Evaluation of CO_2 fixation through dendrochronology for the wood grown in rain forest.

通过树木年代学评估雨林中生长的木材的 CO_2 固定。

• 批准号: 12308031
• 负责人: NAKANISHI Tomoko
• 金额: $ 26.18万
• 依托单位: THE UNIVERSITY OF TOKYO
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12308031/
• 关键词: denndrochrolonlgy; neutron activation analysis; Pb-210 measurement; element distribution; Alstonia species; 熱帯雨林; 微量放射能; 微量元素; 炭酸固定; 微量放射能測定; 炭素固定

Since the wood grown in a rain forest does not form annual rings because of lacking the definite change of the climate, it is difficult to estimate the age of the trees, therefore, the fixation of carbon dioxide at that area is difficult to know. To perform denderochronology, we measured the natural radioactivity of the wood as well as elemental distributions and water distribution in wood disks for both a Japanese tree (Cryptomeria japonica) and an Indonesian tree (Alstonia species) which was grown in a rain forest In the measurement of natural radioactivity, we set up the measuring system for a pure Ge detector. The ^<210>Pb radioactivity in a wood disk, across the annual rings, was reduces from outer to the center part. Though, the decreasing rate of the radioactivity was not exactly equal to that of the half-life of ^<210>Pb, for both wood species, the annual age of the Alstonia was estimated from the measurement of Cryptomeria japonica. In the case of elemental analysis, neutron activation analysis was performed. More than 20 elements were analyzed and was found that Mg was a promising element to estimate the age of the trees, for the Mg concentration was linearly changed within die wood disks. Especially for the Alstonia, the wood age was not shown from neutron Radiograph.

由于雨林中生长的木材由于缺乏明确的气候变化而不形成年轮，因此很难估计树木的年龄，因此很难知道该地区二氧化碳的固定情况。为了进行天然放射性年代学研究，我们测量了生长在热带雨林中的日本柳杉和印尼柳杉的木材天然放射性以及木材中元素分布和水分分布，建立了纯锗探测器测量系统。在年轮上，木盘中的^&lt；210&gt；铅放射性从外到中递减。虽然放射性的下降率并不完全等于~&lt；210&gt；铅的半衰期，但通过对柳杉的测量，可以估算出柳杉的年年龄。在元素分析的情况下，进行了中子活化分析。对20多种元素进行了分析，发现镁是一种很有前途的估算树龄的元素，因为镁在木盘中的浓度是线性变化的。尤其是阿尔斯通木，中子照相没有显示出木材的年龄。

项目成果

Y.Hayashi他: "Element analysis and radioactivity measurement within a wood disk by neutron activation analysis"Journal of Radioanalytical and Nuclear Chemistry. 235. 115-118 (2003)

Y. Hayashi 等人：“通过中子活化分析对木盘进行元素分析和放射性测量”《放射分析和核化学杂志》235. 115-118 (2003)。

Hayashi, Yoshitake: "Element Analysis and Radioactivity Measurement within a Wood Disk by Neutron Activation Analysis"Journal of Radioanalytical and Nuclear Chemistry. 255(1). 115-118 (2003)

Hayashi、Yoshitake：“通过中子活化分析对木盘进行元素分析和放射性测量”放射分析与核化学杂志。

Y.Hayashi他: "Elemet analysis and radioactivity measurement within a wood disk by neutron activation analysis"Journal of Radioanalytical and Nuclear Chemistry. 255. 115-118 (2003)

Y. Hayashi 等人：“通过中子活化分析对木盘进行元素分析和放射性测量”《放射分析与核化学杂志》255. 115-118 (2003)。

Y.Hayashi, et al.: "Radioactivity measurement and element analysis within a wood disk by neutron activation analysis"Journal of Radioanalytical Nuclear Chemistry. (in press).

Y.Hayashi 等人：“通过中子活化分析对木盘内的放射性进行测量和元素分析”放射分析核化学杂志。