Large-scale modeling shows little impact of 20th-century changes in temperature and fire on the central Canadian boreal forest
Ben
Bond-Lamberty, University of Wisconsin-Madison, bpbond@wisc.edu
Stith
Gower, University of Wisconsin-Madison, stgower@wisc.edu
(Presenting)
Ahl
Douglas, University of Wisconsin-Madison, deahl@wisc.edu
Boreal forests are predicted to experience relatively large climate change, and recent increases in wildfire frequency suggest that fire dynamics of this region may not be in equilibrium with the changing climate. We used a distributed computing grid to model a 1,000 km x 1,000 km area of boreal forest, with each grid cell 1 km2, from 1948 to 2005. The modeled area stretched from eastern Manitoba, Canada, to eastern Alberta, and included both the Northern and Southern BOREAS study areas. Input data were assembled from regional ground-based and satellite records; compared to historical norms, temperatures in 1948-2005 were slightly warmer for this region, disturbance increased markedly, particularly in the northern half of the grid, and CO2 levels rose. As a result of these changes the growing season lengthened and the overall forest shifted to a younger and more deciduous state, but mean net ecosystem production (NEP, carbon balance) did not change significantly. This lack of ecosystem response to changing conditions may reveal inadequacies of the model used (Biome-BGC) or reflect a real stability in the boreal system under study.