Physiognomy and Structure: Structural variation within this open woodland or barrens is expressed as a mosaic of exposed bedrock, boulders, large/small rocks, gravel and sand, interspersed and mixed with loess deposits. Soil depth and available water are limiting edaphic factors within this ecosystem. Tall shrubs are 0.5-5 m tall, vine/liana 0.5-5 m and herbaceous 0-2 m.

Floristics: This community is dominated by graminoids, with a scattering of trees. The partial tree canopy cover is probably between 10% and 60%, thus varying from savanna to woodland. The open canopy is dominated by Quercus stellata, along with Quercus alba, Quercus falcata, Quercus coccinea, Carya glabra, and an occasional Quercus imbricaria and Quercus marilandica. Mature trees exhibit short trunks and wide-spreading, open crowns. The subcanopy consists of scattered, small oaks (Quercus stellata, Quercus velutina, Quercus alba) and Carya glabra. The shrub layer is dominated by Cornus florida, but Aralia spinosa, Sassafras albidum, and Rhus copallinum are also common. The herbaceous layer is quite dense, and dominated by Schizachyrium scoparium with a diverse assemblage of grasses and forbs represented. Characteristic grasses and herbs include Dichanthelium spp., Coreopsis tripteris, Elephantopus carolinianus, Agrimonia pubescens, and Symphyotrichum shortii (= Aster shortii). Although Toxicodendron radicans and Parthenocissus quinquefolia occur in abundance here, Smilax glauca is characteristic of this dry environment (TNC 1995a).

This is an edaphic climax natural community. Physiognomic variability and species diversity within and among occurrences of this community is variable, directly proportional to the depth of the soil and water availability. Moisture conditions are dry to dry-mesic. Post oak dominates extremely rocky sites (35-60% stone). White oak is more dominant where dry-mesic conditions persist and prefers less rocky conditions (15-40% stone) and slightly cooler southern to southeastern slopes. Black oak is more prevalent on southwestern to western slopes where dry conditions occur. Drainage related to soil physical properties (stoniness, fragipan) greatly influences the floristic variability of this community. Rangewide vegetative differences are apparently only in the herbaceous species, as woody dominance remains constant.

A mesic variant of this type may also occur on the terraces of creeks (Madany 1981, Anderson and Schwegman 1991).

Dynamics:  Natural disturbance includes periodic fire, wind, storm, and drought. Environmental extremes, including rapidly drained, thin, stony soils, summer droughts lasting 3-5 weeks or more, and limited water availability for most of the growing season, favor the establishment of this woodland association. Periodic fire may help to maintain this community, especially after disturbance from logging or grazing. Fire suppression led to a change from barrens to forest. Prior to their disappearance, herds of elk, deer, and bison roamed these hills and their grazing and browsing provided a primary mechanism for maintaining the "barrens" character (Hall 1970). The vast majority of the original acreage of this community has been destroyed by logging and grazing. Fire also periodically swept through these barrens, killing woody vegetation and encouraging herbaceous growth (Robertson and Heikens 1994). Drought stress is prevalent, and openings are occasionally enlarged when trees are removed by wind or lightning.