Efeito do manejo de baixo impacto sobre a composição, estrutura e dinâmica de uma floresta de terra firme amazônica

Abstract

Tropical forests are ecosystems of great biodiversity and therefore of indispensable ecological value. An alternative for the maintenance of these ecosystems is the Sustainable Forest Management whose objective is to combine conservation with forest use. In the Amazon Forest this practice of Selective Cutting has grown, but there are still many gaps in the understanding of how the forest responds to this practice. In this context, the present dissertation was carried out in two areas of Amazonian land located inside the company Jari Celulose / Orsa Florestal, is part of a large project and aimed to evaluate (a) the ecology of the vegetation of two natural forest areas verifying Their differences and similarities; (B) the impacts of the Selective Cut on vegetation ecology. In 2011, 6 transects were launched in each of the areas and the first sampling (identification, measurement of DBH and height of arboreal and regenerating individuals) was carried out, after that first sampling was carried out in one of the areas and in 2013 the Second sampling. In the pre-management situation, although the vegetation community of both areas presented general characteristics of the Amazonian terra firme forests, they presented a dissimilarity in marked composition, besides being differentiated in the vertical stratification. In the pre - and post - management comparison in the managed area were found decreases in the dominance of the tree class and decrease of density and increase of the diversity of the regenerating class. The management also caused changes in the composition of species of the tree community of the managed area and this change was the result of the substitution of species. Comparing the dynamics of the two areas in addition to finding a higher mortality and lower basal area in the area explored, it was verified that this process is occurring differently in both areas, and that these variations of the dynamics are also being influenced by environmental factors. Thus, it is necessary to study in detail the peculiarities of each community and also of the populations, as well as of the environmental factors acting on these for correct actions of conservation and evaluation of the sustainability of the management.