NIRS CALIBRATIONS FOR THREE CHEMICAL PROPERTIES OF Eucalyptus urophylla WOOD

Abstract

The purpose of this study was to obtain calibration through Near Infrared Spectroscopy Technique (NIRS) for the following properties: total extractive content, total lignin, and wood holocelulose from a natural hybrid of Eucalyptus urophylla owned by V & M Florestal, located in Paraopeba city – MG. The hybrid was seven years old and was planted in 3 x 3m spacing. The sampling was done in a single tree and the specimens were taken throughout the trunk. The calibrations were derived from the milled wood. A spectrometer (Bruker model MPA-R) was used. The spectra were acquired in the range from 750 to 12500 nm in diffuse reflection mode. The models were fitted by PLS-1 method. The cross-validation method was used. The first and second derivative pre-treatment were used. From the results, it was concluded that: a) the highest correlation was obtained for the total lignin content, with value of correlation r = 0.62 and RPD = 1.3; b) the holocellulose content showed r = 0.50 and RPD of 1.8; c) the extractives content showed r = 0.35 and RPD of 1.0; d) the first derived pre-treatment was, for total lignin content and for holocellulose, the one that provided the best calibrations.