Influence of Canopy Density on Ground Vegetation in a Bottomland Hardwood Forest

Abstract

We investigated the influence of canopy density on ground vegetation in naturally formed gap and non-gap habitats (environments) in a blackwater river floodplain. Tree seedlings were more important (relatively more abundant) in the non-gap habitat, and grass was more important in the gap habitat, but there were elevation x habitat interactions. Also, there was an elevation x habitat interaction for species richness, with more species occurring higher on the elevational gradient and in the non-gap habitat. Because tree seedlings were similar in size in the two habitats, we concluded that naturally formed canopy gaps in this bottomland forest neither significantly increase light levels nor stimulate tree seedling growth. Also, because there was a habitat effect even after accounting for the covariates of light and elevation, we concluded that something besides elevation or light level is influencing the ground vegetation composition. Apparently, small canopy openings can increase the importance of competing plant species without improving conditions for tree seedling growth.

Citation

Billups, Sarah E.; Burke, Marianne K. 1999. Influence of Canopy Density on Ground Vegetation in a Bottomland Hardwood Forest. In: Gen. Tech. Rep. SRS-30. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. pg. 195-200