2019 Volume 101 Issue 4 Pages 139-144
In order to clarify the potential range of deer browsing height on Sugi cuttings, as well as the effects of slope gradient on this range, we planted large Sugi cuttings (＞160 cm; n＝300) on slopes with different gradients (0 to 50°) and measured the height of browsing activity over the course of one year. The slope gradient at each site was measured at 5° intervals. The findings showed that the browsing rate and the number of browsed shoots tended to decrease as the gradient became steeper. When the Sugi cuttings were planted on almost level ground (≤5°), 67.4％ of the shoots from 75 to 110 cm were browsed (median height: 96 cm). As the slope gradient exceeded 35°, the median height of the browsing range increased by more than 40 cm. On slopes ＞30°, 81-100％ of the browsed shoots were on the uphill-side of the Sugi crown. The observed range in browsing height (75 to 110 cm) shows that cuttings shorter than this would be at highest risk from deer due to damage to the terminal leader. It is therefore necessary to use Sugi cuttings ＞110 cm on gentle slopes and at least 140 cm on slopes with gradients ＞35°.
