Low rolling hills, dissected plateaus, and basins are found in Tennessee and Kentucky. The northern parts of the province have been glaciated, but not the southern. Rolling surface of a glaciated plain in central Minnesota. Summers are hot, with frequent tornadoes.
Most precipitation takes place during the growing season.
Although other forests have oak and hickory, only this particular forest association has both species in abundance. From eastern Kansas to Indiana, it forms a mosaic pattern with prairie. Widespread dominants are white oak, red oak, black oak, bitternut hickory, and shagbark hickory. The understory is usually well developed, often with flowering dogwood. Other understory species include sassafras and hophornbeam.