A scientific formulation of tropical forest management

The paper introduces a scientific formulation to deal with value judgements, factual knowledge and norms, required for a rigorous treatment of tropical forest management. The model arising from this approach is able to establish norms of natural forest management pursuing the ecological objective of pristine tree species preservation in situ. Consistent with this objective is presented a set of factual sentences about the structure and dynamics of the tropical forest, specifically Atlantic forest. The logarithmic form of the diametric density distribution reveals cohorts of similar adaptive strategies and permits the statistical estimation of survival coefficients from the inventory of a pristine stand. As a consequence of the non-linearity of the density matrix, specific algorithms had to be worked out in order to simulate the dynamics of the pristine forest. Adjoining to the ecological objective of tree species diversity preservation the (simple) economic objective of maximum log output, together with the factual sentences (describing the forest reality from the point of view of a forester or a forest enterprise) entail logically the set of selection criteria or norms for tree felling. The use of these norms to a stand of Atlantic forest is described, demonstrating the preservation of the pristine structure and of all tree populations after logging under natural forest management in a cutting cycle of 23 years. Finally is demonstrated the incompatibility of current felling norms with the ideal of pristine tree-diversity preservation, as for instance the forest legislation for the state of Santa Catarina allowing the felling of 40% of trees with DBH (diameter at breast height) above 40 cm for at most four species.