2 - FOREST HISTORY 2.1 - Pre-European Settlement History (Glaciation to 1800’s) The present physical geography of the State of Michigan is a direct result of the Wisconsinan glaciation of the Pleistocene Epoch, when the state was totally covered by ice. As the present inter-glacial period began and the ice sheet gradually receded, southern Lower Michigan became mostly ice free approximately 13,000 years before present (B.P.). Upper Michigan became ice free approximately 10,000 B.P. The present landform and soils of Michigan are the result of post-glacial lakes, rivers, erosion and soil development processes acting upon the glacial deposits, resulting in a diversity of terrain features including moraines, drumlins, eskers, kames, outwash plains and former lake beds that are interspersed with numerous lakes, streams and depressions, including four of the world’s largest freshwater lakes. It was upon this landscape of raw post-glacial parent material that life gradually returned. The primary succession of plant life was heavily influenced by the nature of the parent material, the climate (that was still very much influenced by the receding ice sheets) and the formation and disappearance of proglacial lakes. Theories of the succession of plant life from barren soil to tundra, and the migration of forest tree species and some animal species from their glacial refugia are fairly well established (Davis 1981 and Pielou 1991). Post- glacial succes sion and development of forest and animal communities were first driven by a gradual warming of the climate, culminating in the hypsithermal of the current interglacial occurring approximately 7,000 B.P., and then by the subsequent and present cooling trend toward the next glaciation. The post-glacial landscape provided an abundance of habitat for a wide diversity of forest, savanna and aquatic plant and animal communities, which were distinctly influenced by Native American cultures that inhabited the two peninsulas, most notably through hunting and fishing activities and their interaction with the fire regimes of both savanna grasslands and pine lands. A comprehensive description of the complexity of the post-glacial climatic and anthropogenic interaction with plant and animal communities can be found in Pielou 1991. The present landscape of Michigan is comprised of four distinct eco-regions (Figure 2.1): Southern Lower Michigan; Northern Lower Michigan; Eastern Upper Michigan; and Western Upper Michigan. Each eco-region is distinct in its climate, physiography, soils and vegetation. These distinctions are a result of the peninsular configuration of the state, which dramatically affects the climatic differences of both peninsulas. The distinctiveness of warm, vegetatively diverse Southern Lower Michigan and cold Upper Michigan is largely due to their latitudinal positions and the continental land masses on their southern borders. The four Great Lakes that surround the state also provide a significant influence upon the climate in portions of both peninsulas (Albert 1995). The pre-European settlement (circa 1800) vegetative patterns for the State are based upon an interpretation of the Federal General Land Office (GLO) surveys of 1816-1856 (Figure 2.2). Between 1816 and 1856 the State was surveyed by the Federal Government’s General Land Office (GLO), with surveys of the Lower Peninsula beginning in 1816 and surveys of the Upper Peninsula beginning in 1840. The interpretation of cover types on these maps is interpolated from section line and corner witness trees, similar landform, surface geology and soils data. Inclusions of dissimilar cover types that do not intersect a section line may not be reflected upon the maps. Despite these qualifications, the GLO survey maps provide a consistent landscape level perspective of the circa 1800 cover types 19 Figure 2.1. Regional Landscapes Ecosystems of Michigan. (Adapted from Albert, 1995) Figure 2.2. Vegetation of Michigan circa 1800. (Michigan Natural Features Inventory, 1998) 20 Figure 2.2 (Continued). Vegetation of Michigan circa 1800. (Michigan Natural Features Inventory, 1998) 21 of the entire state. The maps are useful for assessing broad post-settlement trends for different cover types, the type and scale of pre-settlement disturbance regimes, and for consideration in the restoration of selected cover types. The forest and other landscape communities that existed circa 1800 consisted of a mosaic of vegetative patterns ranging from remnant hypsithermal savanna grasslands and southern hardwood forests in Southern Lower Michigan, to northern hardwood and pine forests in Northern Lower Michigan and all of Upper Michigan (Figure 2.3 and Table 2.1). The pre- settlement landscape was dynamic and was comprised of a mosaic of community types in various stages of ecological succession, driven by long-term shifts in climatic conditions, and short-term natural and anthropogenic disturbance cycles. Four community types dominated the landscape at the time of the GLO surveys: the beech-sugar maple-hemlock northern hardwoods community; the beech-sugar maple southern hardwoods community; hemlock dominated communities; and the mixed conifer swamp community. Eight other sub- dominant communities occurred on the landscape: mixed oak savanna; oak/pine barrens; beech-sugar maple northern hardwoods - absent the hemlock component; mixed oak/hickory forest; mixed hardwood swamps; red/white pine forests; white pine/mixed hardwoods; and cedar swamps. Lesser communities were spruce/fir/cedar forests, seral aspen/birch forests, and black ash swamps. As an aggregate group, pine communities covered 4.1 million acres or 11.8% of the forested landscape. These included pure white pine forests, pure red pine forests, pure jack pine forests, mixed red/jack pine forests , mixed pine/oak forests, and the previously cited red/white pine forests and white pine/mixed hardwood forests. The pine forest communities were fire-driven ecosystems, dependent upon occasional catastrophic stand-replacing fires for regeneration, and frequent low-intensity fires that eliminated competition from non-fire adapted tree species and that in the case of red and white pine maintained a relatively open structure on the forest floor. Conservative estimates of recurrence intervals for fires in jack pine forests in northern Michigan ranged from 59 to 140 years. For red and white pine stands, estimates of recurrence intervals in northern Michigan ranged from 130 - 240 years (Whitney 1986, Price 1994, Cleland et al. 2004). The natural disturbance regime that maintained white pine communities was characterized by a repeating, cyclical sequence of catastrophic fires, with light surface fires occurring at shorter intervals (Frelich 1992). White pine occurred most abundantly in areas where catastrophic fire intervals were about 150 to 300 years. More frequent fires, towards the 100-150 year interval, tended to favor red pine while intervals greater than 300 years tended to succeed to northern hardwoods. As a mid-successional species, white pine occurred most frequently with red pine (Table 2.1) and most often followed jack pine (Frelich 1992). Non-catastrophic surface fires occurred at intervals of 20-40 years (Frissel 1973 as cited in Frelich 1992) and tended to kill hardwoods invading the understory. Gaps created by winds and surface fires created multi-modal diameter distributions and formed increasingly multi- aged stands. White pine stands may have been maintained in the old-multi-aged stage for one to several centuries (Heinselman 1981), until the occurrence of another catastrophic disturbance. A view of the complexity of the landscape and the composition and structure of circa 1800 forests can also be gained through analysis of GLO data for the frequency of association of several major tree species within upland glacial landforms in Northern Lower Michigan (Table 2.2). Strong associations are evident between beech, sugar maple and hemlock 22 Circa 1800 Landscape Communities 7 6 5 4 3 Millions of Acres 2 1 0 Red Pine Hemlock White Pine Jack Pine Aspen/Birch Sand Dune Upland Prairie N. Hardwoods Red/Jack Pine Cedar Swamp Bedrock/Alvar Red/WhiteMixed Pine Pine/Oak Oak/Pine Barrens Spruce/Fir/ Cedar Mixed Oak/Hickory Black Ash Swamp Emergent Wetland Mixed Oak Savanna Shrub-Carr Wetland Southern Hardwoods Mixed Conifer SwampBog/Muskeg/Peatland Wet/Lakeplain Prairie N. Hardwoods/Hemlock White Pine/Hardwoods Mixed Hardwood Swamp Figure 2.3. Circa 1800 Landscape Cover Types. (Michigan Natural Features Inventory, 1998) Table 2.1. Circa 1800 Cover types by acreage and percent relative cover. (Michigan Natural Features Inventory, 1998) Cover Type Acreage Percent N. Hardwoods/Hemlock 6,341,989 18.1 S. Hardwoods 5,845,677 16.7 Hemlock 4,714,602 13.5 Mixed Conifer Swamp 4,290,553 12.3 Mixed Oak/Hickory 2,306,373 6.6 Mixed Hardwood Swamp 1,421,462 4.1 Cedar Swamp 1,254,055 3.6 White Pine/Hardwoods 1,185,681 3.4 N. Hardwoods 1,161,644 3.3 Red/White Pine 1,132,097 3.2 Oak/Pine Barrens 1,101,424 3.1 Mixed Oak Savanna 1,061,564 3.0 Spruce/Fir/Cedar 823,253 2.4 Jack Pine 596,836 1.7 Mixed Pine/Oak 543,562 1.6 Red/Jack Pine 515,819 1.5 Aspen/Birch 292,266 0.8 Black Ash Swamp 280,705 0.8 Red Pine 70,889 0.2 White Pine 69,141 0.2 Totals 35,009,591 100 23 Table 2.2. Frequency of Association of Tree Species with Upland Landforms in the Northern Lower Peninsula prior to European Settlement. (Fisher, 1994) Upland Landform End End End Ground Ground Lacustrine Moraines Moraines Moraines Moraines Moraines Sands Outwash Ice