Floristic, structural, and allometric equations to estimate arboreal volume and biomass in a cerradao site

This objective of this study was to characterize the floristic, structural, and ecological groups and to estimate the arboreal volume and biomass of a cerradao site in Palmas, Tocantins, Brazil. A forest inventory was conducted on 10.15 ha of the study area. Plots of 400-m(2) were used for systematic sampling. All standing trees (dead or alive) with a breast-height diameter (DHB) greater than 5 cm were identified and measured. Floristic diversity and horizontal structure were assessed using the Shannon and importance value indices, respectively. Forest vertical structure was classified into three stratata and the tree species were categorized into ecological groups. Ninety tree volumes were rigorously cubed and weighed. Fresh- and dry biomass were sampled and estimated. Mathematical models were applied and adjusted to estimate tree volume and biomass. It was observed that the species Myrcia splendens and Emmotum nitens and the families Fabaceae and Chrysobalanaceae were dominant in our study site. The pioneer (613 individuals ha(-1)) and climax (530 individuals ha(-1)) tree species group predominated. The floristic diversity index was estimated as 3.35 nats ind(-1). The vertical structure analysis indicated fewer individuals in the superior stratum (13%) compared to the medium (63%) and inferior (24%) stratum. The Schumacher and Hall model showed better results with regard to estimated forest production. Forest volume and biomass estimates were 126.71 m(3) ha(-1) and 61.67 Mg ha(-1), respectively. The studied cerradao area had high floristic diversity and climax species predominated. Since this cerradao is in close proximity to the Amazon biome, its volume and biomass stocks were higher than those estimated for other cerradao and forest formations within the Cerrado biome.