WOODY DEBRIS DECOMPOSITION IN THE ATCHAFALAYA RIVER BASIN OF LOUISIANA FOLLOWING HURRICANE DISTURBANCE

The contribution of moody debris to some biogeochemical functions of f orested wetlands was examined in the Atchafalaya River Basin in Louisi ana following disturbance by Hurricane Andrew, Woody debris decomposit ion processes were characterized in terms of mass, C, N, and P dynamic s. These were compared between different diameters of debris, areas re cieving different intensities of disturbance, and between different po sitions relative to the soil, Disturbance intensity (as defined by can opy closure) had little effect on decomposition processes when compare d with soil orientation (i.e., whether in contact with or suspended ab ove the soil), Rates of mass loss varied between 0.055 and 0.068 for s uspended and ground-contact coarse woody debris, respectively. Fine wo ody debris rate coefficients averaged 0.060 and 0.085 for the same res pective orientations, In general, woody debris displayed strong source activity for P but a greater tendency toward sink behavior for N, In terms of biogeochemical transformations, these data suggest that woody debris might act as a phosphate source during sheet now events but co uld provide short-term retention of inorganic N associated with floodw aters.