The relationship between bark-stripping damage to forest trees caused by sika deer (Cervus nippon) and understory vegetation

Abstract

The relationship between the number of bark-stripped trees and understory vegetation was examined in cypress (Chamaecyparis obtusa) plantations in the Kuma region of Kumamoto Prefecture, Japan. First, the amount of understory vegetation was quantified by taking images using a digital camera. Using TWINSPAN, the 77 surveyed sites were classified into three vegetation types based on the species composition of the understory vegetation: Sasamorpha borealis, pioneer species, and evergreen-tree species. Then, we used the bootstrap method and examined whether there were fewer bark- stripped trees at the surveyed sites with much understory vegetation. The quantity of understory vegetation influenced the number of bark-stripped trees only in the evergreen-tree species category, which suggests that physical and visual shielding by understory vegetation is very useful for preventing bark-stripping.