Project highlights

  • Improve our understanding of the ecology of giant tropical trees (≥50 cm diameter), which play a disproportionate role in carbon cycling and ecosystem functioning. 
  • Development of foundational skills in ecological theory, fieldwork methods, and statistical analysis which will increase professional development and future employability; 
  • Improve the accuracy of global carbon dynamics modelling and learn from a global community of experts in tropical forest ecology, providing opportunities for creating a global network. 

Overview

Tropical forests play a fundamental role in mitigating climate change. They are responsible for 35% of the land carbon uptake and store over 60% of terrestrial biomass carbon, covering only 10% of land surface. The ability of tropical forests to sequester and store carbon is significantly influenced by the survival and growth of rare and large individual trees (≥50 cm diameter). These giant trees store more than 50% of biomass carbon in tropical forests, while accounting for just 1% of the total tree community, and have an important influence on local carbon, nutrient and water cycling. Moreover, they act as important determinants of local diversity, providing key structures and microenvironments for other species, which heavily depends on the giant tree species-specific characteristic such as crown architecture and formation of large cavities. 

Despite their importance, we know very little about the ecology, biogeography, and climate sensitivity of giant trees because they are naturally rare. Most of our current knowledge on tropical forest dynamics comes from sampling plots ranging between 1 – 50 ha, designed to capture the dynamics of stems greater than 10 cm in diameter. Because of their rarity, very few large trees are monitored within these plots, meaning that we lack even basic data about their ecology. Limited data suggest that environmental drivers of tree diversity and distribution are size-dependent, with abiotic drivers (droughts, wind and lightning) playing a greater role in the ecology of giant trees when compared to smaller ones. This hypothesis has great implications for how we model the future of tropical forest, but has not been tested.  

This project will build upon the infrastructure provided by the starting NERC/NSF-funded project Gigante to (1) develop a conceptual model based on the largest datasets of tropical forest dynamics (ForestPlots and ForestGEO) to quantify the specific mortality risk factors for giant trees at the Pantropical scale, (2) determine the local factors (including species-specific and environmental traits) driving the distribution and diversity of giant trees across five large (1500 ha) focal sites and (3) improve the identification of giant trees from satellite imagery at leaf-to-regional scales. 

At the top three photographs showing giant tropical trees which have been killed by wind, drought and lightning. At the bottom a map of the world showing the proposed study sites for data collection.

Figure 1: Giant tropical trees with distinct causes of death: wind (A), drought (B), lightning (C). Map of proposed study sites for data collection (D).  

CENTA Flagship

This is a CENTA Flagship Project

Case funding

This project is suitable for CASE funding

Host

University of Birmingham

Theme

  • Climate and Environmental Sustainability
  • Organisms and Ecosystems

Supervisors

Project investigator

Dr Adriane Esquivel-Muelbert (University of Birmingham) [email protected] 

Co-investigators

Dr Evan Gora (Cary Institute of Ecosystem Studies) [email protected] 

Dr Flávia Costa (National Institute of Amazonian Research) [email protected] 

Dr Lindsay F Banin (UK Centre for Ecology & Hydrology) [email protected]  

Dr Helene Müller-Landau (Smithsonian Tropical Research Institute) [email protected] 

How to apply

Methodology

The PhD student will build a conceptual mortality risk model for giant trees and then evaluate its efficacy in predicting mortality risk for trees of different sizes using integrated data from long-term tropical forest inventory plots (ForestPlots and ForestGEO).  

The student will use inventory plots and large-scale field surveys within the five key Gigante focal sites (Central America, Southern Amazonia, Central Amazonia, Eastern Asia, and Western Africa) to establish the environmental and species-specific traits driving the local diversity and distribution of giant trees. During these field surveys, the student will also collect leaf spectral information to link ground data and satellite imagery to improve giant tree identification at larger scales.  

All the data collected, and the insights developed throughout this PhD project can be integrated into the broader framework of the Gigante project, which will contribute towards the funding of the fieldwork of the PhD. 

Training and skills

Students will be awarded CENTA2 Training Credits (CTCs) for participation in CENTA2-provided and ‘free choice’ external training. One CTC equates to 1⁄2 day session and students must accrue 100 CTCs across the three years of their PhD.  

Training will encompass statistical techniques to link large datasets with locally collected trait data and to integrate remote sensing with ground-based information facilitating the spectral identification of giant trees’ species. It will also support the development of fieldwork skills in tropical forests.  

Working within the diverse team including the University of Birmingham, the Cary Institute, INPA, UKCEH, and research teams at each study site will develop the candidate’s team working skills. This will improve access to local expertise across the tropics and establish international connections for future collaborations. 

Partners and collaboration

The partners are lead scientists in Tropical Forest Ecology with a range of expertise: Dr Gora (Cary Institute/ US-PI of Gigante) specialises in tropical tree mortality with extensive field experience and spearheading research revealing lightning as a major cause of giant tree death. Dr Costa (INPA) investigates the vulnerability of tropical forests to drought and specialises in soil-water availability. Dr Banin (UKCEH) contributed to our understanding of the biogeography of giant trees, with vast experience in the Ecology of forests in Southeast Asia. Dr Müller-Landau (STRI) is a pioneer in the remote monitoring of tropical forests via drones and satellites.  

Further details

Further details on how to contact the supervisor for this project and how to apply for this project can be found here: 

For any enquiries related to this project please contact Dr Adriane Esquivel-Muelbert, [email protected] . 

To apply to this project: 

  • You must include a CENTA studentship application form, downloadable from: CENTA Studentship Application Form 2024. 
  • You must include a CV with the names of at least two referees (preferably three) who can comment on your academic abilities. 
  • Please submit your application and complete the host institution application process via: https://sits.bham.ac.uk/lpages/LES068.htm.   Please select the PhD Geography and Environmental Science (CENTA) 2024/25 Apply Now button. The CENTA application form 2024 and CV can be uploaded to the Application Information section of the online form.  Please quote CENTA 2024-B14  when completing the application form. 

Applications must be submitted by 23:59 GMT on Wednesday 10th January 2024. 

Please find further details for the main partners of this project below: 

https://www.caryinstitute.org/news-insights/feature/whats-killing-giant-tropical-trees-17m-awards-cary-institute-led-team-aims 

https://www.birmingham.ac.uk/schools/gees/people/profile.aspx?ReferenceId=188393&Name=dr-adriane-esquivel-muelbert 

https://www.caryinstitute.org/science/our-scientists/dr-evan-gora  

Possible timeline

Year 1

Literature review, design of hypotheses and methodology. Training in statistical analysis of large inventory datasets, first analyses and first draft of chapter 1. Pilot field survey in the Gigante focal site in Central Amazon to collect species traits of the most frequent giant tree species, including spectroscopy. 

Year 2

Field campaigns in the other remaining Gigante focal sites (Panama, Southern Amazon, Malaysia and Gabon). Finalize chapter 1. Statistical analysis of compiled database and field-collected data, write draft of chapter 2.

Year 3

Receive in-person training at the Cary Institute. Finalize chapter 2, perform analyses linking ground data and remote sensing, and write chapter 3.

Further reading

  1. Buitrago, M. F. et al. (2018) ‘Connecting infrared spectra with plant traits to identify species’, ISPRS Journal of Photogrammetry and Remote Sensing. International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS), 139, pp. 183–200. doi: 10.1016/j.isprsjprs.2018.03.013. 
  2. Durgante, F. M. et al. (2013) ‘Species Spectral Signature: Discriminating closely related plant species in the Amazon with Near-Infrared Leaf-Spectroscopy’, Forest Ecology and Management, 291, pp. 240–248. doi: 10.1016/j.foreco.2012.10.045. 
  3. Enquist, B. J. et al. (2020) ‘The megabiota are disproportionately important for biosphere functioning’, Nature Communications. Springer US, 11(1), pp. 1–11. doi: 10.1038/s41467-020-14369-y. 
  4. Esquivel-Muelbert, A. et al. (2020) ‘Tree mode of death and mortality risk factors across Amazon forests’, Nature Communications. Nature Research, 11(1). doi: 10.1038/s41467-020-18996-3. 
  5. Gora, E. M. and Esquivel-Muelbert, A. (2021) ‘Implications of size-dependent tree mortality for tropical forest carbon dynamics’, Nature Plants. Springer US, 7(4), pp. 384–391. doi: 10.1038/s41477-021-00879-0. 
  6. de Lima, R. B. et al. (2023) ‘Giants of the Amazon: How does environmental variation drive the diversity patterns of large trees?’, Global Change Biology, (June), pp. 1–19. doi: 10.1111/gcb.16821. 
  7. Lindenmayer, D. B., Laurance, W. F. and Franklin, J. F. (2012) ‘Ecology: Global decline in large old trees’, Science, 338(6112), pp. 1305–1306. doi: 10.1126/science.1231070.