Regional Landscape Ecosystems of Michigan, Minnesota, and Wisconsin
SUBSECTION X.3. Laurentian Highlands
DISCUSSION: The drumlin field consists of northeast-southwest-oriented ovoid hills separated by bogs or swamp forests (University of Minnesota et al. 1981b).
SUB-SUBSECTIONS: None.
ELEVATION: 1,350 to 1,900 feet (411 to 579 m).
AREA: 731 square miles (1,892 sq km).
STATES: Minnesota.
CLIMATE: Annual precipitation ranges from 28 to 29 inches (Hargrave 1992). Growing season precipitation is 11 to 12 inches. Annual snowfall ranges from 60 to 64 inches (Wendland et al. 1992). Growing season ranges from 106 to 121 days. Extreme minimum temperature ranges from -40½F to -45½F (Reinke et al. 1993).
BEDROCK GEOLOGY: Glacial drift thickness over bedrock is generally less than 100 feet; and there are localized outcrops of bedrock, especially along the eastern edge (Olsen and Mossler 1982). The bedrock of the entire subsection is Precambrian in age. In the north, Keweenawan bedrock includes sandstone, arkose, shale, basaltic to rhyolitic lava flows and pyroclastic rocks, gabbro, troctolite, ferrogabbro, anorthosite, and peridotite (Morey 1976, Morey et al. 1982). To the south, upper Precambrian quartzite is extensive.
LANDFORMS: Drumlin ridges, about a mile long, a quarter mile wide, and 30 to 50 feet high (University of Minnesota et al. 1981b). The narrow depressions between the drumlins, generally less than a mile wide, are usually poorly or very poorly drained; they support either conifer swamps or bogs.
Subsection X.3 also includes the Brimson outwash plain along its eastern edge. Most of the plain is level, but there are steep slopes along the Cloquet River.
LAKES AND STREAMS: There are 17 lakes of more than 160 acres (University of Minnesota et al. 1977, 1981b). Most of these lakes have narrow basins 1 to 3 miles long and less than a mile wide, oriented in the same direction as the adjacent drumlins. Several rivers and creeks occupy the wetland depressions between the drumlins.
SOILS: Soils on the upland parts of the drumlin field are well-drained gravelly, sandy loams. Between the drumlins are narrow or broad depressions with very poorly drained soils; these account for nearly half of the surface area of the subsection. Almost 90 percent of the soils of the Brimson outwash plain are excessively drained sands; the remainder are very poorly drained.
Soils of the drumlin fields are classified as Ochrepts, Aquepts, and Hemists; those of the outwash are Orthents, Orthods, Ochrepts, and Psamments (Cummins and Grigal 1981).
PRESETTLEMENT VEGETATION: The major forest type mapped on the drumlin ridges was aspen-birch, with only small areas of white pine-red pine forest (Marschner 1974). Mixed hardwood-pine was infrequent. Conifer-swamp or bog occupied the depressions between most of the drumlins.
White pine-red pine was well represented in the Brimson outwash plain, where it was the most common forest type. At the northeastern end of the plain, jack pine barrens dominated a strip 8 to 10 miles long and 1 to 3 miles wide. Small conifer bogs or swamps were scattered across the outwash. Aspen-birch was also present there.
NATURAL DISTURBANCE: Fire was important for maintaining both upland conifer forests and forests of aspen-birch.
PRESENT VEGETATION AND LAND USE: Very little biological survey has been done to determine which plant communities are well represented in this subsection.
RARE PLANT COMMUNITIES: None identified to date.
RARE PLANTS: None identified to date.
RARE ANIMALS: Clemmys insculpta (wood turtle).
NATURAL AREAS:
PUBLIC LAND MANAGERS: Cloquet Valley State Forest, Finland State Forest.
CONSERVATION CONCERNS: Concern has been expressed over accelerated timber harvest.
BOUNDARIES: Subsection is bounded on the east by the Lake Superior Highlands (Subsection X.9), on the north by the Nashwauk uplands (Subsection X.8), on the west by the Tamarack Lowlands (Subsection X.4), and on the south by the Mille Lacs Uplands (Subsection X.2).
Previous Section -- Subsection X.2. Mille Lacs Uplands
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Next Section -- Subsection X.4. Tamarack Lowlands
