Information on historic vegetation conditions helps us understand the landscape structure and composition of native Lake States forests, and explain the changes that have occurred since European settlement. For the National Forests of the Lake States, consideration of this information partially fulfills the requirement of regulations under the National Forest Management Act of 1976 for evaluating "prior conditions" (36 CFR 219.26).
The northern Lake States historic vegetation maps show forest composition based on General Land Office land survey data collected from 1816 to 1907. Disturbances of wind, fire, and flooding, as well as the activities of American Indians, initiated cycles of succession in these original forests, creating temporary patches of early-successional, short-lived species. Ecosystems most susceptible to fire disturbance, particularly conifers on dry, sandy outwash plains, would have experienced more frequent change than other areas because of the relatively short return intervals of catastrophic fire (Whitney 1986). Within these areas, the vegetation at different times and places could have been dominated by jack, red, or white pine forests, spruce-fir and aspen-birch forests, and barrens, savannas, or open grasslands. The hemlock-hardwood forests on moraines and till plains, however, were quite different. These forests, disturbed principally by fine-scale windthrow, tended to perpetuate long-lived species in the overstory and in small windthrow gaps (Davis et al. 1993). Only in the relatively rare instance where a large opening was created by a high-energy windstorm would short-lived species gain temporary dominance of an area. Consequently forest composition on moraines and till plains was quite stable through time (Frelich and Lorimer 1991), whereas composition and age class distributions within pyrophilic (fire-prone) landscapes would have varied according to fire type (crown or ground fire), frequency, and extent.
Effects of people during recent history have strongly influenced ecological processes and patterns. While historic vegetation maps enhance our understanding of past and current ecological conditions, such maps do not suggest that it is possible to fully restore these ecosystems to historic conditions. Restoration opportunities are limited because certain species are now extinct or extirpated from their native ranges, alien species have become established, and there is a highly resource-dependent human presence on the landscape. Nonetheless, some populations of plants and animals adapted to conditions and disturbance regimes that prevailed during their evolutionary period have declined due to human disturbance. Recreating or emulating historic habitat patterns and disturbance processes can aid the recovery of some of these species of concern.
Davis, M.B. 1981. Quaternary history and the stability of forest communities. Pp. 132-153. In: West, D.C., H.H. Shugart, and D.B. Botkin, eds. Forest Succession: Concepts and Application. New York: Springer-Verlag.
Davis, M. B., S. Sugita, R. R. Calcote, J. B. Ferrari, and L. E. Frelich. 1993. Historical development of alternate communities in a hemlock-hardwood forest in northern Michigan, U.S.A. Pp. 19-39. In: P. J. Edwards, R. M. May, and N. R. Webb, N.R., editors. Large-Scale Ecology and Conservation Biology: The 35th Symposium of the British Ecological Society with the Society for Conservation Biology. University of Southampton. Boston, MA: Blackwell Scientific Publications.
Frelich, L. E. 1995. Old forest in the Lake States today and before European settlement. Natural Areas Journal 15:157-167.
Frelich, L. E., and C. G. Lorimer. 1991. Natural disturbance regimes in hemlock-hardwood forests of the Upper Great Lakes Region. Ecological Monographs 61(2):159-162.
Whitney, G. G. 1986. Relation of Michigan's presettlement pine forests to substrate and disturbance history. Ecology 67(6):1548-1559.
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USDA Forest Service--North Central Research Station, Rhinelander, WI
David T. Cleland, Landscape Ecologist
Jim Jordan, Forest Ecologist
Paula Anderson, Fire Ecologist
North Central Research Station, Houghton, MI
Maureen Mislivets, Landscape Ecologist
Michigan Technological University, Houghton, MI
Sari Saunders, Landscape Ecologist
USDA Forest Service--Chippewa National Forest, Cass Lake, MN
David Shadis, Soil Scientist
Available GIS Maps
Northern Lake States Early Settlement Forest Cover
Michigan Early Settlement Forest Cover
Minnesota Early Settlement Forest Cover
Wisconsin Early Settlement Forest Cover
Early Settlement Vegetation in Northern Great Lakes Ecoregions