Processes which combine drying and preservation are first reviewed. Some preliminary experiments are then described in which blocks of green Sitka spruce sapwood were immersed, in a solution of tributyltin oxide (TBTO) in methanol at 60°C. Satisfactory penetration of the preservative and exchange of methanol and water occurred in a few hours. The methanol was removed rapidly from the wood by evaporation. Satisfactory penetration of TBTO into initially methanol-saturated samples occurred in a similar period. The factors influencing. such treatments are discussed. High initial moisture content of the wood and a high operating temperature are particularly desirable. Some aspects of the possible commercial operation of the process are discussed.