Management & Land-Use Effects

Partial Cutting

The idea –

In 1997 we conducted a study to examine the effects of an intermediate level of timber harvesting (commercial thinning, sanitation, sanitation/salvage, and salvage cutting) in mid-elevation, forested habitats on three National Forests in northwestern Montana and northern Idaho. Specific objectives were to conduct bird surveys in intermediate harvested (treated) and relatively undisturbed (control) stands, and to statistically compare bird species composition and relative abundance between treatment and control types. We also developed statistical models that might identify vegetative structure and components important for predicting bird species composition and relative abundance.

Methods –

This study involved 37 "control" sites in uncut forest stands, and 35 "treated' sites in intermediate-cut stands, within Douglas-fir and Grand fir forest types of the Lolo, Kootenai, and Idaho Panhandle National Forests. Based on a study of samples sizes in similar studies (Sallabanks et al. 2000), these plot-based sample sizes larger than any other study ever published on the effects of timber harvesting on birds.

Results –

The abundances of 14 of the 32 species detected on at least 10 sites were significantly different between treatments. Six species (Pileated Woodpecker [Dryocopus pileatus], Common Raven [Corvus corax], Brown Creeper [Certhia americana], Winter Wren [Troglodytes troglodytes], Golden-crowned Kinglet [Regulus satrapa], and Townsend's Warbler [Dendroica townsendi]) were significantly more abundant in uncut sites and 8 species (Cassin's Vireo [Vireo cassinii], Mountain Chickadee [Poecile gambeli], Ruby-crowned Kinglet [Regulus calendula], Townsend's Solitaire [Myadestes townsendi], Orange-crowned Warbler [Vermivora celata], Western Tanager [Piranga leudoviciana], Chipping Sparrow [Spizella passerina], and Dark-eyed Junco [Junco hyemalis]) were significantly more abundant in partially cut sites.