Lake States Aspen Report No. 22
U.S. Dept. of Agriculture, Forest Service, Lake States Forest Experiment Station
So long as aspen was considered primarily a weed species, there was little concern over the enemies which might injure or destroy it. Sometimes these enemies were actually considered "blessings in disguise. Now, however, that aspen not only is the most abundant "but also one of the most widely utilized tree species in the Lake States, there is increasing interest in anything that may affect its future supply. For that reason this brief summary of information on the enemies of aspen has been assembled.
Christensen, C.M. et al. 1951. Enemies of Aspen. U.S. Department of Agriculture, Forest Service. Lake State Forest Experiment Station. No. 22.