短報 SHORT COMMUNICATION

乗鞍岳亜高山帯針葉樹林の台風被害

後藤稔治^1)*・ 田中俊弘²⁾

1) 岐阜県立大垣東高等学校 〒503-0857 大垣市美和町1784
2) 岐阜薬科大学 〒502-8585 岐阜市三田洞東５-６-１

Toshiharu GOTOH^1)*, Toshihiro TANAKA²⁾: Damage of subalpine zone plant communities in Mt. Norikuradake after disturbance by a typhoon attack. Ecol. Civil. Eng. 4(1), 81-86, 2001.

1) Ohgaki-Higashi High School, Ohgaki City, Gifu 503-0857, Japan
2) Gifu Pharmaceutical University, Gifu City, Gifu 502-8585, Japan

Abstract:An investigation was carried out on the extent of damage caused by typhoon 7 on the subalpine coniferous forest in Mt. Norikuradake, central Japan, in 1998. It has been confirmed that sizable amounts of trees were found fallen, on the northwest slope of Nekodake （2200-2350 m）, particularly at 3 spots of 0.9 ha, 1.1 ha and 2.6 ha. According to the belt-transect survey, many canopies of coniferous trees such as Abies mariesii, A. veitchii and Picea jezoensis var. hondoensis, were blown off by the typhoon. However, damage on saplings was slight. Still, many trees were uprooted by the strong southwest wind and resultantly lay perpendicularly to the direction of the slope. As for the forest stands covered with Sasa senanensis, it is better to leave them as they are because it is precisely on these sites that the fallen trees are able to flourish and regenerate themselves.

Key words: belt transect method, disturbance of typhoon, Mt. Norikuradake, regeneration, subalpine coniferous forest

摘要

乗鞍スカイライン沿線の亜高山帯針葉樹林において，台風7号（1998年9月）の被害調査を行った．強風によるまとまった倒木は，風害地形と思われる猫岳の北西斜面（2,200〜2,350 m）で3ケ所（0.9 ha，2.6 ha，1.1 ha）確認された．ベルトトランセクトによる毎木調査の結果，林冠部を形成しているアオモリトドマツ・シラベ・トウヒなどの針葉樹に倒木が多いことが分かった．林冠木の下に位置する若木には影響が少なかった．倒木の多くは，斜面方向に垂直な南西方向からの強風によって根返りを起こしていた．林床の植生がクマイザサで被われている林分については，倒木が実生の唯一の更新立地となるので，一部はそのままにしておくことが大切である．

2001年1月5日受付，2001年5月25日受理
e-mail: tosiharu@sepia.plala.or.jp