Laser scanning accurately ’weighs’ trees

A terrestrial laser scanning technique that allows the structure of vegetation to be 3D-mapped to the millimetre is more accurate in determining the biomass of trees and carbon stocks in forests than current methods, according to new research involving UCL. The research paper, an international collaboration led by Wageningen University, is published today in Methods in Ecology and Evolution and demonstrates the technique in Australian forests. The study authors believe it could be an important development in the monitoring of carbon stocks for worldwide climate policy-making. Both above-ground biomass and carbon stocks are important details for UN-REDD, the United Nations initiative on Reducing Emissions from Deforestation and forest Degradation that is striving to keep the destruction of forests in check and thereby preserve the uptake of carbon by trees. Paper co-author Dr Mat Disney (UCL Geography) said: "This new paper shows how effectively we can now turn highly-accurate laser measurements, comprising millions of 3D laser points, into estimates of tree mass. Weighing trees is really hard - time consuming, expensive and destructive - and so it's done very rarely, particularly in tropical forests where trees can be 50m or more and weigh over 100 tonnes. As a result, all current estimates of tropical forest carbon stocks are based on a very, very small number of weighed trees.