EFFECTS OF SILVICULTURAL ACTIVITY ON ECOLOGICAL PROCESSES IN FLOODPLAIN FORESTS OF THE SOUTHERN UNITED-STATES - A REVIEW OF EXISTING REPORTS

Activities associated with timber harvesting have occurred within floo dplain forests in the southern United States for nearly two hundred ye ars. However, it is only in the last ten years that any information ha s become available about the effects of harvesting on the ecological f unctions of this valuable resource. Hydrology is the driving influence behind all ecological processes in floodplains, and timber harvesting alone usually has little long-term effect on hydroperiod. However, lo gging roads, built in association with harvest sites, can sometimes al ter hydroperiod to the extent that vegetation productivity is raised o r lowered. There is no evidence that harvesting followed by natural re generation represents a threat to ground or surface water quality on f lood plain sites, as long as ''best management practices'' are followe d. Harvested floodplains may increase or have little effect on decompo sition rates of surface organic matter. The nature of the effect seems to be controlled by site wetness. Data from recently harvested sites (i.e. within the last ten years) suggest that vegetation productivity is maintained at levels similar to those observed prior to harvests. D uring the early stages of stand development, tree species composition is heavily influenced by harvest method. Similarly, amphibian populati ons (monitored as bioindicators of ecosystem recovery) seem to rebound rapidly following harvests, although species composition may be diffe rent from that of unharvested stands.