Regeneration in defoliated and thinned hardwood stands of north-central West Virginia

Overstory species regeneration was examined in 1989, prior to gypsy moth defoliation and thinnings, on 16 stands in the West Virginia University Forest. Three stands were thinned and defoliated while five were thinned only and three were defoliated only. Five stands were neither thinned nor defoliated. Data were collected from these stands for three years subsequent to the disturbances. The general response to defoliation was similar in number of seedlings irrespective of thinning, i.e., there was an initial depression of regeneration, although it was more noticeable in stands that were not thinned. Total seedling production increased significantly on thinned stands two years following thinning, but differences disappeared by third year after treatment. For both defoliated and undefoliated stands, any effect of thinning on total seedling abundance was lost by 1992. Oak regeneration was greatest on control stands and stands that were thinned but not defoliated. Defoliation alone was detrimental to oak regeneration, while thinning moderated the defoliation effect. Red maple seedlings dominated numerically, but black cherry was the most abundant species in the larger size classes in all stands irrespective of treatment, and is likely to dominate the next generation of overstory trees in this area.