Abstract:
Populations of breeding birds and forest composition and structure were examined in preconimercially thinned and unthinned ponderosa pine (Pinus ponderosa Laws.) stands in east-central Washington. Stands were composed of predominantly ponderosa pine with a multi-aged structure made up of small even-aged clumps. Thinning reduced the
density and foliage volume of small trees (< 24 cm) and created a substantial slash component. Shrub volume and herbaceous cover also were different between treatments but these differences were probably unrelated to the thinning. Differences in bird densities between thinned and unthinned areas could be directly or indirectly related to these vegetation differences. Total bird densities and avian community structure were similar for unthinned and thinned stands. However, there were differences in bird species composition. Precommercial thinning is likely to result in local increases in the
abundance of some species and decreases for others. The avian community structure, however, is likely to be unaffected by precommercial thinning of multi-aged ponderosa pine.
