FRAGMENTATION AND EDGE EFFECTS IN CENTRAL INDIANA OLD-GROWTH FORESTS

Tree species composition, density, basal area, and population size str ucture were compared in paired edge and interior plots on warm and coo l aspects of seven mesic old-growth forest remnants in central Indiana . Forest edges had higher tree densities, smaller trees, and higher sp ecies richness than interiors, and all differences appeared greatest o n warm aspects. Many species were more abundant or reproducing more su ccessfully along edges than in interiors. Only one, Fagus grandifolia, showed the opposite edge response. There was no evidence that fragmen tation caused either extinctions or alien invasions in the tree stratu m; rather, edges seemed to provide refuges for reproduction of oaks an d other shade-intolerant native species.