Tissue digestibility, essential oils, and levels of several chemical constituents were compared in foliage of Douglas-fir. Genotypes with different susceptibilities to deer browsing were used, and foliage was collected during the dormant season. In general, clones resistant to deer browsing had lower dry-matter and cellulose digestibilities, essential oils with greater inhibitory action on rumen microbial activity, higher content of fats, total phenols, flavanols, and leucoanthocyanins, and lower levels of chlorogenic acid. Results suggest that these resistance characteristics, especially the chlorogenic acid content, might be used instead of conventional bioassays with captive deer, to screen Douglas-fir breeding stock for resistance to deer browsing.