Eunjee Lee, MIT
Abstract: Do you remember the astonishment when you first saw the helicopter seed of maple trees flying in your backyard? Unfortunately, models cannot simulate the astonishment at the memorable moment of your childhood; but they can still capture the mechanism of wind-driven seed dispersal, which is currently not included in Dynamic Global Vegetation Models (DGVMs). We developed an improved tool to simulate time-varying wind-driven seed dispersion as a dynamic constraint to the migration process of natural vegetation. Compared to the satellite-derived treecovers, the result using our SEED model shows significantly improved representation of vegetation in regions such as boreal forests in Western Siberia and temperate forests in Eastern Europe. The prevailing wind pattern, along with the existing vegetation structure in nearby gridcells, alters the competition dynamics of the trees in these regions by filtering unrealistic saplings out and adjusting their establishment rates. Results in projecting future vegetation structures under two climate mitigation scenarios (No-policy vs. 450ppm CO2 stabilization) at the end of 21st century, and their impacts to ecosystems are also addressed.