Breeding bird response to a second-stage shelterwood harvest in an upland hardwood forest
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Post-logging sites were historically assumed to provide unfavorable habitat for songbirds. Timber harvests have always been important for species that require disturbances, but while most studies focus on clearcuts, few examine the harvesting methods ranging between clearcutting and undisturbed forests; such as those created with shelterwood prescriptions. We studied breeding bird community response to different basal area retention levels during the second stage of a two-stage shelterwood harvest, 12 and 13 years postinitial harvest. Study sites were located in an upland hardwood forest in northern Alabama on the southern end of the mid-Cumberland Plateau through territory mapping. This study examined how different retention cuts affect bird species with varying habitat requirements. Bird diversity (calculated using the Brillouin Index) was compared among treatments using analysis of variance with a post-hoc LSD test. The relationship between habitat features and bird diversity were examined using correlation analysis. Breeding bird diversity was significantly lower in the control stands than the 50 percent retention stands (2013 p = 0.002 – 2014 p = 0.007) in both years. Breeding bird diversity was positively correlated with sapling density in 2013 (r = 0.65); showed a quadratic correlation with sapling density in 2014 (r = 0.85), and canopy cover in both years (2013 r = 0.96; – 2014 r = 0.96). Breeding bird diversity was similar across all four shelterwood treatments in both years, although these treatments had structural differences among them. These finding suggest that breeding bird diversity is dynamic and temporally dependent upon timber harvest and subsequent succession.