.3
69.8
81.8
70.8
38.0
74.5
65.0
72.5

.8

67 .0

6 . 0
2 . 0

3.2
2 . 6

3.6
3.6
5.2
2.5
22.5

1

Std.
error
13.3
1 1 . 6

10.4
1 0 . 6

7.5
2 . 0

13.8
0.3
7.0
10.9

ORT.THICKNESS

Mean
38.0
36.6
36.0
20.4
46.3
18.0
33.8
16.0
34.6
45.8
42 . 8
17.5

Std.
error
17.6
1 0 . 8

14.6
4.1
10.7
0 . 0
1 1 . 0

2 2 . 0

2.9
5.7
13.1
7.9
6.5
3.0

5.5

34.0
37.5

15.5

3 .0

33.9

2 . 8

1 1 . 0

4.0
25.5

57

Figure 3. The conglomeate characterstics of an ortstein
layer, sample from the Mason plantation.

58
Table 11. Ortstein layer depth and thickness comparison
between the two study sites.

MIN.DEPTH

Site

Prof.
with
ort.

Mean

Std.
error

ORT.THICKNESS

MAX.DEPTH
Std.
error

Mean

Std.
error

Mean

Manistee

52

33.1a

1.8

67.0a

3.0

33. 8 a

2 . 8

Mason

71

34.8a

1.9

75.3b

2.2

40.5b

2.1

Total

123

34.0

1.3

71.8

1.8

37.7

1.7

* means in each column followed by the same lette
not differ significantly at P = 0.05

Soil nutrient levels
The soil nutrient contents by study sites are shown in
Tables

12

and

respectively.

13

for

the

Mason

and

Manistee

sites

When soil sample means were combined over the

study sites one way analysis of variance showed that there
were significant differences in pH. P . K . Mg. Fe. Mn and Al
levels between Manistee and Mason sites (Table 14 ).
No significant differences (P > 0.05) in nutrient levels
between the ten sample profiles were observed at the Mason
site (Table 15). At Manistee, however, N, Mg, and Al levels
were significantly different in some of the seven sampling
points
horizon,

(Table

16).

however,

Comparison
showed

that

of

nutrient

at

Manistee

contents
only

K

by
was

significantly different between the Ap horizon and the other
horizons

(Table 17), while in Mason pH, P, K, Ca,

Mg,

Fe,

59
Mn, and Al were found to be significantly different between
the horizons (Table 18).
Except for N and Ca the two study sites were different
in their soil nutrient levels

. The Mason site had more P,

K, and Mg than the Manistee site while the reverse was true
for Pe , Mn and A l . More P, Fe and Al were found in the B
horizons (where the ortstein layer was present)

than in the

Ap or E horizons at both study sites.

Table 12.

Average soil nutrient contents (kg/ha) at Mason
sampled from ten profiles (one m deep) with 32
horizons.

:rients

Min.

Max.

Mean

Std.error.

pH

5.0

6.3

5.6

0.1

N

0 . 8

3.9

1.5

0 . 1

1 1 . 6

P

31.4

448.4

100.4

K

9.0

94.6

29.8

3.0

Ca

94.2

1699.3

587.5

53.0

Mg

17.9

299.3

108.7

8 . 8

Fe

4.5

142.4

33.8

4.0

Mn

2.2

15.7

3.6

0.4

Al

4.4

2 0 1 . 8

72.7

6 . 6

60

Table 13. Average soil nutrient contents (kg/ha) at Manistee
sampled from seven profiles (one m deep) with 2 0
horizons.

Std.e

Nutrients

Min.

Max.

Mean

pH

4.7

7.4

5.4

0.1

N

0 . 8

3.7

1.7

0.2

P

9.0

74.0

22.4

2.4

K

9.0

33.6

17.3

1.6

Ca

188.3

1883.1

562 .5

Mg

21.3

169.2

61.1

Pe

4.5

2470.5

389. 1

Mn

2 . 2

2 0 . 2

Al

0.7

546.6

4.5
125.5

90.9
6.2

1 0 1 . 6

1.0

24.6

61

Table 14. Comparison of soil nutrient means
the study sites.

Mason
Nutrient

Mean

Std.
error

Manistee
Mean

Std.
error Signi.

PH

5.6

0 . 1

5.4

0.1

*

N

1.5

0.1

1.7

0.2

ns

P

100.4

1 1 . 6

22.4

2.4

*

K

29 . 8

23.0

17.3

1.6

*

Ca

587 .5

153.0

562.5

Mg

108.7

Fe

8 . 8

61 .1

33.8

4.0

389. 1

Mn

3.6

0.4

4.5

Al

72.7

6 . 6

(kg/ha)

125.5

90.9

ns

6.2

*

1 0 1 . 6

*

1.0

*

24.6

*

* means significantly different at P = 0.05
ns means not significantly different at F = 0.05

between

62

Table

15.

Variation in soil
plantation.

nutrient

levels

at

the Mason

-kg/ha
Pro­
file pH

N

P

K

Ca

Mg

Fe

Mn

Al

1

5.5

1 . 0

87.6

29.9

487.6

140.7

24.3

4.5

62.1

2

5.7

1.2

170.6

23.9

645.1

91.4

47.8

3.0

45.0

3

5.6

2.1

68.9

51 . 6

548.1

67.3

74.5

3.4

69.2

4

5.6

2

.2

122.7

40. 1

384.2

125.5

37.6

4.5

83.7

5

5.3

2.2

66.7

33.1

498.5

60.5

47. 1

5.0

8 6 . 0

6

5.5

2.1

77.6

2 2 . 6

438.5

6 8 . 2

30.0

3.6

108.7

7

5.9

1.3

171.2

25.5

637.2

137.0

29.1

2.8

37.3

8

5.7

1.0

79. 2

27.7

660.5

126.1

18.5

3.9

71 .2

9

5.6

1.1

65.6

21.3

731.7

161.7

17.4

2.8

90.2

5.5

1

72.6

27.7

613.7

1 1 2

1 1 . 8

2.8

85.3

10

.1

.1

* no two profiles differ significantly at
level by Scheffe's multiple range test.

the P = 0.05

63
Table 16. Variation in soil nutrient levels at the Manistee
plantation.

Pro
filei pH

N

P

K

Ca

Mg

Mn

Fe

A1

1

4.8 3. 0 a

25.4 17.0

283.4

2

6.4 1.4b

18.7

942.7 124.4b

844.4 7.5

3

5.1 2. Oab 18.7 17.1

440.9

62.8a

590.4

8.2

171.4a

4

5.2

1

.2 b

24.3 17.0

330.7

49.5a

47.6

2.8

1 2 0

5

5.2

1

.2 b

10.1

25.2

377.7

64.4ab 186.1

2.2

6

5.2

1

,0 b

21.3

1 2 . 0

251.9

21.3a

446.1 3.0 115 .9a

7

6.4

1

.0 b

29.4 13.4 1249.8

68.4a

170.4 6.7

2 2 . 1

40.0a

473.4

302.3a

2 . 6

34.6a

.8 a

63.4a

4.6b

* soil nutrient means in each column followed by the
same letter did not differ significantly at P = 0.05
level by Scheffe's multiple range test.

Table

17. Means of soil nutrients by horizon at
Manistee plantation.

Soil Depth
h or. in cm
Ap
E

N

P

K

Ca

Mg

Fe

Mn

807.8 74.5 218.4 7.1

A1

0 - 2 2

5.4

1.8

16.8 26.9a

22-71

6.1

1.2

2 0 . 1

5.3

2.1

21.5 16.lab 613.8 59.4 780.1 5.0 233.7

Bhs 22-58
Bs

PH

the

12.9ab 377.7 79.6 182.7

52-100 5.6 1.3 30.3 11.9b

2.2

367.2 48.2 198.9 2.5

92.8
12.1

76.6

* means in each column follwed by the same letter
did not differ significantly using Scheffe's
multiple range test at P = 0.05

Table 18. Means of soil nutrients by horizon at the Mason
plantation.

Soil Depth
h o r . in cm
Ap
E

N

P

K

Ca

—kg/ha— --Mg

Fe

Mn

A1

0 - 2 2

5. 8 a

1.4 118 .5ab 62.3a 1144.9a 160.la 3 1 .2a

8

.la

23. 3a

21-45

5.9a

1.4

37.9ac

5. 5ab

1 . 8

Bhs 35-57
Bs

PH

49-100 5.3b

1.3

71 .la

25 .3b

694.lb 147.5a

.2 a

2

.2 b

191 .2b

30.5b

619.5b 138.0a 70.2b

2

.2 b 102.9b

60 .0 a

15 .lb

282.9c

1 1

62 .5b 25.0a 2.4b

92.2bc

* means in each column followed by the same letter did
not differ significantly using Scheffe's multiple range test
at P = 0.05

65
Relationship between soil characters and pest problems
Ortstein layer
Trees were grouped and compared
absence of an ortstein layer.
the

by the presence

or

A t-test of average height of

trees between the two groups showed no significant

differences at P = 0.05 at Manistee. The average height for
trees in the presence of an ortstein layer was 3 m while it
was 3.1 m in the absence of an ortstein layer

(Figure 4).

At

difference

Mason,

however,

there

was

a

significant

between the average height for trees
of an ortstein layer
where

an ortstein

(4.8 m)

growing in the absence

compared to 3.6 m for

layer was present

trees

(Figure 5).

Total

mortality , however, was not different between trees growing
in the absence or the presence of an ortstein layer at
either site.

Percent of dead trees was higher at Manistee

(40% when ortstein present,
at Mason

43% when ortstein absent)

(14% when ortstein present,

15% when

than

ortstein

absent).
Root development and penetration was severely restricted
when the ortstein layer was present as shown in Figures

6

and 7.
The relationships between pest ratings and the effective
soil depth (the soil depth to the cemented ortstein layer)
are shown in Figures

8

, 9 and 10 for the Mason plantation

and in Figures 11,12 and 13 for the Manistee plantation. The
effect of soil depth on the incidence of pests was probably
due

to

its

direct

effect

on

tree

heights.

The

direct

66
relationship between tree heights and pest incidence are
shown in Figures 14, 15 and 16 for the Mason plantation and
Figures 17,18 and 19 for the Manistee plantation.
Genrally the incidence of Septoria canker increased with
increasing soil depth and tree height. Cytospora canker and
poplar and willow borer

incidences,

however,

tended

to

decrease or not change with increasing soil depth and tree
height.

IN M.
HEIGHT
TREE

cP

0

17

34

51

69

86

103

SOIL DEPTH IN CM.

Figure 4. Relationship between soil depth to the ortstein layer
and tree height at the Manistee plantation.
Note: Regression line and 95% confidence limits are
for the mean.

120

CD
LU

OO
UJ

cc

0

17

94

51

•6

10*

SOIL DEPTH IN CM.

Figuer 5. Relationship between soil depth to the ortstein layer
and tree height at the Mason plantation.
Note: Regression line and 953» confidence limits are
for the mean.

120

69

Figure

6

. Hoot development and pattern at a place
where the ortstein layer was absent at Mason.
Note: photograph shows root upside down.

70

Figure 7. Root development and pattern at a place where
the ortstein layer was present.
Note: photograph shows root upside down.

RATING
CANKER
CYTOSPORA

oco

CD

17

0

14

51

•6

10$

SOIL DEPTH IN CM.

Figure

8

. Relationship between soil depth to the ortstein layer
and Cytospora canker rating at the Mason plantation.
Note: Regression line and 95% confidence limits are
for the mean.

120

co
CC)

CO coo

SEPTORIA

CANKER

RATING

CO

0

17

34

51

SOIL DEPTH IN CM.

Figure 9. Relationship between soil depth to the or.tstein layer
and Septoria canker rating at the Mason plantation.
Note: Regression line and 95% confidence limits are
for the mean.

120

RATING

<» -COD

POPLAR AND WILLOW BORER

CD

0

17

84

SI
SOIL DEPTH IN CM.

Figure 10. Relationship between soil depth to the ortstein layer
and poplar and willow borer damage rating at the
Mason plantation.
Note: Regression line and 95% confidence limits are
for the mean.

120

RATING
CANKER
CYTOSPORA

■OO ■ 9 0

•09

oo
OO

0

17

34

51

103

SOIL DEPTH IN CM.

Figure 11. Relationship between soil depth to the ortstein layer
and Cytospora canker rating at the Manistee plantation.
Note: Regression line and 95% confidence limits are
for the mean.

120

RATING
SEPTORIA

CANKER

o
«>

o
o
o
o

•v j
O
l

onoBoqwca oa cooa » o— n p

17

34

51

S3

•s

103

SOIL DEPTH IN CM.
Figure 12. Relationship between soil depth to the ortstein layer
and Septoria canker rating at the Manistee plantation.
Note: Regression line and 95% confidence limits are
for the mean.

120

POPLAR AND WILLOW BORER RATING

-oaxo

109

94
SOIL DEPTH IN CM.

Figure 13. Relationship between soil depth to the ortstein layer
and poplar and willow borer damage rating at the
Manistee plantation.
Note: Regression line and 95$ confidence limits are
for the mean.

120

E2 C

RATING

OOO OCI

'vol

CYTOSPORA

CANKER

6 »
2

e
o
ao
o o
o
o
.o
o o
o
ooo o* o a> o o p
o
oo
o 6 o«
cp oo tb
■oar
~ m — rrrrw
t»
o-ao ooooooo • o

10

TREE HEIGHT IN M.

Figure 14. Relationship between tree height and Cytospora canker
ratir.g at the Mason plantation.
Note: Regression line and 95% confidence limits are
for the mean.

•o* o*

OODO

RATING

oo

oo O

OOD .OB •
o oocpao
OOCD

<a> oo
o •oo
oo

CANKER

oo oo

SEPTORIA

oo

0

2

4

t

REE HEIGHT IN M.

Figure 15. Relationship between tree height and Septoria canker
rating at the Mason plantation.
Note: Regression line and 95% confidence limits are
for the mean

10

oo
oo

oo* o

oo
o oo
oo
oo oo o
oo o

oo oo
RATING

- p - g o.

oo

QDO

OOD

BORER

,ooo
oo

oo

POPLAR

AND WILLOW

00

0

z

4

TREE HEIGHT IN M.

Figure 16. Relationship between tree height and poplar and willow
borer damage rating at the Mason plantation.
Note: Regression line and 95% confidence limits are
for the mean.

10

oo

oo

ooo

RATING

OO'

4D -0 -COO •

CYTOSPORA

CANKER

ooo

O' oo

0

2

A

TREE HEIGHT IN M.

Figure 17. Relationship between tree height and Cytospora canker
rating at the Manistee plantation.
Note: Regression line and 95% confidence limits are
for the mean.

0

2

4

TREE HEIGHT IN M.

Figure 18. Relationship between tree height and Septoria canker
rating at the Manistee plantation.
Note: Regression line and 95% confidence limits are
for the mean.

RATING
POPLAR AND WILLOW BORER

o

1

2

9

4

5

TREE HEIGHT IN M.

Figure 19. Relationship between tree height and poplar and willow
borer damage rating at the Manistee plantation.
Note;: Regression
for the mean.

line and 95%

confidence

limits

are

83
Soil nutrient levels

Pest ratings were correlated with soil nutrients levels
at each horizon.

Simple correlations between soil nutrient

levels by horizon and pest

ratings are

presented

for

Mason (Table 19) and Manistee (Table 20) plantations.

the
In

Table 21 soil nutrients that showed significant differences
in their means when grouped by pest ratings are presented.
In Table 21 the soil and pest ratings data were combined
over

the

two study sites.

Table

21

showed

that Cytospora

canker incidence increased as Fe and A1 levels increased and
K level

decreased.

Septoria

canker

incidence,

however,

increased with increasing levels of P, K and Mg and as Fe
and A1

levels decreased,

while poplar

and willow borer

damage increased with increasing P and K levels.
In French prune orchards in California Cytospora canker
occurance was associated with low level

of K in the soil

(Bertrand, English and Carlson, 1976). As A1 level increased
nutrient uptake of N, K, P, Ca and Mg by birch seedlings
decreased (Goransson and Eldhuest,
Al-induced
Huttermann,

nutrient

deficiency

1987) thereby causing an
(Godbold,

Fritz

and

1988). A similar process is presumed to happen

at the two study sites. As Cytospora chrvsosperma favors
stressed trees,

the high levels of Fe and A1 and the

low

level of K lowered the tree’s vigor and predisposed them to
the fungus. Septoria musiva on the other hand preferably
attacks vigorously growing tree's thus, the incidence of
Septoria canker increased with increasing levels of P, K and

84
Mg (nutrients important for plant vigor and growth), and
with decreasing levels of Fe and A 1 .

85

Table 19. Correlation coefficients between soil nutrient
levels by horizon and disease ratings at Mason
CYTOSPORA
NE47

NE235

CANKER
NE308

SEPTORIA CANKER
NE47

NE235

NE308

BORER
NE47

NE235

NE 308

Ap horizon
0.51
-0.32
-0.26
0.05
0.08
0.41
-0.30
0.26
-0.44

0.29
-0.28
-0.05
-0.28
0.34
0.23
0.35
0. 13
0.16

-0.73
-0.36
-0.66
0.12
0.64
-0. 26
-0. 58
-0.66

0.10
-0.88*
-0.98*
-0.93*
0.54
0.60*
-0.33
-0.94*
0.51

0.04
0.23
-0.36
-0.55
0.46
0.38
-0.19
-0.27
-0.00

-0.09
-0.41
-0.01
-0.51
0.23
0.14
-0.51
-0.73*
0.38

-0.49
-0. 29
0.53
0.03
-0. 34
0.02
-0.60
0.96*

0.73
0. 36
0.66
-0.12
-0.64
0.26
0.58
0.66

0.17
0.41
-0.33
-0.58
-0.04
-0.75
-0.19
-0.72

-0.73
-0.36
-0.66
0.12
0.64
-0.26
-0.58
-0.66

0. 37
0.25
-0.48
-0.30
0.26
-0.38
0.22
-0.96

0.21
-0.50
-0.29
0.57
0.16
0.65
-0.32
-0.40

0.00
-0.36
-0. 24
0.33
-0.09
0.64
-0.66
-0.27

-0.56
0.60
0.02
-0.57
-0.67
-0.55
-0.28
0.60

0.32
0.38
0.54
-0.81*
0.34
-0.06
0.11
-0.17

0.15
0.24
0.65
-0.64
0.33
-0.26
0.36
-0.03

0.45
0.12
0.62
-0.72
0.41
0.49
-0.35
-0.51

-0.12
-0.27
-0.14
-0.61*
-0.14
0.01
0.14
0.09
-0.02

0.05
-0.25
-0.12
0.05
0.18
0.17
-0.38
-0.18
-0.11

0.12
-0.05
-0.22
0.09
-0.00
0.08
-0.02
-0.06
0.01

-0.12
-0.11
0.14
-0.45
-0.58
-0.31
0.20
-0.23
-0.02

0.55 -0.16
0.69* 0.14
0.18
0.71*
0.30 -0.04
0.32
0.14
0.40 -0.32
0.23
0.14 -0.31
-0.95* 0.40
ro

-0.41
-0.67*
-0.09
-0.29
-0.23
-0.36
0.61*
0.00
0. 86*

1
o

pH
N
P
K
Ca
Mg
Fe
Mn
A1

-0.24
-0.01
0.37
0.35
-0.56
-0.50
-0.07
0.13
-0.03

E horizon
pH
N
P
K
Ca
Mg
Fe
Al

Bhs horizon
pH
N
P
K
Ca
Mo
Fe
Al
Bs horizon
PH
N
P
K
Ca
Mg
Fe
Mn
Al

0.56
-0.52
0.01
0.26
0.30
0.12
-0.93*
-0.16
-0.87*

0.92*
-0.92*
0.76*
-0.36
0.99*
0.95*
-0.54
0.86*
0.23

0.11
-0.05
-0.03 -0.39
0.54
-0.29
0.07
0.59
0.49
0.43
0.43
0.33
-0.68* -0.14
0.72*
0.38
0.40
0.31

-0.58
0.53
0.54
-0.39
-0.38
-0.16
0.89*
0.00
0.78*

* correlation coefficients significant at P = 0.05

86
20.

Correlation coefficients between soil nutrient
levels by horizon and Cytospora canker incidence
on NE 47 at Manistee.

Bhs horizon

Bs horizon

N

0.75*

0. 64

P

0.27

0.76

K

0.43

-0.15

-0. 39

Ca

-0.35

-0.35

-0. 30

Mg

CO
0
1

1

0.77

o
I-1
CO

0 . 2 1

r—

Al

00

0 . 0 2

1

-0.40

o
0

Mn

r-

-0.50

-0.33
1

0 . 6 6

0.74

0

-0.46

-0.19

0
1

Fe

00

PH

i
o
**
v-»

Ap horizon

i
o
•
•-J

TABLE

* correlation coefficients significant at P = 0.05

87
TABLE 21. Means of soil nutrients grouped by pest ratings

Pest
Poplar
and
willow
borer

Cytospora
canker

Septoria
canker

Rating * * p

K

1

29. 0 a

2

101.4b

61.lab

3

132.9b

65.5b

___ IKy
rrx/
/Vi\lac.r
Mg

Fe

30. 0a

1

63.5a

28.9a

2

31.2b

113.9ab

3

25.2b

281.3b

4

33.6 ab

448.4b

1

16.8a

3

127.9b

4

30.7b

Al

26.9a

74.6a

.lb

140.2b

37. 6 ab

47.1b

239.3c

5,6b

6 6

218.4a

22.5a
63.7ab
134.9b

92.8a
2 2

.6 b

26.3ab

* means followed by the same letter within a column were
not significantly different by Scheffe's procedure at
P = 0.05
9fc Sfc

Rating

Cytospora Cankers

1
2

Absence of canker
Cankers on branches

3

Cankers on main stems

4

Main stem dieback,
tree dead or dying

r
>
1
a v y A fti
q * iJ
u
willow borer
No apparent injury
Frass on the lower
1/3 of tree
Frass on the lower
2/3 of tree
Frass on the lower
2/3
and
the upper
1/3 of tree

88
Multivariate analyses for the three clones
study

sites

showed

that

soil

nutrient

in the two

levels

and

tree

heights were the factors most related to the incidence of
Cytospora and Septoria canker, and poplar and willow borer
damage.

The following were the variables in the regression

equations that "best" predicted pest incidences at the two
study sites:
Dependent variables
Y]^= Cytospora canker on NE 235 at Mason
Y2 =

Cytospora canker on NE 47 at Mason

Y3 =

Cytospora canker on NE 47 at Manistee

Y 4 = Poplar and willow borer on NE 47 at Mason
Y5 =

Septoria canker on NE 308 at Mason

Yg =

Septoria canker on NE 47 at Mason

Independent variables
Xi = K content in kg/h

1

X2 =

Ca content in kg/ha

X3 =

Mn content in kg/ha

X4 =

P content in kg/ha

X5 =

Mg content in kg/ha

Xg =

A1 content in kg/ha

X7 =

N content in kg/ha

X8 =

Fe content in kg/ha

Xg =

Height of trees in m

89
The equations for Cytospora canker were
Y x « 1.1088-0.0186X1+0.0005X2+0.0545X3
Y2
Y3

= 3.1061-0.0328X 1 -0.0023X 2 +0.OI 7 IX 4 -O.0434X 6
=

1.3248+0.0007X2-0.0758X3-0.0107X5-0.8697X7+0.1743X9
2

The coefficient of multiple determination (R ), which is
the ratio of the model sum of squares to the adjusted sum of
squares, was the primary index of the equations goodness of
fit to the raw data (Hintz,

1987). R

2

for equations Y j , Y 2

and Y 3 were 0.8012, 0.8162 and 0.7069 respectively.
The equation for poplar and willow borer

with an R

2

value

of 0.9061 was:
Y 4 = 1.1046+0.0018X2+0.0197X3-0.0078X6-0.1804X8-0.457X9
The equations for Septoria canker were
Y5 = 1.6625-0.0096X!+0.00124X2+0.OOI4X4-O.0054X5+0 .00443X60.0099X8+0.235X9.
Y8 = 2 .1213-0.0135Xi+0.OO4IX5+O.3687Xg
R 2 values for equations Y 5 and Y 8 were 0.7158 and 0.8371
respectively.

90
DISSCUSSION
The

relationships

between stand

factors

(clone,

study

site, tree vigor and plantation condition), soil factors
(ortstein layer, physical and chemical properties) and major
pests

(Cytospora

chrysosperma,

Septoria

musiva

Cryptorhvncus lapthi) are summarized in Figure 20.
lines

show

either

correlation
significant

a

within

positive

or

(P < 0.05)

(+ )

between

or

a

factors.

correlations

and
Solid

negative

(-)

Some

the

include:

at

of

the Mason

plantation there was positive correlation between Cytospora
canker incidence and P, Mg, Mn and A1 levels

in the soil,

while Septoria canker showed a negative correlation with K,
P, Fe and Mn levels. Poplar and willow borer, however, was
positively

correlated

correlated with A1
plantation

with

level

Cytospora

Mg

in the

canker

level
soil.

occurence

and
At

negatively

the Manistee

was

positively

correlated with P, Fe, Mn and A1 levels. As Figure 20 was
made from the analysis of the correlations between site
factors and pest

incidences,

it may indicate the possible

relationships between the different

factors,

but

it would

not prove a cause and effect relationship. Furthermore, site
factors other than those investigated may be

important

to

the pest frequencies in the plantations.
The performance and productivity of a hybrid poplar
plantation depends on the clones planted,

site factors and

the extent of pest damage. NE 47, which was planted at both
study

sites,

grew

faster

at

Mason

than

at

Manistee,

chemical.

PhTsidl

fret ii(of

loitr

Figure 20. An interaction model between site factors and pests
incidence on hybrid poplar clones at the Mason and
Manistee plantations.

92

indicating inherent difference(s) between the two sites. The
Mason site had more

P, K, Mg and less

the Manistee site.

Thus,

Fe, Mn and A1 than

the Manistee site with

its high

water table, poorly drained soil, and high levels of Fe and
A1 was more stressful to the trees than the Mason site,
hence more Cytospora canker was found. A high level of A1 in
the soil may have been
indirectly
Mg,

K

caused Al-induced

and

C a . The

Manistee were
Septoria

directly

prevalent

deficiency

relatively

thus predisposed

canker

and

poplar

toxic to the roots or
of nutrients

slower

growing

trees

to Cytospora canker,

and

willow

at the Mason plantation where

like
at

while

borer

were

more

the

trees

grew

relatively faster and vigorously.
As the clones in the two study sites were not screened
for

insect

planted

or disease

and

thus

resistance,

the

trees

were

pathogens or damaged by insects.
many studies was

that

susceptible clones
severely

were

infected

by

The general conclusion of

the vulnerability

to some

canker

pathogens increases in areas where soil moisture is low,
particularly

during

stress

periods

(Bier,

1964).

The

presence of an ortstein layer reduced water percolation in
early spring,

thus

causing waterlogging and

physically

prevented water absorbtion from a deeper level by the roots
during the dry periods of the year, thus creating drought.
Therefore,

before

large areas of poplars are

planted,

their disease and insect susceptibility must be determined.
To this effect Ostry (1981) suggested the following:

93
- incorporating disease resistance into tree screening
and improvement programs.
- use of cultural practices which would not predispose
the trees to pathogens

(like deep plowing or subsoiling to

break the ortstein layer).
- monitoring the plantations in order to detect pest
problems early.
- determine

critical

emergency measures

level

to prevent

of

infection and

develop

large losses.

Generally, proper matching of clones to the site results
in

vigorous,

fast

growing

suseptible to pests.

plantations

However,

which

are

less

fast growing trees could be

more susceptible to aggressive pathogens like S_^ m u s i v a .
Usually
widely

the severity of pests and
from clone

upon site

to clone

(Barkley,

1983).

their

in poplars

and depends

Taking this

the Ontario Ministry of Natural

impacts varies

into

Resources

mostly

consideration

(1983)

advises:

"to establish plantations by matching the most suitable
clone to each particular site, plant several rather than one
or two clones on each site and make

clonal blocks in the

plantations, each block being not more than five hectares."
Thus, unlike the PGA large-scale mixed clone plantations, a
geographic mosaic (Pinon, 1984) was a better alternative to
pest management.
The genus Populus offers a diverse genetic make up. But
by

developing

successfully

and

planting

limited

resistance,adaptabilty

the

only

few

genetic

to site

and

clones,

base

for

man

has

disease

harsh environment.

The

94
two plantations, investigated in this study, were even-aged
with one to three clones planted interraixedly. Historically,
pests have

caused

the failure of plantations which

limited genetic base. Thus,
for

failure

stresses

due

or

to

a

these plantations were destined

pathogens,

their combined

had

insects,

interaction.

environmental

Hence,

once

more,

this study showed the importance of pests in plantation
culture, and the risk of even-aged, narrow genetic based
plantations.
The hybrid poplar plantations

established

in the past

have a narrow genetic base, in the future broadenning their
genetic

base

resistance,
Planting

through

especially

for

disease

from natural population might be essential.

hybrid

resistance

selection,

to

poplar

pests

clones

is

with

a

high

degree

of

undoubtedly

a

good

management

strategy.
In order to fully benefit from the fast growing habits
of hybrid poplars and to minimize
pests;

in the short term,

the

loss of yield from

an Integrated Pest Management

(IPM) program with resistant clones as its cornerstone must
be

developed.

through

local

The

resistant

screening

clones

trials.

should
In

be

obtained

establishing

maintaining plantations silvicultural practices

and

that would

alleviate environmental stresses should be practiced. Before
large-scale hybrid poplar plantations are established, more
basic and applied researches should be conducted.
others, these researches should include:

Among

95
-Studies on the heritability of resistnace to disease in
poplars and the kind and number of genes involved.
-Studies on the biochemical bases of pathogenicity of the
major pathogens.
-On regional and local bases,
the environment on the plant,

investigations on effects of
on the pathogen and host-

pathogen relationship, and particularly,

the effect of soil

chemical

the

and

physical

properties

on

host-pathogen

reltionship along with their effect on yield and growth
habits of hybrid polars should be undertaken.
-Since pest incidences vary by clone and location in hybrid
poplars, widespread clone-site trials over a broad range of
sites, locations and over the entire rotation period should
be investigated.

LITERATURE CITED

Barkley, B.A. 1983. A Silvicultural Guide for Hybrid
Poplar in Ontario. Min. of Nat. Resources, Ontario.
PP. 35.
Barnett, H.L. 1959.
Plant disease resistance.
Review of Microbiology.
13:191-210.

Annual

Barnhisel, R. and P.M. Bertsch. 1982. p.275-300.
I N :P a g e ,A .L .,
R.H.
Miller
and
D.R.
Keeney
(Eds.) Methods of Soil Analysis, Part 2. Chemical
ajic| Mirobiological Properties .Agronomy No. 9 Part 2,
2
Edition. Am. Soc. of Agron. Inc. and Soil Sci.
Soc. Am. Inc. Madison, Wisconsin.
Bier, J.E. 1939. Septoria canker of introduced and
native hybrid poplars. Can. J. Research. Vol. 17,Sec.
C.
Bier, J.E. 1964. The relation of some bark factors to
canker susceptibility. Phytopathology. 54:250-253.
Bowersox, T.W. and W.W. Ward. 1977. Soil fertility,
growth and yield of young hybrid poplar plantations
in central Pennsylvania. For. Sci.23(4):463-469.
Broadfoot, W.M. and F.T. Bonner. 1966.
Soil compaction
slows early growth of planted cottonwood.
Tree
Planter's Notes No. 79:13-14.
Broadfoot, W.M. 1967.
Shallow-water impoundment
increases soil moisture and growth of hardwoods.
Soil. Sci. Soc. Amer. Proc. 31:562-564.
Buol, S.W., F.D. Hole and R.J. Mcccacken. 1980. Soil
Genesis and Classification. 2n
ed. The Iowa State
Univ. Prss, Ames. PP. 404.
Dickmann, D.I. and
K.W.Stuart.
1983. TheCulture of
Poplars in Eastern N.America. Dept, of Forestry,
Michigan State University, East Lansing. PP. 168.
Franzmeier,
D.P.
and E.P.
Whiteside. 1963.
A
chronosequence of podzols in northern Michigan. I.
Ecology and description of pedons. Michigan Quarterly
Bulletin. Vol. 46, No. 1:2-20.
Franzmeier,
D.P.
and E.P.
Whiteside. 1963.
A
chronosequence of podzols in northern Michigan. II.
Physical and chemical properties. Michigan Quarterly
Bulletin. Vol. 46, No. 1:21-36.

96

97
Godbold, D.L., E. Fritze and A. Huttermann. 1988.
Aluminum toxicity and forest decline. P r o c . Natl.
Acad. Sci. USA. 85: 3888-3892.
Goransson, A. and T.D. Eldhuset.
1987. Effect of
aluminum on growth and nutrient uptake of Betula
pendula seedlings.
Physiol. Plantarum 69:193-199.
Hintze, J.L. 1987. NCSS: Number Cruncher Statistical
System, Version 5.0 Published by Dr. J.L. Hintze;
Kaysville, Utah.
Keeney,D.R. and D.W. Nelson. 1982. Nitrogen-Inorganic
Forms.p.643-698. J N :Page,A .L ., R.H. Miller and D.R.
K e e n e y (e d s .) Methods of Soil Analysis, Part 2.
Chemical and Mirobiological Properties.Agronomy
No.9 Part 2, 2
Edition. Am. Soc. of Agron. Inc.
and Soil Sci.Soc. Am. Inc. Madison, Wisconsin.
Knudsen, D. 1980.
In: Recommended Chemical Soil
Test Procedures for the North Central Region. North
Central Regional Extension Publication No. 221
(Revised). PP.33
Knudsen, D., G.A. Peterson and P.F. Pratt. 1982.
Potassium, p.225- 246. I N :Page,A .L ., R.H. Miller and
D.R. Keeney (Eds.) Methods of Soil Analysis, Part 2.
Chemical
Mirobiological Properties.Agronomy No.9
Part 2, 2
Edition. Am. Soc. of Agron. Inc. and
Soil Sci. Soc. Am. Inc. Madison, Wisconsin.
Lanyon, L.E. and W.R. Heald. 1982. Magnesium, Calcium,
Strontium, and Barium, p . 247-262. I N :P a g e ,A .L .,
R.H. Miller and D.R. Keeney (Eds.) Methods of Soil
Analysis, Part 2. Chemical and M.irobiological
n — —■ _ J.,

R

____

c i W M C i i l e a >n M i uiiuiuy

m I a
ivu * 9 *

Soc. of Agron. Inc.
Madison, Wisconsin.

nTTTT
rai w

and Soil

A
£

t

A
liU AJJ
..,
6
l u i i jlwaa •

Sci.

Soc.

Am.

R—

* \u i •

Inc.

Mclean, E.O. 1980. IN: Recommended Chemical Soil
Test Procedures for the North Central Region. North
Central Regional Extension Publication No. 221
(Revised). PP.33
Ministry of Natural Resources. 1983. New Forests in
Eastern
Ontario.
Hybrid
Poplar.
Science
and
Technology Series, Vol. 1. PP. 336.
Muir, A. 1961.
The podzol and podzolic
Advances in Agronomy. Vol. 13:1-57.

soils.

Nie, N.H., C.H. Hull, J.G. Jenkins, K. Steinbrenner and
D.H. Bent. iS?5 - SPSS Statistical Package for Social
Sciences. 2
Edition. McGraw Hill Book Company,
New York.

98
Oglenznev, A.K. 1968.
New formations in fine textured
hydromorphic sod-podzolic soils and their importance
of identification purposes.
Soviet Soil Science N3:327-339.
Ostry, M.E. 1979. Disease research of poplars grown
under intensive culture in the north central region
of the United States. IN.1979 Proc. 16
Ann. Meet.,
North Am. Poplar Council, August 14-17, 1979. p.83-91.
Ostry, M.E. and H.S. McNabb, Jr. 1983. Diseases of
intensively cultured hybrid poplars: A summary of
recent research in the North Central Region, p.102-109.
IN: Intensive plantation culture: 12 years research,
U.S. Forest Service General Technical Report, NC-91.
Pinon, J.D. 1984. Management of diseases of poplars.
Eur. J. For. Path. 14:415-425.
Polskiy, B.N. 1961.
Chemistry of ortsteins in sodpodzolic soils. Soviet Soil Science. N-2:198-200.
Quickchem Method. 1987. Quickchem TM Systems,
Division of Lachat Chemicals, Inc. Meguon,Wisconsin.
Roberts, B.A. and M.A.K. Khalil.
1980.
Detailed soil
and site assessment of hybrid-poplar planting areas
in New Foundland.
Environment Canada, For. Serv. Bi­
monthly Res. Note.
36(4):16-18.
Rurark, G.A., D. L. Mader, and T .A. Tattar.
1982.
The
influence of soil compaction and aeration on the root
growth and vigour of trees.
A literature review.
Part I. Arboricultural J. 6:251-265.
Schoeneweiss, d .f .
plant disease.
13:193-211.

1975.
Predisposition, stress and
Annual Review of Phytopathology

Schoeneweiss, D.F. 1978. Water stress as a predisposing
factor in plant disease. Water Deficits and Plant
Growth. T.T. Kozlowiski (Ed.) Vol. V:61-99.
Schoeneweiss, D.F.
1981.
The role of environmental
stress in diseases of woody plants.
Plant Disease
65(4):308-314.
Simonson, R.W. 1968.
Agronomy. Vol. 20

Concept

of

soil.

Advances

in

Steel, R.G.D. and J.H. T o r r i e ..1980. Principles nad
Procedures of Statistics. 2n
Edition. McGraw Hill
Book Company, New York. PP.633.

99
Steiner, K.C., J.R. Barbour and L.H. McCormick. 1984.
Response of Populus hybrids to aluminum toxicity.
For. Sci. 30(2):404-410.
USDA. 1975.
Soil Taxonomy. Soil Cons. Serv., Agric.
Research
and
Development
Program,
Technical
Bulletin Handbook No. 436. PP. 389.
Whitney, D.A. 1980. I1J: Recommended Chemical Soil
Test Procedures for the North Central Region. North
Central Regional Extension Publication No. 221
(Revised). PP.33
Wilson, L.F. 1976. Entomological problems of forest
crops grown under intensive culture. Iowa State J.Res.
50(3):277-286
Winters, E. and R.W. Simonson. 1951. The subsoil.
Advances in Agronomy. Vol.3.
Woods, R.F., L.M. Moore, L.F. Wilson, M.E. Ostry and
D.I. Dickmann. 1982.
Performance of 3-year-old
hybrid poplar clones in relation to soil texture,
natural soil drainage and pest incidence p. 74-83.
IN: Proceedings of the 19th Annual Meeting, North
American Poplar Council. Rhinelander, W I .
Woods, R.F.
1984.
Effect of site on growth of hybrid
poplar clones planted on a commercial scale.
Ph.D.
disser., Michigan State University, East Lansing.
PP. 94.

APPENDIX A

Procedure for estimating starch level in the roots
1.

Dig root samples within 30 to 50 cm of the stem base.

Take

two

root

samples

from

horizontal

approximately equal in diameter

roots

that

are

(one to two cm) , as starch

content is highly correlated to root diameter.
2.

Cut root sample to 30 cms in length and put them in a

polyethylene bag and keep in picnic
ice to take back to the laboratory.
3.

ice box with ordinary
Properly label samples.

If root samples are not to be analyzed immediately keep

them frozen at -20°C.
4.

Thaw root samples rapidly and prepare cross sections to

approximately 50-100 p thick with sliding microtome.

Keep

root cross sections moist at all times.
5.

Put at least two cross sections on a glass slide and

flood

them with

iodine

(I2 KI)

solution.

solution by mixing 15g of Potassium iodine

Prepare

Iodine

(KI) with 3g of

crystalline iodine (I2 ) in one litre of distilled water.
6.

Blot excess solution and add fresh iodine solution.

After five minutes blot the stain and rinse the root cross
sections with distilled water.
7.

Remove excess water, add glycerine and put a cover slip.

8.

Record staining results on polaroid color film or 35 mm

Extachrome (Kodak Co.) color slides.

Pictures should be

taken within 24 hours as stains fade through time.

100

101
9.

Rate roots as high,

based on starch stain.

medium,

low or depleted in starch

APPENDIX B
Procedure for exchangeable Aluminum extraction with IN KC1.
1.

Weigh 5g of soil into 125 ml erlmyer flask

2.

Add 50 ml of 1 N KCl, stopper and shake for 30 min.

3.

Filter the supernatant solution through Whatman No. 42
filter paper.

4.

Collect

filtrate

to

appropriate

container

for

A1

analyses.
5.

Analyze for A1 on the DC-Argon Plasma Spectrophotometer

6 . Prepare standard

of

5 ppm

A1

in

IN KCl

extracting

solution.
Prepare 5 ppm A1 standard from 1000 ppm A1 solution.
a) Make 50 ppm from 1000 ppm A1 solution
b) Make 5 ppm from 50 ppm A1 solution
c) Use the 5 ppm A1 as the standard

102