Despite striking differences in climate, soils, and evolutionary history among diverse biomes ranging from tropical and temperate forests to alpine tundra and desert, we found similar interspecific relationships among leaf structure and function and plant growth in all biomes. Our results thus demonstrate convergent evolution and global generality in plant functioning, despite the enormous diversity of plant species and biomes. For 280 plant species from two global data sets, we found that potential carbon gain (photosynthesis) and carbon loss (respiration) increase in similar proportion with decreasing leaf life-span, increasing leaf nitrogen concentration, and increasing leaf surface area-to-mass ratio. Productivity of individual plants and of leaves in vegetation canopies also changes in constant proportion to leaf life-span and surface area-to-mass ratio. These global plant functional relationships have significant implications for global scale modeling of vegetation-atmosphere CO 2 exchange.

Abstract. Variation in leaflife-span has long been considered of ecological significance. Despite this, quantitative evaluation of the relationships between leaf life-span and other plant and ecosystem characteristics has been rare. In this paper we ask whether leaf lifespan is related to other leaf, plant, and stand traits of species from diverse ecosystems and biomes. We also examine the interaction between leaf, plant, and stand traits and their relation to productivity and ecological patterns.Among all species, both mass-(Amass) and area-based (Aacea) maximum net photosynthesis decreased with increasing leaf life-span, but the relationship was stronger on a mass (P < .001, r 2 = 0.70) than an area (P < .05, r 2 = 0.24) basis. Similarly, mass-based leaf nitrogen (leafNmass) decreased (P < .001, r 2 = 0.52) with 1eaflife-span, but area-based leaf N (leafNare.) did not (P > .25, r 2 = 0.01). Specific leaf area (SLA, leafarealleafdry mass) and leaf diffusive conductance also decreased with increasing leaf life-span. Decreasing Amass with increasing leaflife-span results from the impact of decreasing Nmass and SLA on Amass· Variation in leaf traits as a function of leaf life-span was similar for broad-leaved and needle-leaved subsets of the data. These leaf-scale data from several biomes were compared to a data set from a single biome, Amazonia. For several leaf traits (e.g., SLA, Nmasso and Amass) the quantitative relationship with leaf life-span was similar in the two independent data sets, suggesting that these are fundamental relations applicable to all species. Amass was a linear function ofNmass (P < .001, r 2 = 0.74) with a regression similar to previous analyses, while Aarea was not significantly related to Narea· These results suggest that the photosynthesis-leafN relationship among species should be considered universal when expressed on a mass, but not on a leaf area, basis.Relative growth rates (RGR) and leaf area ratio (LAR, the whole-plant ratio of leaf area to total dry mass) of seedlings decreased with increasing leaf life-span (P < .001, r 2 = 0.61 and 0.89, respectively). LAR was positively related to both RGR and Amass (r 2 = 0.68 and 0.84, respectively), and Amass and RGR were also positively related (r 2 = 0.55).Absolute height growth rates of young trees decreased with increasing leaf life-span (P < .001, r 2 = 0.72) and increased with Amass (P < .001, r 2 = 0.78). It appears that a suite of traits including short leaf life-span and high leaf Nmas.-SLA, LAR, and Amass interactively contribute to high growth rates in open-grown individuals. These traits interact similarly at the stand level, but stands differ from individuals in one key trait. In closed-canopy forests, species with longer lived foliage (and low LAR as seedlings) have greater foliage mass per unit ground area (P < .001, r 2 = 0.74) and a greater proportion of total mass in foliage. The aboveground production efficiency (ANPP /foliar biomass) afforest stands decreased markedly with increasing leaflife-span or total foliage mass...