Supervisors
Brief Summary
How are forests respond to water stress driven by climate change? We already know from forest inventory studies that the mortality of large trees is increasing, but these studies sample just a tiny fraction of forests. Airborne laser scanning is a remarkable technology for mapping the 3D structure of forest canopies at high resolution over large spatial scales. This project will use repeated lidar surveys, alongside traditional field surveys, to map tree mortality and thereby improve understanding of the resilience of forest to climate change.
Importance of Research
Forest planting and proforestation - the protection and restoration of natural forests - are seen as key natural climate solutions. Forests already sequester a significant fraction of CO2 emitted from fossil fuel consumption and many governments have committed to increase forest cover to combat climate change. There is also hope that carbon offsetting payments could help protect beleaguered tropical forests, benefit local livelihoods and save biodiversity. However, raising air temperatures are responsible for increased evaporative demand, placing forest under water stress and leading to tree mortality in many regions. How does this increased mortality affect the global carbon sink and how should forest management adapt to ensure the right trees are planted in the right places to tolerate future climates? A combination of field measurements, remote sensing and modelling are needed to resolve these important issues.
Project Summary
The Coomes group has developed approaches to track changes in forest aboveground carbon at high resolution - down to individual trees - over large spatial scales (see publications). The best approach is to conduct repeated lidar surveys, but airborne photogrammetry and satellite imagery can also be used. The project involves working with an emerging global network of partners to understand how climate change is affecting tree survival by analysing some of these datasets. This remote sensing work will be accompanied by detailed fieldwork in plantations and natural forests to understand the consequences climate change on forest carbon dynamics, including belowground changes.
What will the successful applicant do?
- Review the rapidly advancing literature on repeat lidar surveying of forests
- Work with an emerging network of researchers interested in tracking forest change using high-resolution imagery in selected sites to identify sites for analysis
- Use approaches developed in Cambridge to detect tree mortality and track carbon dynamics over forested landscapes and understand landscape level processes influencing mortality (e.g. topographic position)
- Work in selected field sites to calibrate/validate the remote sensing analyses and collect auxiliary data (e.g. forest soil carbon and tree rings)
- By comparing changes across different sites, generate new knowledge on forest carbon responses to climate change
References
- Wedeux, B. et al. (2020) Dynamics of a Human‐modified Tropical Peat Swamp Forest Revealed by Repeat Lidar Surveys. Global Change Biology. 26 (7), 3947-3964, doi:10.1111/gcb.15108
- Jucker, T. et al. (2018) Estimating Aboveground Carbon Density and Its Uncertainty in Borneo's Structurally Complex Tropical Forests Using Airborne Laser Scanning. Biogeosciences 15 (12), 3811–3830. doi:10.5194/bg-15-3811-2018.
- Nunes et al. (2021) Recovery of Logged Forest Fragments in a Human-modified Tropical Landscape. Nature Communications 12 (1526). doi:10.1038/s41467-020-20811-y
For details on how to apply to the Cambridge NERC Doctoral Training Partnerships see here.