Modeling aspen responses to climatic warming and insect defoliation in western Canada

Effects of climate change at three aspen sites in Saskatchewan were explore d using a climate-driven model that includes insect defoliation. A simulate d warming of 4-5 degreesC caused complete mortality due to drought at all t hree sites. A simulated warming of 2-2.5 degreesC caused complete mortality of aspen at the parkland site, while aspen growth at two boreal sites show ed little change from the present climate until after insect defoliation, w hen dieback was more severe under the warmer climate. The results suggest t hat future impacts of climate change on boreal aspen forests may not become evident until after major insect outbreaks have occurred.