Abstract
The service life of Sugi (Cryptomeria japonica) heartwood treated with wood-vinegar and wood-tar was estimated by a field stake test. The test site was located in Tsukuba, Ibaraki, Japan. Results after 15 years exposure in a outdoor condition indicated that service life of wood-tar treated-heartwood was 6, 15, 15, and 15 years in the uptake of 61kg/m3, 146kg/m3, 149kg/m3 and 227kg/m3, and that of wood-vinegar treated-heartwood was 5, 6, 7 and 5 years in the uptake of 99kg/m3, 260kg/m3, 480kg/m3 and 639kg/m3 and that of untreated-heartwood was 4 years respectively.
