Spatial and temporal dynamics in canopy dominance of an old-growth central Appalachian forest
Many old-growth deciduous forests in eastern North America exhibit dynamics that suggest succession from dominance by oaks (Quercus spp.) to dominance by maples (Acer spp.). We examined this phenomenon using 20 years of vegetation data from an old-growth central Appalachian forest. Considering the site as a whole, the importance of Quercus spp. declined and that of Acer spp. increased. In particular, Acer rubrum L. exhibited increasing importance in the overstory canopy on upper slopes, and Quercus spp. exhibited a contraction in spatial distribution, particularly in the midstory (P < 0.05). This narrowing of distribution in Quercus spp. was associated with regeneration being restricted to dry, acidic sites. We also considered successional dynamics within three previously identified ecological communities in the study area: oak, mixed mesophytic, and beech. This analysis indicated that increased A. rubrum importance was limited to the upper-slope oak community. A successional dynamic was not apparent in the mixed mesophytic community, and the beech community was characterized by increasing importance of Tsuga canadensis (L.) Carr. Our results suggest that ecological communities have distinct successional trajectories and that predictions of future dynamics must consider topographic and ecological gradients.
McEwan, R. W., and R. N. Muller. 2006. Spatial and temporal dynamics in canopy dominance of an old-growth central Appalachian forest. Canadian Journal of Forest Research 36:1536-1550.