Variable effects of tree-cover on plant productivity and diversity of forbs and shrubs

Abstract

In an effort to understand the effect of trees upon plant productivity, and species diversity and richness, all were observed at both the savanna and tree line at Conard Environmental Research Area (CERA). Biomass and necromass (an indicator of plant productivity), species diversity and richness of shrub and forb samples were taken at the savanna with the use of transects from the center of trees. Then we sampled along these transects at 2m (under the canopy) and 10m (outside the canopy) from the base of each of the eight trees. At the tree line, 18 samples were taken from both the forest and the prairie side. The results of biomass and necromass sampling yielded no significant relationship with the proximity of trees. There is a significant difference in species diversity and richness at the tree line; however there is no significant difference at the savanna. Thus, plant productivity has no significant relationship dependent upon the vicinity of trees, but tree cover can affect species diversity and richness.