TEMPORAL EVALUATION OF NATURAL REGENERATION IN A SEMIDECIDUOUS SECONDARY FOREST IN PIRENOPOLIS, GOIAS, BRAZIL

The natural regeneration in forest environments is dynamic, variable in space and time and it is in the development cycle of forests. In seasonal tropical forests, due to seasonal climatic changes, natural regeneration depends mainly on availability of soil moisture, which affects patterns of seed production and germination, survival and development of seedling as well. The objective of this study was to analyze the dynamics of natural regeneration in a seasonal semideciduous secondary forest in Pirenopolis, Goias, Brazil, by analyzing the changes in floristic composition of seedlings and small trees over time and relating them to environmental factors of plots in the study area by using Canonical Correspondence Analysis (CCA). The results indicated that seedlings were more dynamic than small trees mainly because of climate. This occurred because of the greater susceptibility of the seedling to soil water stress and the increase of solar radiation and temperature in the dry season. It was found a high floristic similarity (+/- 50%) among population of natural regeneration and the tree community, indicating an advanced stage of natural regeneration of the forest, with Diversity Index higher than 3.0 nats.indv(-1). Canonical Correspondence Analysis grouped the species according to the environmental gradient of moisture and shade versus soil cover, placing near to each other, species of humid environments versus species of typical cerrado dry environments.