This upland forest community occurs on rich, well-drained loamy soils, mostly on glacial till plains or loess-capped sites south of the tension zone. The dominant tree species is sugar maple (Acer saccharum), but American basswood (Tilia americana), and near Lake Michigan, American beech (Fagus grandifolia) may be co-dominant. Many other trees are found in these forests, including those of the walnut family, ironwood (Carpinus caroliniana), northern red oak (Quercus rubra), red maple (Acer rubrum), white ash (Fraxinus americana), and slippery elm (Ulmus rubra). The understory is typically open, or sometimes brushy with species of gooseberry (Ribes spp.) on sites with a history of grazing, and supports fine spring ephemeral displays. Characteristic herbs are spring-beauty (Claytonia virginica), trout-lilies (Erythronium spp.), trilliums (Trillium spp.), violets (Viola spp.), bloodroot (Sanguinaria canadensis), blue cohosh (Caulophyllum thalictroides), may-apple (Podophyllum peltatum), and Virginia waterleaf (Hydrophyllum virginianum).
Historically, southern mesic forests were quite common throughout southern Wisconsin. For example, forests dominated by sugar maple or beech occupied 41% of the Southern Lake Michigan Coastal, 25% of the Southeast Glacial Plains, and 18% of the Western Coulees and Ridges Ecological Landscapes (Finley 1976). Most of these forests were cleared for agriculture because the soils are very fertile.
