The principle of sustained yield is discussed with reference to the management and conservation of tropical forests. Some previously published data are presented for forests in the Philippines, Malaysia, Surinam and Liberia. If properly planned and executed, disturbance due to selective timber harvesting does not affect the forest ecosystem's capacity for recovery. There is no published evidence that plant or animal species have been exterminated and become extinct as a result of forest utilization. Locally, species may disappear and species composition might be changed. Genetic erosion and shift are unlikely to result from selective harvesting and continued selection silviculture. In contrast, ruthless exploitative forest mining endangers regeneration of sensitive species and the multiple-use value of the forest for local inhabitants. Logging as such is not a primary causal factor which leads to slash-and-burn agriculture. The demand for forest land for agriculture is created in other sectors of the socioeconomic system. Logging only attracts such demand sectors to certain localities. Long-term silvicultural and yield research have convincingly shown that sustainable multi-purpose management of tropical rain forest is technically possible, and ecologically and economically feasible, provided appropriate consideration is given to site and growing stock conditions. The primary obstacles to implementing the prevailing legislative and policy guidelines for land and forest use usually lie in the social and political environment.
