Yellow-Poplar and Oak Seedling Density Responses to Wind-Generated GapsThis article is part of a larger document. View the larger document here.
The effects of wind on upland hardwood forest structure and composition have been studied mostly in the context of either small "gap-phase" openings or in retrospective studies of ancient disturbances. Larger (> 0.1 ha) wind-created openings are common across Southern Appalachian landscapes, and can be impor tant in shaping understory colonization, growth, and survival. On October 5, 1995, Hurricane Opal str uck the Bent Creek Experimental Forest, creating a unique oppor tunity to investigate the effects of wind damage and wind-created large forest gaps on forest understory vegetation. We investigated the relationships of yellow-poplar (Liriodendron tulipifera L.) and oak (Quercus spp.) seedling densities to spatial and structural gradients in and around 12 large, Hurricane Opal created gaps. Seedling densities were modeled with repeated measures regressions over 3 years (1996, 1997, and 1998). Oak seedling density was highest in the south end of gaps and on high-energy aspects. Oak densities were negatively correlated with hurricane-created crown debris cover and large woody debris. Yellow-poplar seedling density was positively related to distance from southern gap edge and predicted soil moisture, and negatively associated with time since disturbance and crown debris. Yellow-poplar density was highest in the light-rich north end of gaps. The oaks were better able to populate the south end of gaps where yellow-poplar competition was less. Forest managers should expect similar natural regeneration trends in manmade gaps, such as group selection openings.