This file contains summary information and calculated effect sizes extracted from studies that measured leaf Nmass and/or Narea along an elevational gradient. Column titles: study, author and year published, see online appendix S1; r, untransformed correlation coefficient (effect size); n. sites, number of sites sampled; indiv.per.site, number of plants sampled per site; n. indiv., total number of plants sampled; n. reg., n used for the regression where r was estimated; by.mass.or.area, which of Nmass or Narea was measured; within.or.among, whether interspecific or intraspecific variation was sampled; pft, plant functional type; biome, which of temperate/tropical/boreal; grad.min, minimum elevation; grad.max, maximum elevation; lat.mean, mean latitude; species, 1 or more species measured; details, notes if necessary.