Propriedades energéticas da madeira e do carvão vegetal de Vernonanthura phosphorica em função da proveniência das árvores

Abstract

The objective of this study was to evaluate the energetic properties of wood and charcoal from Vernonanthura phosphorica of the three provenances, namely: Sussundenga, Moribane and Nhamacari Forest. Five trees were felled for each location and, 3 discs of 6cm thickness were removed near to Breast Height Diameter. One disc weas converted into 4 wedges. Two wedges were used in determining the specific gravity and ash content in wood, and the remaining wedges were converted in 2x2x2cm cubes for carbonization and proximate analysis of charcoal. The results indicate that the specific gravity of the wood varied from 0.44 g/cm3 to 0.50 g/cm3, and the ash content of the wood varied from 1.58% to 1.89%. The gravimetric yield values of carbonization ranged from 33.70% to 34.64%, and the content of volatile materials, ash content and fixed carbon varied from 23.45% to 25.68%, from 3.47% to 4.90% and from 70.70% to 73.08%. It was found that in general, the results of the properties evaluated in the study were within or close to the range referred in the literature, with the exception of the ash content of charcoal, which was found to be higher than those of the literature. The results also show a significant effect of provenance of the tree in the specific gravity wood, where samples from the Nhamacari Forest presented higher values. There was no effect of the ash content of the wood, the gravimetric yield and the contents of volatile materials, ash and fixed carbon of charcoal from Vernonanthura phosphorica on the provenance of the trees. I was concluded that Vernonanthura phosphorica provides in general firewood and charcoal with suitable energetic properties for domestic use.