Regional Landscape Ecosystems of Michigan, Minnesota, and Wisconsin
SUB-SUBSECTION IX.3.1. Brule and Paint Rivers
DISCUSSION: Silt-loam-capped ground moraine and outwash with linear lakes characterize the landscape. The silt cap results in a diverse groundcover flora as well as tree species not commonly occurring on the more prevalent sandy loam soils in this part of the State.
ELEVATION: 1,350 to 1,875 feet (411 to 572 m).
AREA: 1,801 square miles (4,667 sq km).
STATES: Michigan and Wisconsin.
CLIMATE: Continental, with heavy snows and extremely cold winters. See subsection.
BEDROCK GEOLOGY: Glacial drift covers bedrock, which is only locally exposed. The predominant bedrock types are Precambrian basaltic to rhyolitic metavolcanic rock with some metasedimentary rock. In Michigan, the western part of the Menominee Iron Range is within the sub-subsection.
LANDFORMS: Drumlin ridges and adjacent swampy depressions that are oriented northeast-southwest. The ridges are typically one-third to one-half mile wide, 1 mile long, and 80 to 140 feet high (Albert et al. 1986). Glaciofluvial deposits of sand and gravel surround many of the drumlins; but these are often covered with a thin silt cap, resulting in vegetation dominated by northern hardwoods.
LAKES AND STREAMS: Most large lakes here are linear, with the same general trend as the adjacent drumlins; the lake basins were eroded by glacial ice. Among the larger lakes are North Twin, Big Sandy, Long, and Smoky in Wisconsin, as well as Smoky, Brule, Golden, Chicagon, Stanley, Ottawa, and James in Michigan. Smaller kettle lakes are also scattered throughout.
Many small creeks and rivers drain the numerous linear wetlands between the drumlins. Larger rivers include the Paint and Brule.
SOILS: Soils are generally well drained, derived from rocky, red, sandy loam till or gravelly, loamy sand outwash. Often the soils have a silt cap of loess. In Wisconsin, the silt-loam loess is as much as 30 inches deep (Hole and Germain 1994); in Michigan, the loess cap is generally thinner. At the northern edge of the sub-subsection in Michigan, the loess is localized; often one side of an outwash channel will have a thin loess cap, while the other will not. Fragipans are common, often resulting in poor drainage conditions on flat ridge tops. The soils are reddish from the abundance of iron in the local bedrock. This sub-subsection is distinguished from Sub-subsections IX.3.3 and IX.3.4, which have thicker, more continuous loess caps. Nevertheless, the thin loess cap has an important effect on the vegetation here.
PRESETTLEMENT VEGETATION: Northern hardwoods dominated this unit, but with higher amounts of white ash, American elm, yellow birch, and basswood than on sandy loam soils in adjacent Sub-subsection IX.3.2. Larix and black spruce dominated most depressions between the drumlin-like ridges, and the centers of some of these depressions supported bogs and wet meadows. Black ash, yellow birch, and American elm dominated better drained depressions.
NATURAL DISTURBANCE: Windthrows were large and relatively common on broad ridges, as noted by GLO surveyors and more recent field studies (Albert 1990). I observed that the surface of the drumlins is in most cases almost completely covered with windthrow mounds (cradle-knoll).
PRESENT VEGETATION AND LAND USE: Sub-subsection IX.3.1 is managed primarily for forest, but local areas of the broad ridges are pastured. Iron mining was once important near the city of Iron River on the Menominee Iron Range. Northern hardwoods are dominant on both sandy loam and silt loam soils. American elm, basswood, white ash, and yellow birch are much more common on silt loams than on the sandy loams of Sub-subsection VIII.3.2 (Albert 1983, Goff in Milfred et al. 1967). Ground layers are ephemeral rich, unlike those of Sub-subsection IX.3.2. Within the Nicolet National Forest, the best saw timber comes from this sub-subsection.
Where the linear depressions between the drumlinized ridges are drained by streams, American elm and balsam fir are common. In linear depressions undrained by streams, poor fen or bog dominated by sedges and sphagnum mosses is common; tamarack is dominant along the edges of these depressions and is gradually replaced by black spruce toward the center. Northern white-cedar is occasionally present at the edges of depressions, but the ground and end moraines generally contain little of this species.
RARE PLANT COMMUNITIES: None identified to date.
RARE PLANTS: Michigan and Wisconsin: Carex assiniboinensis (Assiniboia sedge), Juncus stygius (moor sedge), and undescribed species of Botrychium. Wisconsin only: Polemonium occidentalis (western Jacob's ladder), and Valeriana sitchensis (marsh valerian). Michigan only: Botrychium hesperium (western moonwort), Botrychium pseudopinnatum (grapefern), Carex arcta (sedge), Petasites sagittatus (sweet coltsfoot).
RARE ANIMALS: Gavia immer (common loon), Haliaeetus leucocephalus (bald eagle), Pandion haliaetus (osprey), Martes americana (marten).
NATURAL AREAS: Michigan: Iron River State Roadside Rest (old-growth northern hardwoods). Wisconsin: State Natural Areas: Giant White Pine Grove, Bose Lake Hemlock-Hardwoods, Marinette County Beech Forest, Scott Lake-Shelp Lake; Wilderness Areas (Nicolet National Forest): Whisker Lake, Headwaters; Research Natural Areas (Nicolet NF): Grandma Lake, McCaslin Mountain, Bose Lake Hemlock-Hardwoods.
PUBLIC LAND MANAGERS: Michigan: State Forests: Copper Country; National Forests: Ottawa. Wisconsin: National Forests: Nicolet.
CONSERVATION CONCERNS: There are no Forest Service Research Natural Areas and few nature preserves in the highly productive northern hardwoods of this sub-subsection. The forests are probably important for breeding songbirds. Breeding bird habitat is probably secure because most of the lands will remain under forest management. However, the impact of present logging practices on songbird breeding success is not known; this question is now being investigated in a Wisconsin Department of Natural Resources research project. In Wisconsin, this area is considered a high priority for identification of potential natural areas.
BOUNDARIES: In Michigan, the boundaries are based on my interpretation of the soils and landforms of Michigan, both my own sampling and Veatch's (1953) soils interpretation. This sub-subsection includes most of the Ottawa National Forest's Map Unit F. In Wisconsin, the ground moraine with (thin) silt cap is separated from the outwash and ice-contact deposits of Subsection IX.5 to the west on the basis of recent soil surveys (Langlade, Vilas, Oneida, Marinette County) and works by Attig (1985) and Mickelson (1986). The extreme northwestern boundary is based on Clayton's Florence County glacial landform map (1986), showing the boundary of silt-capped vs. uncapped glacial drift. The recent Oconto County soil survey did not recognize any silt cap (even where the adjacent Langlade County survey did), so this part of the boundary was based on drumlin features without textural data. I include a larger area of ground moraine and drumlin features than Hole (1968) did in his soils interpretation of Wisconsin.
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