Abstract: The invention is directed to compositions and methods for enhancing the mechanical strength and dimensional stability of composite boards and structures.

Abstract: The specification describes preserved solid wood or wood composites including a copper ammonium acetate complex wood preservative and a drying oil. The wood preservative is present in the wood in an amount effective to improve the resistance of the treated wood to at least one type of decomposition, such as decay or insect attack. The drying oil is present in the wood in an effective amount to accomplish at least one useful end, such as reducing the water absorption or thickness swell of the treated wood or increasing its mechanical strength, even in a wood composite made using less binding resin than usual. Yet another aspect of the invention is a method of making the treated wood from green wood in solid or flaked form. A copper ammonium acetate complex wood preservative and optionally a drying oil are added to the green wood.