Plants are often seen as the sole dynamic components of a vegetative community, but it is important to note that as plant individuals and populations change, their environments are not entirely static. In this study, I investigated how plants shape the environments in which they grow. In particular, I examined the ways in which the two woody plants in a relatively open sandstone grassland, valley oak (Quercus lobata) and coyote bush (Baccharis pilularis), affect their immediate surrounding light environment and local hydrology. I compared these two treatments to a site in the same sandstone grassland without the presence of a large plant. I also looked into the effects of these two plants on the composition, biomass, abundance, and diversity of smaller understory grasses and forbs. I found that for many of the biotic and abiotic characteristics of the environment, the position of a point on either the north or south side of a large tree had a greater effect than the presence or absence of a larger plant.