Early Plant Succession on Abandoned Cropland in the Central Basin of Tennessee

The middle portion of Tennessee includes two physiographic regions, the Central or Nashville Basin, a large low calcareous area that is 60 miles wide and 120 miles long, with an average elevation of 600 feet (Fenneman 1938), and the surrounding Highland Rim that is 400 to 600 feet higher than the Basin. Both Rim and Basin lie within the Western Mesophytic Forest Region of Braun (1950), which is not a climax forest region but a transition zone between the Mixed Mesophytic and the Oak-Hickory Climaxes. The lowest part of the Basin floor, where Lebanon limestone is exposed or thinly covered with soil, supports cedar glade vegetation that is quite distinct (Quarterman 1950) from that of the surrounding and interjacent uplands and rounded hills that comprise the rest of the Basin floor. High hills in the Basin that are outliers of the Highland Rim support plant communities characteristic of Rim vegetation (Braun 1950). For the intermediate slopes, Braun (1950) lists sugar maple as the chief tree in the original forests, with Celtis laevigata, Ulmus americana, U. alata, Juglans nigra, Quercus borealis var. maxima, Q. Muhlenbergii, Q. macrocarpa, Carya ovata, Nyssa sylvatica, Prunus serotina, and Liquidambar Styraciflua as accessory species. Cultivated land is usually on these lower slopes or on bottom land. Flood-plain cropland in the Basin is rarely abandoned and those fields on the uplands that are removed from cultivation are usually converted to pasture. This latter fact, unfortunately, made it impossible to locate more than a few fields of any given age over one year.