森林立地学会誌　森林立地35(2), 1993,pp. 20〜24

 

解　説

 

Difference of Soil and Vegetation on Twe Types

of Slope Controlled by Geological Structure

 

Akio MARUYAMA

 

丸山明雄：流れ盤と受け盤の上の土壌・植生の違いについて−ブルネイダルサラームの第３紀層地帯での観察−　

ブルネイダルサラーム国では第３紀層の分布が広く、この地層の特徴に基づいた地形がいたるところに見られる。この報文では、地層が一方向へ緩やかに傾いている低山地（同斜山稜）によく見られる流れ盤と受け盤との上の土壌・植生の違いに関する観察について述べた。ここで見られた２，３の例によれば、流れ盤の上では土壌がほとんどなく、草さえほとんど生育していなかった。これに対し受け盤の上では、土壌が比較的深く、草や灌木が生育していた。さらに流れ盤と受け盤とのこのような違いが、土木工事や林業経営に関しどのような意味を持つかについて若干の議論をした。

 

　In Brunei Darussalam we could find every here and there some unique landforms which were formed under the influence of the geological structure of Tertiary strate. Among them some examples of a dip slope and a back slope (Nagare-ban and Uke-ban) on homoclinal ridges were taken up, and the difference of soil and vegetation on the two types of slope was described. We found almost no soil on the ground, and even no grass grew on a dip slop. On the contrary, we found relatively deep soil, and grass and shrubs grew on a back slope. The contrast between the two types of slope seemed to be due to the relation between the direction of inclination of slope and the one of strata. In addition, the significance of the difference mentioned above was discussed on engineering works and forestry.

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