USDA Forest Service Agricultural Handbook 511. Scott, V.E. and J.L. Oldemeyer. Cavity-nesting bird requirements and response to snag cutting in ponderosa pine. CO. USDA Forest Service. USDA Forest Service.
Large snags are important.
USDA Forest Service, Southwest Region. USDA Forest Service. Carson Forest Plan. USDA Forest Service, Southwest Region. USGS sections sampled and five one-acre circular plots included in each.