WOODY DETRITUS INPUTS AND DECOMPOSITION KINETICS IN A SOUTHERN TEMPERATE DECIDUOUS FOREST

The dynamics of woody debris input and decomposition in temperate forest ecosystems are rarely examined. Woody detritus inputs in a mesic deciduous forest in Tennessee were followed from 1976 to 1988. Annual inputs were highly variable with a mean of 3.97 Mg ha-1 yr-1, with a range from 0.55 to 16.00 Mg ha-1 yr-1. The woody detritus pool in 1989 was 19.26 Mg ha-1. The stand-level decomposition constant, based on the input/biomass ratio, was 0.21 yr-1 for a half-life of 3.4 years. The decomposition of 14 standing dead and 39 fallen boles of known age since death was also examined. The decomposition rate constant based on a single-exponential decay model was 0.110 yr-1, with a half-life of 6.3 years, for fallen logs and 0.062 yr-1, with a half-life of 11.2 years, for standing dead boles. Detrital turnover is thus rapid and woody debris is not a long-term energy and nutrient sink in this forest.