Cunningham, J.B., R.P. Balda, and W.S. Gaud. Selection and use of Snags by secondary cavity nesting birds of the Ponderosa Pine forest. USDA Forest Service Research Paper RM-222. Rocky Mountain forest and Range experiment Station, Fort Collins, CO. 229p. Davis, J.W. 1983.
Snags are for wildlife.
Hilty, S. 1994. A watcher's introduction to behavior, breeding, and diversity. Goodwin, G. and R.P. Balda 1983. Challenges of snag management. Karlsson, J. and S.G. Nilsson.