Dynamics of radiocesium deposited in forests and within forest trees

2022 Fiscal Year Final Research Report

• Project/Area Number: 15K11950
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: 復興農学
• Research Institution: The University of Tokyo
• Principal Investigator: Masumori Masaya 東京大学, 大学院農学生命科学研究科(農学部), 講師 (50282702)
• Co-Investigator(Kenkyū-buntansha): 丹下 健 東京大学, 大学院農学生命科学研究科(農学部), 教授 (20179922)
• Project Period (FY): 2015-04-01 – 2023-03-31
• Keywords: 原発事故 / スギ / コナラ / 交換性カリウム / 放射能低減

Outline of Final Research Achievements

Dynamics of radiocesium within tree in the forest polluted by The accident of Fukushima Dai-ichi Nuclear Power Plant were investigated to enhance the resumption of forestry, local economy and consequently the restoration of local community of the affected area in wooded western Fukushima, Japan.
Distributions of radiocesium within trunk of Sugi cedar were analyzed by radiographic imaging with storage phosphor screens. The results suggest that some of the radiocesium in the xylem is soluble in water and migrates with the water movement of the apoplastic during wood drying after felling.
Radiocesium in konara oak, a hardwood that can be used for mushroom logs, was also investigated. It was found that applying potassium fertilisers to the ground surface and increasing the amount of exchangeable potassium in the soil inhibited the absorption of radiocesium by newly planted Quercus crispula.

Free Research Field

造林学

Academic Significance and Societal Importance of the Research Achievements

スギ幹材内の放射性セシウムが水分の移動とともない移動することが明らかになった。伐採してから木材として利用するまでの間に放射能分布が変化することを意味している。またシイタケ原木林においては経根吸収する放射性セシウム量が土壌条件に影響される知見が得られた。いずれも汚染地域の木材利用を検討する上での重大な知見である。