Taxonomic and ecological relevance of the chlorophyll a fluorescence signature of tree species in mixed European forests

• The variability of chlorophyll fluorescence parameters (ChlF) of forest tree species was investigated in 209 stands belonging to six European forests, from Mediterranean to boreal regions. • The modifying role of the environmental factors, forest structure and tree diversity (species richness and composition) on ChlF signature was analyzed. • At European level, conifer showed higher potential performance than broadleaves. Forests in central Europe performed better than in Mediterranean and boreal regions. At the site level, homogeneous clusters of tree species were identified by means of a principal component analysis (PCA) of ChlF parameters. The discrimination of the clusters of species was influenced by their taxonomical position and ecological characteristics. The species richness influenced the tree ChlF properties in different way depending on tree species and site. Tree species and site affected also the relationships between ChlF parameters and other plant functional traits (specific leaf area, leaf nitrogen content, light-saturated photosynthesis, wood density, leaf carbon isotope composition). • The assessment of photosynthetic properties of tree species, by means of ChlF parameters, in relation to their functional traits, is a relevant issue for studies in forest ecology. The connections of data from field surveys with remotely assessed parameters must be carefully explored.