Abstract
We tested the hypothesis that species diversity of birds is related to structural diversity of vegetation by using annual controlled burns to reduce the crown volume of the ground vegetation and shrub layer and the basal area of small trees in a pine forest in the Piedmont region of North Carolina. Birds were mist-netted on the treatment and control sites to determine changes in bird species diversity. Diversity of birds on the treatment site declined relative to that on the control site during a 5 year period. This is the first experimental evidence supporting findings of earlier observational studies of the hypothesis.