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Vegetation of the Northern Lake States
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| Pre-settlement Vegetation |
Prior to settlement by Europeans in the late 1800's the northern
portions of Michigan, Wisconsin, and Minnesota were covered by
closed canopy forests of northern hardwoods and conifers interspersed
with lakes, wetlands, and rivers. The forest landscape hadn't
changed drastically for at least the previous 3000 years (Davis
1981), although local variations in soil and topography, coupled
with disturbances by windstorms and fires created a mosaic of
different forest types. Detailed reconstructions of the original
vegetation have been derived from General Land Office surveys
for Wisconsin
(Finley 1976) and Minnesota (Marschner 1975), while an older
map exists for Michigan (Veatch 1928). According to Frelich (1995),
the pre-settlement distribution of forest types in this region
consisted of the following major forest types:
|
Forest Type
|
% Cover
|
| Northern Hardwoods |
47
|
| Swamp Conifer |
13
|
| Red Pine and White Pine |
12
|
| Spruce/Balsam Fir/Paper Birch |
10
|
| Oak-Hickory |
9
|
| River Bottom Hardwoods |
6
|
| Jack Pine |
5
|
Approximately 68% of the 32.7 million hectare
forest area consisted of old growth, only 1.1% of which remains
today. According to Frelich, about 4.4% of the old growth swamp
conifers survived the logging era, along with 0.2% of old growth
northern hardwoods, 0.6% red-white pine, 2.6% spruce-fir-birch,
0.02% oak-hickory, 0.2% river bottom forests, and 3.0% jack
pine. By far the largest area (approximately 40%) of remnant
old growth forest occurs in the Boundary
Waters Canoe Area (BWCA) of northeastern Minnesota.
Other significant areas of old growth forest exist in the Porcupine
Mountains State Park of Upper Michigan, Sylvania
Wilderness Area in the Ottawa National Forest, and private
lands in the Huron Mountains northwest of Marquette, Michigan.
On July 4th, 1999, a major thunderstorm
passed through northeastern Minnesota and blew down or affected
approximately 478,000 acres of forest, including 300,000 acres
in the BWCA Wilderness. This storm disturbed significant areas
of old growth forest and provides an outstanding opportunity
to witness the natural processes of ecological succession in
this region.
Today, the Northern Lake States landscape is
still dominated by forests, but their age and composition have
been modified extensively by human activities. In particular,
early successional stands of aspen and paper birch have replaced
much of the vast old growth hardwoods and pines. Northern hardwoods
still cover much of northern Wisconsin and Upper Michigan, but
most of the forest consists of young or moderately aged trees
that are harvested periodically.
Current vegetation maps of the Northern Lake States
are now available through interpretation of satellite images.
Although age of the forest typically is not depicted on these
maps, they provide useful tools for resource management and
for assessing the potential distribution of plants and animals.
The following links provide current land cover maps for this
region:
Curtis, J.T. 1959. The Vegetation of Wisconsin.
University of Wisconsin Press. Madison.
Davis, M.B. 1981. Quaternary history and the stability
of deciduous forests. pp. 132-153 in D.C. West, H.H. Shugart,
and D.B. Botkin, eds., Forest Succession: Concepts and Applications.
Springer-Verlag, New York.
Finley, R.W. 1976. Vegetation of Wisconsin
in the 1830's (map). Cartographic Laboratory. University
of Wisconsin-Madison.
Frelich, L.E. 1995. Old forest in the Lake States
today and before European settlement. Natural Areas Journal
15:157-167.
Marschner, F.J. 1975. The Original Vegetation
of Minnesota (map). U.S. Department of Agriculture, Forest
Service, North Central Forest Experiment Station, St. Paul,
MN.
Veatch. J.O. 1928. Reconstruction of forest cover
based on soil maps. Quarterly Bulletin of the Michigan Agriculture
Experiment Station 10:116-126.
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