North American subterranean termites are established in a number of locations in southwestern Ontario. They have become one of the major factors limiting the service life of wood products in this area. If preservative treatment can be demonstrated to prevent termite attack, the market for wood products can be maintained and expanded. With the assistance of the city of Kincardine, Ontario, Forintek set up a termite test site in 1988. Most of the lumber for installation in the test plot was provided by Canadian wood treating plants. Additional lumber was purchased at local retailers. The majority of the material was red pine, lodgepole pine, jack pine, white spruce or mixed spruce-pine-fir. Treatments included chromated copper arsenate (CCA), ammoniacal copper arsenate (ACA) and, in western hemlock only, ammoniacal copper quat (ACQ). Both incised and unincised lumber was included in the tests where possible. CCA-treated hem-fir plywood was also used. All the cut ends were brush-treated with copper naphthenate. Some samples were placed with the pressure-treated ends in the ground and others with the brush-treated ends in the ground. The material was inspected in the summer of 1996. There was no indication of a difference in performance depending on which end was in the ground so the data were amalgamated. Treated material for the most part was generally performing well with some pieces starting to show initial signs of termite attack. In most cases this consisted of signs of superficial surface feeding or "cosmetic damage". A few of the samples that had lower assay retentions and preservative penetrations showed more than just trace nibbles where termites appeared to have actually penetrated through the outer treated zone. It also seemed that termite entry occurred in areas on the wood surface where defects may have facilitated such entry. Material that came close to meeting CSA O80 standards for ground contact generally suffered only minor damage.