Application of Near Infrared Spectroscopy to Preservative-Treated Wood

Near infrared (NIR) spectroscopy is now a widely-used technique in the field of forest products, especially for physical and mechanical property determinations. This technique is also ideal for the chemical analysis of wood. There has been a growing need to find a rapid, inexpensive and reliable method to distinguish between preservative-treated and untreated waste wood. It has been demonstrated that NIR spectroscopy, with multivariate analysis (MVA), can be used to distinguish between different preservative treatments. This technique is rapid, non-destructive, portable and relatively low cost. The results clearly demonstrate that this technique has potential for use in a variety of recycling and sorting applications. It has also been successfully used to predict preservative concentrations present in treated wood. A custom-made NIR scanning system, NIRVANA (Near Infrared Visual and Automated Numerical Analysis), was used for the automated scanning and prediction of preservative concentration along cross sections of ACQ-treated timbers. This may have potential for use as a quality control tool for wood treaters, especially for use with organic co-biocides, for which the preservative penetration and concentration cannot be readily assessed.