Wood Preservatives and Termite Attacks

Abstract

IN a recent pamphlet entitled "Effectiveness of Wood Preservatives in Preventing Attack by Termites" (U.S. Dept. of Agriculture. Circ. 683. By T. E. Snyder and J. Zetek. Washington: Gov. Printing Office. 10 cents) the opening paragraphs have a familiar ring to those acquainted with some of the more domestic troubles of early British rule in India and elsewhere in the tropics. "Wood has been classified," says the writer, "in the present global war as a critical structural material. Much of the wood to be utilized for the construction of the large number of necessary barracks and storage depots must be installed in the Tropics. Even in the event of a short War, past experience has shown that structures built to last for only short periods of service must be continued to be used long after the War is over. For the protection of wood from attack considerable research and investigation work has been carried out for some years by several research organisations in the United States, e.g., Forest Products Laboratory of the U.S. Dept. of Agric.; Chemical Warfare Service of the War Dept.; California Termite Investigations Committee; the Western Union Telegraph Company and others." Various wood preservatives have been experimented with, and the writer of the pamphlet deals with them under three heads. Preservative oils, such as creosotes and combinations in petroleum or tar—especially adapted for penetration of timber to be used in contact with the ground. Water-soluble salts, such as zinc chloride, chromated zinc chloride and several proprietary preservatives, are for use as 'white' or clean pretreatments; they are ordinarily used above ground and the wood can be finished or painted after treatment. Certain toxic chemicals which, are nearly colourless, dissolved in light petroleum oils, are adapted for the non-pressure immersion treatment of finished articles. The wood does not swell or shrink, dries rapidly, and is left clean, and after treatment it can be finished or painted. Many methods have now been devised for preserving wood, some simple non-pressure processes, others pressure processes requiring expensive equipment.