Allometric equations for integrating remote sensing imagery into forest monitoring programmes

Overview & Synopsis

Remote sensing is revolutionizing the way we study forests, and recent technological advances mean we are now able– for the first time – to identify and measure the crown dimensions of individual trees from airborne imagery. Yet tomake full use of these data for quantifying forest carbon stocks and dynamics, a new generation of allometric toolswhich have tree height and crown size at their centre are needed. Here, we compile a global database of 108753 treesfor which stem diameter, height and crown diameter have all been measured, including 2395 trees harvested to measureaboveground biomass. Using this database, we develop general allometric models for estimating both the diameterand aboveground biomass of trees from attributes which can be remotely sensed – specifically height and crowndiameter. We show that tree height and crown diameter jointly quantify the aboveground biomass of individual treesand find that a single equation predicts stem diameter from these two variables across the world’s forests. These new allometric models provide an intuitive way of integrating remote sensing imagery into large-scale forest monitoringprogrammes and will be of key importance for parameterizing the next generation of dynamic vegetation models.