Abstract: The invention relates to wood preservation systems which employ impregnating agents comprising halogenated tannin extracts from plant species which are relatively more resistant to fungi, weathering, rotting, insect attack, etc. Materials contained within the tannin extracts are converted to halogenated substances which are absorbed by the wood species to be treated. The halogenated extract materials can be used with or without other treatment agents (e.g., fixatives or metal salts). Bromine is the preferred halogen material, with optimum treatment occurring when the bromine concentration in the extract exceeds about 2% (most preferably, about 4-5%).

Abstract: Wood which is relatively poorer in connection with its ability to resist weathering, rotting, insect attack, etc., is made more resistant to such factors by a two-step process. The first step is to impregnate the poorer quality wood with an aqueous solution of tannin extract taken from a plant species which has superior weathering and other resistance properties. The wood treated with the tannin extract is then further treated with an aqueous solution of a fixative to prevent leaching of the extract during use of the wood, e.g., in exterior applications. The process of the present invention not only results in preservation of the wood, but can also be used for purposes of coloring the initial wood product. Abundant and relatively cheap woods can then be converted into wood products having qualities more closely like those of more expensive woods. In addition to the above-noted advantages, the present invention also uses treating substances which are non-hazardous and which are not damaging to the environment.