Dinâmica da comunidade arbórea de uma mata de galeria do Brasil Central em um período de 19 anos (1985-2004)

Abstract

Tree community dynamics was analyzed with basis on the data from the continuous inventory in an area of 64 ha of the Gama gallery forest at the Fazenda Água Limpa, DF. The inventory consisted of 151 permanent (10 × 20 m) plots located systematically along ten transects placed every 100 m at right angles to the Gama stream. All individuals with diameter at breast height (DBH) equal or greater than 10 cm were mapped in the plots, tagged and measured in 1985, 1988, 1991, 1994, 1999 and 2004. The periodic annual increment (PAI) for the community during the 19 years period (1985-2004) was 0.22 cm yr-1, with coefficients of variation ranging from 84% to 143%. The trend of increment in diameter was characterized by the increase of the increments with the increasing diameter classes up to 52 cm of DBH. The mean annual mortality rate was 2.87% while the recruitment was 2.08%, resulting in a decrease in the density during the 19 years period. The half-life was 24.13 years from 1985 to 2004. The community was dynamic with 92% of all species either suffering mortality or gaining recruits or both but, 83% of total of species found in the forest occurred in all the analyzed periods. Mortality was high but recruitment was also intense leading to a high turnover typical of an environment under strong border effect such as the gallery forests, which are narrow strips of tropical forests surrounded by savanna. These results suggest a very dynamic but stable community.