NIR spectroscopy for rapid estimation of decay resistance
P O Flæte, E Ystrøm Haartveit
In Scandinavia Scots pine (Pinus sylvestris L.) is an important commercial tree species. Its heartwood has traditionally been used in constructions exposed to risk of decay. In a laboratory experiment Scots pine wood specimens sampled from inner heartwood, outer heartwood and sapwood were exposed to the brown rot fungus Poria placenta. In general outer heartwood was more resistant than inner heartwood, but there were variations even within the same wood zone. NIR spectra obtained on solid wood prior to decay testing were used in multivariate calibrations to predict decay resistance of heartwood. Results from segmented cross validated partial least squares (PLS1) regression modelling showed that resistance to decay in Scots pine heartwood could be predicted with satisfying precision using NIR spectroscopy. As NIR spectra were collected on solid wood, development of the method for industrial use is potentially possible.
Keywords: Decay resistance, heartwood, near infrared spectroscopy (NIR), partial least squares (PLS) regression, Scots pine, wood durability