Abstract: A wood preservative composition includes a first solution having: a copper compound selected from the group consisting of copper borate, copper hydroxide, copper acetate, copper chloride, and copper sulfate; a zinc compound selected from the group consisting of zinc borate, zinc acetate, zinc hydroxide, zinc oxide, zinc chloride, and zinc sulfate; and/or a boron compound selected from the group consisting of boric acid and borax; sodium silicate, and a second solution having rare earth chloride or alkaline earth chloride.

Abstract: A wood preservative composition includes a preservative component which is selected from the group consisting of copper borate and zinc borate, a volatile basic compound of, the formula R.sub.3 N, wherein R is one of a hydrogen atom and a lower alkyl group, and water. A process for preserving wood with the wood preservative composition includes impregnating wood with the the wood preservative composition and drying the impregnated wood to remove the volatile basic compound and water. The wood impregnated with the wood preservative composition is protected from wood-attacking organisms for a prolonged period of time without involving environmental pollution.