| Project/Area Number |
17580127
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
林学・森林工学
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| Research Institution | Kyoto University |
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Principal Investigator |
NAKANISHI Asami Kyoto University, Field Science Education and Research Center, Assistant Professor (60273497)
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| Co-Investigator(Kenkyū-buntansha) |
INAGAKI Yoshiyuki Forestry and Forest Products Research Center, Shikoku Research Center, Senior Researcher (00353590)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,050,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥150,000)
Fiscal Year 2007: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2006: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2005: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | hinoki cypress / leaf-litter nitrogen concentration / nitrogen resorption efficiency / climatic condition / nitrogen use efficiency / leaf-fall phenologv / thinning / light availability / 落葉時期 / 気温 / 窒素循環 / 台風 / 斜面位置 / リターフォール / 窒素利用様式 / 窒素引き戻し / 伐採 / 窒素 |
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| Research Abstract |
Changes in resource availability can affect nutrient use efficiency of plants. We investigated the effects of stand characteristics, soil nutrient availability, climatic condition and thinning on nitrogen use strategy in hinoki cypress stands. The study areas were Pacific side of Honshu (Kochi prefecture), Japan Sea side (northern region of Kyoto prefecture) and inland region (Kamigamo, Kyoto city) where climate conditions differ substantially; the means of annual temperature and mean annual precipitation in the stands ranged from 9.1 to 16.3℃ and from 1500 to 3300 mm, respectively. In each forest in Kochi and Kamigamo, we located two study plots: in one plot thinning was conducted and in the other plot no trees were cut as the control. We found the significant effects on nitrogen status of hinoki as following. Nitrogen resorption efficiency was larger in the thinned plots than in the control plots in the thinning experiments. The nitrogen concentration in the leaf litter was lower whe
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n solar radiation from Mardi to October was higher in Kochi forest for 13 years. The results suggest that nitrogen use efficiency (NUE) increases with increasing light availability. By contrast, nitrogen concentration in leaf-litter was not lower in forests with higher annual precipitation, suggesting that NUE does not increase with higher water availability. The time of 50 % annual leaf-fall was later in the warmer climatic condition. Leaf-litter N concentration was lower when leaf-fall occurred later. The results suggest that NUE increases when the climatic conditions are favorable. In addition, the effects of strong wind in typhoons on plants are greater in the stands at higher elevation. In these stands, the time of 50 % annual leaf-fall was earlier and hinoki trees shed their leaves with higher nitrogen concentration. The results indicate that NUE of hinoki cypress is closely related with leaf-fall phenology that is affected by temperature and typhoon. The results of the study suggest that the climatic condition as well as resource availability affects NUE of hinoki cypress. Less
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