According to Munz and Keck (1949) relatively few facts are known about the ecology of native California plants. Work has been done on the general ranges or species of trees of the Pacific Slope by Sudworth (1908) with notes on tolerances and climatic conditions. Abrams (1910) studied the phytogeography of Southern California trees and shrubs and presented the floristic picture or the area. However, knowledge concerning the ecology of specific plants, such as Juniperus californica, is lacking. In light of this lack of information on distribution and ecology of what is an indicator species for a California plant community it seemed desirable to undertake the following problem.