Responses of Small Mammal Populations to Logging of Douglas-Fir

Virgin forest in the Douglas-fir (Pseudotsuga taxifolia) region of northwestern California is a sterile habitat for wildlife. Dense shade and competition from large old trees prevent the growth of nearly all bushy and herbaceous vegetation except a weak understory of tan oak (Lithocarpus densiflora). Food for animals is scarce. The immediate effect of logging is to flood the ground with light. Then tan oak begins a rapid, aggressive growth, and many kinds of herbs, of which fireweed (Erechtites) is one of the most abundant, become established. In terms of plant succession, the cutover changes from bare ground to weeds to brush and finally to a climax of Douglas-fir or more often, tan oak. During the middle stages, food for animals is plentiful. Small seed-eating mammals are one of the factors that result in the economically undesirable climax of oaks instead of conifers. Mice in...