Phenotypic traits and their associated trade-offs have been shown to have globally consistent effects on individual plant physiological functions 1-3 , but how these effects scale up to influence competition, a key driver of community assembly in terrestrial vegetation, has remained unclear 4 . Here we use growth data from more than 3 million trees in over 140,000 plots across the world to show how three key functional traits-wood density, specific leaf area and maximum height-consistently influence competitive interactions. Fast maximum growth of a species was correlated negatively with its wood density in all biomes, and positively with its specific leaf area in most biomes. Low wood density was also correlated with a low ability to tolerate competition and a low competitive effect on neighbours, while high specific leaf area was correlated with a low competitive effect. Thus, traits generate trade-offs between performance with competition versus performance without competition, a fundamental ingredient in the classical hypothesis that the coexistence of plant species is enabled via differentiation in their successional strategies 5 . Competition within species was stronger than between species, but an increase in trait dissimilarity between species had little influence in weakening competition. No benefit of dissimilarity was detected for specific leaf area or wood density, and only a weak benefit for maximum height. Our traitbased approach to modelling competition makes generalization possible across the forest ecosystems of the world and their highly diverse species composition.Phenotypic traits are considered fundamental drivers of community assembly and thus species diversity 1,6 . The effects of traits on individual plant physiologies and functions are increasingly understood, and have been shown to be underpinned by well-known and globally consistent trade-offs 1-3 . For instance, traits such as wood density and specific leaf area capture trade-offs between the construction cost and longevity or strength of wood and leaf tissues 2,3 . By contrast, we still have a limited understanding of how such trait-based trade-offs translate into competitive interactions between species, particularly for long-lived organisms such as trees. Competition is a key filter through which ecological and evolutionary success is determined 4 . A long-standing hypothesis is that the intensity of competition decreases as two species diverge in trait values 7 (trait dissimilarity). The few studies [8][9][10][11][12][13] that have explored links between traits and competition have shown that linkages were more complex than this, as particular trait values may also confer competitive advantage independently from trait dissimilarity 9,13,14 . This distinction is fundamental for species coexistence and the local mixture of traits. If neighbourhood competition is driven mainly by trait dissimilarity, this will favour a wide spread of trait values at a local scale. By contrast, if neighbourhood interactions are mainly driven by the c...

Hurricane Katrina's impact on U.S. Gulf Coast forests was quantified by linking ecological field studies, Landsat and Moderate Resolution Imaging Spectroradiometer (MODIS) image analyses, and empirically based models. Within areas affected by relatively constant wind speed, tree mortality and damage exhibited strong species-controlled gradients. Spatially explicit forest disturbance maps coupled with extrapolation models predicted mortality and severe structural damage to approximately 320 million large trees totaling 105 teragrams of carbon, representing 50 to 140% of the net annual U.S. forest tree carbon sink. Changes in disturbance regimes from increased storm activity expected under a warming climate will reduce forest biomass stocks, increase ecosystem respiration, and may represent an important positive feedback mechanism to elevated atmospheric carbon dioxide.

a high conductivity of 0.46 mS cm −1 at room temperature because the three-dimensional pathways in the open framework benefi t the diffusion of Na ions. [ 5 ] Further improvement (60%, 0.74 mS cm −1 ) has been obtained by substitution of Si on P sites in 94Na 3 PS 4 -6Na 4 SiS 4 . [ 6 ] However, the ionic conductivity is still low in comparison to liquid electrolytes, and therefore SEs with higher ionic conductivity need to be sought.Tatsumisago and co-workers found that an appropriate diffusion channel size is critical for fast ion diffusion and anion substitutions have a greater effect on ionic diffusivity than cation substitutions. [ 7 ] Moreover, Se-substituted lithium sulfi des demonstrate an enhanced ionic conductivity in comparison with their pristine compounds. [ 8 ] The advantages of Se-doping lie in two aspects. On one hand, the atomic radius of Se is bigger than that of S, so Se substitution on S sites may expand the lattice. On the other hand, the higher polarizability of Se 2− may weaken the binding energy between the moving ion and the anion framework. These modifi cations may be benefi cial for Na + diffusion because of the big ionic radius of sodium. It is therefore highly interesting to synthesize Na 3 PSe 4 and evaluate its electrochemical performance.In this study, cubic Na 3 PSe 4 was synthesized for the fi rst time and its crystal structure, spectra, and electrochemical performance were investigated. A ionic conductivity of 1.16 mS cm −1 was observed; to the best of our knowledge, this is one of the best values among sodium ion conductors and is the highest value reported for sulfi des to date. Figure 1 a shows the X-Ray Diffraction (XRD) pattern of Na 3 PSe 4 . The halo patterns in both cases refl ect the polyimide fi lm. The crystal structure of Na 3 PSe 4 has not been reported yet. Here, the integrated intensities from powder XRD data were extracted by the Le Bail method using the FullProf program. The crystal structure was solved by using the direct space method and was then refi ned by the Rietveld method. The crystal structure was determined to be cubic with the space group I -43 m (No. 217) and Z = 2. The plots of the observed, calculated, and difference patterns from the Rietveld refi nement (Figure 1 a) evidence the formation of single-phase Na 3 PSe 4 . The refi ned crystallographic data are listed in Table 1 . The cell has a lattice parameter a = 7.3094(2) Å, which is much larger than that of Si-doped Na 3 PS 4 ( a = 6.9978 Å). [ 6 ] A negative isotropic atomic displacement parameter ( U iso ) for P atoms and large U iso values for Na and Se atoms are obtained, indicating large disorders in the crystal structure. Comparison of the XRD patterns of Na 3 PSe 4 before and after ball milling ( Figure S1, Supporting Information) shows that only peak broadening is observed. This observation is in accordance with Differential scanning calorimetry (DSC) results ( Figure S2,The development of large-scale energy-storage system attracts worldwide attention because of the rapidly increasing de...

Climate change is expected to increase the intensity of extreme precipitation events in Amazonia that in turn might produce more forest blowdowns associated with convective storms. Yet quantitative tree mortality associated with convective storms has never been reported across Amazonia, representing an important additional source of carbon to the atmosphere. Here we demonstrate that a single squall line (aligned cluster of convective storm cells) propagating across Amazonia in January, 2005, caused widespread forest tree mortality and may have contributed to the elevated mortality observed that year. Forest plot data demonstrated that the same year represented the second highest mortality rate over a 15‐year annual monitoring interval. Over the Manaus region, disturbed forest patches generated by the squall followed a power‐law distribution (scaling exponent α = 1.48) and produced a mortality of 0.3–0.5 million trees, equivalent to 30% of the observed annual deforestation reported in 2005 over the same area. Basin‐wide, potential tree mortality from this one event was estimated at 542 ± 121 million trees, equivalent to 23% of the mean annual biomass accumulation estimated for these forests. Our results highlight the vulnerability of Amazon trees to wind‐driven mortality associated with convective storms. Storm intensity is expected to increase with a warming climate, which would result in additional tree mortality and carbon release to the atmosphere, with the potential to further warm the climate system.

carbon balance ͉ forest biomass ͉ hurricanes ͉ spatial-temporal dynamics ͉ wind field

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