Browsing by Autor "Martin J. P. Sullivan"

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Author Correction: Tree mode of death and mortality risk factors across Amazon forests
(Nature Portfolio, 2021) Adriane Esquivel‐Muelbert; Oliver L. Phillips; Roel Brienen; Sophie Fauset; Martin J. P. Sullivan; Timothy R. Baker; Kuo‐Jung Chao; Ted R. Feldpausch; Emanuel Gloor; Níro Higuchi
Consistent patterns of common species across tropical tree communities
(Nature Portfolio, 2024) Declan L. M. Cooper; Simon L. Lewis; Martin J. P. Sullivan; Paulo Inácio Prado; Hans ter Steege; Nicolas Barbier; Ferry Slik; Bonaventure Sonké; Corneille E. N. Ewango; Stephen Adu‐Bredu
Trees structure the Earth's most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations<sup>1-6</sup> in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth's 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories<sup>7</sup>, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world's most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees.
Diversity and carbon storage across the tropical forest biome
(Nature Portfolio, 2017) Martin J. P. Sullivan; Joey Talbot; Simon L. Lewis; Oliver L. Phillips; Lan Qie; Serge K. Begne; Jérôme Chave; Aida Cuní‐Sanchez; Wannes Hubau; Gabriela López‐González
Evolutionary diversity is associated with wood productivity in Amazonian forests
(Nature Portfolio, 2019) Fernanda Coelho de Souza; Kyle G. Dexter; Oliver L. Phillips; R. Toby Pennington; Danilo M. Neves; Martin J. P. Sullivan; Esteban Álvarez‐Dávila; Atila Indalecio Marques Alves; Iêda Leão do Amaral; Ana Andrade
Field methods for sampling tree height for tropical forest biomass estimation
(Wiley, 2018) Martin J. P. Sullivan; Simon L. Lewis; Wannes Hubau; Lan Qie; Timothy R. Baker; Lindsay F. Banin; Jérôme Chave; Aida Cuní‐Sanchez; Ted R. Feldpausch; Gabriela López‐González
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.
Long-term thermal sensitivity of Earth’s tropical forests
(American Association for the Advancement of Science, 2020) Martin J. P. Sullivan; Simon L. Lewis; Kofi Affum‐Baffoe; Carolina V. Castilho; Flávia R. C. Costa; Aida Cuní‐Sanchez; Corneille E. N. Ewango; Wannes Hubau; Beatriz Schwantes Marimon; Abel Monteagudo‐Mendoza
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.
Tree mode of death and mortality risk factors across Amazon forests
(Nature Portfolio, 2020) Adriane Esquivel‐Muelbert; Oliver L. Phillips; Roel Brienen; Sophie Fauset; Martin J. P. Sullivan; Timothy R. Baker; Kuo‐Jung Chao; Ted R. Feldpausch; Emanuel Gloor; Níro Higuchi
Variation in wood density across South American tropical forests
(Nature Portfolio, 2025) Martin J. P. Sullivan; Oliver L. Phillips; David Galbraith; Everton Cristo de Almeida; Edmar Almeida de Oliveira; Jarcilene Silva de Almeida‐Cortez; Esteban Álvarez‐Dávila; Luciana F. Alves; Ana Andrade; Luiz E. O. C. Aragão