NUTRIENT LOSSES IN FOREST PLANTATIONS IN SABAH, MALAYSIA

Inorganic nutrients are lost from terrestrial ecosystems through the h arvesting of plant products, leaching, soil erosion and volatilization of nitrogen and sulfur compounds. In this study, carried out in a tro pical rainforest ecosystem in Sabah, Malaysia, losses of inorganic nut rients through log removal and runoff/leaching to stream water were co mpared in clear-fellings, harvested and prepared for planting in two d ifferent ways: (i) tractor logging/burning; (ii) and manual logging/no burning. The major findings of the study were that nutrient losses in stream water were reduced by 50% and growth of the planted forest was twice as fast on the catchment where soil disturbance was minimized a nd burning not used. Weeds were more abundant after burning, and the e xtra weeding needed increased costs for plantation establishment. Ways of decreasing the loss of inorganic nutrients when clear-felling trop ical rainforests are discussed.