General information

Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.

MLRA notes

Major Land Resource Area (MLRA): 092X–Superior Lake Plain

The Wisconsin portion of the Superior Lake Plain (MLRA 92) corresponds very closely to the Superior Coastal Plain Ecological Landscape published by Wisconsin Department of Natural Resources (WDNR 2015). The following brief overview of this MLRA is borrowed from that publication.

The Superior Coastal Plain is bordered on the north by Lake Superior and on the south by the Northwest Sands, Northwest Lowlands, and North Central Forest Ecological Landscapes. The total land area is approximately 1.2 million acres, which mostly consists of privately-owned forestland. The climate is strongly influenced by Lake Superior, resulting in cooler summers, warmer winters, and greater precipitation compared to more inland locations. The most extensive landform in this ecological landscape is a nearly level plain of lacustrine clays that slopes gently northward toward Lake Superior. The coastal plain is cut by deeply incised stream drainages and interrupted by the comparatively rugged Bayfield Peninsula.

During the Late Wisconsin glacial period, this area was covered with the advancing and retreating lobes of Superior and Chippewa. The landscape was rippled with moraines, but they were subdued by deposition of lacustrine materials. As the glaciers receded, glacial lakes riddled the landscape—most notably, Glacial Lake Duluth. The glacier receded eastward, exposing the western Lake Superior Basin. The ice covered the eastern basin, blocking the outlet of the lake, and continued to recede and contribute meltwaters that filled the glacial lake. The deep, red clays were deposited during this period of glacial lakes. The meltwaters from the glacier also contained sands which were deposited along the edge of the glacial lakes as beach deposits. Deep, narrow valleys have since been carved by rivers and streams flowing north into Lake Superior.

Historically, the Superior Coastal Plain was almost entirely forested. Various mixtures of eastern white pine (Pinus strobus), white spruce (Picea glauca), balsam fir (Abies balsamea), white birch (Betula papyrifera), balsam poplar (Populus balsamifera), quaking aspen (Populus tremuloides), and northern white-cedar (Thuja occidentalis) occurred on the fine-textured glacio-lacustrine deposits bordering much of the Lake Superior coast. Sandy soils, sometimes interlayered with clays, occur in some places. Such areas supported forests dominated by eastern white pine and red pine (Pinus resinosa). Eastern white pine was strongly dominant in some areas, according to mid-19th century notes left by surveyors of the federal General Land Office (Finley, R. 1976). Dry-mesic to wet-mesic northern hardwoods or hemlock-hardwood forests were prevalent on the glacial tills of the Bayfield Peninsula. Large peatlands occurred along the Lake Superior shoreline, associated with drowned river mouths.

Classification relationships

Habitat Types of N. Wisconsin (Kotar, 2002): Six sites key out to Acer rubrum – Abies balsamea / Sanicula spp. [ArAbSn], three sites key out to Acer saccharum / Athyrium felix-femina – Rubus pubescens [AAtRp], one site keys out to Acer saccharum / Sanicula spp. – Mitchella repens [ASnMi], one site keys out to Acer saccharum / Clintonia borealis [ACl], and one site keys out to Acer saccharum – Tsuga canadensis / Maianthemum canadense [ATM].

Biophysical Setting (Landfire, 2014): This is ES is mapped as, Laurentian – Acadian Northern Hardwoods Forest – Hemlock, Laurentian – Acadian Sub-boreal Mesic Balsam Fir-Spruce Forest, Laurentian – Acadian – Northern Pine – (Oak) Forest, North Central Interior Dry-Mesic Oak Forest & Woodland, and North Central Interior Maple – Basswood Forest. The ES is best represented by Northern hardwoods Forest and North Central Interior Maple – Basswood Forest.

WDNR Natural Communities (WDNR, 2015): This ES is most similar to Northern Mesic and Norther Wet-mesic Forests.

USFS Subregions: Superior-Ashland Clay Plain Subsection (212Ya); May contain small areas of Ewen Dissected Lake Plain Subsection (212Jo), Winegar Moraines Subsection (212Jc), Gogebic-Penokee Iron Range Subsection (212Jb), and NorthShore Highlands Subsection (212Lb)*
•Located in Upper Peninsula of Michigan (212J) and Minnesota (212Lb)

Major Land Resource Area (MLRA): Superior Lake Plain (92)

Ecological site concept

Clayey Uplands is the most common ES in MLRA 92. It spans nearly every part of the MLRA. The sites were formed in clayey till or glaciolacustrine deposits, though some sites have a thin (<15 cm) sandy or loamy mantle over the clayey till or glaciolacustrine deposits. Soils are moderately well to well drained, but may have a seasonally high water table with a depth of 0 to 122 cm. The depth to water table can exceed 152 cm during drier periods. Water is received primarily through precipitation. These sites do not remain moist throughout the year. Many sites have carbonates present beginning as shallow as 13 cm, but absent in others. The soils range from strongly acid to moderately alkaline. This range depends on parent materials, whether there is a sandy mantle (acidic, lack of carbonates) or just clayey till or glaciolacustrine deposits. The nutrient availability regime, on a relative scale, is poor to medium. Within the Wisconsin Forest Habitat Type Classification System, this ES most frequently represent the ArAbSn and sometime AAtRp Habitat Types.

Historically, shade tolerant balsam fir and white spruce were best represented tree species on this Ecological Site, but scattered white and red pines were also common. Following early logging, trembling aspen became the dominant forest type, but succession to balsam fir and, to a lesser degree, white spruce and red maple is evident everywhere where seed sources are present. While there is no good record of the degree of red maple representation in the pre-European settlement forests, the species is well represented and successfully reproducing today. Common ground flora species are round-leaved dogwood, wood anemone, sedges, ferns, beaked hazelnut, horsetails, wild strawberry, and raspberries.

This ES differs from Sandy Upland and Loamy Upland based on soil texture, parent material, and depth to seasonally high water table. Clayey Uplands has the finest textures and clayey deposits on every site. This site does not remain saturated for extended lengths of time, differing it from Wet Clayey Lowlands and Moist Clayey Lowlands.

Associated sites

Similar sites

Table 1. Dominant plant species