Structural impact of hurricane Andrew on the forested wetlands of the Atchaflaya Basin in South Louisiana

On August 26, 1992, Hurricane Andrew hit the Louisiana coast and traversed a large portion of the lower Atchafalaya Basin, bounding the largest remaining tract of cypress-tupelo and bottomland hardwood swamp in the United States. Permanent field sites were established following the hurricane to assess the extent of forest damage and to monitor the rate and process of forest recovery. Bottomland hardwood forests had significantly greater damage and mortality than did cypress-tupelo communities. Canopy trees suffered the greatest direct damage, particularly in sites within the storm's eyewall and right quadrant. The type and extent of damage (windthrow, branch loss, and defoliation) generally decreased as distance from the storm path increased. Azimuths of downed trees were strongly correlated with predicted wind vectors derived from a hurricane simulation model of Andrew. Species differences were readily apparent, indicating a high degree of tolerance to windthrow by baldcypress and water tupelo, and intolerance by many common hardwood species. Bottomland hardwood forests are particularly susceptible to catastrophic disturbance by hurricanes such as Andrew, which have significant impact on forest structure and dynamics.