the United States Geological Survey (). The European tree range data were digitized from the European Floristic Atlas (). Both map datasets were re-gridded to 25 x 25 km, 50 x 50 km and 250 x 250 km map grid cells allowing us to repeat the analyses across scales. Trait Data This study utilized data for four traits that indicate where a species falls along spectra of plant ecological strategies. The first trait we quantified was the maximum height. This trait is related to the adult light niche of species, ability to tolerate xeric environments and recruitment (King et al. 2006; Moles et al. 2009). The second trait we quantified was seed mass. Seed mass is related to the regeneration niche of species (Grubb 1977) and represents a fundamental tradeoff between producing many small seeds and few large seeds (Venable 1996). The third trait we measured was wood density. Wood density is often the best predictor of growth and mortality rates in tree datasets and represents a tradeoff between rapid volumetric growth and mechanical instability (on the tissue and organismal scale) versus slow volumetric growth and mechanical stability (on the tissue and organismal scale)(Chave et al. 2009). The last trait we measured was leaf size. Leaf size is related to the area deployed for resource capture for single leaf, but it is not necessarily related to overall canopy leaf area and leaf packing. Leaf size is also related to broad scale climatic gradients given its interaction with leaf boundary layer thickness (Dolph and Dilcher 1980). The trait data for this study were primarily collected from the literature, but were supplemented through field collection of additional trait values by the first author and through the measurement of traits on herbarium vouchers. The maximum height data
the United States Geological Survey (). The European tree range data were digitized from the European Floristic Atlas (). Both map datasets were re-gridded to 25 x 25 km, 50 x 50 km and 250 x 250 km map grid cells allowing us to repeat the analyses across scales. Trait Data This study utilized data for four traits that indicate where a species falls along spectra of plant ecological strategies. The first trait we quantified was the maximum height. This trait is related to the adult light niche of species, ability to tolerate xeric environments and recruitment (King et al. 2006; Moles et al. 2009). The second trait we quantified was seed mass. Seed mass is related to the regeneration niche of species (Grubb 1977) and represents a fundamental tradeoff between producing many small seeds and few large seeds (Venable 1996). The third trait we measured was wood density. Wood density is often the best predictor of growth and mortality rates in tree datasets and represents a tradeoff between rapid volumetric growth and mechanical instability (on the tissue and organismal scale) versus slow volumetric growth and mechanical stability (on the tissue and organismal scale)(Chave et al. 2009). The last trait we measured was leaf size. Leaf size is related to the area deployed for resource capture for single leaf, but it is not necessarily related to overall canopy leaf area and leaf packing. Leaf size is also related to broad scale climatic gradients given its interaction with leaf boundary layer thickness (Dolph and Dilcher 1980). The trait data for this study were primarily collected from the literature, but were supplemented through field collection of additional trait values by the first author and through the measurement of traits on herbarium vouchers. The maximum height data
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