Calibrações NIRS para três propriedades químicas da madeira de Eucalyptus urophylla

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.