Earth Partnership for Schools



General: Pioneers called these forests the "Big Woods." Laura Ingalls Wilder lived next to a maple forest in Dunn County in her book The Big Woods .

Distribution: In presettlement times, mesic forest covered 3,432,00 acres or 9.8% of the total land area. Mesic forests are scattered as disconnected islands in the southern region. Maple woods grow on north slopes and areas protected from fire. The largest stands are in the eastern counties along Lake Michigan; in Richland County, St. Croix, Pierce, and Dunn counties. Smaller sites are in Grant, Green, Sauk, and Dane counties.

Physical Environment: Mesic forests grow best in deep, loamy soils but will grow wherever the topography is not extreme.

Topography: Maple forests often grow on moist but well-drained slopes and uplands; north and east facing slope aspects; wet ravines; and sheltered coves; and areas protected from sun exposure and prevailing dry winds. Before European settlement, mesic forests grew on lands protected from fire such as the leeward side of lakes.

Microclimate: The entire ecosystem is greatly influenced by the life history of the sugar maple. The striking difference between a mesic forest and other southern forests is the low light level on the forest floor in the summer due to the deep shade cast by the sugar maple leaves. Where small patches of light penetrate the canopy, windows of light less than two square feet light up the forest floor. These light patches are known as sun flecks. The dense layering of leaves protects against prevailing winds and increases the humidity levels within the forest. The nutrient-rich leaves rapidly decompose, releasing nutrients that are quickly made available for other plants growing on the forest floor.

Composition: Species listed below are most likely found in the community.

Dominant Trees: Sugar maple, basswood, and beech. Beech is restricted to counties along lake Michigan.

Common Trees: Slippery elm, red oak, and ironwood.

Typical Shrubs: Bladdernut, gooseberry. Vines: woodbine, poison ivy, and bittersweet.

Prevalent Groundlayer: The flowering plants in the groundlayer are primarily spring bloomers; 60.8% bloom before June 15. In the summer 30.2% of the plants bloom; 9% bloom in the fall. Spring ephemerals make up a large portion of the spring bloomers. Ephemerals appear, bloom, set seed, then die back before the canopy leaves are fully expanded. All have underground storage organs such as a corn, tuber, bulb or fleshy rhizome. Prevalent ephemeral species include troutlilies, Dutchman's breeches, squirrel corn, spring beauty, toothwort and false rue-anemone. Other spring bloomers are bloodroot, jack-in-the-pulpit, wild ginger, hepatica, woods phlox, mayapple, cohosh, and trilliums. Several species have seeds, which are dispersed by animals. Wild ginger, Dutchman's breeches, troutlily, bloodroot, and trillium attract ants with a sweet spot on their seed coats. Species such as mayapple, trout lily and waterleaf form large colonies through vegetative reproduction.

Structure: A rich diversity of herbaceous plants carpets the forest floor. The patterns of shade and light influences the distribution of species in the understory. Shrubs and small trees are restricted to patches of light. The result is a forest with a dense canopy and open mid-layers. Only a few trees are able to germinate and persist in the low light levels of a maple-basswood canopy. Shade tolerant sugar maple seedlings and saplings far outnumber any other species growing below the canopy. Slippery elm, basswood, ironwood, and yellowbud hickory are the only other species reproducing.

Soil: Coarse to medium soils, loams. Moist to average moisture in soils. Well to moderately well-drained soil.

Major Soil Series: Warsaw, Fayette, and Downs.


Summary of Soil Analysis:



p H



3655 p.p.m.


96 p.p.m.


34 p.p.m.


9 p.p.m.

Stability: Very stable—a terminal forest. Fire will weaken the entire ecosystem.
Typical Number of Species: Trees 25, Shrubs 33, Herbs 172, Total 230
Species Density: 39
Average Proportion 5.1% 54.3% 20.9% 12.7% 2.2% 0.2% 1.1% 0.5% 3.1%
Guild Key: SE = Spring Ephemeral; ES = Early Summer; LS = Late Summer;
SV = Shrub/Vine; WA = Winter Annual; WG = Wintergreen; DI = Dimorphic; MY = Mycotrophic; EV = Evergreen
Wildlife: Cerulean warbler, wood thrush, wood pewee, white-breasted nuthatch, scarlet tanager, chipmunk, flying squirrel.
Typical Examples: Wyalusing S.A., Wychwood S.A., Grant Park, Milwaukee, Petrifying Springs Park, and Kenosha.
Geographical Distribution: Southern Minnesota and eastern Iowa, south and east into southern Appalachians.