Radial Scanning NIR
Wood is not a uniform material. It is well known that wood properties vary significantly within a tree.
Wood properties vary with the conditions under which they were produced. These conditions vary
continually and considerable within-tree variation exists in most tree species, especially those grown in environments with marked seasonality. Technologies such as SilviScan (www.SilviScan.com) allow key
physical properties (eg. density microfibril angle and stiffness) to be measured in radial samples such as increment cores at high spatial (and therefore temporal) resolution). Over the past few years we have developed NIR calibrations that can also provide measures of key chemical properties (pulp yield, cellulose content) in eucalypt increment cores. This radial scanning application was originally conceived by Rob Evans (inventor/ developer of SilviScan) with the intention of making this one of the suite of tecnologies that comprise SilviScan.
To date our studies have shown that KPY generally increases from pith to bark, and the gradient of change can vary between trees and sites (Downes et al 2012). In E. nitens growing in Tasmania within an annual increment, KPY and cellulose content can vary up to 8%, in addition to the general pattern of radial increase (Downes et al 2010).
Downes G.M., Meder R., Harwood C.E., Evans R., Ebdon N., Bond H., Joyce K., Thumma B. and Southerton S.G. (2010) Radial variation in cellulose content and Kraft pulp yield in Eucalyptus nitens using NIR spectral analysis of air-dry wood surfaces. J. NIRS 18, 147-155
In more recent applications we have developed indicators of non-recoverrable collapse (tension wood) in plantation grown E. globulus.