Background:The full lifespan of long-lived trees includes a seedling phase,during which a seed germinates and grows to a size large enough to be measured in forest inventories.Seedling populations are usually studied separately from adult trees,and the seedling lifespan,from seed to sapling,is poorly known.In the 50-ha Barro Colorado forest plot,we started intensive censuses of seeds and seedlings in 1994 in order to merge seedling and adult demography and document complete lifespans.Methods:In 17 species abundant in seedling censuses,we subdivided populations into six size classes from seed to 1 cm dbh,including seeds plus five seedling stages.The smallest seedling class was subdivided by age.Censuses in two consecutive years provided transition matrices describing the probability that a seedling in one stage moved to another one year later.For each species,we averaged the transition matrix across 25 censuses and used it to project the seedling lifespan,from seed until 1 cm dbh or death.Results:The predicted mean survival rate of seeds to 1 cm dbh varied 1000-fold across species,from 2.9×10 -6 to 4.4×10 -3 ;the median was 2.0×10 -4 .The seedling lifespan,or the average time it takes a seed to grow to 1 cm dbh,varied across species from 5.1 to 53.1 years,with a median of 20.3 years.In the median species,the 10% fastest-growing seeds would reach 1 cm dbh in 9.0 years,and the slowest 10% in 34.6 years.Conclusions:Combining seedling results with our previous study of lifespan after 1 cm dbh,we estimate that the focal species have full lifespans varying from 41 years in a gap-demanding pioneer to 320 years in one shade-tolerant species.Lifetime demography can contribute precise survival rates and lifespans to forestry models.

Across the global flora, interspecific variation in photosynthetic and metabolic rates depends more strongly on leaf area than leaf mass. In contrast, intraspecific variation in these rates is strongly mass-dependent. These contrasting patterns suggest that the causes of variation in leaf mass per area (LMA) may be fundamentally different within vs. among species. In order to explain these contrasting patterns, we developed a statistical modeling framework to decompose LMA into two components—metabolic LMAm (which determines photosynthetic capacity and dark respiration) and structural LMAs (which determines leaf toughness and potential leaf lifespan)—using leaf trait data from tropical forests in Panama and a global leaf-trait database. Decomposing LMA into LMAm and LMAs improves predictions of leaf trait variation (photosynthesis, respiration, and lifespan) within and among species. We show that strong area-dependence of metabolic traits across species can result from multiple factors, including high LMAs variance and/or a slow increase in photosynthetic capacity with increasing LMAm. In contrast, strong mass-dependence of metabolic traits within species results from LMAm increasing from shady to sunny conditions. LMAm and LMAs were nearly independent of each other in both global and Panama datasets, suggesting the presence of at least two important dimensions of leaf functional variation.

Tropical ecosystems contain the world's largest biodiversity of vascular plants. Yet, our understanding of tropical functional diversity and its contribution to global diversity patterns is constrained by data availability. This discrepancy underscores an urgent need to bridge data gaps by incorporating comprehensive tropical root data into global datasets. Here, we provide a database of tropical root characteristics. This new database, TropiRoot 1.0, will be instrumental in evaluating an array of hypotheses pertaining to root functional ecology and plant biogeography, both within the tropics and relative to other global biomes. The data compilation was conducted by the TropiRoot Initiative, in partnership with the Fine-Root Ecology Database (FRED) and the Global Root Trait (GRooT) database, Colorado State University (CSU) and the Smithsonian Tropical Research Institute (STRI). Literature search and data extraction were conducted between 2020 and 2024. Literature was identified using Web of Science, Scopus, and complemented using the expert knowledge of members of TropiRoot. To provide broad environmental and geographical distributions, literature searches included root characteristics (traits) across global change drivers, natural gradients, and from different continents. We adopted FRED standardized data columns and streamlined the format to enhance accessibility for data extraction across various user groups. This optimized framework resulted in a smaller, yet comprehensive datasheet. To make the database compatible with other global root trait initiatives, column identification was standardized following the codes provided by FRED. These efforts culminated in data extracted from 104 new sources, resulting in more than 8000 rows of data (either species or community data). Most of the data in TropiRoot 1.0 include root characteristics such as root biomass, morphology, root dynamics, mass fraction, architecture, anatomy, physiology, and root chemistry. This initiative represents a 30% increase in the currently available data for tropical roots in FRED. TropiRoot 1.0 contains root characteristics from 25 different countries, where seven are located in Asia, six in South America, five in Central America and the Caribbean, four in Africa, two in North America, and 1 in Oceania. Due to the volume of data, when ancillary data were available, including soil data, these data were either extracted and included in the database or its availability was recorded in an additional column. Multiple contributors checked the entries for outliers during the collation process to ensure data quality. For text-based observations, we examined all cells to ensure that their content relates to their specific categories. For numerical observations, we ordered each numerical value from least to greatest and plotted the values, checking apparent outliers against the data in their respective sources and correcting or removing incorrect or impossible values. Some data (soil and aboveground) have different columns for the same variable presented in different units, including originally published units, but root characteristics data had units converted to match those reported in FRED. By filling a gap from global databases, TropiRoot 1.0 expands our knowledge of otherwise so far underrepresented regions and our ability to assess global trends. This advancement can be used to improve tropical forest representation in vegetation models. The data are freely available and should be cited when used.

All species must partition resources among the processes that underly growth, survival, and reproduction. The resulting demographic trade-offs constrain the range of viable life-history strategies and are hypothesized to promote local coexistence. Tropical forests pose ideal systems to study demographic trade-offs as they have a high diversity of coexisting tree species whose life-history strategies tend to align along two orthogonal axes of variation: a growth-survival trade-off that separates species with fast growth from species with high survival and a stature-recruitment trade-off that separates species that achieve large stature from species with high recruitment. As these trade-offs have typically been explored for trees ≥1 cm dbh, it is unclear how species' growth and survival during earliest seedling stages are related to the trade-offs for trees ≥1 cm dbh. Here, we used principal components and correlation analyses to (1) determine the main demographic trade-offs among seed-to-seedling transition rates and growth and survival rates from the seedling to overstory size classes of 1188 tree species from large-scale forest dynamics plots in Panama, Puerto Rico, Ecuador, Taiwan, and Malaysia and (2) quantify the predictive power of maximum dbh, wood density, seed mass, and specific leaf area for species' position along these demographic trade-off gradients. In four out of five forests, the growth-survival trade-off was the most important demographic trade-off and encompassed growth and survival of both seedlings and trees ≥1 cm dbh. The second most important trade-off separated species with relatively fast growth and high survival at the seedling stage from species with relatively fast growth and high survival ≥1 cm dbh. The relationship between seed-to-seedling transition rates and these two trade-off aces differed between sites. All four traits were significant predictors for species' position along the two trade-off gradients, albeit with varying importance. We concluded that, after accounting for the species' position along the growth-survival trade-off, tree species tend to trade off growth and survival at the seedling with later life stages. This ontogenetic trade-off offers a mechanistic explanation for the stature-recruitment trade-off that constitutes an additional ontogenetic dimension of life-history variation in species-rich ecosystems.

Predicting tropical tree demography is a key challenge in understanding the future dynamics of tropical forests. Although demographic processes are known to be regulated by leaf trait diversity, only the effect of inter-specific trait variation has been evaluated, and it remains unclear as to what degree the intra-specific trait plasticity across light gradients (hereafter light plasticity) regulates tree demography, and how this will further shape long-term community and ecosystem dynamics. By combining in situ trait measurements and forest census data with a terrestrial biosphere model, we evaluated the impact of observation-constrained light plasticity on demography, forest structure, and biomass dynamics in a Panamanian tropical moist forest. Modeled leaf physiological traits vary across and within plant functional types (PFT), which represent the inter-specific trait variation and the intra-specific light plasticity, respectively. The simulation using three non-plastic PFTs underestimated 20-year average understory growth rates by 41%, leading to a biased forest size structure and leaf area profile, and a 44% underestimate in long-term biomass. The simulation using three plastic PFTs generated accurate understory growth rates, resulting in a realistic forest structure and a smaller biomass underestimate of 15%. Expanding simulated trait diversity using 18 nonplastic PFTs similarly improved the prediction of demography and biomass. However, only the plasticity-enabled model predicted realistic long-term PFT composition and within-canopy trait profiles. Our results highlight the distinct role of light plasticity in regulating forest dynamics that cannot be replaced by inter-specific trait diversity. Accurately representing light plasticity is thus crucial for trait-based prediction of tropical forest dynamics.

Forests sequester a substantial portion of anthropogenic carbon emissions. Many open questions concern how. We address two of these questions. Has leaf and fine litter production changed? And what is the contribution of old-growth forests? We address these questions with long-term records (≥10 years) of total, reproductive, and especially foliar fine litter production from 32 old-growth forests. We expect increases in forest productivity associated with rising atmospheric carbon dioxide concentrations and, in cold climates, with rising temperatures. We evaluate the statistical power of our analysis using simulations of known temporal trends parameterized with sample sizes (in number of years) and levels of interannual variation observed for each record. Statistical power is inadequate to detect biologically plausible trends for records lasting less than 20 years. Modest interannual variation characterizes fine litter production, and more variable phenomena will require even longer records to evaluate global change responses with sufficient statistical power. Just four old-growth forests have records of fine litter production lasting longer than 20 years, and these four provide no evidence for increases. Three of the four forests are in central Panama, also have long-term records of wood production, and both components of aboveground production are unchanged over 21-38 years. The possibility that recent increases in forest productivity are limited for old-growth forests deserves more attention.

Examining the cues and drivers influencing seed production is crucial to better understand forest resilience to climate change. We explored the effects of five climatic variables on seed production over 22 years in an everwet Amazonian forest, by separating direct effects of these variables from indirect effects mediated through flower production. We observed a decline in seed production over the study period, which was primarily explained by direct effects of rising nighttime temperatures and declining average vapour pressure deficits. Higher daytime temperatures were positively related to seed output, mainly through a flower-mediated effect, while rainfall effects on seed production were more nuanced, showing either positive or negative relationships depending on the seasonal timing of rains. If these trends continue, they are likely to lead to significant changes in forest dynamics, potentially impacting both forest structure and species composition.

AimSuccessional changes in functional diversity provide insights into community assembly by indicating how species are filtered into local communities based on their traits. Here, we assess successional changes in taxonomic and functional richness, evenness and redundancy along gradients of climate, soil pH and forest cover.LocationNeotropics.Time periodLast 0-100 years.Major taxa studiedTrees.MethodsWe used 22 forest chronosequence studies and 676 plots across the Neotropics to analyse successional changes in Hill's taxonomic and functional diversity of trees, and how these successional changes vary with continental-scale gradients in precipitation, soil pH and surrounding forest cover.ResultsTaxonomic and functional richness and functional redundancy increased, while taxonomic and functional evenness decreased over time. Functional richness and evenness changed strongly when not accounting for taxonomic richness, but changed more weakly after statistically accounting for taxonomic richness, indicating that changes in functional diversity are largely driven by taxonomic richness. Nevertheless, the successional increases in functional richness when correcting for taxonomic richness may indicate that environmental heterogeneity and limiting similarity increase during succession. The taxonomically-independent successional decreases in functional evenness may indicate that stronger filtering and competition select for dominant species with similar trait values, while many rare species and traits are added to the community. Such filtering and competition may also lead to increased functional redundancy. The changes in taxonomically-independent functional diversity varied with resource availability and were stronger in harsh, resource-poor environments, but weak in benign, productive environments. Hence, in resource-poor environments, environmental filtering and facilitation are important, whereas in productive environments, weaker abiotic filtering allows for high initial functional diversity and weak successional changes.Main conclusionWe found that taxonomic and functional richness and functional redundancy increased and taxonomic and functional evenness decreased during succession, mainly caused by the increasing number of rare species and traits due to the arrival of new species and due to changing (a)biotic filters.

We present highlights derived from 36 years of weekly observations of flower and seed production and 25 years of annual observations of seedling dynamics at Barro Colorado Island (BCI), Panama. Highlights concern levels and causes of spatial, temporal, and interspecific variation in flower production, seed production, seed dispersal, and seedling recruitment, growth, and survival as well as the consequences for plant regeneration and diversity. Full tree life cycles are assembled by combining seed production, seedling dynamics, and observations of larger plants from the 50-ha Forest Dynamics Plot and are used to evaluate the costs of dioecy, lifetime insights from functional traits, and interspecific variation in the impact of lianas among host tree species. A variety of results demonstrate the importance of long-term observations to understand forest dynamics and responses to rising atmospheric carbon dioxide concentrations and a changing climate.

With rising atmospheric CO2 concentrations, strategies for greater carbon sequestration and long-term storage are urgently needed. Current reforestation schemes typically use fast-growing tree species with low wood density, limiting the amount of carbon stored. In most tropical forests, there are native species with relatively fast growth rates, high wood density and low mortality rates that also achieve large adult size-'exceptional species'.We present a simulated assessment of the carbon sequestration potential using these exceptional species in assisted secondary succession in the Neotropics.In our example, the selected exceptional species could add up to 16.2 Mg C/ha of sequestered carbon in secondary wet forests at maturity.Synthesis and applications. By increasing the representation of exceptional species in reforestation efforts, we could potentially boost long-term carbon storage in reforestation projects focussed on carbon sequestration. However, our approach is not a substitute for protecting existing old primary forests and reforested lands plus reducing deforestation and emissions. Con el aumento de las concentraciones atmosfericas de CO2, se necesitan urgentemente estrategias para una mayor captura y almacenamiento a largo plazo del carbono. Los esquemas de reforestacion actuales suelen utilizar especies de arboles de rapido crecimiento con baja densidad de madera, lo que limita la cantidad de carbono almacenado. En la mayoria de los bosques tropicales, hay especies nativas con tasas de crecimiento relativamente rapidas, alta densidad de madera y bajas tasas de mortalidad que tambien alcanzan un gran tamano adulto-'especies excepcionales'.Presentamos una evaluacion simulada del potencial de secuestro de carbono usando estas especies excepcionales en la sucesion secundaria asistida en el Neotropico.En nuestro ejemplo, las especies excepcionales seleccionadas podrian sumar hasta 16.2 Mg C/ha de carbono secuestrado en bosques humedos secundarios en su madurez.Sintesis y aplicaciones. Al aumentar la representacion de especies excepcionales en los esfuerzos de reforestacion, podriamos impulsar potencialmente el almacenamiento de carbono a largo plazo en proyectos de reforestacion centrados en el secuestro de carbono. Sin embargo, nuestro enfoque no reemplaza la proteccion de los bosques primarios antiguos existentes y las tierras reforestadas, ni reduce la necesidad de disminuir la deforestacion y las emisiones. By increasing the representation of exceptional species in reforestation efforts, we could potentially boost long-term carbon storage in reforestation projects focussed on carbon sequestration. However, our approach is not a substitute for protecting existing old primary forests and reforested lands plus reducing deforestation and emissions.image

Tropical forest productivity represents an important global carbon sink, but many tropical forests grow on infertile soils. Efficient nutrient cycling by litterfall has long been assumed to maintain tropical tree growth, but there is no direct evidence that the nutrients cycled in litterfall are essential for tropical forest productivity.To test whether nutrient cycling by litterfall maintains tropical forest above-ground productivity, we established large-scale long-term litter removal (L-) and litter addition (L+) treatments in a mature lowland tropical forest. We hypothesised that the removal of nutrients in litter would reduce tree growth, survival and litter production in L- plots. By contrast, the addition of nutrients in litter would enhance tree growth, survival and litter production in L+ plots. To test our hypotheses, we recorded tree growth and survival every 2 years, and measured litterfall monthly during 17 years of treatments.Tree growth and litterfall declined over time in L- plots, with consistently lower growth rates compared to controls after 8 years, and lower litter production after 4 years of treatments. By contrast, although litterfall was higher in the L+ plots relative to the controls, there was only a minor transient increase in tree growth immediately after the start of treatments. Tree survival declined over time in all treatments but was not affected by litter manipulation.The long-term decline in tree growth and litterfall in the L- plots provides the first empirical evidence that nutrient cycling by litterfall plays a key role in maintaining above-ground productivity in this tropical forest. By contrast, the transient increase in growth in the L+ plots can be attributed to the large inputs of nutrients with the addition of the entire litter standing crop at the start of treatments. The addition of nutrients in litter over the long term was nonetheless sufficient to enhance litter production, possibly by accelerating leaf turnover.Synthesis: Efficient nutrient cycling by litterfall makes an important contribution to the annual nutrient requirements of mature tropical forest trees, compensating for infertile soils. Disturbances that disrupt this finely balanced cycle could therefore reduce biomass carbon sequestration in tropical forests. La productividad primaria de los bosques tropicales representa un importante sumidero global de carbono, a pesar de que muchos de estos bosques crecen sobre suelos infertiles. Por mucho tiempo se ha asumido que el crecimiento de los arboles en estos bosques esta sostenido por un eficiente reciclaje de nutrientes proveniente de la hojarasca, pero no hay evidencia directa de que los nutrientes reciclados en la hojarasca sean esenciales para la productividad de los bosques tropicales.Para probar si el reciclaje de nutrientes de la hojarasca sostiene la productividad epigea de los bosques tropicales, establecimos tratamientos a largo plazo de remocion (L-) y adicion (L+) de hojarasca en un bosque maduro tropical de bajura. Hipotetizamos que la remocion de los nutrientes contenidos en la hojarasca reduciria el crecimiento, la supervivencia, y la produccion de hojarasca de los arboles en parcelas de L-. Al contrario, hipotetizamos que la adicion de nutrientes en hojarasca aumentaria el crecimiento, la supervivencia, y la produccion de hojarasca de los arboles en parcelas de L+. Para probar nuestra hipotesis, registramos el crecimiento y la supervivencia de los arboles cada dos anos, y medimos hojarasca mensualmente durante 17 anos de tratamientos.El crecimiento de los arboles y la produccion de hojarasca disminuyo con el tiempo en parcelas de L-, con tasas de crecimiento consistentemente menores que en los controles despues de ocho anos, y una menor produccion de hojarasca despues de cuatro anos de tratamientos. En contraste, aunque la produccion de hojarasca fue mayor en parcelas de L+ comparada con los controles, solo hubo un aumento transitorio en el crecimiento de los arboles inmediatamente despues del inicio de los tratamientos. La supervivencia de los arboles disminuyo con el tiempo en todos los tratamientos, pero no fue afectada por la manipulacion de hojarasca.El declive a largo plazo observado en el crecimiento de los arboles y la produccion de hojarasca en las parcelas de L- brinda una primera evidencia empirica de que el reciclaje de nutrientes en la hojarasca juega un papel clave para sostener la productividad epigea de este bosque tropical. En contraste, el aumento transitorio en el crecimiento de los arboles en las parcelas de L+ se puede atribuir a la gran entrada de nutrientes que representa la adicion del mantillo entero al inicio de los tratamientos. La adicion de nutrientes en la hojarasca a largo plazo fue sin embargo suficiente para aumentar la produccion de hojarasca, posiblemente a traves de un aumento en la tasa de recambio de las hojas.Sintesis: El reciclaje eficiente de nutrientes a traves de la hojarasca contribuye significativamente a los requerimientos anuales de nutrientes de los arboles en bosque maduro tropical, compensando la infertilidad del suelo. Por lo tanto, perturbaciones a este delicado ciclo podrian reducir el secuestro de carbono en la biomasa de los bosques tropicales. The maintenance of highly productive lowland tropical forests on infertile soils is often attributed to nutrient cycling via litterfall. Almost 40 years after this theory was first proposed, our large-scale field experiment demonstrates that tree growth and litter production decline in response to long-term litter removal, providing the first empirical evidence that nutrient cycling by litterfall plays a key role in maintaining above-ground productivity in this tropical forest.image

Plants have evolved mechanisms to track seasonal variation in environmental resources, enabling them to time key life-history events to appropriate seasons. While the proximate cues for flowering initiation are well documented in the temperate region, it is still unclear what the flowering cues are in the tropics, especially in the subtropics. Our study compared first flowering dates (FFDs) predicted by eight hypothesized proximate cues concerning photoperiod, mean and directional changes in solar irradiance and warm/cool temperature, and rainfall with flowering dates observed over 19 years of weekly monitoring for 16 species in a subtropical rain forest. We observed considerable interannual variation in the median FFDs for the study species, ranging from 21 to 101 days. The early-spring flowering species tended to have greater interannual variation in FFDs than the summer flowering species. For 13 study species, temperature cues best explained interannual variation in FFDs. Cool temperatures in the previous fall/winter and warm temperatures in the current spring (or previous summer) might trigger the onset of flowering in these 13 species. Cues associated with photoperiod and irradiance also predicted interannual variation in FFDs with small root mean square error (<1.5 census intervals) for 12 species but generally had higher prediction errors than temperature-related cues. Cues associated with seasonal variation in rainfall failed to predict flowering times in any species. Our results suggest that future changes in temperature may alter flowering times for most species in subtropical forests, leading to changes in ecosystem processes and biosphere feedback to the climate system.Abstract in Chinese is available with online material.

Nutrient limitation may constrain the ability of recovering and mature tropical forests to serve as a carbon sink. However, it is unclear to what extent trees can utilize nutrient acquisition strategies - especially root phosphatase enzymes and mycorrhizal symbioses - to overcome low nutrient availability across secondary succession. Using a large-scale, full factorial nitrogen and phosphorus fertilization experiment of 76 plots along a secondary successional gradient in lowland wet tropical forests of Panama, we tested the extent to which root phosphatase enzyme activity and mycorrhizal colonization are flexible, and if investment shifts over succession, reflective of changing nutrient limitation. We also conducted a meta-analysis to test how tropical trees adjust these strategies in response to nutrient additions and across succession. We find that tropical trees are dynamic, adjusting investment in strategies - particularly root phosphatase - in response to changing nutrient conditions through succession. These changes reflect a shift from strong nitrogen to weak phosphorus limitation over succession. Our meta-analysis findings were consistent with our field study; we found more predictable responses of root phosphatase than mycorrhizal colonization to nutrient availability. Our findings suggest that nutrient acquisition strategies respond to nutrient availability and demand in tropical forests, likely critical for alleviating nutrient limitation.

Long-term late-stage changes in the composition and structure of a late-stage secondary forest were quantified by repeated censuses of a 1.5-ha plot starting in 1968. When first established, the plot lacked canopy gaps and was dominated by Gustavia superba. During the following 46 years, canopy gaps have been numerous, small in area, and clustered in a portion of the plot. The dominance by G. superba has declined, but the number of tree species has remained relatively constant (maximum, 129). Stem density declined largely because recruitment was low relative to nearby old-growth forest. BrayCurtis dissimilarity in tree species composition with nearby old-growth forest decli from 0.70 in 1968 to 0.57 in 2014, with most of the decline occurring before 2000. Tree basal area has fluctuated, which might be a characteristic of late-stage secondary forest as large pioneers die off. Much work remains to be done on tree growth rates, the dynamics of recruitment and mortality, and the gradual transition to the species composition of old-growth forest.

We present a representation of nitrogen and phosphorus cycling in the vegetation demography model the Functionally Assembled Terrestrial Ecosystem Simulator (FATES), within the Energy Exascale Earth System (E3SM) land model. This representation is modular, and designed to allow testing of multiple hypothetical approaches for carbon-nutrient coupling in plants. The model tracks nutrient uptake, losses via turnover from both live plants and mortality into soil decomposition, and allocation during tissue growth for a large number of size- and functional-type-resolved plant cohorts within a time-since-disturbance-resolved ecosystem. Root uptake is governed by fine root biomass, and plants vary in their fine root carbon allocation in order to balance carbon and nutrient limitations to growth. We test the sensitivity of the model to a wide range of parameter variations and structural representations, and in the context of observations at Barro Colorado Island, Panama. A key model prediction is that plants in the high-light-availability canopy positions allocate more carbon to fine roots than plants in low-light understory environments, given the widely different carbon versus nutrient constraints of these two niches within a given ecosystem. This model provides a basis for exploring carbon-nutrient coupling with vegetation demography within Earth System Models (ESMs).

Fine roots are key to ecosystem-scale nutrient, carbon (C), and water cycling, yet our understanding of fine root trait variation within and among tropical forests, one of Earth’s most C-rich ecosystems, is limited. We characterized root biomass, morphology, nutrient content, and arbuscular mycorrhizal fungal (AMF) colonization to 1.2 m depths across four distinct lowland Panamanian forests, and related root characteristics to soil C stocks. We hypothesized that: (H1) Fine root characteristics vary consistently with depth across seasonal tropical forests, with deeper roots exhibiting more exploratory traits, such as for deep water acquisition; (H2) fine root characteristics vary among tropical forests mainly in surface soils, where resource availability also varies. We found consistent variation with depth across the four forests, including decreased root biomass, root tissue density, and AMF, and increased specific root length. Among the forests, there was variation in some fine root characteristics, including greater surface root biomass and lower SRL in the wettest forest, and smaller fine root diameter in the driest forest. We also found that root characteristics were related to total soil C stocks, which were positively related to root biomass and negatively related to specific root length. These results indicate emergent properties of root variation with depth across tropical forests, and show site-scale variation in surface root characteristics. Future work could explore the flexibility in root characteristics under changing conditions such as drought.

Tropical forest root characteristics and resource acquisition strategies are underrepresented in vegetation and global models, hampering the prediction of forest-climate feedbacks for these carbon-rich ecosystems. Lowland tropical forests often have globally unique combinations of high taxonomic and functional biodiversity, rainfall seasonality, and strongly weathered infertile soils, giving rise to distinct patterns in root traits and functions compared with higher latitude ecosystems. We provide a roadmap for integrating recent advances in our understanding of tropical forest belowground function into vegetation models, focusing on water and nutrient acquisition. We offer comparisons of recent advances in empirical and model understanding of root characteristics that represent important functional processes in tropical forests. We focus on: (1) fine-root strategies for soil resource exploration, (2) coupling and trade-offs in fine-root water vs nutrient acquisition, and (3) aboveground-belowground linkages in plant resource acquisition and use. We suggest avenues for representing these extremely diverse plant communities in computationally manageable and ecologically meaningful groups in models for linked aboveground-belowground hydro-nutrient functions. Tropical forests are undergoing warming, shifting rainfall regimes, and exacerbation of soil nutrient scarcity caused by elevated atmospheric CO2. The accurate model representation of tropical forest functions is crucial for understanding the interactions of this biome with the climate.

Understanding the distribution of hundreds of thousands of plant metabolites across the plant kingdom presents a challenge. To address this, we curated publicly available LC-MS/MS data from 19,075 plant extracts and developed the plantMASST reference database encompassing 246 botanical families, 1,469 genera, and 2,793 species. This taxonomically focused database facilitates the exploration of plant-derived molecules using tandem mass spectrometry (MS/MS) spectra. This tool will aid in drug discovery, biosynthesis, (chemo)taxonomy, and the evolutionary ecology of herbivore interactions.