EQUATIONS FOR ESTIMATING GROSS CALORIFIC VALUE OF WOOD FROM FOUR TREE SPECIES

uThe objective of this study was to fit regression equations that express the gross calorific power (GCV) of wood from four tree species: Acacia mearnsii De Willd., Eucalyptus grandis Hill, Mimosa scabrella Benth. and Ateleia glazioviana Baill. The backward variable selection procedure was used to formulate GCV equations according to the volatile matter content (VMC), ash content (AC), fixed carbon content (FCC) and organic matter content (OMC). Sample collection was performed one year after planting to determine such variables. All equations performed well: fitted values for the coefficient of determination was greater than 82 %, standard error of the estimate was less than 1.1 % and distribution of residuals was adequate. The equations involving only the VMC for A. mearnsii, AC for E. grandis and A. glazioviana, and elements of proximate analysis for M. scabrella are just as effective at estimating GCV as other equations that include a greater number of independent variables.