Centro de Investigación y Promoción del Campesinado

Objective: To evaluate the effect of two workplace isometric exercise interventions on blood pressure in hypertensive adults. Design and method: A randomized controlled multicenter clinical trial conducted in hypertensive (>130 mmHg systolic blood pressure (SBP)) 35 to 65 years old in work places in Colombia. Participants were assigned to either of two interventions: isometric handgrip dynamometer training at 30% of maximum strength (HGD) or wall squat (WS), or to a control group following standard recommendations. The interventions were performed at the participant's workplace and consisted of 4 sets of 2 minutes of sustained isometric contraction with 2 minutes' rest between sets, 3 times per week for 12 weeks. SBP and diastolic blood pressure (DBP) were measured using an automatic device (Omron) with a standardized protocol before and after the 12-week intervention. Results: Pre and post measurements were completed by 105 hypertensive participants: mean age of 45 years (SD 9.5), 63.8% of which were men. In the HGD group (n = 38) there were significant decreases in SBP [Pre: 141 mmHg (SD 7.8), Post: 127 mmHg (SD 9.1) (p < 0.001)], and in DBP [Pre: 87 mmHg (SD 5.8), Post: 82 mmHg (SD 9.5) (p < 0.001)]. There were also significant decreases in the WS-group (n = 35) in SBP [Pre: 139 mmHg (SD 7.5), Post: 126 mmHg (SD 12.4) (p < 0.001)], and in DBP [Pre: 86 mmHg (SD 5.2), Post 82 mmHg (SD 8.1) (p < 0.001)]. In the control group (n = 32), there were no significant changes in either in SBP [Pre: 140 mmHg (SD 8.4), Post: 137 mmHg (SD 12.9)], or DBP [Pre: 86 mmHg (SD 5.0), Post: 85 mmHg (SD 8.0) (p = 0.71)]. Conclusions: Both workplace isometric training interventions resulted in significant and clinically relevant reductions in blood pressure in subjects with high blood pressure. The combination of effectiveness, modest time commitment (42 minutes per week) and ease with which the interventions can be implemented in the workplace setting makes them both attractive and practical options with minimal barriers for participation. Furthermore, WS can be performed without any equipment.

Frosty pod rot disease of cacao (FPR), caused by the fungus Moniliophthora roreri, has severely impacted the production of cocoa in Latin America since its discovery. Prior to the 1950s, FPR was known only from Colombia and Ecuador. However, beginning in the 1970s, its geographical range has dramatically expanded throughout most of the chocolate‐producing regions of the Americas. The origin of the pathogen remains unknown. In this study we evaluated the genetic diversity of M. roreri from areas spanning, as much as possible, its current geographical range using simple sequence repeat markers and a publicly available single nucleotide polymorphism dataset. Two hotspots of genetic diversity were found: coastal Ecuador and the inter‐Andean Magdalena Valley of Colombia, neither of which correspond to the Amazonian origin of the host. However, both areas were early centers of intense cultivation of cacao. Our results indicate that M. roreri was introduced into both areas from its center of origin, where intensive cacao cultivation likely led to the increase of inoculum and further dissemination of the disease. Current invasions can be traced to two genotypes responsible for all known instances of the pathogen in Central America, the Caribbean, Peru, and Bolivia. We also report for the first time M. roreri in Maynas (Peruvian Amazon), which is likely the result of a recent introduction from Colombia.

Belisario Boeto es una provincia relativamente pequeña, con 15,000 habitantes y una densidad de 8 habitantes por km2. Su capital, Villa Serrano, es el único núcleo importante, con unos 3,000 habitantes. La siguiente población, Mendoza, sólo tiene un centenar de familias. El resto de la población está disperso en unas 170 comunidades pequeñas que, en el mejor de los casos, sólo llegan a tener 30 familias, y en muchos casos no llegan ni a 10. Está en las estribaciones andinas que descienden desde un máximo de 3,840m. hasta los 900 m. en las márgenes del río Grande.

En nuestros pagos se dice que empezar una nueva revista es fácil. El mérito empieza cuando se logra sacar el número dos. La heroicidad está en llegar a cumplir los 20 años de publicación regular. Es el caso de Allpanchis, "Nuestra tierra". En estas páginas daré mis impresiones personales sobre una revista cuyo enfoque y temática andina rebalsa esas ficticias fronteras estatales que hoy parten el mundo andino. Quieren ser también un homenaje a una revista que siempre he guardado cerca, bien al alcance de la mano, y a quienes la hicieron y siguen haciendo posible.

Este trabajo es un análisis sociológico y antropológico de una de las principales celebraciones del tipo de peregrinación dentor de los valles de Cochabamba. En la literatura andina abundan las descripciones y análisis de fiestas y celebraciones rituales. Pero en la gran mayoría de los casos se trata de fiestas locales o regionales de tipo patronal, son menos frecuentes las descripciones de peregrinaciones, aunque no faltan algunas, como por ejemplo la de Ramírez (1969) sobre la novena de Qoyllur Rit'i cerca del Cusco. Hay partes de los andes en que las peregrinaciones son casi inexistentes, como por ejemplo entre los aymaras (Albó, en prensa).

In Bolivia, agricultural and forestry policies are more of redistributive nature, and it is difficult trying to understand the complexity of this type of production. In this respect, this chapter addresses agricultural and forestry public policies that operate in the Bolivian Amazon. In particular, we assessed how these policies affect campesinos’ livelihoods inhabiting the community of Trinchera. Our research used the Sustainable Livelihoods Approach as a multidisciplinary perspective as well as a qualitative scale to measure campesino families’ capitals. The results reveal that families possess a very high and high potential in natural and social capitals, whereas the human, physical and financial capitals are on a low and very low levels. Of five agricultural and forestry programs implemented in Trinchera, only two of them have a moderate contribution to the family capitals, and three of them have a low contribution. The human, financial and physical capitals have low values, which restricts the improvement of the families’ life strategies in the community. In order to achieve better livelihoods and quality of life, the community’s visions for the future are focused on achieving a very high and high level in their capitals supported by their natural capital. The community acknowledged that natural and social capitals are fundamental for the development of strategies and livelihoods of its families, and our study recorded that the programs currently implemented in the community do not contribute significantly in the improvement of their capitals. Consequently, we present a discussion indicating that achieving the community’s visions will depend not only on internal but also on external factors to the community.

The sensitivity of tropical forest carbon to climate is a key uncertainty in predicting global climate change. Although short-term drying and warming are known to affect forests, it is unknown if such effects translate into long-term responses. Here, we analyze 590 permanent plots measured across the tropics to derive the equilibrium climate controls on forest carbon. Maximum temperature is the most important predictor of aboveground biomass (−9.1 megagrams of carbon per hectare per degree Celsius), primarily by reducing woody productivity, and has a greater impact per °C in the hottest forests (>32.2°C). Our results nevertheless reveal greater thermal resilience than observations of short-term variation imply. To realize the long-term climate adaptation potential of tropical forests requires both protecting them and stabilizing Earth’s climate.

Competition among trees is an important driver of community structure and dynamics in tropical forests. Neighboring trees may impact an individual tree’s growth rate and probability of mortality, but large‐scale geographic and environmental variation in these competitive effects has yet to be evaluated across the tropical forest biome. We quantified effects of competition on tree‐level basal area growth and mortality for trees ≥10‐cm diameter across 151 ~1‐ha plots in mature tropical forests in Amazonia and tropical Africa by developing nonlinear models that accounted for wood density, tree size, and neighborhood crowding. Using these models, we assessed how water availability (i.e., climatic water deficit) and soil fertility influenced the predicted plot‐level strength of competition (i.e., the extent to which growth is reduced, or mortality is increased, by competition across all individual trees). On both continents, tree basal area growth decreased with wood density and increased with tree size. Growth decreased with neighborhood crowding, which suggests that competition is important. Tree mortality decreased with wood density and generally increased with tree size, but was apparently unaffected by neighborhood crowding. Across plots, variation in the plot‐level strength of competition was most strongly related to plot basal area (i.e., the sum of the basal area of all trees in a plot), with greater reductions in growth occurring in forests with high basal area, but in Amazonia, the strength of competition also varied with plot‐level wood density. In Amazonia, the strength of competition increased with water availability because of the greater basal area of wetter forests, but was only weakly related to soil fertility. In Africa, competition was weakly related to soil fertility and invariant across the shorter water availability gradient. Overall, our results suggest that competition influences the structure and dynamics of tropical forests primarily through effects on individual tree growth rather than mortality and that the strength of competition largely depends on environment‐mediated variation in basal area.

Higher levels of taxonomic and evolutionary diversity are expected to maximize ecosystem function, yet their relative importance in driving variation in ecosystem function at large scales in diverse forests is unknown. Using 90 inventory plots across intact, lowland, terra firme, Amazonian forests and a new phylogeny including 526 angiosperm genera, we investigated the association between taxonomic and evolutionary metrics of diversity and two key measures of ecosystem function: aboveground wood productivity and biomass storage. While taxonomic and phylogenetic diversity were not important predictors of variation in biomass, both emerged as independent predictors of wood productivity. Amazon forests that contain greater evolutionary diversity and a higher proportion of rare species have higher productivity. While climatic and edaphic variables are together the strongest predictors of productivity, our results show that the evolutionary diversity of tree species in diverse forest stands also influences productivity. As our models accounted for wood density and tree size, they also suggest that additional, unstudied, evolutionarily correlated traits have significant effects on ecosystem function in tropical forests. Overall, our pan-Amazonian analysis shows that greater phylogenetic diversity translates into higher levels of ecosystem function: tropical forest communities with more distantly related taxa have greater wood productivity. Inventory data from 90 lowland Amazonian forest plots and a phylogeny of 526 angiosperm genera were used to show that taxonomic and phylogenetic diversity are both predictive of wood productivity but not of biomass variation.

El cacao Amazónico Boliviano silvestre (Theobroma cacao) es una especie que crece de forma natural en los bosques, se caracteriza por ser único en sabor y aroma dentro de los grupos de cacaos más finos, por este motivo, y durante tres años consecutivos ha sido reconocido y seleccionado en el evento internacional “Salón du Chocolat” Paris Francia, entre los mejores cacaos del mundo, caracterizado por su aroma y sabor. Estas características son directamente relacionadas con el contenido de compuestos químicos tales como los polifenoles y metilxantinas. En la presente investigación se determinaron las características funcionales químicas del cacao Amazónico Boliviano tanto silvestre como cultivadas en parcelas agroforestales de la región amazónica de Bolivia. Se cuantificaron teobromina y catequina por cromatografía líquida de Alta resolución HPLC, la actividad antioxidante total (TAC) por por los métodos ABTS y FRAP y el contenido total de polifenoles (TPH), en muestras, de grano de cacao antes y después del proceso de fermentación. Los valores obtenidos en este estudio son relevantes y esta información servirá para realzar las características que hacen especial al cacao Amazónico Boliviano, incrementando además su valor.

Most of the planet's diversity is concentrated in the tropics, which includes many regions undergoing rapid climate change. Yet, while climate‐induced biodiversity changes are widely documented elsewhere, few studies have addressed this issue for lowland tropical ecosystems. Here we investigate whether the floristic and functional composition of intact lowland Amazonian forests have been changing by evaluating records from 106 long‐term inventory plots spanning 30 years. We analyse three traits that have been hypothesized to respond to different environmental drivers (increase in moisture stress and atmospheric CO2 concentrations): maximum tree size, biogeographic water‐deficit affiliation and wood density. Tree communities have become increasingly dominated by large‐statured taxa, but to date there has been no detectable change in mean wood density or water deficit affiliation at the community level, despite most forest plots having experienced an intensification of the dry season. However, among newly recruited trees, dry‐affiliated genera have become more abundant, while the mortality of wet‐affiliated genera has increased in those plots where the dry season has intensified most. Thus, a slow shift to a more dry‐affiliated Amazonia is underway, with changes in compositional dynamics (recruits and mortality) consistent with climate‐change drivers, but yet to significantly impact whole‐community composition. The Amazon observational record suggests that the increase in atmospheric CO2 is driving a shift within tree communities to large‐statured species and that climate changes to date will impact forest composition, but long generation times of tropical trees mean that biodiversity change is lagging behind climate change.

Species distribution models (SDMs) are widely used in ecology and conservation. Presence-only SDMs such as MaxEnt frequently use natural history collections (NHCs) as occurrence data, given their huge numbers and accessibility. NHCs are often spatially biased which may generate inaccuracies in SDMs. Here, we test how the distribution of NHCs and MaxEnt predictions relates to a spatial abundance model, based on a large plot dataset for Amazonian tree species, using inverse distance weighting (IDW). We also propose a new pipeline to deal with inconsistencies in NHCs and to limit the area of occupancy of the species. We found a significant but weak positive relationship between the distribution of NHCs and IDW for 66% of the species. The relationship between SDMs and IDW was also significant but weakly positive for 95% of the species, and sensitivity for both analyses was high. Furthermore, the pipeline removed half of the NHCs records. Presence-only SDM applications should consider this limitation, especially for large biodiversity assessments projects, when they are automatically generated without subsequent checking. Our pipeline provides a conservative estimate of a species' area of occupancy, within an area slightly larger than its extent of occurrence, compatible to e.g. IUCN red list assessments.

Quantifying the relationship between tree diameter and height is a key component of efforts to estimate biomass and carbon stocks in tropical forests. Although substantial site‐to‐site variation in height–diameter allometries has been documented, the time consuming nature of measuring all tree heights in an inventory plot means that most studies do not include height, or else use generic pan‐tropical or regional allometric equations to estimate height. Using a pan‐tropical dataset of 73 plots where at least 150 trees had in‐field ground‐based height measurements, we examined how the number of trees sampled affects the performance of locally derived height–diameter allometries, and evaluated the performance of different methods for sampling trees for height measurement. Using cross‐validation, we found that allometries constructed with just 20 locally measured values could often predict tree height with lower error than regional or climate‐based allometries (mean reduction in prediction error = 0.46 m). The predictive performance of locally derived allometries improved with sample size, but with diminishing returns in performance gains when more than 40 trees were sampled. Estimates of stand‐level biomass produced using local allometries to estimate tree height show no over‐ or under‐estimation bias when compared with biomass estimates using field measured heights. We evaluated five strategies to sample trees for height measurement, and found that sampling strategies that included measuring the heights of the ten largest diameter trees in a plot outperformed (in terms of resulting in local height–diameter models with low height prediction error) entirely random or diameter size‐class stratified approaches. Our results indicate that even limited sampling of heights can be used to refine height–diameter allometries. We recommend aiming for a conservative threshold of sampling 50 trees per location for height measurement, and including the ten trees with the largest diameter in this sample.

Living well, suma qamaña in Aymara or buen vivir in Spanish, is the fundamental moral logic that guides Aymara and other Andean cultures and has been incorporated into the Constitutions of Bolivia and Ecuador. A linguistic analysis shows that the conceptual root of suma qamaña (buen vivir or living well) is convivial gathering or community in which basic needs are met and relationships, which even extend to the earth, are harmonious. Living well implies a strong ethical component of valuing and appreciating the distinctiveness of others, as well as spirituality or lifestyle, and so can never be just economic. Since the human factor is always in the forefront, quantifiable economic scores cannot be the exclusive measure. Measurable indicators are required for determining the quality of social relations and of relations with nature, as well as for inter-cultural, inter-gender, and inter-whatever, that show the quality of these relationships, such as equitable reciprocity and convivial living. As a starting point, the best way perhaps will be for each people and culture to develop and make explicit their dearest living values (as has been done in Bolivia with suma qamaña) and, from these, to specify some of the desirable relationships of convivial living that indicate their being fulfilled or violated. Finally, living well is not possible if the inequalities of the general power structure are not faced and overcome.

Tropical forests are global centres of biodiversity and carbon storage. Many tropical countries aspire to protect forest to fulfil biodiversity and climate mitigation policy targets, but the conservation strategies needed to achieve these two functions depend critically on the tropical forest tree diversity-carbon storage relationship. Assessing this relationship is challenging due to the scarcity of inventories where carbon stocks in aboveground biomass and species identifications have been simultaneously and robustly quantified. Here, we compile a unique pan-tropical dataset of 360 plots located in structurally intact old-growth closed-canopy forest, surveyed using standardised methods, allowing a multi-scale evaluation of diversity-carbon relationships in tropical forests. Diversity-carbon relationships among all plots at 1 ha scale across the tropics are absent, and within continents are either weak (Asia) or absent (Amazonia, Africa). A weak positive relationship is detectable within 1 ha plots, indicating that diversity effects in tropical forests may be scale dependent. The absence of clear diversity-carbon relationships at scales relevant to conservation planning means that carbon-centred conservation strategies alone would inevitably miss many high diversity ecosystems. As tropical forests can have any combination of tree diversity and carbon stocks both will require explicit consideration when optimising policies to manage tropical carbon and biodiversity.

Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high diversity of angio-sperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic signal (PS) for all traits, consistent with evolu-tionarily related genera having more similar characteristics than expected by chance. Although there is also evidence for repeated evolution of pioneer and shade tolerant life-history strategies within independent lineages, the existence of significant PS allows clearer predictions of the links between evolutionary diversity, ecosystem function and the response of tropical forests to global change.

Understanding the processes that determine aboveground biomass (AGB) in Amazonian forests is important for predicting the sensitivity of these ecosystems to environmental change and for designing and evaluating dynamic global vegetation models (DGVMs). AGB is determined by inputs from woody productivity (woody NPP) and the rate at which carbon is lost through tree mortality. Here, we test whether two direct metrics of tree mortality (the absolute rate of woody biomass loss and the rate of stem mortality) and/or woody NPP, control variation in AGB among 167 plots in intact forest across Amazonia. We then compare these relationships and the observed variation in AGB and woody NPP with the predictions of four DGVMs. The observations show that stem mortality rates, rather than absolute rates of woody biomass loss, are the most important predictor of AGB, which is consistent with the importance of stand size-structure for determining spatial variation in AGB. The relationship between stem mortality rates and AGB varies among different regions of Amazonia, indicating that variation in wood density and height/diameter relationships also influence AGB. In contrast to previous findings, we find that woody NPP is not correlated with stem mortality rates, and is weakly positively correlated with AGB. Across the four models, basin-wide average AGB is similar to the mean of the observations. However, the models consistently overestimate woody NPP, and poorly represent the spatial patterns of both AGB and woody NPP estimated using plot data. In marked contrast to the observations, DGVMs typically show strong positive relationships between woody NPP and AGB. Resolving these differences will require incorporating forest size structure, mechanistic models of stem mortality and variation in functional composition in DGVMs. This article is protected by copyright. All rights reserved.

The Amazon Basin has experienced more variable climate over the last decade, with a severe and widespread drought in 2005 causing large basin-wide losses of biomass. A drought of similar climatological magnitude occurred again in 2010; however, there has been no basin-wide ground-based evaluation of effects on vegetation. We examine to what extent the 2010 drought affected forest dynamics using ground-based observations of mortality and growth utilizing data from an extensive forest plot network. We find that during the 2010 drought interval, forests did not gain biomass (net change: −0.43 Mg ha-1, CI: −1.11, 0.19, n = 97), regardless of whether forests experienced precipitation deficit anomalies. This loss contrasted with a long-term biomass sink during the baseline pre-2010 drought period (1998 − pre-2010) of 1.33 Mg ha-1 yr-1 (CI: 0.90, 1.74, p < 0.01). The resulting net impact of the 2010 drought (i.e., reversal of the baseline net sink) was −1.95 Mg ha-1 yr-1 (CI:−2.77, −1.18; p < 0.001). This net biomass impact was driven by an increase in biomass mortality (1.45 Mg ha-1 yr-1 CI: 0.66, 2.25, p < 0.001), and a decline in biomass productivity (−0.50 Mg ha-1 yr-1, CI:−0.78, −0.31; p < 0.001). Surprisingly, the magnitude of the losses through tree mortality was unrelated to estimated local precipitation anomalies, and was independent of estimated local pre-2010 drought history. Thus, there was no evidence that pre-2010 droughts compounded the effects of the 2010 drought. We detected a systematic basin-wide impact of drought on tree growth rates across Amazonia, with this suppression of productivity driven by moisture deficits in 2010, an impact which was not apparent during the 2005 event [Phillips et al., 2009]. Based on these ground data, both live biomass in trees and corresponding estimates of live biomass in roots, we estimate that intact forests in Amazonia were carbon neutral in 2010 (−0.07 PgC yr-1 CI:−0.42, 0.23), consistent with results from an independent analysis of airborne estimates of land-atmospheric fluxes during 2010 [Gatti et al., 2014]. Relative to the long-term mean, the 2010 drought resulted in a reduction in biomass carbon uptake of 1.1 PgC, compared to 1.6 PgC for the 2005 event [Phillips et al. 2009]. Continue reading full article Ancillary Supporting Information PDF Info The Amazon Basin has experienced more variable climate over the last decade, with a severe and widespread drought in 2005 causing large basin-wide losses of biomass. A drought of similar climatological magnitude occurred again in 2010; however, there has been no basin-wide ground-based evaluation of effects on vegetation. We examine to what extent the 2010 drought affected forest dynamics using ground-based observations of mortality and growth utilizing data from an extensive forest plot network. We find that during the 2010 drought interval, forests did not gain biomass (net change: −0.43 Mg ha-1, CI: −1.11, 0.19, n = 97), regardless of whether forests experienced precipitation deficit anomalies. This loss contrasted with a long-term biomass sink during the baseline pre-2010 drought period (1998 − pre-2010) of 1.33 Mg ha-1 yr-1 (CI: 0.90, 1.74, p < 0.01). The resulting net impact of the 2010 drought (i.e., reversal of the baseline net sink) was −1.95 Mg ha-1 yr-1 (CI:−2.77, −1.18; p < 0.001). This net biomass impact was driven by an increase in biomass mortality (1.45 Mg ha-1 yr-1 CI: 0.66, 2.25, p < 0.001), and a decline in biomass productivity (−0.50 Mg ha-1 yr-1, CI:−0.78, −0.31; p < 0.001). Surprisingly, the magnitude of the losses through tree mortality was unrelated to estimated local precipitation anomalies, and was independent of estimated local pre-2010 drought history. Thus, there was no evidence that pre-2010 droughts compounded the effects of the 2010 drought. We detected a systematic basin-wide impact of drought on tree growth rates across Amazonia, with this suppression of productivity driven by moisture deficits in 2010, an impact which was not apparent during the 2005 event [Phillips et al., 2009]. Based on these ground data, both live biomass in trees and corresponding estimates of live biomass in roots, we estimate that intact forests in Amazonia were carbon neutral in 2010 (−0.07 PgC yr-1 CI:−0.42, 0.23), consistent with results from an independent analysis of airborne estimates of land-atmospheric fluxes during 2010 [Gatti et al., 2014]. Relative to the long-term mean, the 2010 drought resulted in a reduction in biomass carbon uptake of 1.1 PgC, compared to 1.6 PgC for the 2005 event [Phillips et al. 2009].

Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict that most of the world's >40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century.

While Amazonian forests are extraordinarily diverse, the abundance of trees is skewed strongly towards relatively few 'hyperdominant' species. In addition to their diversity, Amazonian trees are a key component of the global carbon cycle, assimilating and storing more carbon than any other ecosystem on Earth. Here we ask, using a unique data set of 530 forest plots, if the functions of storing and producing woody carbon are concentrated in a small number of tree species, whether the most abundant species also dominate carbon cycling, and whether dominant species are characterized by specific functional traits. We find that dominance of forest function is even more concentrated in a few species than is dominance of tree abundance, with only E1% of Amazon tree species responsible for 50% of carbon storage and productivity. Although those species that contribute most to biomass and productivity are often abundant, species maximum size is also influential, while the identity and ranking of dominant species varies by function and by region.