Wood blocks of Cryptomeria japonica, Tsuga heterophylla, and Pinus radiata successively extracted with n-hexane, ether, and methanol were treated with various concentrations of CCA type 3, which were subjected to the decay by Tyromyces palustris. The weight loss were different among species and kinds of extraction. Cryptomeria japonica treated with CCA had higher fungal resistance than Tsuga heterophylla and Pinus radiata. Pre-extraction did not contribute to improve the durability of CCA treated wood of all species. ESCA analysis indicated that the reduction of Cr(IV) to Cr(III) took place, and increase of C1 component (C-H or C-C bond) of C 1s spectra occurred during drying. Fixation of CCA was restricted in the shallow region of blocks in the case of 1.6% concentration. The CCA treatment increased the water repellency of all species, but there were not a wide difference among species. Leachability was high in the section specimens treated with CCA. But the amount of CCA leached was small and reached area was restricted near the surfaces in the block specimens. Amounts of nitrogen in wood surface influenced the decay resistance of wood. The fungal growth on ager-malt mediums containing extractives and CCA was smaller in methanol extractives than the others. The cause of species difference of CCA efficacy was not still explained well.

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