The BeechCOSTe52 includes phenotypic trait measurements from individual trees measured in an international network of provenance tests compiled by the COST Action E52 (2006 – 2010). It comprises 39 trial sites and 217 provenances covering the distribution of European beech (Fagus sylvatica L.). The BeechCOSTe52 database provides individual tree phenotypic measurements of height, diameter at breast height, basal diameter, mortality, spring and autumn leaf phenology