title: Changes in the distribution of radiocesium in the wood of Japanese cedar trees from 2011 to 2013.
abstract: The changes in the distribution of (137)Cs in the wood of Japanese cedar (Cryptomeria japonica) trunks within three years after the Fukushima Dai-ichi Nuclear Power Plant (FDNP) accident in 2011 were investigated. Thirteen trees were felled to collect samples at 6 forests in 2 regions of the Fukushima prefecture. The radial distribution of (137)Cs in the wood was measured at different heights. Profiles of (137)Cs distribution in the wood changed considerably from 2011 to 2013, and the process of (137)Cs distribution change in the wood was clarified. From 2011 to 2012, the active transportation from sapwood to heartwood and the radial diffusion in heartwood proceeded quickly, and the radial (137)Cs distribution differed according to the vertical positon of trees. From 2012 to 2013, the vertical diffusion of (137)Cs from the treetop to the ground, probably caused by the gradient of (137)Cs concentration in the trunk, was observed. Eventually, the radial (137)Cs distributions were nearly identical at any vertical positions in 2013. Our results suggested that the active transportation from sapwood to heartwood and the vertical and radial diffusion in heartwood proceeded according to the vertical position of the tree and (137)Cs distribution in the wood approached the equilibrium state within three years after the accident.
authors.affiliation: Graduate School of Urban Environmental Science, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo 192-0397, Japan; Fukushima Prefectural Forestry Research Centre, Nishi-Shimasaka, Asaka, Koriyama, Fukushima 963-0112, Japan. Electronic address: ogawa_hideki_01@pref.fukushima.lg.jp.
authors.forename: Hideki
authors.initials: H
authors.lastname: Ogawa
authors.affiliation: Graduate School of Urban Environmental Science, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Yurika
authors.initials: Y
authors.lastname: Hirano
authors.affiliation: Graduate School of Urban Environmental Science, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Shigemitsu
authors.initials: S
authors.lastname: Igei
authors.affiliation: Graduate School of Urban Environmental Science, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Kahori
authors.initials: K
authors.lastname: Yokota
authors.affiliation: Graduate School of Urban Environmental Science, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Shio
authors.initials: S
authors.lastname: Arai
authors.affiliation: Fukushima Prefectural Forestry Research Centre, Nishi-Shimasaka, Asaka, Koriyama, Fukushima 963-0112, Japan.
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Ito
authors.affiliation: Fukushima Prefectural Forestry Research Centre, Nishi-Shimasaka, Asaka, Koriyama, Fukushima 963-0112, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kumata
authors.affiliation: Graduate School of Urban Environmental Science, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Yoshida
mesh_terms: D002588:Cesium Radioisotopes / Q000378:metabolism*; D032485:Cryptomeria / Q000378:metabolism*; D062406:Fukushima Nuclear Accident; D007564:Japan; D011834:Radiation Monitoring / Q000379:methods; D011848:Radioactive Pollutants / Q000378:metabolism*; D014934:Wood / Q000378:metabolism*
chemical_list: D002588:Cesium Radioisotopes; D011848:Radioactive Pollutants
keywords: Fukushima Dai-ichi Nuclear Power Plant accident; Japanese cedar tree; Radiocesium; Tree contamination; Wood