Community dynamics and topographic controls on forest pattern in Shenandoah National Park, Virginia

Woody species in an Appalachian Oak watershed in Shenandoah National Park, VA, were intensively sampled to investigate spatial vegetation patterns with respect to topography, and to predict future forest dynamics. Canonical correlation, cluster analysis, and discriminant analysis demonstrate that both individual species and species assemblages are significantly related to topographic variables; however, there is a great deal of unexplained variance in the data. Correlation analysis on a subset of the data shows that factors such as shrub cover and surface rockiness, which are relatively independent of topography, tend to be more important predictors of forest composition. A study of diameter distributions suggests that most species' populations are stable or increasing in number. Exceptions to this include the dominant species in the watershed, Quercus spp., in particular, Quercus prinus, all of which have relatively low numbers of seedlings. Nevertheless, analysis of life-history attributes of these species, as well as a computer simulation of forest dynamics for this area, suggest that Quercus spp. will continue to retain their position of dominance in the future, with Quercus rubra becoming increasingly important relative to Quercus prinus.