Changes in early-successional hardwood forest area in four bird conservation regions across four decadesThis article is part of a larger document. View the larger document here.
Early successional hardwood forests constitute important breeding habitat for many migratory songbirds. Declines in populations of these species suggest changes in habitat availability either on the species’ wintering grounds or on their early successional breeding grounds. We used Forest Inventory and Analysis data from 11 states across four decades to examine changes in early successional (small-diameter) hardwood forests in four Bird Conservation Regions (BCRs) where migratory songbirds of interest have exhibited population declines: Appalachian Mountains, Central Hardwoods, Piedmont, and Southeastern Coastal Plains. We hypothesized that 1) proportional to the amount of timberland on the landscape, hardwood area in the four BCRs of interest has remained stable across the four decades studied and 2) proportional to the total amount of hardwood timberland on the landscape, the area of small-diameter hardwood forest in the four BCRs of interest has declined across the four decades studied. In the Central Hardwood BCR, proportional hardwood area declined slightly (P=0.0033), while in the Southeastern Coastal Plain, proportional hardwood area remained stable (0.2705). The Appalachian Mountains and Piedmont experienced increases (P=<0.0001). Total timberland area and proportional area of early successional forests across the entire sample of interest remained stable from the 1970s through the 1980s, experienced an increase in the 1990s, then declined in the 2000s (P<0.0001)—a pattern reflected in the individual BCRs. Implications of our findings are discussed.