Regional Landscape Ecosystems of Michigan, Minnesota, and Wisconsin
SUB-SUBSECTION VI.4.2. Greenville
DISCUSSION: Sub-subsection is considered transitional from Section VI to Section VII because of its sandy soils and intermediate elevations. The vegetation also reflects this transition, with increased conifer dominance in both uplands and wetlands.
ELEVATION: 800 to 1,122 feet (243 to 342 m).
AREA: 811 square miles (2,100 sq km).
STATES: Michigan.
CLIMATE: Growing season ranges from 130 to 150 days (Eichenlaub et al. 1990). Snowfall ranges from 50 to 70 inches, and annual precipitation ranges from 30 to 32 inches. Extreme minimum temperature ranges from -26½F to -30½F.
BEDROCK GEOLOGY: See subsection.
LANDFORMS: Generally hilly terrain, dissected by outwash channels. The hills, up to 140 feet high, are moderately to steeply sloping. Both the ground moraine and end moraine are moderately to steeply sloping, but the ground-moraine ridges are generally smaller than those of the end moraine.
LAKES AND STREAMS: Many small kettle lakes, typically less than 1 square mile in area, on outwash, end moraine, and ground moraine.
SOILS: Soils are well drained and excessively drained sands and loamy sands on the uplands. Sand outwash deposits are common on lower slopes. Most of the outwash soils are poorly drained. Soils are classified by the Soil Conservation Service (1967) as Haplorthods plus Glossoboralfs and Udipsamments.
PRESETTLEMENT VEGETATION: The upland vegetation was a mosaic of beech-sugar maple and oak-hickory forests. Oak-hickory forest was more common at the southern edge of the sub-subsection; beech-sugar maple was more common to the north. This pattern is likely the result of gradual climatic changes that occur as the terrain rises northward into the Highplains subsection (VII.2). White pine was once locally common on the drier upland sites, often growing with white oak in either open forests or savannas.
The lowland vegetation also contained elements of both the deciduous hardwood swamp and hardwood-conifer and conifer swamps. Most of the swamp forests in the outwash channels were hardwood-conifer swamps containing hemlock, balsam fir, northern white-cedar, white pine, trembling aspen, and paper birch.
NATURAL DISTURBANCE: Fires were probably important for maintaining the oak-pine and oak forests and savannas. Windthrows, probably relatively small due to the irregular, small ridges of the sub-subsection, were probably more common in the beech-sugar maple-dominated forests.
PRESENT VEGETATION AND LAND USE: Parts of this sub-subsection were farmed, both for row crops and pasture after logging; but much of the farmland has been abandoned due to low productivity and cold climate. Large parts of the sub-subsection remain forested. Most agricultural activities have been concentrated in uplands with the richest soils. Most wetlands have not been significantly impacted by agricultural activities.
RARE PLANT COMMUNITIES: None identified to date.
RARE PLANTS: None identified to date.
RARE ANIMALS: Asio otus (long-eared owl), Lycaeides melissa samuelis (Karner blue).
NATURAL AREAS: MacCurdy Ecological Tract.
PUBLIC LAND MANAGERS: State Game Areas: Flat River, Rouge River, Stanton, Lanston; National Forests: Manistee.
CONSERVATION CONCERNS:
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