Dinâmica de incremento e estoque de carbono em uma Floresta Estacional Semidecidual

Abstract

In Brazil, areas covered by remnants of the Semideciduous Seasonal Forest (FES) are found in the Atlantic Forest, Cerrado and transition areas biomes. This forest formation plays an important role in offering ecosystem services essential for the ecological balance of a region. In this context, the objective of this study was to evaluate the diameter increment, carbon content, carbon and biomass stock, influence of successional groups and growth rings of six tree species from FES. The study was conducted in a fragment of native vegetation, located at Fazenda Capivara, headquarters of Embrapa Rice and Beans, in the municipality of Santo Antônio de Goiás, Goiás. The six species were studied: Aspidosperma polyneuron Müll.Arg., Callisthene major Mart., Didymopanax morototoni (Aubl.) Decne. & Planch., Hirtella gracilipes (Hook.f.) Prance, Hymenaea courbaril L. and Tapirira obtusa (Benth.) J.D.Mitch. The selected species belong to different successional groups, and six trees were chosen for each one. A dendrometric band was installed on the bole of each tree, with the aim of monitoring, every fortnight, the growth in diameter for a year. Growth rings were analyzed from wood samples collected with an auger, allowing the age of the trees to be determined. The carbon content was evaluated through laboratory analyses, while the carbon and biomass stock was estimated from the basic density of the wood and specific allometric equations. Furthermore, species were categorized into successional groups (pioneer, secondary and climactic) to evaluate their influences on growth and carbon allocation. The results indicated that the average annual increase was minimum for C. major (0.083 mm.year-1) and maximum for H. courbaril (1.309 mm.year-1). The carbon content varied from 42.10% (D. morototoni) to 44.68% (C. major). Carbon stock and biomass differed between species, but no statistically significant differences existed between successional groups. Growth ring analysis demonstrated variation in carbon allocation over time, reflecting the influence of environmental conditions on forest dynamics.