Damage to young Cryptomeria japonica and Chamaecyparis obtusa plantations enclosed by deer fences in Shikoku Island, Japan

Abstract

To evaluate the browsing damage caused by sika deer (Cervus nippon), we surveyed damage to planted trees in young coniferous plantations where deer exclosure fences had been installed. We recorded the number, height and damage status of planted trees in 100 m² study plots (width 2 m, length 50 m) in 18 Cryptomeria japonica stands and 27 Chamaecyparis obtusa stands in Shikoku Island, Japan. Damage was observed in 23.3% of the surveyed C. japonica trees and 44.6% of C. obtusa trees: damage to C. obtusa was characterized by bark stripping. The percentage of study plot in which the number of healthy tree was < 15 per 100 m² was 22.2% (4 of 18) for C. japonica and 55.6 (15 of 27) for C. obtusa. It is assumed that such stands might not grow economically due to low tree density and low tree height. We found a tendency that the number of healthy trees decreased as slope inclination increased and as estimated deer density increased. Caution should be paid when we install and maintain deer fences in such a place.