其他摘要：We conducted two questionnaires on wood characteristics to understand the demands of end-users in terms of wood properties. We asked which properties were disliked, and which properties consumers hoped will be improved. In both questionnaires, the most common response was a preference for wood that is resistant to termites. Based on the responses from potential wood end-users, we conducted a study to select termite-resistant sugi (Cryptomeria japonica) cultivars. The termites Coptotermes formosanus and Reticulitermes speratus were cultured in Petri dishes with meals consisting of heartwood of various sugi cultivars, which were identified by DNA analysis. The cultivars Akaba and Iwao showed higher rates of termite mortality and fewer days to reach 50% termite mortality than those of the other tested cultivars. These results suggested that Akaba and Iwao had strong termiticidal activities. In Akaba, the termite mortality rates were equally high in two distinct ramets from different plantations. In contrast, Honsugi consistently showed weak termiticidal activities in all tests. When R. speratus was cultured with heartwood meals from which volatile compounds had been extracted, the termiticidal activities of all tested sugi cultivars including Akaba greatly decreased. Under culture conditions in which R. speratus was not fed sugi meals but exposed to volatile compounds extracted from the heartwood, Iwao and Akaba showed high termite mortality rates compared with the negative control. These results suggest that termiticidal activity of sugi is closely related to cultivar-specific extractives including volatile compounds. Together with reproducibility of cultivar-specific termiticidal activity, clonal forestry with termite-resistant sugi cultivars is one option for foresters to meet the demands of end-users.
