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THEUlS This is to certify that the thesis entitled A RECONSTRUCTION OF POST-GLACIAL VEGETATION IN THE NORTHWESTERN PORTION OF MICHIGAN'S LOWER PENINSULA presented by Nancy N owak Cle land has been accepted towards fulfillment of the requirements for Botany & Plant Path. M.S. degree in WJW Major professor Date May 16, 1979 0-7639 . JAN 0312001 we at: 521919111 01 NOV 1 5 2001 w: , D‘xo 25¢ Per day per item RETURNING LIBRARY MATERIALS: Place ‘ln book return to remove charge from circulation records . A RECONSTRUCTION OF POST-GIACIAL VEGETATION IN THE NORTHWESTERN PORTION OF MICHBGAN'S LOWER PENINSULA By Nancy Nowak Cleland A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Botany and Plant Pathology 1979 ABSTRACT A RECONSTRUCTION 0F POST-GIACIAL VEGETATION IN THE NORTHWESTERN PORTION OF MICHIGAN'S LOWER PENINSULA By Nancy Nowak Cleland A history of the post-glacial vegetation of the northwestern portion of Michigan’s lower peninsula has been traced through the analysis of pollen and spores recovered from three bogs in the region. As the glaciers retreated from the area about 11,000 years ago, it supported forests primarily dominated by spruce. This boreal forest was gradually replaced with pine forests at about 9,500 BP. The pine forest declined in dominance as hemlock migrated into the region by approximately 7,400 BP and as hardwood species became established around 6,300 BP. A xerothermic climate influenced the region's vegetation from approximately 6000 BP to 3000 BP de- laying the establishment of a northernhardwood forest until about 3000 DP when climatic conditions began to approach those of the present. As Euro-American settlement of the region was initiated during the mid nineteenth century, extensive tracts of land were cleared. These have since supported seral communities of the field and forest. To My Family ii ACKNOWLEDGEMENTS As with most endeavors of this nature, this study could not have been completed without the assistance of a number of individuals. I would like to extend my sincere appreciation to those who have given me guidance throughout my graduate career. Professor Aureal T. Cross, my Committee Chairman, has given support, advice, and assistance in many aspects of this study. Professor Ralph EL Taggart provided helpful, innovative suggestions in his appraisal of my work. Professors Stephen Pt Stephenson, William B. Lrew, and william B. Iovis offered valuable counsel as committee members. I would also like to express my graditude to Professor Ronald O. Kapp of Alma College for his helpful comments in the preliminary stages of this report. I would also like to gratefully acknowledge the following: Professor Charles E. Cleland, my husband and dearest friend, for his support and encouragement through all phases of this endeavor and for his assistance in the collection of sediment samples; Professor William B. Iovis, for his help in aquiring financial support: Ms. Margaret Uland for the drafting of many of the figures which appear in this text; and Ms. Colleen Isslieb, for the con- struction of postsettlement vegetation maps of most portions of the study region. To these, my family, and my friends I am greatly indebted. iii TABLE OF CONTENTS List Of Tables 0 O O O O O O O I O O I O O O O O O C I O O I I O 0 Vi List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . vii Introduction 0 O O O O O O O O O O O I 0 O O O O O 0 0 O O O O I O 1 Region Of St udy O O O O O O O I O I O O O I O O I O O O O O O O O I 2 N Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bedrock Geology . . . . . . . . . . . . . . . . . . . . . . . . Physiography and Glacial History . . . . . . . . . . . Soils and Drainage . . . . . . . . . . . . . . . . . . . . . . Cultural History . . . . . . . . . . . . . . . . . . . . . . Present-day vegetation o o o o e o o o o o o e o e o a o o o o o \D (I) O\ O\ 4? N Bog Localities Sampled . . . . . . . . . . . . . . . . . . . . . Reconstruction of the Region's vegetation Cover . . . . . . . . . 11 The Presettlement Forest: An Overview . . . . . . . . . . . . ll Vegetation Analysis Based on Land Surveyors' Notes . . . . . . 13 Correlation of Modern Forest Composition and Pollen Assemblages . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Field Techniques . . . . . . . . . . . . . . . . . . . . . . . 26 Laboratory Techniques . . . . . . . . . . . . . . . . . . . . . 27 iv Results .. . . . . Sommers Lake Bog .. . . . . . . . . . . . . . . . . . Lyman Lake Bog . Mission Point Bog . Zonation of Pollen Stratigraphy . . . . . . . . . . Zonal Criteria . . . . . . . . . . . . . . . . . . . Zonal Characteristics . . . . . . . . . . . . . . . . . Zones Represented at the Sommers Lake Bog . . . . . . . Zones Represented at the Lyman Lake Bog . . Zones Represented at the Mission Point Bog . . . . . . Interpretation of Region's Post-Glacial Vegetation History . Zone I. . . . . . . . . . . . . . . . . . . . . . . Zone II. Zone III. Zone IIIA. Zone IIIB. . . . . . . . . . . . . . . . . . Zone IIIC. . . . . . . . . . . . . . . . . . . . . Zone IV. . . . . . . . . . . . . . . . . Summary and Conclusions . . . . . . . . . List of References . . . . . . . . . . . . . . . . 31 . 31 36 39 46 . 47 48 ._ 53 55 59 60 61 62 67 72 75 77 LIST OF TAB LES Relative Percent Occurrence of Genera in the Vegetation and Pollen Record of Northwestern Lower Michigan . . . . . . . . 24 Relative Percent of Dominant Arboreal Genera in the Pollen Record and Forest Composition of Zone IIIC . . . . . . . . . 69 vi 10. ll. LIST OF FIGURES Sketch Map of Northwestern lower Michigan . . . Natural Vegetation of Northwestern Lower Michigan . . . Vegetation of Emmet, Charlevoix, and Antrim Counties as Recorded on Land Surveys 1839-1854 . . . . . . . . . . . . Vegetation of Cheboygan County as Recorded on land Surveys 1839-1854 a o e o o o c c o o o e o o o Vegetation of Kalkaska and Missaukee Counties as Recorded on land Surveys 1839-1854 . . . . . . . . . . . . . . . . Vegetation of Portions of Grand Traverse, Benzie, and Ieelanau Counties as Recorded on land Surveys 1839-1854 . Aerial View of the Sommers lake Bog . . . . Pollen Diagram Obtained from the Sommers Lake Bog . . . Aerial View of the Lyman Lake Bog . . . . . . . . Pollen Diagram Obtained from the Iyman Lake Bog . . . . Aerial View of the Mission Point Bog . . . . . . . . . . Pollen Diagram Obtained from the Mission Point Bog . . . vii . 16 18 20 33 35 INTRODUCTION . This study attempts to trace the post-glacial history of the northern hardwood forest in northwestern lower Michigan by means of pollen analysis. Three bogs in the region were cored to obtain a stratigraphic sequence of samples containing sufficient identifiable pollen and spores to represent the post-glacial vegetation of the region. The bogs selected for coring are filled with peat of the Green- . wood series, which is a highly acidic type (Weber et al, 1966). Initial testing of the bogs demonstrated them to be relatively dry, continuous and deep. Selecting bogs with these physical attributes enhanced the possibility of obtaining a complete chronological se- quence in the pollen.record. In addition to desired physical attri- butes, the bogs were selected on the basis of geographic location to provide the best possible coverage along the major north-south axis of the study area. REGION OF STUDY. Location. The study region is located in the most northwestern section of Michigan's lower peninsula in the vicinity of 85° W longitude and 45° N latitude. It extends along the lake Michigan coastline from the base of the Leelanau peninsula to the Straits of Mackinac (Figure l). Portions of eight counties are included in the region: Benzie, leelanau, Grand Traverse, Kalkaska, Antrim, Charlevoix, Emmet, and Cheboygan. Generally the region follows the shoreline of Lake Michigan, northeast to southwest, and is approximately 128 km (80 miles) in length and 29 km (18 miles) in width. The region‘s southeasternmost point lies approximately 112 km (70 miles) due south and 128 km (80 miles) due west of its northeasternmost extremity. The topography of the region generally varies from 182 to 234 m (600 to 800 feet) above sea level with the exception of occasional highlands with elevations up to 334 m (1100 feet) (Sommers, 1977). The region has a mean annual temperature of 60 C (AZ-AA F), a grow- ing season of 125 days, and a mean annual precipitation of approxi- mately 0.8 m (30.5 inches) (Sommers, 1977). Bedrock Geology. Glacial drift covers the bedrock of most of the study region with an average thickness of 60 m (200 feet) (Sommers, 1977). The bedrock was deposited during the Devonian and Mississippian Periods of the Paleozoic Era. Devonian marine limestones, siltstones, and shales are distributed in an are from the Ieelanau Peninsula to the 2 IO 0 20 , lllLlllllll L J MIIQS 10 O :0 km I liJJlllllll I (9?? Q a ' \c : é I Q little traverse Bay ~| 2 | ( 9. ' 9 a- ---= V . '3 s ARLEVOIX : I Grand ' Q Iraverse _ - _ _ _ ._ -- -J / Bay T K Mission 9, . 30: l orseoo ‘ ANIRIM ) KALKASKA TRAVERSE C}: 3’} Figure 1 Sketch Map of Northwestern lower Michigan tip of northern lower Michigan. They surround the younger Missis- sippian strata of the Michigan Basin. The Devonian limestone is quarried in this region for building material, cement and road surfacing (Hudgins, 1961). The underlying bedrock in the southern portion of the study region of Mississippian age includes some salt and gypsum as well as sandstone, limestone and shale. Gas and oil are produced from various petroliferous reservoirs. Pbysiography and Glacial History. Northwestern lower Michigan is characterized by a rolling landscape, numerous inland lakes, and sandy beaches along the Lake Michigan shoreline. These features, like those of the entire Great lakes region, were primarily determined by the activities of the Pleistocene glaciers. The final retreat of the glaciers from the Great Lakes region, which began approximately 14,800 B.P. is discussed by Kelly and.Farrand, 1967 and Dorr and Eschman, 1971. By 11,000 BP northern lower Michigan was deglaciated and partially inundated by an extensive body of water known as lake Algon- quin (Kelly and Farrand, 1967). Situated along the ice front with an elevation of 182 m (605 feet), lake Algonquin occupied the basins, as well as adjacent lands of Lakes Michigan and Huron. Its high- level waters cut a somewhat continuous beach ridge which can be traced throughout the study region as it generally parallels the present day shorelines of Lake Michigan and the inland waterway system. Initially, Lake Algonquin was drained to the south by the Illinois River and later by the St. Clair-Detroit Rivers. As the glaciers retreated from the Great Lakes, they formed many of the region's inland lakes as well as most of the region's hills and ridges and flat to rolling plains. Deglaciation of the land to the northeast of the Michigan-Huron basins provided a series of drainage outlets which were progressively lower in elevation than the St. Clair channel. Consequently drainage of the basins shifted to the northeast through the North Bayr and Ottawa River resulting in the formation of low level lakes Chippewa and Stanley. As the glaciers continued to retreat, however, the earth's crust, depressed from the weight of the ice masses, began to rebound. While the drainage of the basins continued through the North Bay outlet, it rose in elevation resulting in the formation of Lake Nipissing at approximately 4500 BP (Kelly and Farrand, 1967) which stood at an elevation of 182 m (605 feet) and occupied the Michigan, Huron, and Superior lake basins and surrounding areas. Lake Nipis- sing, stabilized by three channels, the North Bay-Ottawa River, the St. Chair-Detroit Rivers, and the Illinois River, endured for about 1000 years. During this time its high waters cut a prominent beach which can be readily observed as it generally follows the coastline of Lake Michigan and the inland waterway system. At approximately 3500 BP (Kelly and Farrand, 1967), rebound of the crust had resulted in a rise in elevation of the North Bay outlet beyond 182 m (605 feet) thereby shifting drainage to the southern outlets. Erosion of the St. Clair River initiated the formation of the present day Great lakes through an alteration of lake levels and a final shift in drainage to the southeast. As the water levels of Lakes Michigan and Huron receded to their present day levels, the extensive belt of sand dunes along the coastline of western lower Michigan was formed. Soils and Drainage. The soils of the region, also primarily the products of glacia- tion, are relatively young and scrambled in occurrence. Basically, however, they are classified as spodosols, which are formed beneath a mixed hardwood-conifer forest and have accummulations of iron, aluminum and humus or partially decayed organic material in the B horizon (Sommers, 1977). The impact of glaciation is also reflected on the region's drainage systems which are generally haphazard and immature. The coastal areas drain directly into Lake Michigan and the Straits of Mackinac. The interior areas to the northeast are part of the Cheboygan watershed which includes the Pigeon, Sturgeon, and Black Rivers (Sommers, 1977). Cultural History. As the glaciers retreated from northwestern lower Michigan at approximately 11,000 BP, nomadic bands of prehistoric Indians entered the region in pursuit of fish, game, and edible wild plants. From the archaeological record it is known that the region's prehistoric inhabitants established camp, village, quarry and burial sites along a transportation network of lakes and streams. The cultural evolu- tion of these native inhabitants can be traced through the dating of artifacts recovered lg situ from these localities. Consequently, it is known that by approximately 625 RP (1350 A.D.), Indians of this region cultivated a few domesticated crops such as corn and squash, but remained heavily reliant on the provisions of fishing, hunting, and the gathering of wild plants. As such, their subsistence and settlement patterns had little effect in altering their natural environment. Contact between Europeans and Native American populations of the region was first initiated as early as 1615. During the follow- ing one hundred and fifty years, French explorers, missionaries. and traders entering the territory encountered Algonquian speaking people residing in the northwest portion of Michigan‘s lower peninsula. It has been impossible to trace directly the cultural heritage of the Algonquian speaking tribes of the Ottawa, Ojibwa and Potawatomi back to their prehistoric ancestors since aboriginal traditions and artifacts were so rapidly replaced by those of European origin. French influence in the region was superceded by British following the conclusion of the Seven Years liar in 1763. Although title to the region passed to the United States following the Revolutionary War, the British delayed the surrender of Michigan's forts until 1796. 1 Michigan became a State in 1837 but it had been included as a Territory of the United States as of 1787. Northwestern lower Michigan originally comprised a portion of the extensive Michilimackinac County. As the region became settled, present day county divisions were established. While the tip of the lower peninsula was among the earliest settled areas of the state, the Mission Peninsula, located in Grand Traverse Bay, and the lake Michigan coastline directly southwest of the Straits of Mackinac were settled between 1820 and 1839. Settlement continued along the lake Michigan shoreline until approximately 1860 at which time settlement of the interior portions of the region commenced. By 1880, settlement of northwestern lower Michigan had been firmly established. Present-day Vegetation. The composition and distribution of the present day vegetational communities have been determined by man's activities within the region during the past one—hundred years. During this time lumber- ing, post-logging fires, and agriculture cleared vast tracts of land which had long supported a mature northern hardwood forest. Today, seral forest communities are developing throughout the region and comprise approximately 67% of the vegetation cover. These forests are mainly composed of immature stands of 59;; saccharum (sugar maple), EEEE§ grandifolia (beech), Tsuga gépadensis (hemlock), and Betula lutea (yellow birch). If allowed to continue their development, a climax forest of these northern hardwood spec- ies would most likely result. Portions of the region which had supported conifer dominated forests, either spruce-fir or mixed pines, presently support forests 9 dominated by Bgtplé papyrifera,(white birch), Populus tremuloides (quaking aspen), and P. grgpdidentata (largetooth aspen). These early colonizing species are more prevalent in recently as well as severely disturbed areas throughout the region. A substantial portion of the region remains cleared and sup- ports either meadow, oldfield or crop vegetation. Approximately 26% of the region's land is utilized for agricultural purposes. Dairy farming is predominant in the northern counties and fruit farming is foremost in the southern counties (Sommers, 1977). Bog Localities Sampled. The Sommers Lake bog was the northernmost locality sampled. It is located in northern lower Michigan approximately 19 km (12 miles) from Lakes Michigan and Huron and the Straits of Mackinac (Figure 1). It is located approximately 3.2 km (2 miles) north of levering and 1.6 km (1 mile) south of Carp Lake, in the Nat, sws, Sec. 25. Carp Lake Twp., T. 38 N., R. 4 W., Emmet County, Michigan. Its geo- graphic coordinates are 45°39'24" N and 84°44'36" W. The bog surrounding Lyman Lake provided the central sampling locality. lyman Lake is located in northern lower Michigan approxi- mately 11 km (7 miles) inland from the Lake Michigan coastline approximately midway between the Straits of Mackinac and the base of Grand Traverse Bay (Figure 1). It is located approximately 3.2 km (2 miles) north of the town of Ellsworth and about 9.6 (6 miles) south of Lake Charlevoix. lyman lake is situated in the st, swt, Sec. 1 and N%, NW%, Sec. 12, Banks Twp., T. 32N., R. 8 W., Antrim 10 County, Michigan. Its coordinates are 45°11'27" N latitude and 85°14'12" w longitude. The Mission Point Bog, the southernmost bog locality sampled for pollen, is located near the tip of the Mission Peninsula in Grand Traverse Bay (Figure l). The Mission Point bog is located in the NE%, %, Sec. 26, Peninsula Twp., T. 30 N., R. 10 N., Grand Traverse County, Michigan (44°58'18" N and 85°29'12" M). It is situated near the tip of the 24 km (15 mile) long peninsula. The bog is less than 1.6 km (1 mile) from the waters of Grand Traverse Bay to the west, north or east. Approximately 8 km (5 miles) of bay separate the point from eastern and western extensions of the northwestern lower Michigan mainland. RECONSTRUCTION OF THE REGION'S VEGETATION COVER. The Presettlement Forest: An Overview. Previous to American settlement, which became substantially established between 1860 and 1880, the area was nearly entirely covered with a mature northern mixed hardwood-conifer forest (Figure 2). According to Kfichler (1964), this forest was dominated by Aggr_saccharum (sugar maple), Betul§_1utea (yellow birch), Eggug grandifolia (beech), and Tsuga canadensis (hemlock). Other compon- ents included Acer pennsylvanicum (striped maple), A, rpbrgm (red maple), A. spicatum (mountain maple), Fraxinus americana (white ash), Kalmia latifolia (mountain laurel), Pinus strobus (white pine), Prunus serotina (black cherry), Taxus canadens_is (american yew), Tilia americana (basswood), and Ulmus americana (american elm). A conifer bog forest covered far less extensive areas within the study region (Ibid). This forest was directly inland of Little Traverse Bay as well as directly south of the Straits of Mackinac thereby covering the northernmost portion of Michigan’s lower peninsula. Dominants of this forest were Larix laricina (tamarack), Picea mariana (black spruce), and Thuja occidentali§_(white cedar). Also occurring were Acer rubrum (red maple), Carex spp. (sedge), Chamaedaphne caliculata (leatherleaf), Ilex verticilla__t_a (holly), figlmi§_polifolia (bog kalmia), lggpm,groenlandiggm (labrador tea), Nemopanthus mucronata (holly), and Sphagnum spp. (peatmoss) . Kfichler (1964) also indicates isolated extensions of the Great Lakes pine forest into northern and southern interior portions of 11 12 E Conifer Bog Forest 1. , u , , 1 U1 4 ‘1 an ” IO 0 Great Lakes Pine Forest 20 I ......... 1 J I km D Northern Hardwood Forest % & StlAlts OF MACKINAC I Lakes B L I Douglas Lake p, '- Mission Pt. Bog ’/ / /// W/////A Figure 2 Natural Vegetation of Northwestern Lower Michigan (Kiichter, I964) ///”"a 13 the study region. Three species of pine, Pigu§_b§nk§i§gg (jack pine), P. rgsipg§§_(red pine) and P. strobus (white pine), were the dominant components of this forest. Species of minor impor- tance included Kalmia angustifoli§_(sheep laurel), Populus grandi- dentata (largetooth aspen), P; tremuloides (quaking aspen), Quercus coccinea (scarlet oak), q. ellipsoidalis (northern pin oak), g. rubra (red oak). and Q. velutina (black oak). Vegetation Analysis Based on Land Surveyor's Notes. Although Kfichler (1964) provides a generalized overview of the pre-settlement vegetation of the region, additional information on the distribution of plant communities can be gained through the construction of maps based on the records of government land sur- veyors who zoned the region into township units of thirty six one- mile square sections prior to American settlement. As teams of land surveyors walked the perimeters of each township section they recorded the locations of alterations in the vegetational cover. From their notes, dating from 1839-1851, on file in the Lands Division of the Michigan Department of Natural Resources, maps were constructed which plotted the documented changes in vegetation. Reconstruction of the vegetation of northwestern lower Michigan based on land surveyors' notes was begun in 1968 by Colleen Isslieb, a graduate student working in the AnthrOpology Division of the Michigan State University Museum. Ms. Isslieb plotted the outlines of vegetational communities occurring in Emmet, Charlevoix, Antrim, Kalkaska, Missaukee, leelanau and portions of Grand Traverse and l4 Benzie counties. The author constructed comparable maps for Cheboygan county, the Beaver Island Archipelago and South Manitou Island. With the assistance of Dr. Peter Murphy, a plant ecologist on the staff of the Department of Botany and Plant Pathology, Michigan State University, a code was devised to denote the types of plant communities encountered by the surveyors (Figure 3). Ap- plying this legend to a township map and following the recorded course of survey, the boundaries of these coumunities were charted along each section line of every township. The vegetational cover of the interior portions of each section was determined from cor- related factors of land elevation and drainage. As the mapping of each township was completed, it was compiled into county maps which were then frequently compiled into more extensive regional portions in order to facilitate study and use (Figures 3-6). The locations of archaeological sites were also plotted and the bog localities cored in this study have been designated on these maps. As can be seen in Figures 3-6, prior to intense American settlement, much of northwestern lower Michigan (approximately 72%) was covered by a mixed hardwood forest of Acer saccharpm (sugar maple), £35113 grandifolia (beech), and Tspga p_anadensi§ (hemlock), with Pinus strobus (white pine), Ulmus americana (american elm), Tilia americapa_(basswood), Betula lutea (yellow birch), Ostrya virginiana (ironwood) and Prunus serotina (cherry) (designated by number 8 on the map). Low, poorly drained areas were primarily covered by Thuja.cscidsnialis (cedar). larix laziging,(tamarack), 15 Figure 3. Vegetation of Emmet, Charlevoix, and Antrim Counties as Recorded on Land Surveys 1839-1854. (Compiled by Isslieb). 16 2 WEN LEGERD l~ Own-mt 2' (Intent. 3 - tie-Jenna.“ Melon can mean", Masha“ ed etutl pm 4' m.» 5' em- 5' lemma-u 7-Mtw O-Sfilfle,mdw.mfiepu, u.m.ms.n—uumn, 9‘ manna-menace D‘Iflhfllfliflflflflflflflttfllh ll - Mmmthfiuhew. aim “IR-t Iz- nmuum.~qmmn entmwmndfl 134mm 1’75 '3‘- IIDIAtt SETTLEIEIYS . Lets“ sites 0 Chan mama I ma: .:‘\\.‘ K '\ .:\\\ K; 1 35H ,x-- 4 If N 9 I xi ‘ cweoovoa \. 113w / J cuss: BOVOAN €935” V ,_ _ _ OT OEOO COLJN'r V I v st e I ken m 0 l 2 3 l S “In i: O . : “I“ N" U M't’l. .MIS .' I ”'1'“ I'- I: I COUNTY arc-teen I'a'l wvllsl'v up you elf! Figure 3 17 Figure 4. Vegetation of Cheboygan County as Recorded on Land Surveys 1839-1854. (Compiled by Cleland). 18 TJON TSON 736.4 mteovcm county - .4 EMU: 1. couwn T33N . > g'CHEBOYGAN 00.»!va . A‘s, ‘. l. i orssco couw'rv i uoeruoeewcv county I "3" new me was COVER LEGEND l-Opeeenh Z'Olhryh 3 - (cane-erected lemon mm wow", Inset .ew ed emu we 4- Canon 5‘Illhe 6 - baa-nun“ 7 - New .- hm.m~hhct,emwnem. “.vachm—ummn, 9- neutron-memo“:- D- announcement-nucleu- ll ' M~,Itm”NWI. elem-enemies IZ- naming-.u-equumu mmmntflmdm l3- has IUMN SUTLLIEITS 0 Let! Iceland we: 0 cm museum: I mm: 19 Figure 5. Vegetation of Kalkaska and Missaukee Counties as Recorded on Land Surveys 1839-1854. (Compiled by Isslieb). TIIN '26:: YZSN TICK 722» 72th 20 '9' are COUNTY COUNTY KALKASKA - C Y8K j— T25». MISSAUKEE m _.-l U --._"i ', l . _ l x I» r x 'D in x D I“1 I? .m IX I 2 i i. m a 0’ ‘ah a l g’ . I} an I I . I n 'i I MISSAUKEE [ COI MTV 2 5 IO! .7. TIIN 2 GOV/[R LEGEND t ‘ Open an» 2 - Camry In 3 - CeaIJemrecLont lemon with sauce . 'u. flat at .eler and white um 4- loam 5-min- 6 - mailman-Id T-Mttm: 8 ' ”wettest “Mathew um: punt. stemmed murmurs-sen and cum, 9 - Mien .mtt eh". em all ell- D: lune one and aspen enh hath:- m in II ' nmm.-nha~munw, I“ men-t MID with! IZ- mu u ammonia-mp“ net-m with ecceuenl pt pencil! mete |3~ Am lIOIAN SETTLEUE N15 0 Low who sum 0 Circular Mtbsum . Arches acme-u 007 0! lowest elm-cu n: W! I II" ocean ste't wwlIlI'V II' [63 on: 21 Figure 6. Vegetation of Portions of Grand Traverse, Benzie, and leelanau Counties as Recorded on Land Surveys 1839-1854. (Compiled by Isslieb). 22 :3 en.- en! etnauZt: :1: 110.19! :2! eat-i; I. 9 . avg :53: 3 KB e359! 5 "w .0 II. n e n n _ o a — t .w "A 3 M i mom .cmoa co_mn_ It: I 858.8. .135 O Sallie... O wpxuluazwm 239.. 33.2 1.21.! 3:38....- easieszzuliseeiezzeé .gggte .gelteiaiilgi... 5"355'gtogcts .9 Estateiesdssié res .8 Selene... . Bins . s. fountain-issueeiilzia . a 51:23.. .5 1.3.3.3....o 8..., an $38.. .v lazilieifns 523...... ei.3.!l..!la..§6 .n Iris... .~ gigs -_ oz 33 ¢m>8 30“.. SIZNBE . w a. ”tram... .. . n00 WOCHZPF 024! O ... .. . w_NZwm m 3424JUwJ A o £9; ........ .1... ......_..__...... \t a NHQWSVQK ‘/ J . / .a / norm..." .\. Q2 ka k paw. RV). .\\ L O to -w.\........n e . o m¢36_m —-—.-\-n-——-.=u Huang-sh w_"_.- . gums—lash- ---—o- 11......__.—7— 23 and Tgpgg canadensis (hemlock) in association with 2ig§§_mariana (black spruce), Abie§_balsamea (fir), Fraxinus nigrg (black ash), Algp§,r§gpgg (alder) and.§lgg§ strobus (white pine). This conifer dominated forest community covered approximately 20% of the area (designated by number 3 on the map). The third most common type of forest community to occur in the region, representing 4-5% of the study area (designated by number 12), was dominated by Pipp§,§tr9bg§ (white pine), P. resinosa (red pine), and 99ergg§_alba (white oak) and g. nigra (black oak) with occasional Pinus banksiana (jack pine) and Acer spp. (maple). Correlation of Modern Forest Composition and Pollen Assemblages. Webb (1974) made a quantitative analysis of the geographic distribution or abundance of modern forest genera of lower Michigan and the frequency of occurrence of their pollen in the top two on of surface sediments. Two maps were constructed for each genus: one illustrated the relative abundance of a particular genus in the vegetation: the other demonstrated its relative abundance in the pollen record (Table 1). Table 1 shows the relative abundance of genera in the vegeta- tion and pollen record of northwestern lower Michigan. Eggp§ and glgu§_are equally represented in the vegetation and pollen record. Representation between the two variables fluctuates slightly for Picea, Abies, Fraxinus, and 93ercus. The frequencies of represen- tation of pollen of Tilia, Acer, Populus, and M, however, are considerably less than their frequencies of occurrence in the Table 1. Relative percent occurrence of genera in the vegetation and pollen record of northwestern lower Michigan. (From data by Webb, 1974). VEGETATION POLLEN GENERA RELATIVE % OCCURRENCE RELATIVE % OCCURRENCE Em 5-10 5-10 glmus 5 - 10 5 - lO Eigga O - 5 0 - 2 Abigg 0 - 5 O - 1 Fraxinus 5 0 ' 5 Quercus O - 10 10 Tili§_ 5 - 10 0 - 1 Aggr, 30 - 40 5 - lO Populus 10 0 - 3 2921. 10 l - 3 ggugi O - 5 10 - 15 Betula 5 l5 - 20 Pinus O - 10 20 - 30 25 vegetation. The pollen frequency of Tilia is only about one- seventh of its relative abundance in the plant cover. Aggg, Po ulus, and Ihgja are underrepresented by approximately one-fifth of their occurrences. Relative frequencies of representation of pollen of nggg, figtgla, and Einus greatly exceed their relative percentage occurrences in the vegetation. While the frequencies of occurrence of Tsuga and.§§tul§ pollen exceed their vegetational representation approximately three-fold, the frequency of occurrence of Rings pollen is five times that of its occurrence in the vegetation. An understanding of the relationship which exists between the relative percent of occurrence of each genus in the pollen record and the plant cover should aid in the reconstruction of past en- vironments based on the analysis of relative pollen frequencies. METHODOLOGY. Field Techniques. Peat samples were collected from the three bog locations using a Hiller sampler (Borros, Solna, Sweden). This instrument has a 50 cm chamber which fills along the side or length of the barrel. A sleeve fits over the opening to prevent loss and contamination of material. The Hiller sampler is a particularly good collecting instrument in fibrous peat of variable compactness since, by the nature of its design. there is minimal stratigraphic distortion from compaction of the peat by the instrument. A boring tool, however, is mounted at the head of the sampling chamber. As a 50 cm core interval is being obtained, therefore, the top of the next 50 cm interval of the core is being disturbed. Consequently, in order to obtain an undisturbed sample at all levels, it is necessary to collect alternate samples from two adjacent core holes. The location for the coring site at each bog was determined by preliminarily probing with the rods of the sampler to determine the area which contained the thickest peat deposit. Alternate 5 cm intervals of the peat were collected.from each core. The sampling chamber of the Hiller sampler is marked at intervals of 5 cm so that alternate sampling was easily accomplished. Before and after each sample was taken, the sampler tube was thoroughly cleaned with water sprayed from a hand-pumped, portable sprayer 26 27 (Hudson Mfg. Co.) and dried with paper toweling. When the sampler was pulled from the hole, with the recovery of each 50 cm core interval, the outside of the barrel of the tool was cleaned with paper toweling to prevent contamination of the sample in the chamber when it was opened. Each 5 cm sample was then removed individually with a clean knife, wrapped separately in aluminum foil and labelled according to stratigraphic depth and location. The samples were stored in a cooler of dry ice until they could be transferred to a freezer for more permanent storage. Freezing the samples until their maceration in the laboratory insured that the stratigraphy of the core would not be altered during handling or transport. Laboratory techniques. The removal of larger organic and extraneous inorganic material from soil and peat samples concentrates the pollen and spores for easier examination and identification. All samples were macerated as follows according to a procedure adapted from Erdtman (Faegri and Iversen, 1975): l. Weigh out 3 gms of wet peat in a #0 ml test tube. 2. Cover sample with 2% potassium hydroxide and boil in steam bath for 5 min. Centrifuge at 1600 rpm for 2 min. and decant. 3. Sieve sample through 250 um and 177 um mesh sieves with distilled water into 250 ml beaker. Transfer to no ml tubes. 4. Centrifuge sample at 1600 rpm for 2 min. or longer, until sample is concentrated at the bottom of the tube. Decant. 28 5. Wash in glacial acetic acid three times. Centrifuge at 1600 rpm for 2 min. and decant each time. 6. Boil in acetolysis solution for 3.5 min (9% acetic anhydride and 1% sulfuric acid). Centrifuge for 2 min. at 1600 rpm and decant. 7. Wash in glacial acetic acid twice (centrifuge at 1600 rpm for 2 min. and decant each time). 8. Wash in distilled water three times (centrifuge at 1600 rpm for 2 min. and decant each time). 9. Transfer to small storage vials, centrifuge and decant. Store in HEC (m'droethyl cellulose). Four to six slides were made of each sample. A drop or two of the residue dispersed in EEG (Hydroethyl cellulose) was pipetted onto a glass cover slip, smeared evenly with a toothpick and allow- ed to dry on a slide warming table at about 42° C (1080 F). A drop or two of HSR (Harleco synthetic resin, Hartman-ledden Co., Philedelphia, item 7885) was then pipetted onto the cover slip and dispersed by gently and evenly dropping the slide onto the cover slip. The slide and cover slip were then allowed to dry in an upright position on the slide table or in an oven (ca 30° C). The meceration number of each sample was inscribed into each slide along one of the short edges with a diamond pencil. Each slide was then labelled with location, depth, date, preparation and preparator information marked on a paper label attached to the left side of the slide. As mentioned.previously, while making the slides, an attempt was made to distribute the palymorphs evenly on the cover slip. It has been demonstrated that if the spores and pollen grains are distributed on the slide by flow currents or gravity from 29 one central point, there is some sorting which results in a strong correlation between the size and weight and hydrodynamic character- istics of a grain and the distance travelled (Taggart, personal communication). The failure to systematically and equally view all sections of the slide could result in a distortion of the rela- tive frequencies of occurrence of pollen which are calculated from the counts made. A few simple precautions were taken, consequently, to avoid obvious sources of error. Portions of at least three slides per sample were viewed under the microscope. Equidistant traverses were made across the slide using a mechanical stage so that representative sections of each slide were examined equally. Generally, pollen and spores were viewed, identified and counted on a Zeiss microscope at a magnification of 320 X. Occa- sionally, identification of palymorphs required additional magni- fication to 800 X with an oil immersion lens. At least 250 grains were counted in nearly all samples. The sum of the number of grains of arboreal pollen (AP) and non-arboreal pollen (NAP) (excluding aquatics) comprised the percentage base from which relative pollen frequencies were calculated for each sample. A variable number of grains were counted for each sample but generally more than 250 grains were counted. Standard pollen and spore identification manuals (McAndrews, et a1, 1973: and Kapp, 1969) as well as a convenient collection of reference slides of frequently encountered pollen and spore types greatly facilitated the task of identification. Those 30 grains which were either partially destroyed or obscured were classified as unidentifiable. Sommers Lake Bog. Sommers Lake covers an area of approximately 3.6 hectares (9 acres) (Figure 7). The bog surrounding the lake increases the acreage to approximately 11.2 hectares (28 acres). The bog encom- passes the lake irregularly with its greatest extension to the northwest. It is in this portion of the bog that a core sample was taken. Present Vegetation. The density and diversity of vegetation supported by the Sphagnum spp. mat increases with distance from the lake. The bog immediately surrounding the lake supports low herbs and shrubs such as Sarracenia purpurea, Chamaedaphne calyculata, flaccinium spp. Alnu§_spp., and Salix spp. With the establishment of a tree canopy a few yards from the lake, the shrubs and herbs are replaced by taller bog species such as Thuja occidentalig, La;ix_laricina, and Picea mariana. These species dominate the vegetation surround- ing the area that was selected for sampling. Beyond the bog in all directions, the land rises approximately 3 m (10 feet) to an elevation of 225 m (750 feet). To the north it supports a mixed northern hardwood forest dominated by Eagu§_g;and_- folia, Acer saccharum, and Populus tremuloides. Oldfield vegetation covers the outlying areas to the east and south. 31 32 Figure 7. Aerial View of the Sommers lake Bog. I Bog Sediments. The Sommers lake bog was cored to a depth of nearly 5.5 meters (18 feet). The stratigraphy encountered varies as follows: Top 0.00 - 0.35 m sediment dry; with coarse plant debris; reddish brown 0.35 - 2.70 m peat: with Sphagnum and variable plant debris: coarse near top and becoming finer with depth; deep brown 2.70 - 4.70 m gyttja; soft and somewhat gelatinous: deep brown 4.70 - 4.90 m silty clay; somewhat gelatinous; bluish gray 4.90 - 5.30 m mottled gyttja with silty clay; somewhat gelatinous; variable deep-brown to bluish gray 5.30 - 5.50 m silty clay: somewhat gelatinous but becoming coarse with gravel downward; gray-beige. Penetration impossible beyond this depth. bottom Pollen Stratigraphy. The pollen stratigraphy of the Sommers Lake bog is illustrated in Figure 8. Strata of the lower third of the column are dominated by pollen of coniferous genera. Pigga_pollen dominates the lower- most strata. It declines in frequency in subsequent strata as Pinu§_increases as the dominant taxa. Approximately midway up the column Tsuga, Aggry and Eagu§_pollen increase in their occurrences. Strata of the upper half of the column are dominated by pollen of a mixture of hardwood and softwood genera. AEV face 0 36 Lyman Lake Bog. lyman Lake covers an area of approximately 8 hectares (20 acres) (Figure 9). Together, the lake and surrounding bog encompass an area of 28 hectares (71 acres). The bog was sampled where it is most extensive, to the west of the lake. Present Vegetation. Tall trees and shrubs are supported by the bog‘s Sppagnum spp. mat to the lake‘s edge. The species which dominant the vegetation of the bog are consistantly mature specimens of larix laricina, Pip§§_mariana, and Thuja occidentalis, Outward from the bog and lake there are occasional depressions which support Typha latifolia, and glppg americana. Beyond this, the land rises approximately 6 m (20 feet) in elevation through a series of ridges or terraces which support a northern hardwood forest dominated.by Eggp§Igp§pg_- folia, Acer saccharum, Tspga ganadensis, Populus ppemuloides, and Betula lptga, Beyond this, the land rises an additional 6 m (20 feet) to an elevation of 227 m (760 feet) and remains relatively level for miles. The land at this elevation is occupied by cultivated fields to the west of the bog and a northern hardwood forest to the north, east and south. Bog Sediments. The Lyman Lake bog was cored to a depth of 3 meters (10 feet). The following stratigraphy was encountered: 37 Figure 9. Aerial View of the Lyman lake Bog. 39 Top 0.00 - 0.10 m peat; humified; deep reddish-brown 0.10 - 2.00 m peat; with Sphaghum and variable plant debris; coarse near surface but becoming increasingly fine downward; deep reddish-brown 2.00 - 2.95 m gyttja: soft and somewhat gelatinous; deep- brown 2.95 - 3.00 m clay; silty with gravel: gray-beige. The sediment could not be penetrated further with equipment used. Bottom Pollen Stratigraphy. Figure 10 illustrates the pollen stratigraphy encountered in the sediments of the byman Lake bog. Observation of the diagram shows fluctuations in representation of pollen or arboreal and non— arboreal genera. Pollen of arboreal taxa. both coniferous and deciduous, dominate nearly the entire column. The uppermost strata of the column are dominated by non-arboreal taxa. namely Compositae. Mission Point Bog. The Mission Point bog covers an area of approximately 13 hec- tares (32 acres) (Figure 11). Although there are some small, shallow ponds within the bog, it does not presently encompass a lake per as. Present Vegetation. These, and other wet areas of the bog support stands of Typha latifolia. The Sphaghum spp. mat of the bog premarily supports herb and shrub vegetation dominated by Chamaedaphne calyculata and 7 :5 {as _ O _/ 2 10. Figure 41 Figure 11. Aerial View of the Mission Point bog. 42 43 Vaccinium spp. There are small, scattered stands of Picea_mariana and Pinus spp. An area surrounded primarily by Chamaegaphne caly- culata was selected for coring. The bog is immediately surrounded by a northern hardwood for- est which stands at an elevation of approximately 182 m (620 feet) and is dominated by Eagaa grandifolia, Acer saccharum, Tsuga cana- densis, Pppulus tremuloides and Betula lutea. Beyond the immediate vicinity of the bog, there are fruit tree orchards to the north and west and open fields to the south and east. Bog Sediments. A core was driven through the bog to a depth of two meters (7 feet). The stratigraphy was as follows: Top 0.00 - 0.08 m peat: humified; deep reddish-brown 0.08 - 1.40 m peat: with Sphagnum and coarse plant debris; deep reddish-brown 1.40 - 1.95 m gyttja; fine somewhat gelatinous; deep reddish- brown 1.95 - 2.00 m clay; dense with gravel near bottom; gray. Further penetration impossible. Bottom Pollen Stratigraphy. The pollen stratigraphy encountered at the Mission Point bog is illustrated in Figure 12. Most of the column is dominated by arboreal pollen of both coniferous and deciduous genera. A notable fluctuation is a consistantly lower representation of Iaaga pollen in the lower strata of the column followed by higher occurrences Depth (m) “figzv. 45 within the upper strata. The uppermost strata are dominated by pollen of non-arboreal taxa. notably Compositae. ZONATION OF POIlEN STRATIGRAPHY. Zonal Criteria. To facilitate discussion of the post-glacial pollen strati- graphies produced from the bogs of this study, zones have been established. These zones are characterized by distinctive fluc- tuations in the percentages of certain pollen types and they represent particular floras. The divisions employed in this study correspond to zones identified in late and post-glacial sediments throughout northeastern Nerth America. Although standardization exists in zone identification, sub-divisions of the zones are not yet uniformt This is primarily due to the fact that zonal sub-divisions are not uniformily represented throughout the region. Generally, zonal sub-divisions are established to identify less pervasive floral communities influenced chiefly by micro—climatic conditions. The nomenclature employed in zone description has not been standardized. Miller (1973) and others employ an alphabetical system of zonal nomenclature developed by Deevey (1939). Davis, et a1 (1975), Kapp, et a1, (1969) as well as others, follow a system by which the zones are designated by Roman numerals. In a system of nomenclature developed by Cushing (1967) the zones are named after the primary dominant generic components which comprise it. The zonal nomenclature which appears in this study most closely resembles that employed by Kapp, et a1 (1969) and Deevey, et al (1975) since the zones are designated by Roman numerals, I, 46 47 II, III, and IV. Only Zone III has been sub-divided with letter designations A, B, and C. Zonal Characteristics. Pollen Zone I is the lowermost zone identified from the pollen stratigraphy of the bogs of this study. It is characterized by high percentages of spruce and pine pollen. Pollen Zone I is comparable to Deevey's (1939) Zone A and Cushing's (1967) gapaa- Pahpa zone. Of the three bogs sampled, this zone is represented solely at the Sommers Lake bog. Pollen Zane II comprises the subsequent interval of pollen stratigraphy produced by the bogs of this study. This zone is distniguished by an overwhelming dominance of pine pollen. Pollen Zone II is equivalent to Deevey's (1939) Zone B and Cushing's (1967) Pinus-Betula-Alnus zone. It is represented only in the strati- graphy of the Sommers Lake bog of the localities sampled in this study. Pollen Zone III is dominated by a fluctuating mixture of ar- boreal pollen of both hard and softwood genera. It has been fur- ther divided into three sub-zones: A. B, and C. These sub-divisions most closely resemble Deevey's (1939) sub-divisions of Zone C: l, 2, and 3a. Sub-Zone IIIA is characterized by the initial signifi- cant influx of the pollen of hardwood genera as well as Tahga and a corresponding decrease in the pollen of softwoods, particularly pine. This zone is represented in the pollen stratigraphies of the Sommers Lake and Mission Point bogs. Sub-Zone IIIB is characterized 48 by a significant decrease in the representation of Tahga pollen. The zone continues to be dominated by the pollen of arboreal genera, both coniferous and deciduous. Zone IIIB is represented in the stratigraphies of the Sommers Lake, byman lake and Mission Point bogs. Sub-Zone IIIC is characterized by a shift in the pollen frequencies of arboreal taxa, hard and softwood genera included, to accommodate a substantial increase in Taaga. This zone is represented in the stratigraphies of all three bogs of the study. Pollen Zone IV is characterized by a substantial increase in pollen of non-arboreal taxa and a corresponding decrease in arbor- eal pollen. It is comparable to Deevey's (1939) Zone C-3b. Pollen Zone IV is represented in the stratigraphies of the lyman lake and Mission Point localities. Zones Represented at the Sommers lake Bog (Figure 8). Pollen Zone I. The most abundant pollen type represented, Papaa, ranges in relative frequency from 34 to 62% with an average representation of 50%. EEEEE pollen, the second most common type, represents 10 to 18% of the relative frequency with an average value of 13%. 0f the hardwoods, Qaercus is the sole genus showing a significant representation in this zone. It ranges in frequency from 5-12% with an average representation of 8%. Pollen of other arboreal genera, both hardwood and softwoods included, are represented in very low frequencies. Softwood genera, Abies, Tsuga, and Larix are represented by values of l to 6%, l to 2%. and 2 to 4% respectively. The pollen of hardwoods, Acer, Eagaa, 49 Qappya, glaaa. and Populus do not exceed values of 3% in this zone. ngala pollen, however, with a relatively high initial value of 7%, decreases to 1%, thereby averaging 3% in occurrence. Castanea and Thpja each comprise 1% or less of the pollen represented in this zone. Non-arboreal pollen occurs in low frequency in pollen Zone I and comprises approximately 2% of the total. §§ll§ and Cogylus pollen each represent roughly 1% of the total count. Pollen of members of the Compositae and Gramineae show minimal representa- tion as do the spores of Sphagnum and members of the Polypodiaceae. Pollen Zone II. Pahaa pollen clearly dominates this zone as it ranges from 33 to 42%. This average signifies nearly a three- fold increase in EEEEE over its previous representation in Zone I and constitutes the maximum average value this genus achieves in the vegetational history of this bog. Papaa pollen is also well represented in this zone although its frequency has significantly decreased to roughly 40% of its previous average occurrence in Zone I. Papaa represents 10-30% of the pollen (average 19%). During Zone II hapala pollen increases in frequency to nearly three times its average occurrence in Zone I. Betula fluctuates in frequency of occurrence from 4-13% (average 9%). Qpercus continues to represent 4 to 12% of the total as in Zone I. The remaining hardwood and softwood genera which occur in Zone II are scantily represented. Abies, Tsuga, and Thuja each range between 0-2% in relative percentage of the pollen flora. Larix, however, represents a maximum of 4% of the total pollen (average 3%). Pollen of Acer ranges in values from 2-5%»of the 50 total. Pollen of Eagpa. 0stgyaq Ulmus, POpulus,,ga;ya, and Tilia each represent a mere 1-2% of the total. Non-arboreal pollen comprises approximately 6% of the total. Of this, gorylus represents approximately 3%, while members of the Compositae and Gramineae comprise 2% and 1% respectively. The pollen of §éll£ and alhaa have only trace occurrences as do the spores of §phaghap. Lycopodiaceae and Polypodiaceae. Pollen Zone III. In Zone IIIA, Picea and Pinus each represent an average of 18% of the total pollen count. While this percentage represents a slight decrease from previous values for Papaa, it represents a substantial decrease, approximately 50% for Pahaa. As a result of this decrease, Elflfl§ is reduced to a frequency of occur- rence comparable to that of Zone I. Zone IIIA shows the first significant influx of Tahga pollen. In this zone, Tapga reaches a maximum representation of 25% of the total count (average 18%). Increases in relative percentages of agap_and Eagaa pollen in Zone IIIA indicate their growing establishment into the region‘s flora. On the average, asap represents 10% of the total while Eagaa represents 4%. Bapala_pollen decreases in occurrence to 6%. or approximately two-thirds of its representation in Zone II, Qpercus remains unchanged at about 7%, Most of the remaining arboreal species which occur in this zone continue to occur in low frequencies as in Zone II. glhaa pollen represents approximately 2% of the total: Po ulus, Talia, and Ahaaa each comprise 1%. lapaa and Qappya_each comprise about 2%. Trace occurrences of gapya_and Castanea are noted. Non-arboreal pollen comprises roughly 2% of the total with 51 gagyla§_and members of the Compositae at about 1% each. §aaaa, alpha, and Ilaa_have minimal representation in this zone. Spores of Lycopodiaceae and Polypodiaceae together show a frequency of %. Pollen of the Nymphaeaceae and Alismaceae families comprise about 1% of the total. In Pollen Zone IIIB Tapga pollen decreases significantly to a minimal level of representation. Papaa and Pahaafalthough con- tinuing as dominant genera, decrease somewhat in their representa- tion to 133 and 12% averages respectively. Eagp§_pollen increases in representation to values ranging from 7-15% (average 10%). Other important hardwood genera, gharcus, Acer, and Bapala, show minimal fluctuations in representation. Qaercus and apap_pollen each com- prise approximately 8-9% of the total; Bapala remains at an average value of 5%. Softwood genera of ahaaa and Thaja continue to represent less than 1% of the total. lapaa_pollen increases to an average of 4%. Of the minor hardwood genera. only Populus increases to 4%.of the total pollen flora. In this zone Qappya shows little fluctuation in values (averages 2%). glppa, gapya, Illlév and.Qalpaa_each are present in percentages of about l%. Jaglans and Caatanea show only a trace in Zone IIIb. Non-arboreal pollen occurs in the sediment at an average valpe of 10%. Of this, only gala; and Gramineae show substantial increases in representation, comprising 4% and 3% respectively. Alhga, Qgpylus, and members of the Compositae continue to each represent approximately l% of the total. Pollen of 212;, Typha, and members of the Ericaceae continue to occur in traces. Spores from the 52 lycopodiaceae and Polypodiaceae occur in a frequency of about 2% of the total. Sphaghum is present as a trace. In Pollen Zone IIIC an increase in occurrence of Tahga pollen to an average of 8% is accompanied by an increased frequency of Eghaa and lapaa, which average respectively 16% and 7%. The fre- quencies of occurrence of Pagaa and aha; pollen decrease in this zone to 8% and 6%, respectively. The pollen frequencies of guercus and Eagaa remain unchanged from Zone IIIA as does Bapala, which continues to represent approximately 6% of the count. 0f the minor arboreal components occurring in Zone IIIC, Pppplaa represents roughly 2% of the total pollen count while 9stgya and Ulmus each comprise an average of l%. Carya, Tilia, gaatahaa, and Thhja show scant occurrences in this zone. Non-arboreal pollen comprises approximately 7% of the total count in pollen Zone IIIC. Of this, members of the Gramineae represent 3% while §§ll§ represents 2%. Each representing an average of 1% of the total count are members of the Compositae and Cyperaceae. alpha; Corylus, Ilex, Polygonaceae, and Typha have only trace occurrences in this zone. Spores of the lycopodiaceae and Polypodiaceae families occur in a frequency equivalent to 3% of the total count. S num continues to occur only in traces as does the pollen of the Nymphaeaceae and Alismaceae. Pollen Zone IV. Since satisfactory pollen samples could not be retrieved from the uppermost 20 cms (0.66 ft) of the core ob- tained from the Sommers lake bog, this zone is not represented at 53 this locality. Zones Represented at the lyman Lake Bog (Figure 10). Pollen Zone III. In Pollen Zone IIIB the pollen of Agap_and Eagaa occur most frequently at the lyman Lake bog. While aha; com- prises an average of 15% of the total count, Eagaa accounts for an average of 12%. Occurring at considerably lower frequencies but still amply represented are Qpercus, Betula, and Pahaa, ercus pollen represents an average of % of the count in this zone and Bappla and Pahaa pollen each represent 7% of the total. Taaga and Pipaa pollen fluctuate in percent of representation from 0 to ll%. Iaaga pollen averages 6%, however. and Papaa_shows an average value of 5%. The pollen of a number of hard and softwood genera occur in low frequencies in this zone. Each representing an average of 4% of the total count are Qapgya and glhha, gagya averages 3% and Populus 2% Trace occurrences of ahaaa, LEELE:.IEEJ§’ Ellie. Castanea. galpaa. and hppaa are identified. Non-arboreal pollen comprises approximately 12% of the total count in Zone IIIB at the byman Lake bog. §éll£ has the highest frequency averaging 4%. The Compositae and Gramineae each repre- sent 2% of the total and alpha, Qppylaa, Ilaa, and Typha each account for l%. The Ericaceae and Polygonaceae are rare. Spores of lycopodiaceae, Polypodiaceae, and §phaghah together occur in a frequency equivalent to 2%. Aquatic pollen occurs only in traces. 514 In Pollen Zone IIIC Tsuga pollen increases three-fold from earlier Zone IIIB values to an average representation of 9%. Pollen of dominant hardwood genera continue to occur at approximately the same percentages of representation. ahap_represents 13% and Eagaa pollen ll%. Quercus and Bapala each average 7% of the count and ElEQé and QlEE§ 3%. Ostrya, Populus, and gapya occur in low frequencies. Qapgya pollen represents 3% of the total, POpulus 2%, and gapya_l%. Ar- boreal genera of hapaa, Thaja, Tilia, Juglans, Fraxinua, Qaatahaa, Qalpaa, and hppaa each represent averages of less than 1% of the total count. Non-arboreal pollen makes up approximately 9% of the total count in this zone. §§ll£ averages 3% and Capylus 2%. Each representing averages of 1% of the total count are Alnus, Typha, and members of the Compositae and Gramineae. Trace frequencies of Ila; and members of the Ericaceae, Cruciferae, Polygonaceae, Nymphaeaceae, Alismaceae, Sphaghum, lycopodiaceae, Polypodiaceae, Selaginellaceae, and Osmundaceae occur. Pollen Zone IV. In this zone, the pollen of non-arboreal genera collectively average 42% of the total pollen count. More than half of the non-arboreal genera belong to the Compositae which comprises an average of 26% of the total count. Pollen of the Gramineae account for approximately 6%. This increase in rela- tive percent of representation occurs primarily at the expense of the formerly dominating genera of Zone IIIC, Fagus, Acer and.T§aga, which each average 5 or 6%. 55 Of the remaining dominant genera represented in this zone. the pollen of Bapala and Papaa_increase in occurrence while Bahaa_and guercus show little fluctuation. Bapala pollen repre- sents 12% of the total, Papaa_and Pahaa each average 8%, and Qaapgha comprises 7% of the count. Arboreal genera exhibiting low frequencies of occurrences in- clude Qapppa,'glha§, Po ulus, and Talia. With the exception of Qappya_pollen which accounts for 2% of the total, pollen of the remaining genera each represent 1% of the count. Of the remaining non-arboreal taxa, Alnus, Corylus, and members of the ChenOpodiaceae and Polygonaceae families each comprise an average of 2% of the total. Salia represents l% of the count. Spores occur in low frequencies: Sphagnum, 2%. the chopo- diaceae, 1%. Pollen of aquatic plants, the Nymphaeaceae and Alis- maceae, average 1% of the total. Zones Represented at the Mission Point Bog.(Figure 12). Pollen Zone III. In Pollen Zone IIIA Quercus pollen is the most abundant type representing an average of 18% of the total. agar and ElflEé each account for 13% of the total. Taaga pollen comprises 8% of the total and hapala 5%. Eagaa and POpulus each represent 4% of the pollen in this zone. Softwood genera with low percentages of representation are Papaa_and lapaa, each at 2% and Thu'a, at 1%. Ulmus, Carya, and Tilia pollen each represent 2% of the total count and Ostpya, 56 Fraxinus, Castanea, and Celtis each comprise 1%. Non-arboreal pollen represents 13% of the total in pollen Zone IIIA. Of this, the shrubs represent 3% of the total: Salix, comprising 3% and Cogylus, 2%. Members of the Compositae and Polygonaceae each represent 2%. Ilex, Typha and members of the Graminaeae and Chenopodiaceae families each make up 1% of the total. Spores of Sphagnum as well as members of the Polypodiaceae, together occur in a frequency equivalent to 3% of the total count. Aquatic plants of the Nymphaeaceae and Alismaceae show minimal occurrences. In Pollen Zone IIIb. Eagu§_pollen increases substantially in occurrence ultimately establishing itself as the dominant genus. Eagus ranges between 12 and.27% in frequency for an average of 21%. guercus pollen attains 12% relative frequency, the second highest in this zone. This represents a considerable decrease from Zone IIIA values. 522; and.Pigga each represent an average of 9% of the total pollen count in Zone IIIB. This average indicates a slight decrease in occurrence of Age; but represents a considerable increase in the frequency of Pigga_pollen. Arboreal genera of minor importances are Pinus, Tsuga, and ggtula. Pings represents an average of 7% and Esuga and.§gtgla each have an average value of 6%. In pollen Zone IIIB, gstgya pollen comprises 3% of the total; glmus and Populus each comprise 2%, and gagya, 3%. Arboreal genera with trace occurrences include Abies, Larix, Tilia, Fraxinus, and Castanea. 57 Approximately 6% of the total pollen count is represented by non-arboreal taxa. Of these, Cogylus and members of the Ericaceae eaCh represent 2%: §a1i§_and members of the Compositae each com- prise l%. Genera having only scant representation are Ilex, Eypha, and members of the Cruciferae, Chenopodiaceae, Polygonaceae, and Gramineae families. Pollen of aquatic plants and spores are scarse in this zone. In Pollen Zone IIIC Isugg pollen increases in frequency two- fold averaging 12% of the total. Agg; pollen, which also increases to 12%, represents a small gain from earlier values. Eggus pollen, however, still continues to be the dominant type, fluctuating bet- ween 16-26%, for an average representation of 20%. Quercus and Picea. pollen decrease slightly to average values of 18% and 7% respective— ly. Pings and Egtula continue to represent 7% and 3% of the total respectively. Arboreal taxa with low pollen frequencies include Ulmus, Ostrya, Populus, and Carya. Ulmus pollen represents 4% of the total, Ostgya, 3%, and Populus and Cagya each 2%. Abies, Larix, Tilia, Fraxinus, and Castanea are present in trace occurrences only. Six percent of the total pollen are non-arboreal genera. Of these, Cogylus and members of the Compositae each comrpise 2%, and Salix_and members of the Ericaceae, Polygonaceae, and Gramineae, occur minimally. Spores show trace representation while aquatic plant pollen are absent in this zone. Pollen Zone IV. In this zone non-arboreal pollen comprises approximately 42% of the total count. Members of the Compositae 58 show the highest frequency of occurrence as they represent an average value of 19% of the total count or nearly half of the pollen from non-arboreal genera. Betg;§_and ggercus each represent 10% of the total. Quercus pollen occurs in the same relative frequency as in the previous zone, but there is a considerable increase in fig}ula_pollen in the bog in Zone IV. Egggs and Gramineae each com- prise 8% of the total in this zone. This represents an important decrease for Eggp§_to two-thirds of its previous average occurrence, but it also represents a substantial increase in Gramineae pollen. Ag§r_pollen also decreases substantially to an average value of 3%. Pollen of Pinus, Tsuga, and Pipe; decrease substantially to average values of 3% or less. Conversely, pollen of P0 ulus, gstggg, and glEEs, show little fluctuation and continue each to represent about 2-3% of the total. Minor non-arboreal taxa include Salix, 3%, Co lus, 2%, and members of the Polygonaceae, 2%. Spores of Sphagnum increase con- siderably in this zone to about 10% of the count. INTERPRETATION OF REGION'S POST-GIACIAL VEGETATION HISTORY. As the glaciers retreated northward at the close of the Pleistocene, vegetation began to become re-established in com- munities along the glacial front. The components of these communi- ties as well as their pattern of succession can be determined through the analysis of pollen and spores deposited and preserved in bog and lake sediments during post-glacial times. When radio- carbon dates are known and associated with pollen spectra, the time of occurrence as well as the length of duration of these communities may often be determined. Although radiocarbon dates were not obtained from the bogs cored in this study, the relative time of establishment and duration of forest communities can be extrapolated.from the radiocarbon dated pollen spectra of nearby sites. Zone I. The region's earliest post-glacial vegetation is represented at the Sommers Lake bog in pollen Zone I. Consistantly high percentages of Pigg§_pollen (50%) indicate that a northern boreal forest became established in northwestern lower Michigan as the glaciers and associated inundating waters of Lake Algonquin re- treated from the region. A spruce-fir forest covering a broad region south of the glacial front extended nearly continuously across northeastern North America (Bernabo and Webb, 1977). By approximately 11,000 IEP this forest had migrated northward to 59 60 include the Upper Great Lakes region (Kelly and.Farrand, 1967). During this time the climate would have been colder and wetter than that of the present day (Dorr and Eschman, 1971). Since low percentages of pine, oak, and birch pollen are initially represented in the lower strata of this zone, it is believed that the spruce-fir forest must have initially been open and dominated by Picea glauca, white spruce, before becoming a closed stand of both Picea glauca and P. mariana, black spruce (Kapp, 1977). Unlike the bottom strata of a number of other Michigan localities (Kapp, et a1, 1969; Miller and Benninghoff, 1969) and throughout the Great Lakes region (Bernabo and Webb, 1977), non-arboreal, mostly herb, pollen of tundra components is very poorly represented at the Sommers lake bog. Since the lower strata of the Cheboygan Bryophyte bed (Miller and Benninghoff, 1969) has been dated between 13,300 and 12,500 BP, it may be that late glacial as well as early post-glacial vegetation of the region is not recorded at the Sommers Lake bog. Zone 11. The spruce-fir forest continued to dominate the region landscape until approximately 9,500 BP (Bernabo and Webb, 1977). By this time, with a gradual warming trend, the boreal forest migrated northward and was gradually replaced by forests dominated by species of pine. Pigg§_rose to dominance in Zone II (32%). Again, as in Zone I, Zone II is represented only at the Sommers 61 Lake bog of the three bogs analyzed in this study. As species of Picea declined, Pinus banksiana, jack pine and P. resinosa. red pine were the initial species to migrate westward to northwestern lower Michigan (Bernabo and Webb, 1977). Their establishment was followed by the arrival of Pinu§ strobusJ white pine. Since the frequency of occurrence of Pipps pollen in the bog sediments greatly exceeds its frequency of occurrence in the vegetation (Table 1), it has long been debated whether the high relative percentages of representation of Pigpg pollen in this zone accurately reflected a dominance of this genus in the vegeta- tion. Davis (1967) demonstrated that pine was actually an impor- tant component of the forest during this period by determining the absolute pollen frequencies of genera occurring in this zone. Although the occurrence of Picea had diminished during this time, it continued to be a well-represented component of the vege- tation. Also during this time, populations of hardwood genera of oak and birch became permanent components of the community. Zone III. Pine forests dominated the landscape of northwestern lower Michigan for approximately 2000 years until roughly 7500 to 7000 BP (Bernabo and Webb, 1977). Zone III, which begins at approximately this time, traces the initial establishment and continued develop- ment of the northern hardwood forest. This zone is further divided 62 into three sub-zones: A, B, and C. The lowermost, Zone IIIA, is represented at the Sommers Lake and the Mission Point bogs. Zone IIIA. The appearance of Igggg in the region indicates the lower boundary of Zone IIIA. Igggg is believed to have entered the state from the east, having migrated across southern Ontario and the eastern Great Lakes. It appears to have arrived in central lower Michigan at approximately 7900 to 7500 BP (Kapp, 1977). From this central locality it migrated in both northward and southward directions so that by approximately 7200 BP (Kapp, et al, 1969) it had established itself in the Beaver Island group. Therefore, it most likely had arrived in northwestern lower Michigan by roughly 7&00 BP and rapidly increased in abundance. This is reflected in the pollen record despite its over-represen- tation in the pollen flora. I§gg§ declined in abundance as rapidly as it had increased. This decline most likely reflects not only a deterioration of optimum climatic conditions for Isggg, but also increased competition for sites with the influx of hardwood species. Acer became established in the region just prior to the migration of T§2g_. ‘Unlike Teggg, however, once becoming estab- lished, Aggg_increased in its abundance gradually and steadily, never deviating significantly in its population. This phenomena is reflected in the pollen record.from Sommers Lake. The preva- lence of maple in the flora may not be readily apparent from its pollen profile, however, because it is inferred that Acer is 63 underrepresented in the pollen spectra. Other hardwood genera migrated into and became established in the region during Zone IIIA. Following the arrival of nggg, Q§tgy§ entered the region and became established in the vegetation. Just prior to the close of Zone IIIA Eéggg migrated into the region and began to increase in its abundance. Like Igggg, Egggg is believed to have entered Michigan from the east as it migrated through southern Ontario and the lower Great Lakes. It has been suggested, however, that Eggge may have migrated into the upper and lower peninsulas of Michigan independently from the vicinities of the northern and southern extremities of Lake Huron. In the north, near Sault Ste. Marie, Ontario, Egggs may have been present as early as 6700 BP (Kapp, 1977). Radiocarbon dates from central lower Michigan show that Egggs had established itself in that area by 7.900 to 7,100 BP (Kapp, 1977). Like '_I‘_s_u_g§, Eagps migrated to the north and south from this area. By approximately 6000 BP (Kapp, et a1. 1969) Ease had established itself as a component in the vegetation of the Beaver Islands. Consequently, having migrated from either northern or southern Michigan, Eggg§ most likely was present in northwestern lower Michigan by approximately 6300 BP. These trends can readily be seen in the pollen diagram from Sommers Lake bog. Little distortion occurs in the pollen profile of Egggg since it closely reflects its frequency of occurrence in the vegetation. Zone IIIB. Zone IIIB, which is represented at the Sommers Lake, Iyman Lake and Mission Point bogs begins at approximately 6000 BP, shortly after the arrival of Eaggs to the region. While the forests present during this time continue to be dominated by a mixture of hard and softwood species, the occurrence of Iggga is significantly and consistantly lower in its representation than its occurrences in previous and subsequent phases of Zone III. The region‘s record of forest history encompassed within Zone IIIB is believed to reflect a time during which climatic conditions were warmer and drier than that of the present. These xerothermic conditions which began to develop at approximately 6000 BP reached their optimum in the Great Lakes region at approxi- mately 4000 BP (Dorr and Eschman, 1971; Kapp and Kneller, 1962). Then, according to Hushen and Benninghoff (Miller, 1973) by roughly 3200 BP or 2500 BP (Dorr and Eschman, 1971) the climate had once again altered to approximate conditions of the present day. A warmer and drier climate during this period is evidenced by the development and establishment of plant communities which favor these conditions as well as the absence of others intolerant of it. A forest component intolerant of prolonged warm and dry conditions is Isgga. Not only does Eggs; prefer an environment which is wet and cool but it also requires these conditions to sustain its shallow root system. Studies have shown that Igngg root tips die rapidly during periods of drought (Miller, 1973). 65 This gradually results in the deterioration of the root system and the eventual attack of the organism by parasites. As previously noted, Igpga_which was a dominant component of the landscape in this region during Zone IIIA is present in extreme- 1y low frequencies during Zone IIIB. I§pg§ pollen, which exceeds the frequency of the whole plant in nature by roughly three-fold (Table 1), is present in an average value of l% of the pollen in the Sommers Lake bog and 8% in the lyman Lake and Mission Point bogs during this period. Egggg appears to have been virtually eliminated as a component of the region's forests during this time. According to Bernabo and Webb (1977) prairie vegetation migra- ted to its maximum eastward post-glacial advance as compared with its present position during the period from 9,000 to 7,000 BP. From roughly 7,000 to 2,000 BP, however, it again slowly retreated to its present day position. Although a warmer and drier climate particularly affected the vegetation of the region south and west of the Great Lakes with an influx of prairie species, its influence was, nonetheless, recorded in the vegetational history of Michigan and the Great Lakes area. Wilson and Webster (1942) postulated that in all likelihood during this period the oak-hickory forests extended approximately 90 miles (144 km) north of their current limit in Wisconsin. While the present study notes no increases in occurrence of guercus in northwestern lower Michigan during this period, increases in the frequencies of occurrence of garya are Observed at the Sommers Lake and Lyman Lake localities. Meanwhile, 66 in southern portions of the state, Zumberge and Potzger (1956) noted an increase in prairie components in southwestern Michigan while Kapp and Kneller (1962) have documented an increase in the abundance of Carya, Juglans, and Platanus in southeastern Michigan. Further, according to Bernabo and Webb (1977) an additional effect of the climate of this period on the vegetation of the Great Lakes region was the delayed dominance of a northern hard- wood forest. Whereas this forest type became established in New England immediately following the arrival of its primary components, namely Betula, Acer, Fagus, and Tsuga, it did not achieve its potential prevalence in the Great Lakes region for 2,000 to 5,000 years after its initial arrival. Specifically in northwestern lower Michigan, the northern hardwood forest became firmly estab- lished at approximately 3,000 BP.. Bernabo and Webb (1977) attri- bute the delayed establishment of the northern hardwood forest in the Great Lakes region to the influence of drier climatic conditions associated with the migrating border of the prairie tension zone. Until it had retreated sufficiently westward at roughly 3,000 BP to approximate its present day position, components of the northern hardwood forest had to compete for sites with previously estab- lished prairie taxa. The final establishment of a northern hard- wood forest in this region is indicative of a climatic shift to wetter conditions. Differences in the extensiveness of the northern hardwood forest during this time are noted in northwestern lower Michigan. While the pollen of the dominant components of the northern hardwood forest together comprise an average value of only 21% at the 6? Sommers Lake bog, they comprise averages of 40% and 42% respectively at the Byman Lake and Mission Point bogs. Further examination of pollen histograms produced from the sites indicates that the region surrounding the Sommers Lake bog, the most northerly and most interior locality sampled, supported a greater number of coni- fers than did the areas to the south. In all instances, however, the percentages of representation of northern hardwood components represent approximately 9% less than their respective average values in Zone IIIC. A shift to drier conditions during this period may be observed locally at the Sommers Lake bog. The influx of herbs and shrubs such as Papulus, Salix, and members of the Gramineae, chopodiaceae, and Polypodiaceae may be indicative of the colonization of newly exposed areas surrounding a dessicated lake. Then, as the climate becomes colder and wetter, these taxa decrease in abundance. Zone IIIC. This zone is represented in the stratigraphy of all three bog localities of this study. A gap in the record, however, occurs within this subdivision at the Sommers lake bog. As the previous subdivisions of Zone III, C is dominated by a mixed assemblage of coniferous and deciduous genera. Its lower boundary is identified by the re-establishment of Tsuga in the region which persists abundantly throughout this zone. Zone IIIC began approximately 3000 BP. It is characterized by the development of the northern hardwood forest which may have 68 been long delayed but which has dominated the region's landscape until its destruction approximately 100 BP. It is believed that cooling of the climate and an increase in moisture quite similar to that of the present made possible the return of Eggga and the establishment of the northern hardwood forest. This forest type was prevalent throughout the region. Some similarities and differences are indicated in its extent and com- position based on records obtained from the bogs studied. At the Sommers Lake bog the pollen of the dominant components of the northern hardwood forest together comprise only 30% of the total. Arboreal pollen which are characteristic of other forest types account for 43%. In contrast, the pollen of northern hardwood genera com- prise 48% and 49% of the totals of the Lyman Lake and Mission Point bogs, respectively. At these sites pollen of other arboreal taxa are reduced to approximately 22%. Clearly, the pollen stratigraphy produced from the Sommers Lake area shows the influence of more than one forest type. In order to gain a better understanding of the forest composi- tion of the region during this period the average relative percent of representation of the pollen of each genus has been converted to its corresponding relative average percent of representation in the forest. This conversion has been made for all dominant arboreal components through the employment of the data incorporated in Table l. The results of this conversion are presented in Table 2. The area of the study region encompassing the Sommers lake bog chiefly supported a northern hardwood forest dominated primarily - - a a - - mama H m «A a NA o g 8 .2 no 2 on o .32 n n u n m m xHHdH we, 3 NH 0 3 m m mmmnle a a m m m w 8mm. om em 3 Z S 2 g S S a m. 3 ca weapon a a N a m 3 mg monounsmwo oocowHSooo coconhsooo coconhsooo coconhsooo oocohusooo R o>HpmHom R o>apmaom & o>wpmflom & o>HpmHom R o>avmaom. R o>apdaom :oHHom coapmuowo> coHHom coavmvomo> coHHom 00m BZHOm onmmHz mom mxapmaom .N canoe 70 by species of Acer and secondarily by Egggg. Other components of this forest such as Tsuga, Pinus, and Bgtgla also occurred in the association but to a much lesser extent. Another forest type, dominated by species of ggercus and Piggs was common throughout this portion of northwestern lower Michigan. Either of these forest communities would have found the area's well-drained uplands to be suitable for habitation. The relatively high percent of representation of Picea may be indicative of sizable portions of the area having supported swamp and/or bog vegetation. This is plausible since this most northern portion of the study region is characterized by many extensive areas whcch are poorly drained. The presence of Larig, however, while comparable to Pipe; in representation, may only be interpreted as indicative of the bog's local environment at this time. The portion of the study region located in proximity to the Lyman Lake bog also primarily supported a northern hardwood forest. Species of Apex: clearly dominated this forest while less abundant components included Egggg, igggg, leps, Pigp§, and Betgla. During this time Acer, Tsuga, and glgg§_ probably occurred at least twice as frequently within the vicinity of Byman Lake as were present near the Sommers Lake bog. Clearly, a major por- tion of this vicinity's landscape was covered by a northern hard- wood forest. Forests dominated by species of Quercus and Piggs also were present, but were not nearly as prevalent in this area as they were in the vicinities of the Sommers Lake and Mission Point 71 bogs. The area surrounding the Mission Point bog also chiefly supported a northern mixed hardwood-conifer forest. As in the vicinity of Iyman Lake, this forest was outstandingly dominated by species of Aggr, although Pagus also occurred to a considerable extent as well. Its presence here was probably twice its occurrences in the Sommers Lake and Lyman Lake areas. less frequently occurring components of this forest also included Iggga. Ulmus, Pinus, and Pgigii. Pipgg and Pgigii were represented in the forest at approximately the same frequencies as they occurred within the Sommers Lake and.Iyman Lake areas. While iggggis repre- sentation in the landscape, however, was similar to its occurrence in the Sommers Lake vicinity, Ulmus occurred at approximately the same frequency as it did within the Lyman Lake area. Despite regional differences in species composition, however, the area predominantly supported a northern hardwood forest. Forest communities dominated by species of Quercus and Pipgg as well as those dominated by 212E; also occurred within this por- tion of the study region. Given the converted percentages of representation of guercus and.Pigea in the area's landscape, it could be interpreted that their prevalence was comparable to that of the Sommers Lake vicinity. The frequency of occurrence of Piggi, may, however, represent local as well as regional forest composition. A comparison among the forest histories produced by the three locations of this study shows that there are variations in the composition and extensiveness of the northern hardwood forest in 72 northwestern lower Michigan. At the Sommers Lake bog there is considerable influence of genera not intrinsic to the northern hardwood forest. This is most likely due to its northernmost, interior location in close proximity to extensive low and poorly drained areas. Conversely, the Lyman Lake and Mission Point bogs record an almost ubiquitous distribution of the northern hardwood forest. At both sites the most dominant genus, iggg, is significantly more abundant than its occurrence in the Sommers Lake vicinity. Further, in the area of the southernmost site, Mission Point, nggg, the second most important genus, is twice as common as it is in the Sommers and Lyman Lake areas. The increased representation of the northern hardwood forest at the Lyman Lake and Mission Point bogs is most likely due to the bogs' more southerly locations within predominatly well drained rolling uplands. Zone IV. Zone IV is represented in the stratigraphy of the Lyman Lake and Mission Point bogs. This zone is characterized by a radical influx on pollen of non-arboreal species and represents the youngest unit recognized in this study. The lowermost boundary of Zone IV dates to approximately 100 BP. Since this time vast tracts of land in northwestern lower Michigan were cleared by agricultural and/or lumbering activities. The clearing of the land resulted in an increased abundance and diversity of non-arboreal taxa characteristic of fields and meadows. 73 During Zone IV, pollen of non-arboreal taxa represent 58% of the total at both the Lyman Lake and Mission Point bogs. Members of the Compositae represent the highest average freqeuncy of occur- rence, 26% at Lyman lake and 19% at Mission Point. Members of the Graminaae account for 6% of the total at both localities. Pollen of arboreal taxa represents 42% of the total at each bog site. Of the arboreal genera, Peigii occurs at the highest average frequency of representation accounting for approximately 11% of the total at each site. Arboreal genera which represented lesser, but significant percentages of the vegetation at Lyman Lake during this period included Pinus, Picea, Quercus, Fagus, Acer, and Iggga. At the Mission Point bog, Quercus, Fagus, and Acer are locally im- portant. Although Zone IV is not represented in the stratigraphy of the Sommers Lake bog, it is found at the Inverness Mud Lake Bog, located in close proximity to Sommers Lake in nearby Cheboygan County (Benninghoff, 1960). A pollen profile was obtained from each phytographic community of this bog, including one dominated by Ihgja which was similar in composition to the area cored at the Sommers Lake locality. As the upper strata of the Lyman Lake and Mission Point bogs, the most recent zone of the Inverness Mus Lake bog was also dominated by the pollen of non-arboreal taxa. Pollen of Aings and members of the Compositae each comprised 23% of the total while that of Betula, Thuja, and members of the Gramineae each represented approximately 13%. While the major portion of the landscape of northwestern 74 lower Michigan has supported field vegetation during the past one hundred years, a substantial area has remained forested. The Zone IV forests, however, differ somewhat in composition as compared to those dominating the landscape during Zone IIIC. While forest composition during Zone IIIC is indicative of the prevalence of a climax forest of northern hardwood and conifer species throughout northwestern lower Michigan, the composition of the forests of the region during Zone IV suggests sucessional forest communities as the result of extensive regional disturbance. SUMMARY AND CONCLUSIONS. The history of the vegetation of portions of northwestern lower Michigan since the close of the Pleistocene has been traced through the analysis of the pollen preserved in the sediments of three bogs. As the glaciers retreated from northwestern lower Michigan approximately 11,000 iEP, the region supported forests dominated Primarily by spruce and fir. As the climate became more equitable at about 9,500 JBP, however, the boreal forest was gradually re- placed with forests dominated by species of pine (Pipes st bus, white pine, P. resinosa, red pine, and P, bankisana, jack pine). The pine forest declined in dominance initially with the migration of hemlock into the region at approximately 7,400 BP and secondarily with the arrival and establishment of mixed hard- wood species at roughly 6300 BP. The influence of a xerothermic climate throughout the Great Lakes region from approximately 6000 BP to 3000 BP delayed the extensive establishment of a northern hardwood forest dominated by species of maple, beech, hemlock and birch. This forest community, which prevailed throughout the region, became established at roughly 3000 BP as climatic conditions approximated those of the present. While the composition and abundance of components of this forest were generally similar throughout northwestern lower Michigan, differences have also been noted. As Euro-American settlement of the region was initiated approxi- mately 100 BP, extensive tracts of land were cleared and the 75 76 vegetation of the region was drastically altered. Areas which had supported a climax forest dominated by Acer, F us, Ts a, and Betula were shifted to dominance by seral communities of colonizing taxa. The cliseral progression of the establishment, develOpment, and replacement of vegetational communities both natural and artificial of northwestern lower Michigan has been traced for nearly 11,000 years. LIST OF REFERENCES LIST OF REFERENCES Benninghoff, William S., 1960, Pollen spectra from bryOphytic polsters, Inverness Mud lake Bog, Cheboygan County, Michigan: Pap. Michigan Acad. Sci. Arts, Lett. 45:41-60. Bernabo, J. 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Van Winter, Soil Survey gi_§rand Traverse County, Michigan. US. Dept. Agric. Soil Conserv. Serv. and Michigan Agric. Exper. Stat., Series 1958, No. 34., 141 p. + maps. 79 Wilson, L. R., and R. M. Webster, 1942, Fossil evidence of wider post-Pleistocene range for butternut and hickory in Wisconsin: Rhodora, 44:409-414. Zumberge, J. H. and J. E. Potzger, 1956, Late Wisconsin chronology of the Lake Michigan basin correla- ted with pollen studies: Bull. Geol. Soc. Am. 67:271-288. "ImmmmES