Community Structure and Stability in the Giant Sequoia Groves of the Sierra Nevada, California

Abstract

The vegetation of the giant sequoia groves is dominated by Abies concolor, with Pinus lambertiana as a characteristic associate. Sequoiadendron giganteum is of small importance in relative density, but includes the majority of basal area of canopy species within the groves. Despite its great basal area, crown coverage of Sequoiadendron seldom exceeds 5%. Libocedrus decurrens is an important associate in lower-elevation groves, particularly following fire disturbance. Groundcover vegetation is extremely variable. Present grove boundaries appear to be remarkably stable. There is no evidence of any change in grove boundaries during the last 500 years or longer. A great majority of groves are undergoing a gradual decrease in density of giant sequoias due to low levels of regeneration. This decline in density began long before the influence of Western civilization on the groves.