The effects of treefall gaps on understory vegetation in New York State

Abstract. Treefalls are a common form of disturbance in northeastern United States forests. The resultant gaps contribute to a high degree of environmental heterogeneity in the understory of these forests. Plant density, plant cover, and species richness in understory plant communities were monitored for three years during the growing season, May - September. Differences between treefall gap and closed canopy vegetation were less pronounced early in the growing season for plant density and leaf cover. Species richness was significantly greater within treefall gaps during the entire growing season. Eight species were found in greater abundance within treefall gaps (i.e., gap-phase species), while one species was found more commonly under closed canopy. Ordination results suggest that time since gap creation and treefall gap size marginally affect the species composition of vegetation found within treefall gaps.