Regional Landscape Ecosystems of Michigan, Minnesota, and Wisconsin
SUB-SUBSECTION IX.3.4. Chippewa-Green Bay Lobes
DISCUSSION: Sub-subsection IX.3.4 consists of a narrow band of stagnation moraine that separates Subsection IX.3 from IX.4. In the east, there are several parallel end moraines separated by outwash, and also inclusions of ground moraine (till plain). In the west, there is a broad area of stagnation moraine, with end moraine along its margins.
ELEVATION: 688 to 1,952 feet (210 to 595 m).
AREA: 5,997 square miles (15,539 sq km).
STATES: Wisconsin.
CLIMATE: Continental, with moderately heavy snowfall and extremely cold winters. See subsection.
BEDROCK GEOLOGY: See subsection. Because of its length, this map unit is underlain by a broad range of Precambrian bedrock.
LANDFORM: Sub-subsection is a narrow band of stagnation moraine formed at the front of the Chippewa, Wisconsin Valley, Langlade, and Green Bay lobes during the Wisconsin Glaciation (Clayton et al. 1991). The Green Bay lobe part of the sub-subsection to the east consists of several narrow end-moraine ridges separated by outwash channels and includes areas of ground moraine. At the western edge, there is also stagnation moraine (Goebel et al. 1983).
LAKES AND STREAMS: Small kettle lakes are common on the moraines, but there are few large lakes. The moraines are also headwater to several streams.
SOILS: Diverse soils, as could be expected from a linear ridge that crosses much of Wisconsin. Soil texture is typically sandy loam to loam, developed from either brown or red glacial drift. To both the east and west, substrates are neutral; in the center of the State, substrates are acidic. Stoniness is variable. Soils of the Wisconsin Valley lobe are rich in fragments of iron formation and basalt. Soils of the Green Bay lobe are typically underlain by outwash deposits of sand and gravel.
Wetland soils are not extensive, but peat bogs are common throughout in ice-block kettles. Soils are classified as Fragiochrepts, Eurochrepts, Fragiorthods, Hapludalfs, and Glossoboralfs (Hole 1976).
PRESETTLEMENT VEGETATION: Northern hardwoods, dominated by a mix of hemlock, sugar maple, basswood, and white pine, were present throughout. American beech occurred at the eastern edge.
NATURAL DISTURBANCE: Windthrow as documented by Canham and Loucks (1984).
PRESENT VEGETATION AND LAND USE: Most of the sub-subsection remains forested. Major land uses are forestry and recreation.
RARE PLANT COMMUNITIES: None identified to date.
RARE PLANTS: None identified to date.
RARE ANIMALS: None identified to date.
NATURAL AREAS: State Natural Areas: Flora Spring Pond, Blue Hill Felsenmeer, Dory's Bog, Jung Hemlock-Beech Forest, Atkins Lake, Krueger Pines, Oxbow Rapids, Mud Lake Bog, Keller Whitcomb Creek Woods, Dalles of the St. Croix River, Interstate Lowland Forest, Tula Lake.
PUBLIC LAND MANAGERS: National Forests: Chequamegon, Nicolet.
CONSERVATION CONCERNS: The Menominee Indian Reservation, near the eastern edge of the sub-subsection, is unique in Wisconsin, in that much of the forested land there has never been clearcut. The forest probably closely approximates the presettlement conditions in ways that small isolated old-growth remnants elsewhere cannot.
BOUNDARIES: It has been suggested that the Green Bay lobe, at the eastern edge of the sub-subsection, should be treated as a separate sub-subsection. Based on differences in soils (more calcareous) and vegetation (large amounts of American beech), it is reasonable to separate the Green Bay lobe from the remainder of the sub-subsection. However, I would separate the lobe at the next, more local level of the hierarchy.
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