The aim of the study is to reveal the performance of Tanalith C and new Tanalith CA on pinus sylvestris stakes at 10 different Iocalities. One of them \vas established in the Belgrad Forest near İstanbul. Test result for 10 Years of service betvveen 1966 -1976 were summarized in this paper. Cooısequently these preservatives \vere only found effektive against decay and termites when they -vvere treated vvith high concentrations like 2 percent and more.