Nine .16 ha study areas were established in Appalachian oak forests on Potts Mountain in Craig County, Virginia to assess vegetation structure and its relationship to differences in site. A number of structural parameters were measured by height strata to determine vertical stratification patterns. Foliage density was used in subordinate strata (< 5.0 m) as a comparative measure of vegetative structure. The results indicate that the contribution of shrubs to vegetation structure is much higher on xeric than mesic sites, while trees are of greater significance on mesic sites. This suggests a proportionally higher utilization of site resources by subordinate strata on xeric sites. A cluster analysis of the study areas based on several structural parameters indicated that differences in stand structure may be associated with differences in available moisture. Foliage density in subordinate strata appeared to have some value as an integrator of vegetative structure on the study areas.