Development of wood decay in bark-stripped Sugi (Cryptomeria japonica (Thunb. ex L.f.) D. Don) stem by Japanese black bear (Ursus thibetanus japonicus Schlegel) (Ⅱ):

A case study of Sugi 5 years after bark-stripping

Abstract

Longitudinal wood decay progress was investigated for Sugi (Cryptomeria japonica (Thunb. ex L.f.) D. Don) trees 5 years after bark-stripping by Japanese black bear (Ursus thibetanus japonicus Schlegel). Longitudinal variation of dynamic Young's modulus was unclear in all individuals. Longitudinal variation of moisture content in all bark-stripped trees showed lower value than partially bark-stripped and non-bark-stripped trees. On the other hand, longitudinal variation of basic density in bark-stripped trees showed constant lower values than those in non-bark-stripped trees. 1% NaOH extract contents of sapwood in bark-stripped trees were higher than those in non-bark-stripped trees at 0.2 m above ground. Thus, wood decay of trees 5 years after bark-stripping progressed in sapwood at 0.2 m above ground.