Natural re generation in tropical forests

Abstract

The sustainability of forest management is supported by the natural regeneration of species, whose mechanisms have been investigated by foresters and ecologists. Numerousstudies have addressed the dynamics of tropical forests, always based on a previously existing vegetation and fl oristic composition. However, in assessing the population dynamics of isolated species, concepts such as recruitment and ingrowth, generally taken as synonyms, can express distinct principles that will be discussed in this review, whose aim is to analyze the strategies of natural regeneration of tree species in tropical forests and models used to evaluate its dynamics, some of which show mathematical indeterminacy in evaluating recruitment and ingrowth. The Rate of Natural Regeneration (NR) proposed in this studyrepresents an approach that eliminates this problem of mathematical indeterminacy. Strategies for natural regeneration of tree species include concepts such as seed or seedling banks, and classifi cation in ecological groups as pioneer and climax species based on seed size, germination, seedling establishment, demand for gaps, etc. The classifi cation based on the diameter distribution of tree species considers that this structure expresses their life story, as the result of the interaction of genetic factors with biotic and abiotic factors of the ecosystem. Therefore, many timber species whose static natural regeneration does not exist in the primary forest, but present mature trees, have as regeneration strategy a strong dependence on disturbances to regenerate and grow. Thereat, the lack of continuous anddecreasing distribution cannot prevent their use via forest management.