Forest response to catastrophic wind: Results from an experimental hurricane

Infrequent, intense wind disturbance is an important factor in northeastern U.S. forests, yet little is known about the early stages of vegetation reo rganization, or the processes that facilitate biotic regulation of ecosyste m function after such storms. We designed an experiment, based on a simulat ed hurricane blowdown, to examine the relationship of tree damage patterns to mortality and regeneration, community dynamics, vegetation recovery, and ecosystem processes. In October 1990, selected canopy trees in a 50 x 160 m area within a 75-yr-old Quercus rubra-Acer rubrum forest in central Massa chusetts were pulled over by a winch, using records from the 1938 hurricane to determine the number of trees and direction of fall. The resulting dama ge to 65% of trees closely approximated effects of the 1938 storm on New En gland forests. Damage and mortality varied by tree species and size, indica ting the importance of pre-disturbance forest structure and composition in determining the range and severity of impact. Measurements of vegetation an d environment in the experimental area and control indicated that, although the manipulated stand sustained dramatic damage and structural reorganizat ion, resilience of trees and understory vegetation provided tight biotic co ntrol of ecosystem processes, including nutrient cycling. Continued leaf-ou t and induced sprouting by damaged trees, increased growth by saplings and understory plants, and seedling establishment on disturbed microsites stabi lized the microenvironment. Our findings are in contrast to studies of dist urbances in which mortality was higher when damaged trees were removed from the site. This suggests that salvage logging following wind disturbance ma y have serious long-term implications.