Western wood species treated with chromated copper arsenate: Effect of moisture content

The effect of wood moisture content on treatability with chromated copper arsenate was examined for western hemlock, mountain hemlock, grand fir, white fir, noble fir, Pacific silver fir, and Douglas-fir lumber. Samples were removed over the course of drying, their moisture contents were determined, and the samples were treated with chromated copper arsenate by a full-cell process. Treatment of samples from individual boards varied widely, reflecting the inherent variations in treatability found in these species. Comparisons between rate of drying and treatability for individual boards suggested that sorting by drying rate could be used to improve treatment for western hemlock and grand fir. The implications of these findings are discussed with regard to current practices and commercial feasibility.