Response of Woody Plant Communities in Power-Line Corridors to Frequent Anthropogenic Disturbance.

Ecological theory predicts that diversity should decline as disturbance frequency increases beyond an intermediate level. However, few data exist on the responses of deciduous forests to high-frequency disturbance. We compared regenerating woody plant communities in northern Kentucky power-line corridors to adjacent second-growth forests to determine if high-frequency disturbance (5-6 yr mechanical or manual cutting cycle) modifies forest development. Black locust (Robinia pseudoacacia) and white ash (Fraxinus americana) dominated corridor communities. Still, many species present in adjacent forests persisted in corridors, with the result that 15 of 20 corridor samples were classified by TWINSPAN close to samples taken from adjacent forests. Of the most important tree species found in the study sites, sugar maple (Acer saccharum) was least favored by high-frequency cutting. In general, high-frequency cutting did not totally inhibit regeneration of a single species, diversity showed a small but nonsignificant increase, and several early-successional, shade-intolerant species established anew. When forests are repeatedly cut before stems reach the stem exclusion stage, individualistic patterns of sprouting and carbon allocation will likely determine dominance. White ash and black locust will assume greater importance in fragmented forests as disturbance frequencies increase. © 1992 by the Ecological Society of America.