Tree species selection for flood-prone urban areas is an important aspect of urban forests' climate resilience. However, most current knowledge of flooding tolerance comes either from natural stands or long-term experimental studies that may not well reflect responses to the shorter flooding episodes common in urban settings. We examined the sensitivity to, and the ability to recover from, flooding of 16 broadleaf tree species with varying traits, natural habitats, and expected levels of stress tolerance. Young potted trees growing outdoors were exposed to one out of three treatments: control (watered regularly), short flooding (SF; 3 days), or long flooding (LF; 10 days). A variety of ecophysiological, morphological, and structural response variables and traits were measured before and at the end of the flooding periods, and after a 16-day recovery period. Net photosynthesis (Anet) decreased significantly in two species in response to SF and in ten species in response to LF. Reduced Anet and the ability to recover were linked to reduced stomatal conductance and/or maximum quantum efficiency of photosystem II. The vitality response, estimated from wilting and leaf discoloration, also differed significantly among species and treatments. Low vitality was often associated with lower capacity for physiological recovery. While some correlations between the measured functional traits and ecophysiological responses were observed, no clear patterns emerged between trait combinations and species’ flooding sensitivity. When selecting species for urban sites prone to sporadic flooding, the ability to recover from short-term flooding events is an important factor, alongside the ability to tolerate flooding stress.

BACKGROUND AND AIMS:Tropical forests exchange more carbon dioxide (CO2) with the atmosphere than any other terrestrial biome. Yet, uncertainty in the projected carbon balance over the next century is roughly three times greater for the tropics than other for ecosystems. Our limited knowledge of tropical plant physiological responses, including photosynthetic, to climate change is a substantial source of uncertainty in our ability to forecast the global terrestrial carbon sink. METHODS:We used a meta-analytic approach, focusing on tropical photosynthetic temperature responses, to address this knowledge gap. Our dataset, gleaned from 18 independent studies, included leaf-level light-saturated photosynthetic (Asat) temperature responses from 108 woody species, with additional temperature parameters (35 species) and rates (250 species) of both maximum rates of electron transport (Jmax) and Rubisco carboxylation (Vcmax). We investigated how these parameters responded to mean annual temperature (MAT), temperature variability, aridity and elevation, as well as also how responses differed among successional strategy, leaf habit and light environment. KEY RESULTS:Optimum temperatures for Asat (ToptA) and Jmax (ToptJ) increased with MAT but not for Vcmax (ToptV). Although photosynthetic rates were higher for 'light' than 'shaded' leaves, light conditions did not generate differences in temperature response parameters. ToptA did not differ with successional strategy, but early successional species had ~4 °C wider thermal niches than mid/late species. Semi-deciduous species had ~1 °C higher ToptA than broadleaf evergreen species. Most global modelling efforts consider all tropical forests as a single 'broadleaf evergreen' functional type, but our data show that tropical species with different leaf habits display distinct temperature responses that should be included in modelling efforts. CONCLUSIONS:This novel research will inform modelling efforts to quantify tropical ecosystem carbon cycling and provide more accurate representations of how these key ecosystems will respond to altered temperature patterns in the face of climate warming.

Climate warming increases the risk of harmful leaf temperatures in terrestrial plants, particularly in tropical tree species that have evolved in warm and thermally stable environments. We examined heat tolerance thresholds of photosynthetic light reactions in sun-exposed leaves of 12 tropical montane tree species with different strategies for growth and water use. Leaf chlorophyll a fluorescence, gas exchange, morphology and thylakoid membrane lipid composition were measured at three common gardens along an elevation and temperature gradient in Rwanda. Tree species with traits predisposing them to higher leaf temperatures, such as lower stomatal conductance and large leaves, had higher photosynthetic heat tolerance, but narrower thermal safety margins (TSMs). Photosynthetic heat tolerance partially acclimated to increased growth temperature, increasing by 0.31°C on average for every 1°C increase in growth temperature. Thus, TSMs were narrower for trees grown at the warmer sites. Heat tolerance and its acclimation were linked to the adjustment of thylakoid membrane lipid composition. Moreover, TSMs were larger in species with high leaf mass per area. Our results show that (i) leaf temperature is more important than heat tolerance in controlling interspecific variation in TSMs, and that (ii) tropical trees have limited ability to thermally acclimate to increasing temperatures.

Elevated ground-level ozone, a result of human activity, is known to reduce plant productivity, but its influence on tropical forests remains unclear. Here we estimate how increased ozone exposure has affected tropical-forest productivity and the global carbon cycle. We experimentally measure the ozone susceptibility of various tropical tree species, and then incorporate these data into a dynamic global vegetation model. We find that current anthropogenic-derived ozone results in a substantial decline in annual net primary productivity (NPP) across all tropical forests, with some areas being particularly impacted. For example, Asia sees losses of 10.9% (7.2-19.7%) NPP. We calculate that this productivity decline has resulted in a cumulative loss in carbon drawdown of 0.29 PgC per year since 2000, equating to similar to 17% of the tropical contemporary annual land carbon sink in the twenty-first century. We also find that areas of current and future forest restoration are disproportionately affected by elevated ozone. Future socioeconomic pathways that reduce ozone formation in the tropics will incur benefits to the global carbon budget by relieving the current ozone impacts seen across both intact forest and areas of forest restoration, which are critical terrestrial regions for mitigation of rising atmospheric carbon dioxide.

Urban air quality is influenced by vegetation through alterations in airflow and pollutant deposition processes. We investigated these interactions by integrating the Vegetation Impact Dynamic Assessment model (VIDA) with the Large-Eddy Simulation model PALM. Our analysis focus on nitrogen dioxide (NO2) and particulate matter (PM) concentrations at the local scale, considering three tree genera. Our findings reveal the necessity of accounting for both gaseous pollutants and particles separately due to their differing mechanisms of deposition onto leaves. The coupled PALM-VIDA model demonstrates a significant reduction in PM levels across the modelling domain and within street canyons when deposition to vegetation is incorporated. Reduction in NO2 through deposition to vegetation is lower but human NO2 exposure can still be decreased if tree species selection and placement leads to desirable effects on air flow. Sparse tree arrangements or species with sparse crowns facilitate ventilation and are often better at reducing NO2 concentrations in street canyons compared to denser vegetation with higher deposition but negative effects on ventilation. Our study informs urban planning and green infrastructure design, underscoring the multifaceted role of urban greenery in air pollution mitigation strategies. Its main conclusion is that both deposition processes and the influence of air mixing and ventilation need to be considered to accurately assess the effects of urban trees on local air quality. Ill-considered placement and species selection may cause a net increase in pollutants underneath the trees. However, careful planning can address this risk and instead improve overall air quality.

Plants face a trade-off between hydraulic safety and growth, leading to a range of water-use strategies in different species. However, little is known about such strategies in tropical trees and whether different water-use traits can acclimate to warming.We studied five water-use traits in 20 tropical tree species grown at three different altitudes in Rwanda (RwandaTREE): stomatal conductance (gs), leaf minimum conductance (gmin), plant hydraulic conductance (Kplant), leaf osmotic potential (psi o) and net defoliation during drought. We also explored the links between these traits and growth and mortality data.Late successional (LS) species had low Kplant, gs and gmin and, thus, low water loss, while low psi o helped improve leaf water status during drought. Early successional (ES) species, on the contrary, used more water during both moist and dry conditions and exhibited pronounced drought defoliation. The ES strategy was associated with lower mortality and more pronounced growth enhancement at the warmer sites compared to LS species. While Kplant and gmin showed downward acclimation in warmer climates, psi o did not acclimate and gs measured at prevailing temperature did not change.Due to distinctly different water use strategies between successional groups, ES species may be better equipped for a warmer climate as long as defoliation can bridge drought periods.

Summary Current estimates of temperature effects on plants mostly rely on air temperature, although it can significantly deviate from leaf temperature (Tleaf). To address this, some studies have used canopy temperature (Tcan). However, Tcan fails to capture the fine‐scale variation in Tleaf among leaves and species in diverse canopies. We used infrared radiometers to study Tleaf and Tcan and how they deviate from air temperature (ΔTleaf and ΔTcan) in multispecies tropical tree plantations at three sites along an elevation and temperature gradient in Rwanda. Our results showed high Tleaf (up to c. 50°C) and ΔTleaf (on average 8–10°C and up to c. 20°C) of sun‐exposed leaves during 10:00 h–15:00 h, being close to or exceeding photosynthetic heat tolerance thresholds. These values greatly exceeded simultaneously measured values of Tcan and ΔTcan, respectively, leading to strongly overestimated leaf thermal safety margins if basing those on Tcan data. Stomatal conductance and leaf size affected Tleaf and Tcan in line with their expected influences on leaf energy balance. Our findings highlight the importance of leaf traits for leaf thermoregulation and show that monitoring Tcan is not enough to capture the peak temperatures and heat stress experienced by individual leaves of different species in tropical forest canopies.

Decline in mesophyll conductance ( g m ) plays a key role in limiting photosynthesis in plants exposed to elevated ozone (O 3 ). Leaf anatomical traits are known to influence g m , but the potential effects of O 3 ‐induced changes in leaf anatomy on g m have not yet been clarified. Here, two poplar clones were exposed to elevated O 3 . The effects of O 3 on the photosynthetic capacity and anatomical characteristics were assessed to investigate the leaf anatomical properties that potentially affect g m . We also conducted global meta‐analysis to explore the general response patterns of g m and leaf anatomy to O 3 exposure. We found that the O 3 ‐induced reduction in g m was critical in limiting leaf photosynthesis. Changes in liquid‐phase conductance rather than gas‐phase conductance drive the decline in g m under elevated O 3, and this effect was associated with thicker cell walls and smaller chloroplast sizes. The effects of O 3 on palisade and spongy mesophyll cell traits and their contributions to g m were highly genotype‐dependent. Our results suggest that, while anatomical adjustments under elevated O 3 may contribute to defense against O 3 stress, they also cause declines in g m and photosynthesis. These results provide the first evidence of anatomical constraints on g m under elevated O 3 .

<p>The responses of tropical forests to climate change depends on the ability of trees to acclimate to warming, as well as how interspecific variation in these responses affect tree community composition. In a unique tropical elevation gradient experiment in Rwanda, Rwanda TREE, we examine the sensitivity of tropical trees and forest stands to warming and altered water supply. Mixed multi-species plantations (20 tree species, 1800 trees per site) have been established at three sites with large variation in elevation (1300-2400 m) and climate (17-24 °C mean daytime temperature), with additional water and nutrient manipulation treatments being applied at each site. Here we present an overview of results obtained this far regarding: (1) leaf gas exchange physiology; (2) photosynthetic heat tolerance; (3) water-use traits; (4) tree growth and mortality; (5) stand-level tree community composition. We also discuss the potential implications of our findings for the biodiversity and carbon storage of tropical forests in a changing climate.</p>

<p>Tropospheric ozone (O<sub>3</sub>) reduces plant productivity by entering leaves, generating reactive oxygen species and causing oxidative stress which in turn increases respiration, decreases photosynthesis, plant growth, biomass accumulation, and consequently reduces the land carbon sink. Tropical forests are potentially most vulnerable to future O<sub>3</sub> scenarios given their high productivity, generally high stomatal conductance and environmental conditions conducive to O<sub>3</sub> uptake (eg precursor emissions during biomass burning).</p> <p>Here we present the first comprehensive set of measurements of O<sub>3</sub> effects on plant physiology and biomass accumulation in tropical forests. We exposed twelve tropical tree species to elevated O<sub>3</sub> concentrations in Open Top Chambers (OTCs) based at the James Cook University O<sub>3</sub> experimental facility in Cairns, Australia, from which we generate O<sub>3</sub> dose-response functions for each species. We test the importance of Leaf Mass per unit Area (LMA) as an indicator of O<sub>3</sub> sensitivity.</p> <p>We use these relationships to parameterize the global land-surface model JULES, and apply the model over the pan-tropical region using contemporary near-surface O<sub>3</sub> concentration fields. For the first time we quantify the impact of O<sub>3</sub> on contemporary tropical productivity.</p>

Aim Leaves display a remarkable variety of shapes, each with potential ecological advantages in specific climates. While relations between leaf shape and either climate or height has been relatively well studied in eudicots, the macroecological drivers of shape remain poorly known in monocots. Here, we investigated associations between climate and plant height with the evolution of leaf shape in a clade with high species and morphological diversity. Location Global. Time period Cretaceous to contemporary. Major taxa studied Palms (Arecaceae). Methods We apply a Bayesian phylogenetic mixed model to test for associations between climate and leaf shape (all entire-leaved, pinnate-dissected, palmate-dissected, and costapalmate). We further reconstruct the ancestral leaf shape using multistate speciation and extinction models and compare the frequency of shapes with global temperatures through time. Results We find that plant height associates with dissected leaves and that annual precipitation associates with pinnate shapes. The ancestral leaf shape is unclear but early diversification was dominated by pinnate-dissected palms, which has remained the most species-rich form of leaves throughout palm history. Main conclusions Palms that are tall and live in humid regions are more likely to have pinnate leaves. Through geological time scales, temperature did not play an obvious role in determining leaf shapes. This study contributes to our understanding of how the diversity of leaf shapes is linked to biological and climatic factors.

Summary Climate warming is causing compositional changes in Andean tropical montane forests (TMFs). These shifts are hypothesised to result from differential responses to warming of cold‐ and warm‐affiliated species, with the former experiencing mortality and the latter migrating upslope. The thermal acclimation potential of Andean TMFs remains unknown. Along a 2000 m Andean altitudinal gradient, we planted individuals of cold‐ and warm‐affiliated species (under common soil and irrigation), exposing them to the hot and cold extremes of their thermal niches, respectively. We measured the response of net photosynthesis ( A net ), photosynthetic capacity and leaf dark respiration ( R dark ) to warming/cooling, 5 months after planting. In all species, A net and photosynthetic capacity at 25°C were highest when growing at growth temperatures ( T g ) closest to their thermal means, declining with warming and cooling in cold‐affiliated and warm‐affiliated species, respectively. When expressed at T g , photosynthetic capacity and R dark remained unchanged in cold‐affiliated species, but the latter decreased in warm‐affiliated counterparts. R dark at 25°C increased with temperature in all species, but remained unchanged when expressed at T g . Both species groups acclimated to temperature, but only warm‐affiliated species decreased R dark to photosynthetic capacity ratio at T g as temperature increased. This could confer them a competitive advantage under future warming.

Tropospheric ozone (O-3) is a gaseous phytotoxic plant stressor known to reduce wheat (Triticum aestivum) crop yields at current concentrations. O3 is predicted to increase in many crop-growing regions, together with higher frequencies of heatwaves and droughts. In this study, wheat crops were exposed to two levels of O-3 (ambient and similar to 70 ppb) in combination with ambient or elevated temperature (+8 degrees C) and two watering regimes (well-watered and 50% reduced water supply) during the grain-filling period. With this experimental setup, we assessed the interactive effects between O-3, temperature and water supply on wheat yield and grain quality, and measured leaf gas exchange to explore the underlying mechanisms. Overall, O-3, warming and drought all decreased grain yield and average grain mass but increased grain concentration of N and other nutrient elements. Increasing daytime O-3 from 25 to 73 ppb resulted in a 25% yield reduction in treatments with ambient temperature and well-watered soil. Drought reduced the impact of O-3 on light-saturated photosynthesis, grain mass, total aboveground biomass and grain concentrations of K, Ca, Mg, Mo. In contrast, concentrations of K and Ca increased to a larger extent when O-3 stress was combined with elevated temperature. Grain concentrations of N, Ca and Zn were closely and negatively related to grain yield regardless of O-3, heat and drought stress, likely explained by the reduction in grain filling period, with starch accumulation reduced to a larger extent than that of these elements. P, K, Mg, Mn, Mo concentrations were weakly related to grain yield, but were clearly altered by environmental stress. The modifying effect of water availability is crucial to include in assessments of O-3 impacts on global food production in relation to climate change, considering effects on wheat yield variables and grain nutrient concentrations.

Urban trees provide numerous ecosystem services including the mitigation of urban heat. However, this cooling effect is often restricted due to poor tree growth and health caused by harsh growing conditions. The aim of this study is to analyse the influence of surface paving on the physiology, growth and cooling benefits of street trees of three common species with contrasting drought tolerance (Aesculus hippocastanum, Tilia x europaea and Quercus palustris) in Gothenburg, Sweden. Tree structural parameters, leaf water potentials, gas exchange, leaf area density and chlorophyll content were measured in three summertime periods in 2017 and 2018. Moreover, based on the measured data, the cooling effects of studied trees due to shading and transpiration were modelled. For all species, trees at highly paved sites were found to have significantly reduced growth, physiological performance and cooling effects compared to sites with a higher degree of permeable surfaces. This negative effect of surface paving was stronger than the effect of species, despite differences in drought tolerance and water use strategy between studied species. Based on the sensitivity of species to surface paving, we recommend Q. palustris and T. europaea for sites with good growing conditions due to their potential to maintain high water use and growth rates, and A. hippocastanum for highly paved sites where shading is not the primary ecosystem service sought. Our findings emphasise the importance of tree planting design in supporting urban tree growth and the continuous provision of ecosystem services, particularly in the context of the changing climate.

Abstract. The response of tropical trees and tree communities to climate change is crucial for the carbon storage and biodiversity of the terrestrial biosphere. Trees in tropical montane rainforests (TMFs) are considered particularly vulnerable to climate change, but this hypothesis remains poorly evaluated due to data scarcity. To reduce the knowledge gap on the response of TMFs trees to warming, we established a field experiment along a 1300–2400 m elevation gradient in Rwanda. Twenty tree species native to montane forests in East and Central Africa were planted in multispecies plots at three sites along the gradient. They have overlapping distributions but primarily occur in either transitional rainforest (1600–2000 m a.s.l) or mid elevation TMF (2000–3000 m a.s.l.), with both early- (ES) and late-successional (LS) species represented in each elevation origin group. Tree growth (diameter and height) and survival were monitored regularly over two years. We found that ES species, especially from lower elevations, grew faster at warmer sites while several of the LS species, especially from higher elevations, did not respond or grew slower. Moreover, a warmer climate increased tree mortality in LS species, but not much in ES species. ES species with transitional rainforest origin strongly increased in proportion of stand basal area at warmer sites, while TMF species declined, suggesting that lower-elevation ES species will have an advantage over higher-elevation species in a warming climate. The risk of higher-elevation and LS species to become outcompeted by lower-elevation and ES species in a warmer climate has important implications for biodiversity and carbon storage of Afromontane forests.

Optimal stomatal theory predicts that stomata operate to maximise photosynthesis (Anet ) and minimise transpirational water loss to achieve optimal intrinsic water-use efficiency (iWUE). We tested whether this theory can predict stomatal responses to elevated atmospheric CO2 (eCO2 ), and whether it can capture differences in responsiveness among woody plant functional types (PFTs). We conducted a meta-analysis of tree studies of the effect of eCO2 on iWUE and its components Anet and stomatal conductance (gs ). We compared three PFTs, using the unified stomatal optimisation (USO) model to account for confounding effects of leaf-air vapour pressure difference (D). We expected smaller gs , but greater Anet , responses to eCO2 in gymnosperms compared with angiosperm PFTs. We found that iWUE increased in proportion to increasing eCO2 in all PFTs, and that increases in Anet had stronger effects than reductions in gs . The USO model correctly captured stomatal behaviour with eCO2 across most datasets. The chief difference among PFTs was a lower stomatal slope parameter (g1 ) for the gymnosperm, compared with angiosperm, species. Land surface models can use the USO model to describe stomatal behaviour under changing atmospheric CO2 conditions.

<p>Current estimates of temperature effects on plants are usually based on air temperature (<em>T</em><sub>air</sub>), although it is well known that leaf temperature (<em>T</em><sub>leaf</sub>) can deviate considerably from <em>T</em><sub>air</sub>. In some studies, to overcome the problem of <em>T</em><sub>air</sub> often being a poor proxy of <em>T</em><sub>leaf</sub>, measurements of canopy temperature (<em>T</em><sub>can</sub>) have been used instead. However, <em>T</em><sub>can</sub> data do not capture the spatial variation in <em>T</em><sub>leaf</sub> among leaves with different thermoregulatory traits. This may be particularly problematic for highly diverse and heterogeneous tropical forest canopies. In this study, we used infrared thermometers to study <em>T</em><sub>leaf</sub> and <em>T</em><sub>can</sub> in multispecies tropical tree plantations established at three sites along an elevation gradient from 2,400 m a.s.l. (17.1°C mean daytime temperature) to 1,300 m a.s.l. (24.0°C) in Rwanda.  Measurements of chlorophyll fluorescence were also conducted to study the photosynthetic heat tolerance of these species. Our results showed high <em>T</em><sub>leaf</sub> (up to ~50°C) and leaf-to-air temperature differences (Δ<em>T</em><sub>leaf</sub>; on average 8-10°C and up to 24°C) of sun-exposed leaves. Both leaf size and stomatal conductance were important traits in controlling <em>T</em><sub>leaf</sub>. The <em>T</em><sub>leaf</sub> (and thus Δ<em>T</em><sub>leaf</sub>) of sun-exposed leaves greatly exceeded the simultaneously measured values of <em>T</em><sub>can</sub> (and Δ<em>T</em><sub>can</sub>). Photosynthetic heat tolerance partially acclimated to increased growth temperature; on average 0.31°C increase in heat tolerance per 1°C increase in growth temperature. Consequently, thermal safety margins were narrower for species at the warmer, lower-elevation sites. Our findings highlight the importance of leaf traits for leaf thermoregulation and show that monitoring of canopy temperature is not enough to capture the peak temperatures and heat stress experienced by individual leaves in diverse tropical forest canopies. They also suggest that tropical trees have limited abilities to thermally acclimate to increasing temperatures.</p> <p><em>Keywords:</em> Canopy temperature, elevation gradient, fluorescence, heat tolerance, leaf area, leaf temperature, stomatal conductance, thermoregulation, tropical forest.</p>

A major limitation in modeling global O3 vegetation damage has long been the reliance on empirical O3 sensitivity parameters derived from a limited number of species and applied at the level of plant functional types (PFTs), which ignore the large interspecific variations within the same PFT. Here, we present a major advance in large-scale assessments of O3 plant injury by linking the trait leaf mass per area (LMA) and plant O3 sensitivity in a broad and global perspective. Application of the new approach and a global LMA map in a dynamic global vegetation model reasonably represents the observed interspecific responses to O3 with a unified sensitivity parameter for all plant species. Simulations suggest a contemporary global mean reduction of 4.8% in gross primary productivity by O3, with a range of 1.1%-12.6% for varied PFTs. Hotspots with damages > 10% are found in agricultural areas in the eastern U.S., western Europe, eastern China, and India, accompanied by moderate to high levels of surface O3. Furthermore, we reveal an inherent plant sensitivity spectrum for O3 which is highly linked with plant leaf trait trade-off strategy, revealing high risks for fast-growing species with low LMA, such as crops, grasses and deciduous trees.

Tropical montane forests are among the most productive ecosystems within the tropical region and store a significant amount of carbon in live biomass. With ongoing global climate warming, tropical climates are also getting warmer. The productivity and climate feedbacks of future tropical montane forests depend on the ability of trees to acclimate their photosynthetic metabolism to these new, warmer conditions. However, knowledge of acclimation ability of photosynthesis and its underlying biochemical processes to warming in trees grown under natural field conditions is currently limited due to data scarcity. To reduce this knowledge gap, we used two separate field experiments located in Colombia (with 15 species) and Rwanda (16 species), and for each experiment, tree species were grown at three different sites along an elevation gradient differing in ambient air temperature. At all three sites, we measured the responses of net CO2 assimilation at different CO2 concentration (50 to 2000 ppm) and at different leaf temperatures (15 to 40 °C) in ≈ 3 years old trees. We used these data to derive key photosynthetic biochemical parameters (maximum Rubisco carboxylation capacity - Vcmax and maximum electron transport rate - Jmax) and their temperature sensitivity, as well as the thermal optimum of net photosynthesis (ToptA). We show that tropical montane tree species from the two continents are generally able to acclimate their ToptA by increasing in trees grown in warmer conditions, but the magnitude of change in ToptA differs among species from different successional groups (early- versus late succession) and climate of origin (lowland versus montane). Shifts in ToptA are largely driven by concomitant changes in thermal sensitivity parameters of underlying biochemical processes of photosynthesis (Vcmax and Jmax) with warming. We also show that, at a standard temperature of 25 °C, Vcmax is largely constant, while Jmax decreases with warming. Our findings indicate tropical montane tree species from Latin America and Africa can thermally acclimate their photosynthetic physiology, but that this thermal acclimation ability is related to species successional group and their climate of origin.

A major limitation in modeling global ozone (O-3) vegetation damage has long been the reliance on empirical O-3 sensitivity parameters derived from a limited number of species and applied at the level of plant functional types (PFTs), which ignore the large interspecific variations within the same PFT. Here, we present a major advance in large-scale assessments of O-3 plant injury by linking the trait leaf mass per area (LMA) and plant O-3 sensitivity in a broad and global perspective. Application of the new approach and a global LMA map in a dynamic global vegetation model reasonably represents the observed interspecific responses to O-3 with a unified sensitivity parameter for all plant species. Simulations suggest a contemporary global mean reduction of 4.8% in gross primary productivity by O-3, with a range of 1.1 %-12.6% for varied PFTs. Hotspots with damage > 10% are found in agricultural areas in the eastern US, western Europe, eastern China, and India, accompanied by moderate to high levels of surface O-3. Furthermore, we simulate the distribution of plant sensitivity to O-3, which is highly linked with the inherent leaf trait trade-off strategies of plants, revealing high risks for fast-growing species with low LMA, such as crops, grasses, and deciduous trees.