| Project/Area Number |
16K14943
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Forest science
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| Research Institution | Kyoto University |
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Principal Investigator |
OKADA NAOKI 京都大学, 地球環境学堂, 准教授 (40335302)
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| Research Collaborator |
OHASHI Shinta
NAKAI Wataru
Amir Affan Abdul Azim
Venin Teera
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000)
Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2016: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
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| Keywords | 酸素同位体 / 熱帯樹木 / 年輪 / 降水 / 酸素同位体比 / 熱帯季節林 / 熱帯山地林 / 水素・酸素同位体比 / 高電圧パルスマーキング / 成長輪 |
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| Outline of Final Research Achievements |
Many tropical trees do not form visible annual rings, but even such trees show cyclic changes of stable oxygen isotope ratio in xylem along radius, which changes are considered to be formed annually. These cyclic variation is caused by seasonal variation of oxygen isotope ratio of rain water, which is absorbed via roots and incorporated into plant tissue through photosynthesis. Seasonal variation of oxygen isotope ratio in xylem is more conspicuous in the trees growing in seasonal tropics than those growing in wet tropics.Radial changes in oxygen isotope ratio in xylem are similar in a tree individual, but are variations among trees of a species. Radial changes in oxygen isotope ratio in xylem of different species growing in a site showed seasonal trends but their patterns were slightly different.
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| Academic Significance and Societal Importance of the Research Achievements |
熱帯樹木の酸素同位体比（δ18O）は温帯樹木と同様に季節変化を示すこと明らかとなり、この変化は年輪に相当するものと考えられた。したがって、木部の酸素同位体比の変化を解析することによって、熱帯では研究の進んでいない樹木年輪研究の発展につながるものと考えられる。この研究を発展させていけば、過去の気象観測データの少ない熱帯地域における古気候の解明や、熱帯樹木の成長動態の解析につながり、森林管理や将来予測に資するものと考えられる。
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