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): 113X–Central Claypan Areas

The eastern Illinois portion of the Central Claypan Areas MLRA is in the Till Plains Section of the Central Lowland Province of the Interior Plains (USDA-NRCS, 2006) and includes the Southern Till Plain Natural Division of the natural divisions of Illinois (Schwegman, 1973; 1997; IDNR, 2018) in south-central Illinois. South-central Illinois is a dissected Illinoisan till plain south of the terminal Wisconsin moraine. This region consists of nearly level to gently sloping, old till plains. Stream valleys are shallow and generally are narrow. Elevation is about 660 feet (200 meters), increasing gradually from south to north. Local relief is generally low on the broad, flat till plains and flood plains and high on the dissected hills bordering rivers or drainage systems. The Kaskaskia, Little Muddy, Little Wabash, Embarras, and Skillet Fork rivers are part of this area. This region is covered with loess, which overlies old glacial drift (Illinoisan till) that has a high content of clay. Fragipans are also present. Pennsylvanian limestone and shale bedrock underlay the glacial till. The dominant soil orders in this region are Alfisol and Mollisol. The soils in the area predominantly have a mesic soil temperature regime, an aquic or udic soil moisture regime, and mixed or smectitic mineralogy. They generally are very deep, well drained to poorly drained, and loamy or clayey. (USDA-NRCS, 2006).

Classification relationships

Major Land Resource Area (MLRA) (USDA-NRCS, 2022):
113 – Central Claypan Areas

U.S. Forest Service Ecoregions (Cleland et al. 2007):
Domain: Humid Temperate Domain
Division: Hot Continental Division
Province: Eastern Broadleaf Forest (Continental)
Province Code: 222
Section: Central Till Plains, Oak-Hickory Section
Section Code: 222G

Relationship to other established ecological classifications:
Biophysical Setting (LANDFIRE, 2018); the reference community of this ecological site is most similar to: South-Central Interior/Upper Coastal Plain; CES203.479.

National Vegetation Classification System (NatureServe, 2018): the reference community of this ecological site is most similar to the following NVC Association: Quercus palustris - Quercus bicolor – Acer rubrum. Flatwoods Forest; CEGL002101.

Illinois Natural Areas Survey (INAS) (White, 1978); the reference community of this ecological site is most similar to: INAS Community Class – Forest; Natural community – Southern Flatwoods

Ecological site concept

This woodland community type is found in south-central Illinois throughout the Central Claypan Areas MLRA. Wet Upland Woodland ecological sites occur on broad, flat summits of hillslopes and knolls with slopes of 0 to 2 percent in soils that formed in clayey glacial till containing a strongly developed brownish colored paleosol that seasonally perches water. The historic reference plant community had an open tree canopy dominated by pin oak (Quercus palustris Münchh.1) and swamp white oak (Quercus bicolor Willd.) (White, 1978; NatureServe, 2017).

Wet Upland Woodlands are dominated by broadleaf deciduous trees, with sparse to well-developed understory, shrub, and herbaceous strata. The dominant canopy species is typically pin oak (Quercus palustris Münchh.). Other trees often encountered include American elm (Ulmus americana L.), ash (Fraxinus spp.), southern red oak (Quercus falcata Michx.), and post oak (Quercus stellata Wangenh.). Swamp white oak (Quercus bicolor Willd.) can be plentiful in this type. The subcanopy is sparse, although a diverse mixture of bottomland species such as sweet woodreed (Cinna arundinacea L.) can be present as well. Possumhaw (Ilex decidua Walter) and green hawthorn (Crataegus viridis L.) dominate the shrub layer. Sedges (Carex spp.) dominate the herbaceous layer, but a diverse mixture of forbs can also be present. Narrowleaf mountainmint (Pycnanthemum tenuifolium Schrad.), an aromatic herbaceous species more commonly associated with dry uplands, is frequently present and reflects the dry conditions seasonally found in this forest. Numerous ubiquitous species grow in this natural community; the most commonly encountered are trumpet creeper (Campsis radicans (L.) Seem. ex Bureau) and eastern posion ivy (Toxicodendron radicans (L.) Kuntze) which dominate the vine stratum (LANDFIRE, 2018; NatureServe, 2018; White 1978).

Woodlands were distinguished from forest, by their relatively open understory, and the presence of sun-loving ground flora species (White, 1994). Fire was the primary disturbance factor that maintained this ecological site, while drought, windthrow, and grazing were secondary factors (LANDFIRE 2009).

1 All plant common and scientific names in this document were obtained from the U.S. Department of Agriculture – Natural Resources Conservation Service National PLANTS Database (USDA NRCS, 2018).

Associated sites

Similar sites

Table 1. Dominant plant species