Near infrared (NIR) spectroscopy has been used to predict the modulus of elasticity (stiffness) of samples taken from knot-free sapwood specimens of radiata pine ( Pinus radiata D. Don). The method shows the potential of using NIR spectroscopy for assessment of lumber stiffness. A model based on NIR spectra taken on the radial face of 404 samples of radiata pine clearwood was established to predict stiffness. Samples were moved past the detector at a rate of 900 mm min−1. This model then was used to predict the stiffness of a further 80 samples and the results show an error in prediction of 14% of the mean measured value.

This paper describes a method for the two-dimensional mapping of chemical composition on the transverse face of cross-sectional discs from trees. The method uses an imaging spectrograph coupled to a near infrared (NIR) camera (900-1700 nm) to obtain NIR hyper spectral data sets which are processed using partial least squares regression to visualise the distribution and variation of lignin, galactose and glucose in Pinus radiata discs with R 2 /standard error of performance values of 0.84/1.48 (lignin), 0.87/0.68 (galactose) and 0.87/0.95 (glucose). The hardware design and software control are described along with a method for calibration based on one dimension spatially resolved predictions of chemical composition from conventional NIR spectroscopy. The NIR imaging system was designed as a rapid and cost-effective means of mapping chemical composition over the entire disc at a spatial resolution of ~4 mm 2 /pixel. The resulting maps of chemical composition clearly indicate, at high spatial resolution, the extent of heterogeneity that occurs in logs.

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Near infrared spectroscopy has been used to predict the stiffness of radiata pine (Pinus radiata D. Don) veneers. Spectral data obtained from 1.2·2.4 m veneer sheets was corellated against stiffness data obtained from 6-ply mini-LVL panels prepared from the sheet. This paper describes the method used to prepare the mini-LVL test pieces and the results of multivariate regression of NIR spectra with the test piece stiffness. The results show the potential for using NIR spectroscopy for on-line assessment of veneer stiffness prior to layup of plywood or LVL panels. Selection of high stiffness veneers for layup would enable engineered panels of high uniform stiffness to be produced. Zur Vorhersage des Biegeelastizitätsmodul von Sperrholzfurnieren und Preßschichthölzern mit NIR SpektroskopieDie Elastizität von Schichtholzfurnieren aus Montereykiefer (Pinus radiata D. Don.) wurde unter Verwendung von NIR Spektroskopie vorhergesagt. Spektroskopische Daten von 1.2·2.4 m grossen Schichtholzfurnieren wurden korreliert mit der Elastizität von 6-schichtigen mini-Furnierschichtholzplatten, welche aus diesen Schichtholzfurnieren hergestellt worden waren. Dieser Artikel beschreibt die Methode, mit welcher die mini-Furnierschichtholzplatten hergestellt wurden, und die Ergebnisse der multivariaten Regression von NIR Spektren und der Elastizität der Proben. Die Methode zeigt, daß eine prinzipielle Möglickkeiten besteht, NIR Spektroskopie für eine on-line Beurteilung der Furnierelastizität zu verwenden, bevor diese zu einer Sperrholzplatte geschichtet werden. Eine Auswahl von Funieren mit geringer Elastizität vor der Schichtung würde es ermöglichen, Platten mit geringer, einheitlicher Elastizität herzustellen.