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Update:October 29, 2019

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How high can deer eat Sugi cuttings ?


Article title

Slope gradient determines deer browsing height on large planted Sugi. (Cryptomeria japonica) cuttings.

Author (affiliation)

Haruto Nomiya (a), Hiromi Yamagawa (b), Hidetoshi Shigenaga (c), Satoshi Ito(d), Ryoko Hirata (d), Kiyotaka Sonoda (e, f)

(a) Kyushu Research Center, FFPRI, Kumamoto, Japan.

(b) Department of Forest Vegetation, FFPRI, Tsukuba, Ibaraki, Japan.

(c) Department of Plant Ecology, FFPRI, Tsukuba, Ibaraki, Japan.

(d) University of Miyazaki, Miyazaki, Japan.

(e) Ooita District Forest Office, Forest Agency, Ooita, Japan.

(f) Fukuoka District Forest Office, Forest Agency, Fukuoka, Japan.

Publication Journal

Journal of Japanese Forestry Society, 101(4):139-144, August 2019 DOI:10.4005/jjfs.101.139( External link )

Content introduction

Sugi and Hinoki (Chamaecyparis obtusa) trees planted after World War II have grown, and they are now ready for logging throughout Japan. After logging, Sugi and Hinoki are replanted to promote sustainability. However, browsing damage caused by animals, especially by deer, is a major concern. Therefore, to prevent deer from entering newly planted areas, the areas are enclosed with fences. However, the installation and maintenance of fences require many resources. Therefore, a method called “large cutting planting,” which uses cuttings too large to be damaged by deer, is being considered. The question we address herein is, “How tall should these cuttings be?”

In this study, we planted tall Sugi cuttings with an average height of 160 cm. We found that deer browsed the most branches at a height of approximately 100 cm on gentle slopes. However, on steep slopes, the range of browsing height became increased, extending to approximately 150 cm at a slope gradient of 45°.

When planting large cuttings to avoid browsing damage caused by deer, the height of the cuttings must be ≥120 cm from the level ground; however, larger cuttings are necessary on steep slopes. To date, research on feeding damage has been qualitative. In this study, we could show the height of evidence of browsing and the relationship between this height and the slope gradient. We believe that these results contain useful information on developing successful countermeasures for future browsing damage caused by deer.


 Figure1: Distribution of leaves of Sugi planted

Figure 1: Distribution of leaves of Sugi planted on the level ground and the height of browsing signs caused by deer.

Leaf distribution (green) shown is one year after planting large Sugi cuttings (average height of 160 cm) on level ground (slope gradient of ≤5°). The height of browsing signs was measured for one year, and the number of browsing signs per leafed tree is shown by height (red). The browsing signs were concentrated around a height of 100 cm.

Note: In small cuttings of ≤100 cm, main axis important for growth will be eaten with high frequency.

Figure2: The height of the browsing signs caused

Figure 2: The height of the browsing signs caused by deer increases as the slope gradient increases.

Circles in the figure indicate average values, and bars indicate standard deviations. On steep slopes exceeding 30°, browsing signs were divided into those on the upper slope (green) and those on the lower slope (brown), and the height of browsing signs increased on the upper slope.