Cesium absorption through bark of Japanese cedar (Cryptomeria japonica). Issue 5 (1st October 2016)

• Record Type: Journal Article
• Authors: Wang, Wei; Hanai, Yuichi; Takenaka, Chisato; Tomioka, Rie; Iizuka, Kazuya; Ozawa, Hajime
• Is Part Of: Journal of forest research. Volume 21:Issue 5(2016)
• Page Start: 251
• Page End: 258
• Publication Date: 2016-10-01
• Subjects: Radiocesium -- Stable cesium -- Heartwood -- Fukushima Dai-ichi -- Radioactive contamination; Forests and forestry -- Periodicals; Forests and forestry -- Japan -- Periodicals; 634.905
• DOI: 10.1007/s10310-016-0534-5
• Languages: English
• ISSNs: 1341-6979

Abstract

Abstract: Absorption of radiocesium ( 137 Cs and 134 Cs) through bark, and its subsequent translocation into wood and needles, has been suggested as a potential source of tree contamination, but the process is not well understood. Field experiments were conducted to confirm whether Cs could enter a Japanese cedar tree through the bark and how Cs moves within a tree. Stable Cs ( 133 Cs) was applied to the bark at 1.2-m height on 10- and 26-year-old Japanese cedars. The 133 Cs concentrations were determined in the bark, sapwood, and heartwood (for 26-year-old cedar only) of stem disks from several heights, as well as in current-year needles from the canopy. The 133 Cs concentrations were considerably higher in the sapwood and heartwood of stem disks from 1.2-m height in treated trees than in untreated trees, suggesting that 133 Cs penetrated the bark to enter the wood. The average 133 Cs concentrations were higher in the heartwood than the sapwood, indicating 133 Cs accumulation in the heartwood. High 133 Cs concentrations in the needles of treated trees implied acropetal movement of 133 Cs to actively growing organs. Our results demonstrate that Cs can enter Japanese cedar trees through the bark and that Cs is transported radially to the heartwood and vertically to the apex.