Plant trait and forest data were retrieved from the Ecological and Forest Inventory of Catalonia (IEFC), carried out between 1988 and 1998 (Gracia et al. 2000‒2004). The subset of the IEFC was limited to 13 study species. Forest structure, lithology and sampling information for each plot were retrieved from the IEFC database. Climate data were obtained from the Climatic Digital Atlas of Catalonia, with a spatial resolution of 180 m (Ninyerola et al. 2000). We selected five plant traits (leaf mass per area, LMA, mg cm-2; leaf nitrogen per unit mass, Nmass, %mass; maximum tree height, Hmax, m; wood density, WD, gm cm-3; leaf biomass to sapwood area ratio, BL:AS, t m-2) that are used to describe major plant functional strategies. The auxiliary variables we considered were species identity, a set of climatic variables (mean annual temperature, annual thermal amplitude, both in °C), a set of forest structure variables (total aboveground biomass [T ha-1] and stem density [stems ha-1]), a set of topographical variables (county, elevation [m.a.s.l.], slope [°] and aspect), lithology (calcareous, non-calcareous or undetermined) and sampling month.

{"references": ["Vil\u00e0-Cabrera, A., Mart\u00ednez-Vilalta, J. and Retana, J.: Functional trait variation along environmental gradients in temperate and Mediterranean trees, Global Ecology and Biogeography, 24(12), 1377\u20131389, doi:10.1111/geb.12379, 2015.", "Laforest-Lapointe, I., Mart\u00ednez-Vilalta, J. and Retana, J.: Intraspecific variability in functional traits matters: case study of Scots pine, Oecologia, 175(4), 1337\u20131348, doi:10.1007/s00442-014-2967-x, 2014.", "Gracia, C., Burriel, J., Mata, T. and Vayreda, J.: Inventari Ecol\u00f2gic i Forestal de Catalunya: Centre de Recerca Ecol\u00f2gica i Aplicacions Forestals. 10 volumes., CREAF, Bellaterra, Spain., 2000.", "Ninyerola, M., Pons, X., Roure, J. M., Ninyerola, M., Pons, X. and Roure, J. M.: A methodological approach of climatological modelling of air temperature and precipitation through GIS techniques, A methodological approach of climatological modelling of air temperature and precipitation through GIS techniques, International Journal of Climatology, International Journal of Climatology, 20(14, 14), 1823\u20131841"]}