Spatially-Resolved Radial Scanning of Tree Increment Cores for near Infrared Prediction of Microfibril Angle and Chemical Composition

A fibre-optic accessory with a linear drive transport system has been coupled to a near infrared (NIR) instrument to enable solid samples, in this instance increment cores from standing trees, to be scanned at 1 mm increments along the length of the sample. This allows the NIR prediction of wood properties (oven-dry chemical composition and microfibril angle) to be undertaken so that the radial profile of chemistry or microfibril angle can be determined from the pith to the bark. Calibration models provided prediction errors for microfibril angle in Pinus radiata softwood of 4.1° while for Eucalyptus globulus the error is 3.9°. The errors for prediction of chemical composition in Pinus radiata are 0.2% (arabinose) 1.1% (galactose), 2.3% (glucose), 0.7% (mannose), 0.7% (xylose) and 1.6% (lignin).