Contribution of the co-authors Marco Ferretti: co-designing and supervising the work, and co-writing the paper. Marco Calderisi: designing the statistical analyses. Peter Waldner: co-designing the work, compiling the data set in collaboration with national experts and revising the paper. Aldo Marchetto: co-designing the work, performing the quality control, running the statistical analyses and co-writing the paper. Anne Thimonier, Matthiew Jonard, Nathalie Cools, Pasi Rautio, Nicholas Clarke, Karin Hansen, Päivi Merilä and Nenad Potočić: contributing important parts of the discussion of the results. Science (2015) 72:897-906 DOI 10.1007 cation resulted important factors (although with possible diverse effect) in explaining the variability of F 25 among plots.