AbstractsBiology & Animal Science

The purpose of this thesis was to develop regression equations for predicting diameter inside bark at various heights up the stem N for four tree species, noble fir (Abies procera Rehd.), Pacific silver fir (Abies amabilies (Doug.) Forbes), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and western hemlock (Tsuga heterophylla (Raf.) Sarg.). Data from scattered plots on the upper slopes of the Cascade Mountain range in Oregon and Washington were analyzed in a stepwise regression computer program. A significant difference was found between observations in Oregon and Washington for three species, noble fir, Pacific silver fir, and Douglas-fir. In addition to the equations for the combined Oregon Washington data, separate equations were developed for each state. Diameter outside bark always entered the stepwise equation first. Regression equations were also developed using this single independent variable to predict diameter inside bark.