[Microfibril angle prediction of Eucalyptus pellita wood samples based on radial and tangential section by near...

Near infrared spectroscopy (NIR) technique was applied to predict wood microfibril angle (MFA) of eucalyptus pellita in radial/tangential section. The MFA of small clear increment core samples were measured by X-ray diffractometry. After collecting the near infrared reflectance spectra of each sample, the NIR spectra were preprocessed with the second-derivative and the regression models were built for certain spectra. The calibration models were established using at least 159 samples with the partial least squares method and validated with full cross validation method. The results showed that high correlation coefficients were obtained between the laboratory-determined data and NIR fitted data. The finding suggests that an NIR instrument could be calibrated to estimate the limited MFA range of the increment core samples of eucalyptus pellita in radial/tangential section rapidly. Further work is required using different species wood sample sets that display a wide range of MFA variation.