Effects of Disturbance History on Forest Soil Characteristics in the Southern Appalachian Mountains

Minimally disturbed virgin forest soils in the Little Santeetlah Creek (LSC) watershed of western North Carolina were sampled along with soils from the adjacent disturbed Slickrock Creek (SRC) watershed. Soils with similar elevation/landform/vegetation/parent material characteristics were initially sampled at nine random locations each on north and south aspects within each watershed with a soil push probe. Some differences in parent materials were noted on south aspects (metasandstone vs. phyllite), but parent materials under north aspect soils were identical (metasandstone). Soils in LSC were significantly deeper and relatively free of solum coarse fragments while SRC soils were shallower and higher in coarse fragments. Subsequent auger observations of three typical pedons on each aspect indicated that soils in LSC were well-developed with gradual horizon boundaries and common diffuse transition horizons, while soils in SRC were more compact in horizonation and lacked diffuse transitional horizons. Vegetation communities were similar across both watersheds, except that SRC south sites were higher in Pinus spp. Litter layer morphology differed strongly between the two watersheds. Specifically, well-developed humus (H) layers were typical in LSC, but completely absent in all typical pedons described in SRC. Data obtained from these two watersheds indicate strong differences in surface soil (O + A horizon) properties between the two. These observed differences could be due to differential anthropogenic effects, particularly logging and associated erosion in the early 1920's. However, further study over multiple disturbed watersheds in the region, and of the distribution of sediments and colluvium within them would be required to test this hypothesis.