The Similarity and Difference of Factors that Determine the Intensity of Debarking by Sika Deer:

An Examination with a Multiple Prefecture Data Set

Abstract

Population expansion of sika deer (Cervus nippon) and the resulting increase of debarking have been reported throughout Japan. For effective management of such debarking, the factors that determine the intensity of debarking should be clarified by each management unit. In this study, we analyzed the relationship between the sight per unit effort (SPUE) of sika deer, which is one of the density indicators of sika deer, slope, snow depth, tree diameter at breast height, tree species, and the occurrence probability of debarking by sika deer at a stand unit and an individual tree unit. The analyses were conducted in Gifu Prefecture, Yamanashi Prefecture, Tochigi Prefecture, and nine prefectures around the Kanto region. The occurrence probability of debarking at a stand unit initially increased with the increase of snow depth but decreased in deeper snow depth. The effects of SPUE and slope on the occurrence of debarking at a stand unit differed among prefectures. The occurrence probability of debarking at an individual tree unit increased with the increase of SPUE and deer preference of debarking by tree species was generally similar among prefectures. In conclusion, factors that determine the intensity of debarking were mainly common among prefectures in the Kanto region.