A B S T R A C T
Two-age (deferment or leave tree) harvesting is used increasingly in even-aged forest management,
but long-term responses of breeding avifauna to retention of residual canopy
trees have not been investigated. Breeding bird surveys completed in 1994–1996 in twoage
and clearcut harvests in the central Appalachian Mountains of West Virginia, USA
allowed us to document long-term changes in these stands. In 2005 and 2006, we conducted
point counts in mature unharvested forest stands and in 19–26 year-old clearcut
and two-age harvests from the original study and in younger clearcut and two-age stands
(6–10 years old).We found differences in breeding bird metrics among these five treatments
and temporal differences in the original stands. Although early-successional species are
typically absent from group selection cuts, they were almost as common in young twoage
stands as clearcuts, supporting two-age harvests as an alternative to clearcutting.
Although older harvests had lower species richness and diversity, they were beginning to
provide habitat for some species of late-successional forest songbirds that were absent
or uncommon in young harvests. Overall, late-successional forest-interior species were
more flexible in their use of different seral stages; several species used both age classes
and harvest types in addition to mature forest, which may reflect the lack of edges in
our heavily-forested landscape. Consequently, two-age management provides habitat for
a diverse group of species as these stands mature and may be an ecologically sustainable
alternative to clearcutting in landscapes where brown-headed cowbirds (Molothrus ater) are
uncommon.