Abstract
An equatorial rain forest in West Sumatra suffered defoliation and severe stem damages from two storms in early 199S, Intensity of litter production at a storm generated gap site was 225 ton ha-1, and big woody debris over 10 cm in diameter accounted for 78%. A mass of fine litter promptly lost its weight of dry matter in Ao layer directly after the event, and the Tate tended to have a positive correlation to the initial amount of accumulation. An impact of these mass litter production on a material cycling of an equatorial rain forest ecosystem was simulated basing on these field data and monitoring data of a forest since 1981. The simulation showed that fine litter would supply nutrients enough for revegetation at an initial stage in particular, and a great amount of woody debris would contribute to the process at later stages because of their low decomposition rate. The time needed for 95% loss of initial litter amount by decomposition at a gap site was estimated at 11 years in this forest i[respective of amount, when the composition of litter is same. This average decay rate overcomes a net primary productivity. From a carbon balance between both potential rates of decay and growth for initial 11 years after a damage, it shows that about 100(organic matter) ton ha-1 of litter production is a boundary value between its sink and source for this stand.
