Hygroscopicity of decayed wood: Implications for weight loss determinations

Hygroscopicity changes were observed in red maple blocks subjected to brown rot, white rot, and soft rot. Brown rot reduced hygroscopicity, soft rot increased hygroscopicity, and white rot showed no change in hygroscopicity. The effect of these changes on weight loss tests when using moisture-conditioned block weights is a slight overestimation of weight loss for brown rot, a slight underestimation for soft rot, and no apparent change for white rot. When comparing changes in hygroscopicity prior to oven-drying with those observed after oven-drying, there were no differences for white rot and soft rot, while for brown rot, the reduction in hygroscopicity was enhanced by oven-drying.