Establishment of estimation method for devastation in forest using natural or artificial radionuclides.

建立利用天然或人工放射性核素估算森林破坏的方法。

• 批准号: 10556032
• 负责人: TAKENAKA Chisato
• 金额: $ 7.1万
• 依托单位: NAGOYA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10556032/
• 关键词: radionuclides; ^<137>Cs; ^<14>C; soil erosion; erosion rate; organic matter; tree rings; 侵食; 堆積速度; ウラン系列; トリウム系列; K-40; 土砂移動; ヒノキ人工杯; δ13C; 安定同位体; 放射性同位体

Forests in Japan have been devastated because of the depression of forestry during a few decades. The serious problems caused by devastation in forest are soil erosion in forest floor, the succeeding muddy water in stream, and growth decline of trees. It is important to estimate the degree of devastation of forest using some useful indicator. Therefore, the purpose of this research is to establish the estimation method of devastation in forest using natural or artificial radionuclides.As a result of this research, we confirmed that ^<137>Cs should be a useful tracer to estimate the amount of soil erosion in forest. In order to improve the precision of the estimation, we concluded that the behavior and change in chemical form of ^<137>Cs during transportation relating with organic matter is important. For the identification of erosion site from the sediments, it was suggested that the ratios between radionuclides such as ^<40>K, ^<214>Pb, ^<214>Bi, ^<208>Tl, and ^<212>Pb are useful. In addition this, the environmental changes caused by forest devastation could be investigated by the analysis using ^<14>C in tree rings combined with dendrochronology.

由于几十年来的林业萧条，日本的森林遭到了破坏。森林破坏造成的严重问题是林地水土流失、河流泥沙淤积和林木生长衰退。使用一些有用的指标来估计森林的破坏程度是很重要的。因此，本研究的目的是建立一种利用天然或人工放射性核素估算森林破坏的方法，并证实~（60）<137>Cs是估算森林土壤侵蚀量的有效示踪剂。为了提高估算的精度，我们认为，在迁移过程中与有机质有关的^ Cs的行为和化学形态变化<137>是重要的。为了从沉积物中识别侵蚀部位，建议使用放射性核素之间的比值，如^<40>K、^<214>Pb、^<214>Bi、^<208>Tl和^<212>Pb。此外，树木年轮中^ C的分析还可以结合树木年轮学研究森林破坏引起的环境变化<14>。

项目成果

Takenaka, C., Onada, Y.and Hamajima, Y.: "Distribution of Cesium-137 in Japanese forest soils -Correlation with thecontents of organic carbon-."The Science of the Total Environment. 222. 193-199 (1998)

Takenaka, C.、Onada, Y. 和 Hamajima, Y.：“日本森林土壤中铯 137 的分布 - 与有机碳含量的相关性 -”。总体环境科学。

Tsujimura,M.,Tanaka,T.and Onda,Y.: "Effect of subsurface flow on the isotopic composition of soil water in headwater basin."International Association of Hydrological Sciences Publications. 248. 343-351 (1998)

Tsujimura,M.、Tanaka,T. 和 Onda,Y.：“地下水流对源头流域土壤水同位素组成的影响。”国际水文科学协会出版物。

Yonenobu,H.,Takahashi,H.and Wada,H: "Seasonal fluctuation of stable carbon isotopic composition within annual rings of Japanese cypress grown in the last glacial period."Radiocarbon. (in press).

Yonenobu，H.，Takahashi，H.和Wada，H：“末次冰期日本柏树年轮内稳定碳同位素组成的季节性波动。”放射性碳。

Tsujimura,M.,Onda,Y.,Fujiwara,J. and Ito,J.: "Hydrometric and tracer approaches to investigate rainfall-runoff processes in mountainous basins with different geology"International Association of Hydrological Sciences Publication. 288. 159-166 (1999)

辻村，M.，恩田，Y.，藤原，J.

Onda,Y,Fukuyama,T.and Kashiwagi,A.,: "Downstream effect of Hinoki (Chamaecyparis obtusa) forest floor erosion : Isotopic evidence from a small and a large reservoir sediments"Proceedings of the Advisary Group meeting of IAEA, Vienna 2000, IAEA. (in press)

Onda，Y，Fukuyama，T. 和 Kashiwagi，A.，：“Hinoki (Chamaecyparis obtusa) 森林地面侵蚀的下游影响：来自小型和大型水库沉积物的同位素证据”国际原子能机构顾问组会议记录，维也纳 2000 年