Patterns of seedling and overstory composition along a gradient of hurricane disturbance in an old-growth bottomland hardwood community

Disturbance patterns and species composition in the seedling and canopy lay ers were examined across the range of post-hurricane damage in an old-growt h bottomland hardwood forest. Canopy coverage, tip-up number and area, snag s, and coarse woody debris were quantified in plots along randomly oriented transects established in bottomland hardwood stands and mixed Pinus taeda L. - bottomland hardwood stands. Wilcoxon rank sum tests of these individua l disturbance features indicated greater disturbance in plots containing th e early successional species, Pinus taeda, than in mixed bottomland plots w ithout it. Principal components analysis (PCA) using these features illustr ated much overlap between the two assemblages and suggested a continuum of canopy and soil disturbance conditions from windthrows along axis I and a c ontinuum of canopy disturbance due to snag formation along axis II. Woody s eedlings and trees were inventoried in 30 plots spanning the range of distu rbance. Seedling species richness exhibited a rank order increase along axi s I. Floristic trends in both seedling and tree layers we-significantly cor related with disturbance represented by PCA axis I scores. Removal from the canopy and lack of successful recruitment of Pinus taeda, a former canopy dominant, suggest that the hurricane has shifted this old-growth floodplain forest to a different successional state.