Modelos de calibração e a espectroscopia no infravermelho próximo para predição das propriedades químicas e da densidade básica da madeira de Eucalyptus

Abstract

Near infrared spectroscopy (NIRS) is a fast, accurate and non-destructive method, capable of predicting wood technology properties. The aim of this study was to apply the NIRS technique for fast prediction of chemical properties and basic density of Eucalyptus wood. Clones of three-year-old Eucalyptus, from commercial plantations in Cocais, Guanhaes, Rio Doce and Santa Barbara localities in the state of Minas Gerais were used. The chemical properties and basic density of the trees were determined using traditional laboratory methods and correlated with the spectral information by Partial Least Squares Regression. The calibrations to estimate basic density showed coefficients of correlation in cross-validation (Rcv) ranging between 0.56 and 0.97 and ratio of performance to deviation (RPD) between 1.1 and 4.7. The carbohydrate, xylan and glucan contents were predicted through models with Rcv ranging from 0.39 to 0.88 and RPD from 1.1 to 2.1. For cellulose, lignin and extractive contents, the models presented Rcv between 0.10 and 0.87 and RPD values between 0.9 and 2.0. The calibration to predict S/G monomer ratio that showed the best adjustment=0.90 and RPD=2.3) was in the trees from Rio Doce site. The near infrared spectroscopy proved to be satisfactory to provide the basic density and chemical properties of clones of Eucalyptus wood.