Anti-termite Performance of Japanese and Foreign Timber Species under Different Degradation Environments

Abstract

Anti-termite performance of fifteen species of Japanese and foreign timbers was evaluated using two subterranean termites, Reticulitermes speratus (Kolbe) and Coptotermes formosanus Shiraki in laboratory tests. In addition, field trials in nine sites were conducted under protected above-ground conditions to know the effects of peripheral environment and termite species on the performance of tested timbers. In the results of laboratory tests with un-weathered samples, lower anti-termite indices of 80%, which was set as a threshold of anti-termite performance, were observed in Sequoia sempervirens, Eucalyptus diversicolor, and Cryptomeria japonica for C. formosanus, and in S. sempervirens, E. diversicolor, and C. japonica for R. speratus. After weathering, anti-termite indices were decreased remarkably in Thujopsis dolabrata, S. sempervirens and C. japonica for R. speratus, whereas, they were almost the same as those of the un-weathered samples for C. formosanus. The field trials resulted in greater damage by E. diversicolor among high-density hardwood species. Damage ratings of tested species strongly varied with different test sites. © 2011, The Japan Wood Research Society. All rights reserved.