University College London (UCL) research has generated new 3D measurements of trees to improve calculations of forest carbon stocks and validate new space-based observations from NASA and the European Space Agency.
Issue
There is significant uncertainty around the response of trees and forests to climate disturbance due to the difficulty of measuring the size and mass of trees, particularly in the tropics. The best global maps of forest biomass rely on extrapolating data from a very small sample of trees that have been harvested and weighed to estimate the total pan-tropical count of 3 trillion trees.
Approach
Geographers at UCL, drawing on expertise in observational methods, models, and ecological applications, developed a new approach to ‘weighing’ trees using Terrestrial Laser Scanning (TLS). This provides detailed 3D measurements of tree size, mass, and structure and is changing the way forest carbon is measured from the ground and from satellites.
Impact
NASA and European Space Agency space missions have used the TLS methods, for example, in NASA’s Global Ecosystem Dynamics Investigation (GEDI) mission. GEDI measures the height and structure of forests, helping quantify their role in global climate and global biodiversity.
The research has changed international policy guidelines for national greenhouse gas inventory reporting, provided by the United National Intergovernmental Panel on Climate Change (IPCC). The work is citied by the IPCC Good Practice Guidelines (GPG) as a transformative approach, and has led to direct change in IPCC GPG policy recommendations which help to meet the COP21 Paris Agreement targets.
While the importance of urban forests for climate resilience, health, and wellbeing is clear, this work shows that urban forests are likely to be undervalued by urban planning policymakers and practitioners. Tools have been developed to assist the UK charity Trees for Cities in monitoring the success of their planting projects. Since 1999, they had been unable to assess the health of 20 woodlands in London.
The research has reached a large public audience, raising awareness of the value of trees through television programmes, press coverage, and a major design exhibition at the V&A. Data have also been used by charities and policymakers to demonstrate the value of trees, for example, the Friends of the Earth’s campaign ‘More Trees Please’.
More information
Institution: University College London
Researchers: Professor Mathias Disney, Professor Philip Lewis, Dr Phil Wilkes, Dr Andrew Burt