Periodic outbreaks of the spruce budworm (SBW; Choristoneura fumiferana) in eastern Canada create large patches of standing dead spruce and fir forest. Of particular concern to forest and fire managers is whether these patches of standing dead timber represent areas of significantly greater fire risk, for how long such increased risk persists, and how these relationships vary through space and time. Using historical data on fire ignitions and spruce budworm defoliation this research examines the relationship between defoliation and fire in the province of Ontario, Canada. Previous work has suggested a temporary increase in flammability in budworm-killed forests but regional and seasonal variability in these relationships has not been examined.
We are currently modelling how the probability of lightning-caused ignition, the probability of escape from initial control, and final fire size vary as a function of a set of spatial and temporal covariates, including SBW defoliation up to 10 years prior to ignition. Our goal is to create predictive spatial models that can be used in combination with forecasted future climate and fire weather to predict changes in fire risk. Through this research we hope to develop a better understanding of the contribution of insect outbreaks to fire risk in boreal and mixed-wood forest systems. In the context of recent increases in the extent and severity of insect outbreaks in northern forests, this work is relevant to quantify the potential for increased insect-related lightning-caused fire risk that may be further exacerbated by drier and warmer conditions due to climate change.
Students : Louis-Etienne Robert
Collaborators : Mike Wotton (CFS, UofT), Dave Martell (UofT), Rich Fleming (CFS)
Photo credit: Terry Chapin. http://www.lternet.edu/node/49513.