1 Center for Forest Restoration and Radioecology, Forestry and Forest Products Research Institute, Japan. Electronic address: miura@ffpri.affrc.go.jp.
2 School of Biosciences, University of Nottingham, UK. Electronic address: george.shaw1@nottingham.ac.uk.
3 School of Biosciences, University of Nottingham, UK; UK Centre for Ecology and Hydrology, UK. Electronic address: bjho@live.com.
4 Department of Forest Soils, Forestry and Forest Products Research Institute, Japan; Graduate School of Agricultural and Life Sciences, The University of Tokyo, Japan. Electronic address: shojih@ffpri.affrc.go.jp.
5 Andra, Research and Development Division, France. Electronic address: Yves.Thiry@andra.fr.