Investigation of factors affecting bark-stripping by Japanese black bears (Ursus thibetanus japonicus Schlegel) in Sugi (Cryptomeria japonica (Thunb. ex L.f.) D. Don) plantation

Abstract

We analyzed forest cover, structure and environment of bark-stripped stands by Japanese black bear (Ursus thibetanus japonicus Schlegel) in Sugi plantations (Cryptomeria japonica (Thunb. ex L.f.) D. Don) of Utsunomiya University Forest and investigated factors affecting bark-stripping. Bark-stripped stands had lager DBH, crown length and volume, and lower clear length ratio, form ratio, species number and vegetation cover percentage of shrub layer. These were located apart from national road and close to ridge top. Multiple regression analysis revealed crown length, relative spacing, slope angle and distance from ridge top were significant independent variables for percentage of bark-stripped trees.