Prediction of the Decay and Termite Resistance of Western Red Cedar Heartwood

Abstract

Western red cedar (WRC; Thuja plicata) is highly valued for its natural durability. Rapid methods to assess heartwood durability are needed to identify breeding stock that will ultimately yield trees with durable wood when harvested. Chromatographic methods to detect heartwood extractives have been developed, but these still require significant time and laboratory resources and rely upon an understanding of the relationship between extractives and durability that is still incomplete. Visible/near-infrared (VIS/NIR) spectroscopy combined with multivariate statistical analysis has been used to rapidly predict a wide range of wood properties, including extractive content and decay resistance. The present work investigates the ability of VIS/NIR spectroscopy to predict extractive content, decay resistance, and termite resistance of WRC heartwood and explores the association between extractive content and durability. Partial least squares (PLS) models based on VIS/NIR spectra had moderate predictive ability for lignans, plicatic acid, beta-thujaplicinol, and total extractives. Other extractives were poorly predicted. Developed PLS models were not predictive for decay resistance but were moderately predictive of termite resistance. Decay and termite resistance were not strongly associated with any measured extractive. A moderately strong correlation was observed between termite resistance and red coloration (a*). Some of the models developed may be suitable for screening, but none are accurate enough for phenotyping.

Chemical characterization, hardness and termite resistance of Quercus cerris heartwood from Kosovo

“…Decay resistance also varies within the stem e.g. it tends to increase radially from pith to the heartwood-sapwood boundary and longitudinally from crown to base (Stirling et al 2015), and is typically connected to the wood chemical composition, in particular, with the extractives present (Daniels and Russell 2007, Gierlinger et al 2003, Pâques and Charpentier 2015. Nevertheless, the reasons of resistance to decay may not be directly translated into resistance to insect attacks: for instance, Taylor et al (2006) found that the total wood extractives amount was important but alone could not explain termite durability in Thuja plicata and Chamaecyparis nootkatensis, and Stirling et al (2015) confirmed the findings for Thuja plicata.…”

Termiticidal activity of oil from Jatropha curcas L. and Azadirachta indica A. Juss against Coptotermes sjostedti Holmgren (Isoptera: Rhinotermitidae)

“…observed in the study. Stirling et al (2015) reported similar outcome on Coptotermes formosanus Shiraki mortality and damage caused on Western Red Cedar Heartwood (Thuja plicata L.).…”