Succession on the debris flow deposits in a subalpine area of the Oku-Nikko region, in relation to the subsequent movement of depositional materials.

• Yoshikawa Masato

  The United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology

• Hukusima Tukasa

  Faculty of Agriculture, Tokyo University of Agriculture and Technology

Bibliographic Information

Other Title

• 奥日光の亜高山帯域における土石流堆積地上の遷移と堆積物の二次移動との関係

Abstract

We surveyed the distribution of vegetation and substratum of the ground surface on the depositional landform developed by some debris flows in a subalpine area of the Oku-Nikko region, Central Japan, and discussed the effect of subsequent movement of debris flow deposits on succession of vegetation. The substratum of the ground surface was divided into three types according to the difference in deposited materials : 1) BS-type, consisting of boulder with sandy soil matrix, and retaining the features of debris flow deposits ;2) B-type, consisting of boulder without matrix, and suffering erosion ; 3) S-type, consisting of sandy materials transported by water flow. This depositional landform contained some depositional surfaces formed by past debris flows. However the three types of deposits were located in order of B, BS, S (B in the upper part of the depositional landform, down to S), and not corresponding to the age of depositional surfaces. This reflects the subsequent movement of debris flow deposits through the different depositional surfaces. There were young forests dominated by Alnus matsumurae, Pterocarya rhoifolia, and Salix sachalinensis which are regarded as the primary phase, or old forests of A. matsumurae and P. rhoifolia with juveniles of Tsuga diversifolia in the B-type deposit areas. Abies veitzcii forest, more than 55 years old, was dominant in the BS-type deposit area. Furthermore, S. sachalinensis was dominant in the area buried by S-type deposits. This distributional pattern is considered to be developed by the subsequent movement of debris flow deposits which affect on the speed and direction of succession on the depositional landform. In the B-type areas, the pioneer stage of succession occurs repeatedly due to the destruction of the site by erosion, however, these areas have potentiality to proceed T. diversifolia forests. In the BS-type area, which had been stable since a major debris flow more than 55 years ago, succession proceeded to A. veitzcii forest. In the S-type areas, only S. sachalinensis survived deposition, while conifer trees failed to invade.

Journal

• Vegetation Science

  Vegetation Science 14 (2), 91-104, 1997

  The Society of Vegetation Science

Keywords

• Abies veitzcii
• debris flow
• depositional landform
• Salix sachalinensis
• succession

Details

• CRID: 1390282679462918912
• NII Article ID: 110008145199
• NII Book ID: AA11347548
• DOI: 10.15031/vegsci.14.91
• ISSN: 21894809
• ISSN: 13422448
• Text Lang: ja
• Data Source:
  • JaLC
  • CiNii Articles
• Abstract License Flag: Disallowed