Edge Effects on Forest Composition and Structure

Forest fragmentation arising from modern forestry practices has dramatically increased the amount of edge habitat relative to interior habitat. Edge habitats have unique microenvironments that have the potential to profoundly impact forest communities. In this study, we characterized the forest composition and structure of edge and interior plots within a second growth big leaf maple-Douglas fir stand on Blanchard Mountain, Washington from 2001 to 2007. We found the edge environment was characterized by high stem densities and basal areas of young, early seral stage species like big leaf maple. Interior sites were characterized by greater tree diameter and favored an overstory of Douglas fir and an understory of sword fern. We discuss the mechanisms that likely contribute to the edge effects we describe, and suggest future studies to determine if these effects are unique to the age of this forest stand or may be more universal among big leaf maple-Douglas fir forests.