Plant association and management guide for the Pacific silver fir zone Gifford Pinchot National Forest.
The study of plant communities provides useful information about the environment in which they occur. Communities are a product of long-term interaction between factors in the physical environment and the organisms present. Environmental factors such as temperature, moisture, light and nutrients act as selective influences on plant populations, favoring species best adapted to a particular type of site. While random chance and genetic adaptation within species are also important in the development of community composition and structure, research by Waring (1969) and Zobel et al. (1976) has documented the relationship between plant communities and the complex of environmental factors which influence them.