Effects of incising on treatability and leachability of CCA-C-treated eastern hemlock

Abstract

Incising is used to increase exposed wood surface and improve uptake and penetration of preservative during pressure treatment of refractory species. However, incising may also cause increased leaching of preservative when the wood is placed in service. This study compared the rate of leaching from unincised eastern hemlock to that of wood that had been incised to two depths and with two density patterns. Incising greatly increased both the penetration and retention of preservative in the incised wood compared to unincised wood. Doubling the depth of the incisions further improved retention and penetration, but doubling the density of the incisions appeared to benefit primarily the uniformity of preservative penetration. Incising did not increase the percentage of copper, chromium, or arsenic that leached from the wood. This study indicates that the benefits of incising can be obtained without the risk of increased leaching.