Thin veneers of Pinus radiata were treated with dilute aqueous solutions of chromium VI and iron III compounds and exposed to natural weathering for 35 days. Zero-span tensile strength and weight losses of treated veneers were compared with losses observed in untreated specimens In a study designed to demonstrate the applicability of strength and weight loss measurements to the rapid quantitative assessment of wood surface protective treatments. The application of the recognised surface protective agent chromium trioxide restricted weight loss after weathering, although at the rate applied of 0.4 mg chromium per cm², strength loss was similar to that observed in untreated weathered specimens. The application of ferric nitrate to veneers at 0.43 mg iron per cm² slightly reduced weight loss, but increased strength loss compared to untreated controls. Ferric chloride at the same application rate increased both weight and strength loss compared to untreated controls. This was unexpected as previously ferric chloride was reported to have a photoprotective effect. It is suggested that while both zero-span tensile strength and weight loss of treated wood veneers during weathering are caused by radical induced oxidative processes, the former results from depolymerization of cellulose whereas the latter results from degradation and loss of lignin. The strength and weight loss criteria may therefore be used as a quantitative means of assessing the ability of chemical treatments to protect respectively, the cellulose, or the lignin components of wood during weathering.

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