contaminated site observatory Forest observatory site in Yamakiya The Forest observatory site in Yamakiya, Japan, is a semi-natural terrestrial forest contaminated primarily with radiocaesium (Cs-137) following the Fukushima Daiichi nuclear accident in 2011, with additional contamination from Pu and Sr-90. As one of the ALLIANCE observatory sites, it offers a radiation contamination gradient largely free from non-radioactive chemical pollutants, enabling studies on radionuclide behaviour in forest ecosystems, soil-to-plant transfer, and ecological effects. Access requires permission from the Institute of Environmental Radioactivity (IER) at Fukushima University. Located at IER. http://www.ier.fukushima-u.ac.jp/index_e.html Yoschenko V. et al., J Environ Radioact, 166, 45-55 (2017) Paul Schofield