ABSTRACT

Military training and land management practices influence vegetation and nitrogen dynamics at Fort Benning. Our longterm goal is to identify thresholds beyond which upland forest communities cannot sustain the combined effects of forestry practices (burning and thinning to promote a longleaf pine ecosystem) and military traffic disturbances. We hypothesize that soil type influences disturbance thresholds. We compared vegetation and soil N of sandy (S) and clayey (C) sites subjected to heavier (H) or lighter (L) military use (8 400m x 400m sites of each combination). All sites were burned in spring, 2000. Prior land use, including the recent history of military and forestry practices, has influenced these sites. Remnant and active trails and roads, and gullies, are frequent disturbance features. Soils in heavily used sites tend to be higher in sand content, perhaps as a result of deposition from upslope. Canopy tree density is greater (p = 0.06) on LC sites; ground layer richness grades from a high in HC sites through LC and LS sites to a low in HS sites. Multidimensional scaling of canopy tree and ground layer composition revealed patterns related to land use intensity. Our results suggest clayey sites at Fort Benning are richer and more productive. Heavily used sites have a high proportion of pines in the canopy, lower tree density, and more "open site" ground layer. These results can be used to guide management practices to yield upland forests that sustain military training and forest management goals.