Wood density is a critical control on tree biomass, so poor understanding of its spatial variation can lead to large and systematic errors in forest biomass estimates and carbon maps. The need to understand how and why wood density varies is especially critical in tropical America where forests have exceptional species diversity and spatial turnover in composition. As tree identity and forest composition are challenging to estimate remotely, ground surveys are essential to know the wood density of trees, whether measured directly or inferred from their identity. Here, we assemble an extensive dataset of variation in wood density across the most forested and tree-diverse continent, examine how it relates to spatial and environmental variables, and use these relationships to predict spatial variation in wood density over tropical and sub-tropical South America. Our analysis refines previously identified east-west Amazon gradients in wood density, improves them by revealing fine-scale variation, and extends predictions into Andean, dry, and Atlantic forests. The results halve biomass prediction errors compared to a naïve scenario with no knowledge of spatial variation in wood density. Our findings will help improve remote sensing-based estimates of aboveground biomass carbon stocks across tropical South America.

Understanding how the traits of lineages are related to diversification is key for elucidating the origin of variation in species richness. Here, we test whether traits are related to species richness among lineages of trees from all major biogeographical settings of the lowland wet tropics. We explore whether variation in mortality rate, breeding system and maximum diameter are related to species richness, either directly or via associations with range size, among 463 genera that contain wet tropical forest trees. For Amazonian genera, we also explore whether traits are related to species richness via variation among genera in mean species-level range size. Lineages with higher mortality rates—faster life-history strategies—have larger ranges in all biogeographic settings and have higher mean species-level range sizes in Amazonia. These lineages also have smaller maximum diameters and, in the Americas, contain dioecious species. In turn, lineages with greater overall range size have higher species richness. Our results show that fast life-history strategies influence species richness in all biogeographic settings because lineages with these ecological strategies have greater range sizes. These links suggest that dispersal has been a key process in the evolution of the tropical forest flora.

The vegetation composition in green areas plays an important role in obtaining ecosystem benefits within these spaces. Therefore, this research aimed to characterize the floristic and phytosociological composition of the tree canopy in the squares of Santarém, Pará. To achieve this, a floristic survey was conducted in 38 squares, considering trees with a height greater than 1.5 m. Taxonomic and phytogeographical information of the trees was identified, and phytosociological parameters such as frequency (AF and RF), density (AD and RD), dominance (ADo and ADr), cover value index (CVI), importance value index (IVI), and Shannon-Wiener diversity index (H') were evaluated. A total of 686 trees were identified, with 54.60% of them being native species of Brazil and 45.40% exotic to the country. The Fabaceae family stood out with the highest number of species (19), while Anacardiaceae had the highest number of individuals (219). The species with the highest Af and Rf were Mangifera indica (78.95 - 14.71%) and Moquilea tomentosa (43.74 - 8.33%), and for Da and Dr, Mangifera indica (10.51 - 27.16 ind/ha) and Azadirachta indica (4.72 - 12.21 ind/ha) were prominent. In terms of DoA and DoR, Mangifera indica (7.85 - 48.48 m2/ha) and Spondias mombin (1.67-10.32 m2/ha) were highlighted. In IVI, M. indica also stood out (90.34%). The overall H' for the squares was 2.85, with Parque da Cidade (2.85) and Jati (2.23) squares being the most prominent. Only two squares showed moderate to high diversity (H' > 2.22). The floristic composition is predominantly composed of exotic individuals (54.60%), especially the species M. indica.

Tree growth and longevity trade-offs fundamentally shape the terrestrial carbon balance. Yet, we lack a unified understanding of how such trade-offs vary across the world’s forests. By mapping life history traits for a wide range of species across the Americas, we reveal considerable variation in life expectancies from 10 centimeters in diameter (ranging from 1.3 to 3195 years) and show that the pace of life for trees can be accurately classified into four demographic functional types. We found emergent patterns in the strength of trade-offs between growth and longevity across a temperature gradient. Furthermore, we show that the diversity of life history traits varies predictably across forest biomes, giving rise to a positive relationship between trait diversity and productivity. Our pan-latitudinal assessment provides new insights into the demographic mechanisms that govern the carbon turnover rate across forest biomes.

Agroforestry systems (AFS) represent an alternative production method for family farmers, allowing for the optimization of land use through product diversity and income generation. Considering that the socioeconomic condition of floodplain communities is based on extractive economies and that the implementation of intercropped crops should be done in a participatory and constructive manner, this work aims to report an experience emphasizing the steps and main tools adopted in the planning and establishment of an AFS. The fieldwork was conducted in the community of Ipaupixuna, in the floodplain region of Lake Maic´ a, municipality of Santar´em, Par´ a, Brazil. The actions of this work were concentrated between February and October 2019, as part of the research project ”Floodplains and Riverbanks of the Lower Amazon.” The main tools used in this work were a systemic approach with the community of Ipaupixuna, which sought to understand the environment and its interactions, through various stages such as mapping, workshops, interviews, planning, area preparation, and logistical organization for implementation. The actions and results of the project showed that participatory planning and community knowledge are crucial for the successful establishment of an AFS in communities. It was concluded that the community embraced the intercropping project and showed interest and collaboration in the activities carried out. This work reinforces the need to consider resources and tools for the necessary mapping and development of appropriate agroforestry designs for producers in similar initiatives.

Tropical forests face increasing climate risk 1 , 2 , yet our ability to predict their response to climate change is limited by poor understanding of their resistance to water stress. Although xylem embolism resistance thresholds (for example, 50 ) and hydraulic safety margins (for example, HSM 50 ) are important predictors of drought-induced mortality risk 3 – 5 , little is known about how these vary across Earth’s largest tropical forest. Here, we present a pan-Amazon, fully standardized hydraulic traits dataset and use it to assess regional variation in drought sensitivity and hydraulic trait ability to predict species distributions and long-term forest biomass accumulation. Parameters 50 and HSM 50 vary markedly across the Amazon and are related to average long-term rainfall characteristics. Both 50 and HSM 50 influence the biogeographical distribution of Amazon tree species. However, HSM 50 was the only significant predictor of observed decadal-scale changes in forest biomass. Old-growth forests with wide HSM 50 are gaining more biomass than are low HSM 50 forests. We propose that this may be associated with a growth–mortality trade-off whereby trees in forests consisting of fast-growing species take greater hydraulic risks and face greater mortality risk. Moreover, in regions of more pronounced climatic change, we find evidence that forests are losing biomass, suggesting that species in these regions may be operating beyond their hydraulic limits. Continued climate change is likely to further reduce HSM 50 in the Amazon 6 , 7 , with strong implications for the Amazon carbon sink.

A fava arara é uma espécie florestal muito importante para o bioma brasileiro, bem como para a indústria madeireira. O presente trabalho teve como objetivo testar tratamentos pré-germinativos em sementes dessa espécie. Os tratamentos foram constituídos por: testemunha, escarificação química com Ácido Sulfúrico a 10 min (H2SO4), escarificação térmica (10 min a 100°C) e escarificação mecânica com lixa. Dentre os tratamentos, a escarificação ácida e a escarificação mecânica demonstraram maior potencial para a superação de dormência.

Aim Water availability is the major driver of tropical forest structure and dynamics. Most research has focused on the impacts of climatic water availability, whereas remarkably little is known about the influence of water table depth and excess soil water on forest processes. Nevertheless, given that plants take up water from the soil, the impacts of climatic water supply on plants are likely to be modulated by soil water conditions. Location Lowland Amazonian forests. Time period 1971-2019. Methods We used 344 long-term inventory plots distributed across Amazonia to analyse the effects of long-term climatic and edaphic water supply on forest functioning. We modelled forest structure and dynamics as a function of climatic, soil-water and edaphic properties. Results Water supplied by both precipitation and groundwater affects forest structure and dynamics, but in different ways. Forests with a shallow water table (depth <5 m) had 18% less above-ground woody productivity and 23% less biomass stock than forests with a deep water table. Forests in drier climates (maximum cumulative water deficit < -160 mm) had 21% less productivity and 24% less biomass than those in wetter climates. Productivity was affected by the interaction between climatic water deficit and water table depth. On average, in drier climates the forests with a shallow water table had lower productivity than those with a deep water table, with this difference decreasing within wet climates, where lower productivity was confined to a very shallow water table. Main conclusions We show that the two extremes of water availability (excess and deficit) both reduce productivity in Amazon upland (terra-firme) forests. Biomass and productivity across Amazonia respond not simply to regional climate, but rather to its interaction with water table conditions, exhibiting high local differentiation. Our study disentangles the relative contribution of those factors, helping to improve understanding of the functioning of tropical ecosystems and how they are likely to respond to climate change.

O objetivo do trabalho foi analisar a diversidade de espécies utilizadas na arborização urbana do bairro Liberdade, município de Santarém, PA. Para isso, foi realizado um inventário de 100% utilizando uma planilha estruturada e, posteriormente, realizada um levantamento das espécies arbóreas e a diversidade florística do bairro, utilizando o Índice de Diversidade de Shannon-Weiner (H´). O bairro Liberdade apresenta alta diversidade de espécies, porém, é notório a abundância de espécies exóticas, má distribuídas no bairro, característica de um planejamento inadequado de arborização.

O conhecimento sobre as espécies vegetais com destaque no âmbito social e produtivo para as comunidades amazônicas pode auxiliar na elaboração de projetos mais adequados à realidade local. Assim, com a finalidade de contribuir para a sistematização de informação sobre características sociais e, ainda, abordar espécies com aptidão regional para introdução em cultivos consorciados, este estudo teve por objetivo realizar um levantamento de aspectos socioprodutivos, por meio de entrevistas com questionários semiestruturados, com ênfase nas espécies vegetais de importância para cultivo e extrativismo nas atividades familiares e espécies de interesse para cultivo em sistemas agroflorestais. O levantamento foi realizado na comunidade indígena de Ipaupixuna, Santarém, Pará. A pesquisa mostrou que a dinâmica local se baseia em famílias populosas com atividade econômica alicerçada em ocupações agroextrativistas, onde as espécies vegetais de uso alimentar, em especial com a produção de frutos, são protagonistas nas escolhas para cultivo ou extrativismo na comunidade. O levantamento fornece subsídios para a escolha de espécie para cultivo que apresentaram importância e que poderão subsidiar propostas de sistemas agroflorestais mais adequados as demandas e aptidões locais.

O mogno africano vem se destacando no Brasil em plantios comercias. Neste trabalho objetivou-se avaliar o desenvolvimento inicial de mudas de mogno africano em diferentes tipos de substrato. Foi utilizado delineamento inteiramente casualizado e quatro tratamentos para o crescimento das plântulas: terra preta, fibra de coco, fibra de coco associada a terra preta em proporção 1:1 e casca de arroz carbonizada associada a terra preta em proporção 1:1.Verificou-se que os tratamentos mais adequados ao desenvolvimento de mudas de são: terra preta, fibra de coco e fibra de coco associada a terra preta em proporção 1:1.

O objetivo deste estudo foi avaliar o potencial de germinação da Enterolobiumschomburgkii sob diferentes tratamentos. As sementes foram submetidas a 4 tratamentos, sendo o tratamento testemunha, escarificação química com ácido sulfúrico (H₂SO₄) 98%, escarificação térmica por 10 minutos a 100ºC e escarificação mecânica com lixa. Os tratamentos mais indicados são a escarificação química com ácido sulfúrico e a escarificação mecânica com lixa, pois apresentaram maior taxa de germinação quando comparados ao tratamento testemunha. Não se recomenda o tratamento com escarificação térmica por 10 minutos a 100ºC pois não houve germinação das sementes submetidas a este.

O mogno brasileiro é uma espécie encontrada naturalmente na região amazônica. Por apresentar alto valor comercial sofreu intensa extração de suas matrizes, sendo atualmente protegida por lei. O objetivo do estudo foi avaliar o tempo de armazenamento e a germinação em diferentes condições ambientais. Utilizou o delineamento inteiramente casualizado (DIC) com o controle e dois tratamentos caracterizados pelos diferentes ambientes, câmara úmida e geladeira. Os resultados mostraram que o armazenamento em câmara úmida apresentou melhor desempenho em relação a geladeira, entretanto, o dado teve decréscimo relevante em relação ao controle.

Gombeira (Swartzia Laurifolia Benth.) é uma espécie florestal muito importante para a flora brasileira, bem como para a indústria madeireira. O presente trabalho teve como objetivo testar tratamentos pré-germinativos em sementes com e sem cascas dessa espécie. Os tratamentos foram constituídos por: testemunho/controle em areia, sementes com casca em substrato vermiculita e sementes sem casca em substrato vermiculita. F. Após as análises estatísticas usando o teste não paramétrico de Kruskal-Wallis à 95% de confiança foi possível verificar que dentre os 3 tratamentos a submissão de sementes sem casas ao substrato vermiculita foi o que apresentou um melhor resultado.

Este trabalho tem como objetivo caracterizar o estado atual da arborização urbana no bairro Laguinho, na cidade de Santarém, Pará. A diversidade florística foi analisada através do Índice de Diversidade de Shannon-Weiner (H’). Foram encontradas 174 árvores referentes a 36 espécies compondo a arborização do bairro Laguinho. O valor encontrado para a diversidade avaliada através do Índice de Shannon-Weiner foi 3,0, que é um bom valor quando comparado a outros estudos. Apesar disso, é necessário a adoção de um plano diretor municipal para arborização adequado e efetivo.

A Copaifera martii (Hayne) faz parte da família botânica Fabaceae, e apresenta dormência tegumentar. Neste trabalho objetivou-se avaliar a resposta de sementes de Copaifera martii (Hayne) submetidas a diferentes tipos de tratamentos. Os tratamentos testadosforam: testemunho controle, escarificação química com ácido sulfúrico (H2SO4), escarificação térmica de 10 min a 100 ºC e escarificação mecânica com lixa. Os melhores resultados para a superação da dormência de sementes de Copaifera martii (Hayne) foram escarificação mecânica e escarificação química em ácido sulfúrico.

Tropical forests are the most diverse and productive ecosystems on Earth. While better understanding of these forests is critical for our collective future, until quite recently efforts to measure and monitor them have been largely disconnected. Networking is essential to discover the answers to questions that transcend borders and the horizons of funding agencies. Here we show how a global community is responding to the challenges of tropical ecosystem research with diverse teams measuring forests tree-by-tree in thousands of long-term plots. We review the major scientific discoveries of this work and show how this process is changing tropical forest science. Our core approach involves linking long-term grassroots initiatives with standardized protocols and data management to generate robust scaled-up results. By connecting tropical researchers and elevating their status, our Social Research Network model recognises the key role of the data originator in scientific discovery. Conceived in 1999 with RAINFOR (South America), our permanent plot networks have been adapted to Africa (AfriTRON) and Southeast Asia (T-FORCES) and widely emulated worldwide. Now these multiple initiatives are integrated via ForestPlots.net cyber-infrastructure, linking colleagues from 54 countries across 24 plot networks. Collectively these are transforming understanding of tropical forests and their biospheric role. Together we have discovered how, where and why forest carbon and biodiversity are responding to climate change, and how they feedback on it. This long-term pan-tropical collaboration has revealed a large long-term carbon sink and its trends, as well as making clear which drivers are most important, which forest processes are affected, where they are changing, what the lags are, and the likely future responses of tropical forests as the climate continues to change. By leveraging a remarkably old technology, plot networks are sparking a very modern revolution in tropical forest science. In the future, humanity can benefit greatly by nurturing the grassroots communities now collectively capable of generating unique, long-term understanding of Earth's most precious forests.

A Correction to this paper has been published: https://doi.org/10.1038/s41467-020-20537-x

Aim Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change. Location Tropical and subtropical moist forests. Time period Current. Major taxa studied Palms (Arecaceae). Methods We assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., >= 10 cm diameter at breast height) abundance relative to co-occurring non-palm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure. Results On average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of long-term climate stability. Life-form diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many non-tree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of above-ground biomass, but the magnitude and direction of the effect require additional work. Conclusions Tree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests.