Oak regeneration after clearcutting on steep slopes in the ridge and valley province of southwest Virginia

The development of oak stems of advance regeneration and stump sprout origin was studied during a two-year period following clearcutting and whole-tree removal in eight midslope stands in the Ridge and Valley Province of southwestern Virginia. Oak regeneration was also characterized in several older clearcuts. Height and diameter of oaks of stump sprout origin in the two-year-old stands was significantly greater than that of advance regeneration stems, and the difference in size among regeneration types appeared to persist into the oldest (17- and 28-year-old) stands sampled. Chestnut oak, which had been the dominant oak species in most pre-harvest stands, had higher density of advance regeneration stems, higher frequency of stump sprouting, and greater sprout production per stump than scarlet or black oak two years after harvesting. However, shoot growth of advance regeneration during the two-year period did not differ among oak species when initial stem site and vigor were accounted for taller stump sprouts in the two-year-old stands were associated with more productive sites (as indicated by site index, topographic variables, and vegetation composition), whereas biomass production per stump was less closely related to site quality. Height and diameter growth of oak advance regeneration during the two-year post-harvest period were significantly greater on sites of medium quality than OD sites of low quality. Density of well-established oak stems of advance regeneration origin two years after harvest was greatest in stands of site index 55-65 (base age 50), and fell off on sites of higher and lower quality. Models developed to predict two-year stump sprout production from characteristics of the parent tree generally explained less than 40 percent of the variation among stumps, while models describing growth of advance regeneration individuals from pre-harvest measurements accounted for as much as 82 percent of the variation. Regeneration in most of the two-year-old stands appeared adequate for restocking of oaks to at least their pre-harvest level, although stems will probably be widely spaced and mostly of stump sprout origin on both the poorest and the most productive sites.