ORGANIC MATTER DYNAMICS IN FOUR SEASONALLY FLOODED FOREST COMMUNITIES OF THE DISMAL SWAMP

Abstract

Budgets of organic matter dynamics for plant communities of the Great Dismal Swamp were developed to summarize an extensive data base, determine patterns of biomass allocation, transfer and accumulation, and make comparisons with other forested wetlands. Aboveground net primary production on the flooded sites (1,050–1,176 g m‐2 yr‐1) was significantly greater than on a rarely flooded site (831 g m‐2 yr‐1). Estimates of belowground net primary production were comparable to aboveground production on flooded sites (824–1,221 gm‐2 yr‐1). However, productivity was nearly three times greater belowground than aboveground on the rarely flooded site (2,256 g m‐2 yr‐1). Aboveground productivity in Dismal Swamp forests is relatively high compared to other forested wetlands. This is attributed to the timing and periodic nature of flood events. Fine root turnover is shown to be an important source of soil organic matter. Estimates indicate that roots contribute about 60% of the annual increment to soil organic matter. Leaflitter contributes 6–28% and wood debris contributes 5–15%. Comparisons with other forested wetlands suggest that detritus accounts for greater than half of the total organic matter (living + dead) in many wetland systems.