Wood preservative compositions are disclosed. Treatment of lumber, plywood, and other wood products with a novel composition comprising the boron source composition, a melamine binder resin, and a urea casein activator resin protects lumber, plywood, and other wood products from attack by termites, fungi, fire and flame. The preservative can be formed by combining a source of boron such as boric acid and the water-soluble salts thereof, a melamine binder resin, and a urea casein resin. A wood preservative is characterized by a weight ratio of the urea casing activator resin to the melamine binder resin ranging from about 1:20 to 1:4 and a weight ratio of the boron source composition to the melamine binder resin ranging from about 1.3:1 to 9.6:1.