View presentation: Weighing trees with lasers
Speaker: Dr Mathias Disney, Senior Lecturer in Remote Sensing, UCL Department of Geography
Measuring forest structure – the size and location of leaves, branches and trunks – allows us to estimate the amount of biomass stored in a forest. This is a key property as it indicates the size and variability of forests as a store (and flux) of atmospheric CO2. Our current best estimates of forest C stocks are based on empirical extrapolations of the masses of a small number of trees that have been destructively harvested. Due to the difficulty of weighing trees, these measurements are also heavily biased towards smaller, non-tropical trees. As a result our knowledge of forest C stocks are highly uncertain. Mathias will show how new observations, using lasers in particular, are providing us with a new way to estimate the mass of trees. These measurements also provide a wealth of other information that allows us to build new 3D models to better exploit satellite and airborne observations and explore theories of metabolic scaling. He will also show how these highly-detailed 3D models, based on film industry animation techniques, can give us a ‘virtual laboratory’ for testing simpler models and methods, and are being used for a variety of applications. He will present results from recent tropical expeditions in Africa, Australia and Brazil, as well as a new view of the English oak, a bit closer to home.
Mathias is a senior lecturer in Remote Sensing in the Department of Geography and member of the Environmental Monitoring and Modelling Group. He is also a member of the NERC National Centre for Earth Observation (NCEO), and is funded through the Carbon Cycle theme. He was also involved in the precursor NERC Centre for Terrestrial Carbon Dynamics. His background was a BSc in physics, followed by UCL MSc in remote sensing. He then studied radiative transfer modelling of crop canopies for his PhD, using detailed 3D models to explore the information content of moderate resolution satellite data, to test simpler models and validate new (at the time!) satellite albedo products based on these simpler approaches. This led to work with NASA colleagues on the MODIS BRDF/albedo product, amongst other things