| Project/Area Number |
63480008
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
生態学
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| Research Institution | Kagoshima University |
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Principal Investigator |
TAGAWA Hideo Kagoshima Univ., Coll. Liberal Arts, Prof., 教養部, 教授 (90041756)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAKUBO Nobumitsu Kagoshima Univ., Fac. Science, Assistant, 理学部, 助手 (60204690)
KOHYAMA Takashi Kagoshima Univ., Fac. Education, Ass. Prof., 教育学部, 助教授 (60178233)
SUZUKI Eizi Kagoshima Univ., Coll. Liberal Arts, Ass. Prof., 教養部, 助教授 (10128431)
SHIMOKAWA Etsuro Kagoshima Univ., Fac. Agric., Ass. Prof., 農学部, 助教授 (60041670)
MIYAUCHI Nobufumi Kagoshima Univ., Fac. Agric., Ass. Prof., 農学部, 助教授 (70041621)
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| Project Period (FY) |
1988 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 1990: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1989: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1988: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | Plant succession / Landslide of top substrata / Lithocarp forest / Turnover of forests / Distribution of root system / Rhododendron / Process of soil formation / Sprouting regeneration / 照葉樹林 / 表層滑落型崖崩れ / 限界表土層厚 / 萠芽更新 / 森林の回転周期 / 直径分布 / 植生と亜硫酸ガス / ムラサキシキブ / 崩壊周期 / モミ・ツガ林 / イスノキ林 / ミツバツツジ群 / 土壌形成過程 |
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| Research Abstract |
(1) Interrelationships among landslide periodicity, process of top soil formation and vegetations were investigated, and the possibility for the prediction of potential landslide sites was discussed. In the places with high turnover rate of top substratum such as steep weathered granite and shirasu (pyroclastic deposits) slopes, landslide periodicity, process of top soil formation and vagetation were closely related with each other. In this connection, we can predict the place for frequent landslide.
(2) The turnover period of top substrata was estimated to be 250 years for granite slope, and 70-80 years for shirasu. The Process of soil development after landslide was intensively studied, and the direct cause of landslide was in the mechanical weathering stage and seldom in the chemical process of soil formation.
(3) Lithocarpus edulis forest is said to be produced by artificial managements in the western and southern Kyushu, but it is not true, for it was found on an uninhabited island. Lithocarp produces a number of sprout stems, and responsible factor for gap formation was a few stems of one or two stumps. The area of gap was, therefore, so small that characteristic species of secondary succession did not invade into gaps. Lithocarp seedlings did not play any meaningful role for regeneration of the forest. Lithocarp forest, therefore, is a considerable method to prevent landslide on the steep slopes.
In Yakushima Island, the stability of top substrata was estimated by the existence of the pyroclastic flow from Iwo-jima (Kohya P. f.) in the subterranean horizon. A number of plant species on the Kohya pyloclastic flow was examined, and classification of the species characteristic for unstable and stable substrata was carried out.
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