Effects of silvicultural treatments on wintering bird communities in the Oregon coast range
Chambers, Carol L.
McComb, William C.
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Changes in forest management policies in the Pacific Northwest have resulted in a broad array of management alternatives to clearcutting on state and federal forest lands. These management alternatives should be monitored for their effects on animal use, particularly during critical periods for survival. We compared abundance of resident birds among three alternative silvicultural treatments (modified clearcut, two-story, small-patch group-selection) and unharvested controls during winter. Total bird abundance was highest in small-patch stands and lowest in modified clearcuts during winter. Species richness was highest in smallpatch stands and lowest in control and clearcut stands. Two species (Steller's jays (Cyanocitta stelleri) and golden-crowned kinglets (Regulus satrapa)) were most abundant in control stands and small-patch stands. Spotted towhees (Pipilo erythrophthalmus) were more abundant in two-story stands; dark-eyed juncos (Junco hyemalis) were more abundant in harvested stands than control stands. The small-patch group-selection treatment retained structural and compositional complexity of vegetation and provided habitat for more individuals than two-story or modified clearcut treatments. However, two-story and modified clearcut treatments with components of mature and old-growth forests (snags, logs, large trees) provided habitat for several bird species during winter. Silvicultural treatments that retain structural and compositional vegetation complexity or develop late-successional characteristics more quickly than stands regenerating following traditional clearcutting practices may be used by more bird species and should be considered when developing stand management guidelines