Predicting Microfibril Angle in Eucalyptus Wood from Different Wood Faces and Surface Qualities Using near Infrared Spectra

Abstract

all rights reserved Microfibril angle (Mfa) is a property of the cell wall of wood fibres, which is made up of millions of strands of cellulose called microfibrils. 1 this elementary wood trait represents the orientation of crystalline cellulose in the cell wall with respect to the stem axis. 2 It is of particular interest for breeding programmes 3,4 since Mfa has major effects on two key properties of wood: its stiffness and longitudinal shrinkage. 5 among all available techniques, only X-ray diffractometry (Xrd) provides quick Mfa measurements for a large number of samples; 6,7 however, sample preparation is often time-consuming. Xrd has been largely used because of the crystalline arrangement of cellulose microfibrils in the wood cell wall; it allows a study of not only its organisation (such as Mfa) but also its apparent crystal size 8 or its mechanical state. 9 numerous papers have proposed near infrared (nIr) spectroscopy to determine Mfa (table 1). nIr spectroscopy is a rapid method for the determination of many chemical properties which have been successfully related to physico-mechanical properties of wood. 26 one of its main advantages is the possibility of estimating a range of wood traits from the same nIr spectra. to explain the results of these established nIr-based calibrations for Mfa, a common assumption is that the supposed correlation that exists between a cIrad-perSySt department-production and processing of tropical Woods, 73 rue Jean-françois Breton ta B-40/16, b laboratoire de Mécanique et Génie civil, cnrS, université Montpellier 2, place e. Bataillon, cc 048, 34095 Montpellier, cedex 5, france c cIrad-BIoS department-Genetic diversity and Breeding of forest Species, 73 rue Jean-françois Breton ta B-40/16, 34398 Montpellier, cedex 5, franceThe microfibril angle (MFA) of crystalline cellulose in the wood cell wall along the stem axis has major effects on stiffness and longitudinal shrinkage of wood and is of key importance to timber quality. The aims of this study were: (1) to develop partial least square (PLS) regression models for microfibril angle (measured on tangential sections by X-ray diffraction) based on NIR spectra measured on tangential and on radial surfaces; (2) to develop PLS regression models for MFA based on radial NIR spectra collected from wood surfaces of different quality; and (3) to verify the reliability of these PLS-R models by external validations. T values were recorded by X-ray diffraction on tangential sections while NIR spectra were taken on tangential and radial wood surfaces. PLS-R calibrations for MFA based on tangential NIR spectra were better (r 2 p = 0.72) than those using radial NIR spectra (r 2 p = 0.64). The key role of the chemical components and the effect of surface quality of wood on NIR spectroscopy calibrations are discussed. Considering the differences between experimental conditions, these findings showed the potential of the NIR-based models for predicting MFA in Eucalyptus wood, even using spectra taken from different wood faces and surface qua...

Determination of Heat-Treated Eucalyptus and Pinus Wood Properties Using Nir Spectroscopy

“…Keywords: Timber quality, nondestructive evaluation, multivariate analysis, vibrational spectroscopy moisture content (Yang et al 2017), microfibril angle of cellulose deposition in wood cell wall (Hein et al 2010), wood chemical composition (Leblon et al 2013), physical and mechanical properties (McLean et al 2014, Todorovic et al 2015 and wood genetic parameters (Hein & Chaix 2014). There are studies reporting the use of NIR spectroscopy associated with multivariate analyses for predicting heat-treated wood properties (Tsuchikawa & Kobori 2015).…”

Juvenile Wood Characterization of Eucalyptus botryoides and E. maculata by using SilviScan

“…The results indicated that MFA is the prime determinant of MOE (Evans and Ilic 2001;Yang and Evans 2003), as well as a useful parameter to indicate MOE and strength in juvenile eucalypts from short-rotation plantations . Studies on MFA prediction have found correlations with lignin content (Baillères et al 1995;Barnett and Bonham 2004;Via et al 2009;Hein et al 2010). The microfibril angle has also been known to influence dimensional changes in wood with changes in the moisture content (Meylan 1968;Yamamoto et al 2001).…”

A novel method to correct for wood MOE ultrasonics and NIRS measurements on increment cores in Liquidambar styraciflua L

“…MOE can be determined in cores by ultrasonic or near infrared spectrometry (NIRS) assessment. The studies conducted by Schimleck et al (2003), Baillères et al (2002); Schimleck and Evans (2004), Hein et al (2010), Chaix et al (2010), Leblon et al (2013), and Tsuchikawa and Schwanninger (2013) showed that NIRS is useful for predicting certain physicomechanical properties of wood. Bucur (1981) conducted ultrasonic measurements on 5-mm-diameter cores.…”