Regional Landscape Ecosystems of Michigan, Minnesota, and Wisconsin
SUB-SUBSECTION VIII.2.2. Grand Marais Sandy End Moraine and Outwash
DISCUSSION: Sandy ridges of end moraine and pitted outwash are characteristic of the sub-subsection. Lacustrine deposits of glacial and postglacial origin are also located along the northeastern edge.
ELEVATION: 602 to 1,300 feet (184 to 396 m).
AREA: 1,765 square miles (4,562 sq km).
STATES: Michigan.
CLIMATE: Average growing season ranges from 140 days very close to Lake Superior to less than 100 days farther inland (Eichenlaub et al. 1990). Extreme minimum temperature ranges from -30½F along Lake Superior to -40½F or less at the southern inland edge. Average annual precipitation is relatively uniform, between 32 and 34 inches. Annual snowfall is as high as 180 inches on the uplands near Lake Superior, decreasing to approximately 100 inches in the south.
BEDROCK GEOLOGY: An east-west-trending sandstone escarpment of Cambrian age is exposed in several waterfalls, including Tahquamenon Falls, Au Train Falls, Miner's Falls, and Laughing Whitefish Falls, and along the Lake Superior shoreline at Pictured Rocks National Lakeshore (Dorr and Eschman 1984, Reed and Daniels 1987). Farther inland, Ordovician sandstone and dolomite are the underlying bedrock (Reed and Daniels 1987). Bedrock is locally exposed, but drift can be at least 200 feet thick, both on the outwash plains and on the moraine ridges (Vanlier 1963a).
LANDFORMS: Sandy ridges of end moraine and pitted outwash. Lacustrine deposits of glacial and postglacial origin are also located along the northeastern edge. The recent geomorphological interpretation is that many of the end moraines (as originally interpreted by Leverett 1929) are actually heads of outwash and related stagnation landforms (Blewett and Rieck 1987).
Lacustrine deposits within the sub-subsection can be broken into two major types: the droughty sand dunes and beach ridge deposits and the poorly and very poorly drained glacial lacustrine deposits. Along the Lake Superior shoreline, sand dunes, sand spits, and beach ridges form a broad zone characterized by vast expanses of excessively drained sand soils, unlike most shorelines of the Great Lakes.
The Grand Sable Dunes, west of the town of Grand Marais, are large, steep dunes perched upon till. The dunes are active, supporting only local areas of forest. At their protected east end, they support a small area of northern hardwood forest. A few small pockets of jack pine also persist within the dunes.
The poorly drained deposits are concentrated in northern Luce County. These are of the same age and support vegetation similar to that of the more extensive peatlands of Sub-subsection VIII.2.1. An extensive complex of sandspits at Whitefish Point in northwestern Chippewa County produced hundreds of alternating swales and sandspits.
Outwash plains are concentrated along the southern edge of the sub-subsection, and a relatively small area of poorly drained outwash is at the extreme west edge. Along the shoreline, outwash is restricted to areas west of Munising and west of Grand Marais.
Most of the moraine ridges and pitted outwash have well-drained, sandy soils. Kettles within the pitted outwash and moraines contain bogs with thick deposits of sphagnum peat. At the far western edge of the sub-subsection, where sandstone bedrock is only thinly covered by till, soils are moderately well drained. The soils are classified as Histosols and Entisols (Aquepts), with some Orthods and Aquods (USDA Soil Conservation Service 1967).
LAKES AND STREAMS: Numerous kettle lakes in local areas of the pitted outwash.
SOILS: Most of the moraine ridges and pitted outwash have well-drained, sandy soils.
PRESETTLEMENT VEGETATION: Sandy lake plain along Lake Superior supported several wetland and upland communities. Emergent marshes, bogs, and speckled alder-willow swamps were common in the swales associated with the shoreline and small lakes immediately inland.
Peatlands were dominated by stunted black spruce, northern white-cedar, and tamarack; narrow beach ridges within the peatlands were dominated by white and red pine (Comer et al. 1993a). Excessively drained, fire-prone portions of the lake plain supported forests dominated by jack pine and red pine-jack pine. Jack pine-dominated forests were extensive along the shoreline between Grand Marais and Whitefish Point. Upland portions of the lake plain that were better protected from wildfires were extensive along the shoreline west of Grand Marais. These areas supported forests dominated by hemlock, northern hardwoods, and hemlock-white pine.
Extensive complexes of beach ridges and swales occurred on the sandy lake plain along Lake Superior. Most examples were excessively drained throughout and supported jack pine and redpine. However, the complex at Tahquamenon Bay was mostly spruce and tamarack-dominated swamp, and the swales at Au Train and Whitefish Point included tamarack swamp and shrub swamp.
The Grand Sable Dunes were active, supporting only local areas of forests. At their protected east end, they supported a small area of northern hardwood forest and a few, small pockets of jack pine.
GLO surveyors noted extensive emergent marshes near the mouth of the Au Train River and at the southeast end of Grand Island. The Au Train marsh is best described as a fresh water estuary or drowned river mouth created when dunes restricted the river's flow into Lake Superior.
Small areas of clay lake plain at Tahquamenon Bay supported spruce and tamarack-dominated swamps. Narrow strips of clay lake plain along the shore in Luce County supported hemlock-white pine forests.
Coarse-textured moraines, most common south of Tahquamenon and Pendills Bays, supported northern hardwoods, often with significant amounts of hemlock. Forests of red pine and white pine and red pine "openings" were also common on these moraines; and small swamps dominated by northern white-cedar, tamarack, and spruce were also found in depressions on these moraines. On somewhat poorly drained tills, where bedrock is near the surface, hemlock and white pine were dominant species. Small cedar and tamarack-dominated swamps also occurred on the end moraines east of Munising.
Poorly drained outwash was uncommon in this sub-subsection. Where it did occur, just west of Munising, there was cedar-dominated swamp. Well-drained outwash supported northern hardwood forest. Somewhat poorly drained outwash near the edges of wetlands often supported hemlock. Droughty, flat outwash plains supported open jack pine barrens, or where conditions were not quite so fire prone, forests of jack pine, red pine, and occasionally, white pine.
NATURAL DISTURBANCE: GLO surveyors mentioned fires in the pineries on the sand ridges between Whitefish Point and Grand Marais and at the mouth of the Tahquamenon River. A large windthrow was noted in the cedar-tamarack swamps near the Lake Superior shoreline.
PRESENT VEGETATION AND LAND USE: Surveyors noted several Native American trails, fields, and sugar camps west of Tahquamenon Bay and near Munising. Early European settlements were established on Grand Island and west of Munising at the time of the surveys.
The dominant use of this sub-subsection has been for commercial timber production. Urban development has been limited mainly to the Munising area. Although most of the wetlands in this region persist, they were probably altered by logging and post-logging fires. Roads and small dams have had the most significant impact on wetland hydrology.
The upland forests have also been greatly affected by logging-era activities. On the droughty Raco Plains, jack pine dominance expanded, but areas of white and red pine have had poor regeneration. The Kingston Plains were originally dominated by forests of red and white pine, and northern hardwoods with white pine. On the areas of these plains most severely burned by post-logging fires, the only existing vegetation consists of lichens, sedges, and scattered understory black cherries. Subsequently, parts of both plains have been planted to red pine or jack pine.
RARE PLANT COMMUNITIES: None identified to date.
RARE PLANTS: Botrychium acuminatum (acute-leaved moonwort), Botrychium campestre (prairie moonwort), Botrychium hesperium (western moonwort), Cirsium pitcheri (Pitcher's thistle), Elymus mollis (American dune wild-rye), Empetrum nigrum (black crowberry), Littorella americana (American shore-grass), Potamogeton confervoides (alga pondweed).
RARE ANIMALS: Charadrius melodus (piping plover), Falco peregrinus (Peregrine falcon), Gavia immer (common loon), Haliaeetus leucocephalus (bald eagle), Lycaeides idas nobokovi (northern blue), Martes americana (marten), Pandion haliaeetus (osprey), Sterna hirundo (common tern), Trimerotropis huroniana (secretive locust).
NATURAL AREAS: Research Natural Areas: Betsy Lake (State), Betsy Lake River (State), Grand Island (Hiawatha NF), Au Train Gorge (proposed, Hiawatha NF); Wilderness Areas: Rock River Canyon (Hiawatha NF); State Scenic Sites: Wagner Falls; The Nature Conservancy Preserves: McMahon Lake, Swamp Lakes; Michigan Nature Association Preserves: Lake Superior, Twin Waterfalls; Other: Whitefish Point Bird Observatory.
PUBLIC LAND MANAGERS: National Park Service: Pictured Rocks National Lakeshore, including Grand Sable Dunes, Grand Island; National Forests: Hiawatha; State Forests: Lake Superior; State Parks: Tahquamenon Falls, Muskallonge Lake; State Environmental Areas: Tahquamenon Island, Williams Island.
CONSERVATION CONCERNS: Parts of the Lake Superior shoreline support some of the most extensive natural stands of red pine in the State; none of these red pines have special designation. Two areas of wetland within the sub-subsection are being protected: McMahon Lakes patterned peatland and the extensive shallow peatlands surrounding Betsy Lake. Old-growth northern hardwoods and some white pine are protected within the Tahquamenon Falls State Park. Whitefish Point on Lake Superior is a famous migratory route for hawks, owls, and other birds. The Grand Sable Dunes and coastal sandstone cliffs of the Pictured Rocks National Lakeshore are protected.
Protection should be considered for some areas of the "pine stump plains" for scenic and educational value. Identification of potential future natural areas where white pine is successfully regenerating should also be considered; our present natural areas of white pine are overmature stands that may not survive long into the future.
BOUNDARIES: The Hiawatha National Forest's Ecological Classification System further subdivides this sub-subsection into several finer mapping units.
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