Structure and composition of streamside management zones following reproduction cutting in shortleaf pine stands

Abstract

Streamside management zones (SMZs) in the Ouachita Mountains of Arkansas and Oklahoma are frequently established along headwater ephemeral and intermittent streams to protect water quality, provide wildlife habitat, and increase landscape diversity. To better understand the function of these riparian forest corridors, we characterized the tree density and composition, forest floor mass, and downed woody debris volume within SMZs located in undisturbed, mature, upper mid-slope shortleaf pine stands and then compared these attributes to those in upland portions of these stands. In addition to evaluate the impact of upland forest harvesting on these riparian corridors, we compared the amounts and distribution of forest floor, downed woody debris (DWD), snags, and windthrows in SMZs within shortleaf pine stands that had been clearcut, had a shelterwood harvest, and had no recent management activity (uncut stands). Total tree and hardwood basal area was significantly higher (4.4 and 4.2 m 2 ha −1) while forest floor mass was significantly lower (0.5 kg m −2) in the SMZs than in the upland portion of the undisturbed stands. Five years following the reproduction cuttings tree basal area, DWD volume, and forest floor mass within SMZs did not significantly differ among stands that had or had not been harvested. Snag density was significantly lower within SMZs that occurred in clearcut stands compared to those in the uncut or shelterwood stands. Harvesting activities that retain few or no residual trees appear to increase the degradation of snags. This study provided evidence that clearcutting may also increase the risk of windthrow in SMZs as well. There was little difference in the distribution of forest floor within SMZs regardless of whether the stand was harvested or the type of harvesting that occurred in the stand. However, DWD amounts were higher near the SMZs edge than in the interior of the SMZs with the greatest differences in distributions in stands that were clearcut.