Wetting Agent and Ultrasonic Cavitation Effects on Drying Characteristics of Three U.S. Hardwoods

Newly formed outer sapwood in all trees is extremely permeable and therefore easy to dry. However, as sapwood becomes heartwood, extractives deposited in the cell lumens and on the pit membranes tend to block the flow of fluids in wood. As a result, drying rates of sapwood and heartwood differ greatly. This paper describes an evaluation of the combined effects of a wetting agent and ultrasonic cavitation on the drying characteristics of sugar maple, black walnut, and white oak. Soaking in a wetting agent for one week increased the subsequent drying rates of sugar maple and black walnut heartwood, but not white oak, around and below fiber saturation point (fsp). Ultrasonic cavitation did not increase the subsequent drying rate and shrinkage of sugar maple and white oak. Soaking in a wetting agent for one week increased thickness shrinkage of black walnut and white oak heartwood, and increased width shrinkage of sugar maple and white oak heartwood upon subsequent drying