Fitossociologia e estrutura diamétrica na mata de galeria do Pitoco, na reserva ecológica do IBGE, DF

Abstract

The gallery forest, in the cerrado region, has a very important function on the environmental and social equilibrium. Despite been protected by law, gallery forests have been systematically replaced by agriculture and other regional uses. One thousand trees (DAP 5cm) were sampled using point centered-quarter (PCQ) method. Sampling lines were established, from the head to the mouth of the stream and from the stream margins to the forest-cerrado border, of the Pitoco gallery forest, in the IBGE Ecological Reserve, in Federal District, Brazil. Results showed 99 species of 46 families in the area. The most important families were: Leguminosae, Vochysiaceae, Rubiaceae, Anacardiaceae, Euphorbiaceae, Lauraceae, Burseraceae, Moraceae, Annonaceae e Symplocaceae, while the most important species were: Callisthene major, Tapirira guianensis, Protium almecega, Copaifera langsdorffii, Sclerolobium paniculatum var. rubiginosum, Pseudolmedia guaranítica, Faramea cyanea, Emmotum nitens, Lamanonia ternata, Maprounea guianensis, excluding the group of dead trees which was ranked in the 5th position. Density and basal area were estimated as 1971 trees.ha-1 and 38,8 m².ha-1 ,respectively. Diameter distribution showed a tendency to an inverted J curve revealing low levels of disturbance in this gallery forest. A floristic comparison carried out with 21 gallery forests in the Federal District indicated Pitoco gallery forest as a rich site including 99 (26,2%) of the total of 378 species recorded, a Shannon & Weaver diversity index estimated as 3,86 nats.ind-1 and Sørensen similarities ranging from 0,29 to 0,80 with DF gallery forests.