We compared vegetation establishment in twenty-five treefall pits and mounds along a hillside elevational gradient in a fourth- year catastrophic windthrow in eastern North America. Plant communities differed greatly between pits and mounds, with pit microsites having significantly greater species richness, total biomass, and total tree stem density.
Species richness in pits and on mounds decreased with increasing elevation from the bottom of the hillside, although the effect of elevation on mound species richness was less than that of elevation on pit species richness. Biomass of Erechtites hieraciifolia decreased significantly, while that of Betula alleghaniensis increased significantly with elevation. However, total biomass of both pit and mound microsites was unrelated to elevation. Total stem density decreased with elevation in pits, but was unaffected by elevation on mounds.
This study shows that both small-scale (microsite) effects and intermediate-scale effects influence the reestablishment of plant communities within this catastrophic windthrow. Consideration of both microsite and position along intermediate-scale gradients may allow more precise prediction of plant community composition and dynamics in recovery of disturbed areas.