A LINEAR-PROGRAMMING MODEL FOR PREDICTING THE SUSTAINABLE-YIELD OF TIMBER FROM A COMMUNITY FOREST ON THE OSA PENINSULA OF COSTA-RICA

The establishment of cooperative or 'community' forests in buffer zone s surrounding national parks in developing countries is a popular mean s for protecting the parks. The success of such endeavours depends, in part, on a sustainable supply of timber. Consequently, comprehensive forest management planning and, specifically, the determination of ann ual timber harvests must be made an integral part of management activi ties of project staff and supporting organizations. The regulation of a community forest on the Osa Peninsula was achieved by specifying and simulating polycyclic silvicultural prescriptions to generate the req uired periodic timber yields. The long-term scheduling of harvests was formulated as a classic 'Model I' linear programming problem, modifie d for polycyclic systems. First period harvest was maximized subject t o area, cutting cycle, and volume control constraints. The model was u sed in a case study of a 1200 ha community forest comprised of 15 land owners. The results suggest that the cooperative will have difficulty supplying a proposed portable sawmill, particularly once the conversio n of the forest from the unmanaged to managed state is complete.