Changes in the distribution of radiocesium in the wood of Japanese cedar trees from 2011 to 2013

Ogawa, Hideyuki; Hirano, Yurika; Igei, Shigemitsu; Yokota, Kahori; Arai, Shio; Ito, Hirohisa; Kumata, Atsushi; Yoshida, Hiroyuki

doi:10.1016/j.jenvrad.2015.12.021

Cited by 21 publications

(10 citation statements)

References 20 publications

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“…Although the contamination levels are of the same order of magnitude, a positive gradient from external (sapwood) rings to internal rings (heartwood) can be observed as a trend, implying that Cs + cation has a strong radial mobility37. This positive gradient of concentration from sapwood to the pith was previously observed for potassium and caesium for Japanese cedar383940 and their accumulation in heartwood was associated with the formation of these tissues39.…”

Section: Resultssupporting

confidence: 58%

Radiocaesium partitioning in Japanese cedar forests following the “early” phase of Fukushima fallout redistribution

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Loffredo

et al. 2016

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Our study focused on radiocaesium (137Cs) partitioning in forests, three vegetation periods after the Fukushima Daiichi nuclear power plant accident. 137Cs distribution in forest components (organic and mineral soil layers as well as tree compartments: stem, bark, needles, branches and roots) was measured for two Japanese cedar stand ages (17 and 33 years old). The results showed that around 85% of the initial deposit was found in the forest floor and topsoil. For the youngest stand almost 70% of the deposit is present in the forest floor, whereas for the oldest stand 50% is present in the 0–3 cm mineral soil layer. For trees, old and perennial organs (including dead and living needles and branches, litter fall and outer bark) directly exposed to the fallout remained the most contaminated. The crown concentrated 61–69% of the total tree contamination. Surprisingly the dead organs concentrated 25 ± 9% (young cedars) to 36 ± 20% (mature cedar) of the trees’ residual activity, highlighting the importance of that specific compartment in the early post-accident phase for Japanese cedar forests. Although the stem (including bark) represents the highest biomass pool, it only concentrates 3.3% and 4.6% of the initial 137Cs deposit for mature and young cedars, respectively.

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Section: Resultssupporting

confidence: 58%

Radiocaesium partitioning in Japanese cedar forests following the “early” phase of Fukushima fallout redistribution

Coppin

Hurtevent

Loffredo

et al. 2016

Sci Rep

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show abstract

“…Recently, it was reported that the radiocesium emitted by the accident in 2011 may be translocated to the stem wood of Japanese cedar via the foliar surface [7], bark surface [8], and root uptake [9]. Similar results have been obtained on the radioactive contamination of stem wood of other forest tree species [10][11][12][13]. Furthermore, Aoki et al [14] suggested that stable cesium ( 133 Cs) was radially transported from the bark to stem wood via ray parenchyma cells in 3-year-old Japanese cedar seedlings.…”

Section: Introductionmentioning

confidence: 54%

Relationship between 137Cs concentration and potassium content in stem wood of Japanese cedar (Cryptomeria japonica)

et al. 2017

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“…Due to the complex and uncertain transfer processes described above and the heterogeneous distribution of water, especially in the heartwood [15,16], 137 Cs is expected to show non-uniform distribution in stem wood. Actually, the radial and/or vertical distributions of 137 Cs activity concentration in stem wood affected by the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident have been found to be heterogeneous and species-dependent [4,14,[17][18][19][20]. In addition, a monitoring survey has suggested the possibility of temporal change in 137 Cs distribution (progression of 137 Cs transfer to the inner parts of the heartwood) [18].…”

Section: Introductionmentioning

confidence: 99%

Tracing radioactive cesium in stem wood of three Japanese conifer species 3 years after the Fukushima Dai-ichi Nuclear Power Plant accident

et al. 2020

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To understand the dynamics of accident-derived radioactive cesium (137 Cs) in stem wood that had a substantial amount of heartwood at the time of the Fukushima Dai-ichi Nuclear Power Plant accident, the radial and vertical distributions of 137 Cs activity concentration in stem wood of Japanese cedar (Cryptomeria japonica), cypress (Chamaecyparis obtusa), and larch (Larix kaempferi) were investigated. In addition, the natural distribution of stable cesium (133 Cs), rubidium (85 Rb), and potassium (39 K) concentrations was analyzed to determine the characteristics of 137 Cs distribution. Wood disks were collected from the tree stems of six cedars, three cypresses, and two larches at multiple heights in 2014, and the concentrations were measured every 2 cm in the radial direction. 137 Cs distribution in stem wood differed among tree species, sampling site, and vertical position of the stem within a tree. Statistical analyses suggested that the radial distribution of 137 Cs within the heartwood can be explained by the heartwood moisture content and the distance from the treetop, regardless of species, while the distribution between sapwood and heartwood was dependent on the heartwood cross-sectional area and was additionally different between larch and other species. Similarly, the heartwood/sapwood concentration ratios of stable alkali metals differed between larch and the other species. In the larch, the ratio was ca. 0.5 for all elements, but the ratio was over 1.0 and differed among elements in the other species. Consequently, the species-specific difference in the distribution of 137 Cs between sapwood and heartwood was considered to be due to different activity levels of radial transport toward the heartwood. The radial variation pattern of the 137 Cs/ 133 Cs concentration ratio showed that less 137 Cs was transferred to the inner heartwood compared with the 133 Cs distribution pattern in many trees; however, there was also a tree in which 137 Cs was excessively transferred to the inner heartwood compared with the 133 Cs distribution pattern. Such patterns may result from a combination of significant foliar uptake of 137 Cs and poor root uptake after the accident, in addition to the high moisture content of the heartwood.

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Changes in the distribution of radiocesium in the wood of Japanese cedar trees from 2011 to 2013

Cited by 21 publications

References 20 publications

Radiocaesium partitioning in Japanese cedar forests following the “early” phase of Fukushima fallout redistribution

Radiocaesium partitioning in Japanese cedar forests following the “early” phase of Fukushima fallout redistribution

Relationship between 137Cs concentration and potassium content in stem wood of Japanese cedar (Cryptomeria japonica)

Tracing radioactive cesium in stem wood of three Japanese conifer species 3 years after the Fukushima Dai-ichi Nuclear Power Plant accident

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