Weighing trees with lasers

UK Research and Innovation Fund

ECI lead: Professor Yadvinder Malhi

Weighing trees with lasers: reducing uncertainty in tropical forest biomass and allometry is a project led by UCL to scan tropical forests using laser instruments to measure carbon and forest structure.

Our work

The project showed that our new approach to measuring forest biomass (weighing trees), particularly in the tropics, can provide much improved estimates of forest carbon stocks. We have also found that current estimates appear to be an underestimate of perhaps as much as 20%. This has potentially important implications for scientific understanding of tropical forest C budgets and climate, as well as for policies aimed at protecting these forests through investment in keeping C locked up and reducing deforestation.

We have also shown via destructive harvesting, that tree mass in forests is distributed in a different way than previous assumptions. This is likely to have implications for our understanding of the way trees operate in forests under changing climate and disturbance. We have developed a new analysis of the uncertainties that underpin current allometric estimates, based on this work, which in turn will allow better estimates of tropical forest biomass.

We have demonstrated the benefits of using new laser-based methods compared with current models, and shown where the weaknesses in those models lie. We have shown that there are major uncertainties in our current knowledge of the carbon stored in large trees and carbon-dense forests, and we have proposed ways to address these problems.

We have provided new evidence that tree structure does not adhere to the assumptions made in current models, with significant implications for how we measure forest carbon in the future. We have developed theoretical and empirical evidence to provide guidance on how satellite data can be used more effectively to address these issues.