Estimation of basic density of Eucalyptus globulus using near-infrared spectroscopy

Basic density and pulp yield are two very important factors in determining the economics of chemical pulping. A method for estimating pulp yields has been developed by measuring the near-infrared spectra of wood powders from cores withdrawn from standing eucalypt plantation trees using motorized equipment. This paper examines the precision with which the basic density of the woods might be predicted from the same near-infrared spectra. We found that the basic densities of woods from plantation-grown 8-year-old Eucalyptus globulus Labill. subsp. globulus (Tasmanian blue gum) ranging from 378 to 656 kg/m3 could be determined with an accuracy of prediction of ca. ±30 kg/m3. This error compares with the accuracy of prediction of pilodyn density measurements on similar samples of ca. ±22 kg/m3. The basic densities of increment cores having relatively low basic densities were consistently overestimated and those having relatively high basic densities were consistently underestimated by the near-infrared spectroscopic method.