1997 Fiscal Year Final Research Report Summary
Developments of principles and methods to keep ecological functions of riparian forests
| Project/Area Number |
08556022
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
林学
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| Research Institution | HOKKAIDO UNVERSITY |
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Principal Investigator |
NAKAMURA Futoshi HOKKAIDO Univ., FAC.OF AGR,ASSOCIATE PROF., 農学部, 助教授 (90172436)
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| Co-Investigator(Kenkyū-buntansha) |
KURIYAMA Kouichi HOKKAIDO Univ., FAC.OF AGR,INSTRUCTOR, 農学部, 助手 (50261334)
KIKUCHI Shunichi HOKKAIDO Univ., FAC.OF AGR,INSTRUCTOR, 農学部, 助手 (10250490)
YAJIMA Takashi HOKKAIDO Univ., FAC.OF AGR,ASSOCIATE PROF., 農学部, 助教授 (90142702)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Riparian forest / River management / Water temperature / Fich habitat / Sediment dynamics / Stone-mulching / Revegetation work / Soil moisture |
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| Research Abstract |
We examined sediment routing system in a basin and regeneration process of riparian forests in order to present a framework for keeping ecological functions in stream management. A time lag between sediment production and transport promotes rapid aggradation and degradation of a streambed, resulting in creating terraced lateral deposits. These laterl deposits and associated braided pattern are clearly observed in a unconstrained reach. This reach has secondary and abandoned channels, lateral bars and floodplains, which provide regeneration sites for many species requiring a variety of moisture, substrate, and disturbance frequency. Once bare sites are created, tree seedlings are wstablished, resulting in uniformeed-, even-aged forests. Yhe substrate and stream landforms are closely correlated and we could explain the distribution of dominant tree species along the elevation gradient in the Tokachi River.
The ecological functions of riparian forests were examined especially on shading and providing fish habitat. The shading by riparian forest crown was examined by heat-budgets and by statistical analysis, and them compared to verify the accuracy of regression analysis. The fish habitat ws investigated as a basis of multi-scale approach. These results indicated the importance of riparian forest, and difference in factors controlling fish abundance between scales. We focused on a revegetation method covering the site with boulders (stone-mulching), which improve site conditions by keeping soil moisture high and soil temperature low. The results proved that this method is very effective to improve dry stress and promotes an increase in growth of reparian trees.
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