Data comprise stable element concentrations for a range of elements, radionuclide activity concentrations for the isotopes K-40 and Cs-137 and radionuclide and stable element concentration ratios. Samples of soil, water, vegetation (grasses, trees, herbaceous plants and shrubs), fungi, earthworms, bees, wood mice, bank voles, common frogs, frogspawn and European toads were collected between March 2015 and October 2016 from two forests in north-east England. The study was conducted to target representative terrestrial species of the ICRPs Reference Animals and Plants. Funding for this work was via the TREE project funded by NERC, the Environment Agency and Radioactive Waste Management Ltd. under the RATE programme.