Effects of bucking and thinning seasons of hinoki cypress Chamaecyparis obtusa on the emerging density of the Japanese horntail Urocerus japonicus

Abstract

The effects of the thinning season and the bucking method on the emergence of Urocerus japonicus adults, which can discolor the wood of conifers, were investigated. Three thinning seasons (November, February or May) and two treatments (bucked to 2 m or non-bucked) were examined at a hinoki cypress Chamaecyparis obtusa plantation. The density of emergence was higher in bucked to 2 m than in non-bucked for both sexes. The density of male emergence was lowest in the November thinning, but there was no significant difference in the density of female emergence among thinning seasons.