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ELEVATION: 900 to 1,300 feet (274 to 396 m).

AREA: 1,543 square miles (3,996 sq km).

STATES: Michigan.

CLIMATE: Growing season is 70 to 120 days. It is longest near Lakes Michigan and Huron and shortest in outwash channels near the center of the sub-subsection, where elevations drop rapidly to the north (Eichenlaub et al. 1990). Frost danger is extreme throughout the growing season. Snowfall ranges from 140 inches in the northwest to 60 inches in the southeast. Heavy snows in the northwest are lake-effect snows off Lake Michigan. Annual precipitation is relatively uniform across the sub-subsection, 28 to 32 inches. Extreme minimum temperature ranges from -36½F to -50½F, warmest near Lakes Michigan and Huron and coldest in the outwash channels near the southern edge of the sub-subsection.

BEDROCK GEOLOGY: No exposures of bedrock. Glacial drift ranges from 100 to 800 feet thick and is thickest at the southern edge of the sub-subsection (Akers 1938). Underlying bedrock is of Paleozoic age, Devonian and Mississippian sandstone and shale (Dorr and Eschman 1984, Milstein 1987).

LANDFORMS: Steep moraine ridges surrounded by outwash channels and plains. Outwash deposits occur both as relatively narrow channels between the steep moraines and as broad plains. The broader channels have excessively well drained soils; many of the narrower outwash channels have poorly drained soils.

Most of the moraines have steep slopes and sandy, well-drained soils. Northern hardwood forests of beech, sugar maple, yellow birch, hemlock, and associated species dominate these steep sites. Fires from adjacent outwash plains burned parts of the northern hardwood forests.

LAKES AND STREAMS: Few lakes in the sub-subsection. Most are small kettle lakes on outwash; almost no lakes are on the steep moraines. Several large rivers originate here, including the Black, Sturgeon, Thunder Bay, and Pigeon. These are rapid ground water fed streams, noted for their fine canoeing and trout fishing.

SOILS: Most of the moraines have steep slopes and sandy, well-drained soils. Excessively well drained sands are found on the broader outwash plains; very poorly and poorly drained soils, with sandy or gravelly substrate, occupy narrow channels. Soils are classified as moderately sloping Haplorthods plus Glossoboralfs and Udipsamments (USDA Soil Conservation Service 1967).

PRESETTLEMENT VEGETATION: Northern hardwood forests of beech, sugar maple, yellow birch, hemlock, and associated species dominated most of the steep moraines. Some of the narrower outwash channels have poorly drained soils that supported either conifer or hardwood-conifer swamps. The broader channels have excessively well drained soils that supported jack pine and red pine.

NATURAL DISTURBANCE: GLO maps showed large fires in the larger outwash plains. Fires from outwash plains burned parts of the northern hardwood forests on adjacent moraines.

PRESENT VEGETATION AND LAND USE: Many of the lands are State owned and managed for both timber and wildlife. The area is a favorite for recreation, including hunting, fishing, and canoeing.

RARE PLANT COMMUNITIES: None identified to date.

RARE PLANTS: Amerorchis rotundifolia (round-leaved orchis), Cirsium hillii (Hill's thistle), Cypripedium arietinum (ram's head lady's slipper), Mimulus glabratus var. jamesii (James' monkey-flower), Sarracenia purpurea f. heterophylla (yellow pitcher-plant).

RARE ANIMALS: Brychius hungerfordi (Hungerford's crawling water beetle), Buteo lineatus (red shouldered hawk), Martes americana (marten).

NATURAL AREAS: State Natural Areas: Pigeon River (proposed); Michigan Nature Association Preserves: Lost Lake.

PUBLIC LAND MANAGERS: Mackinaw State Forest, Huron National Forest, Petoskey State Park, Oden State Fish Hatchery.

CONSERVATION CONCERNS: Although the wetlands are recognized as diverse by botanists, there are few threatened and endangered plant records and almost no ecological data on any of the wetlands. Large parts of the sub-subsection are under State forest management, probably because of the steepness of the terrain, which does not allow agricultural development. The large, unbroken tracts of forest are probably important for migratory songbirds, although studies are lacking.