With the rapid trend in the climate shift, the spruce budworm (SBW) (Choristoneura fumiferana), is increasing its damage and distribution area making forests more vulnerable. Despite its major ecological implications, challenges remain in understanding the historical impact of climate on defoliation caused by the SBW, the severity of its impact on host trees and how it has changed over time. Thus, we aim to evaluate the trend and the impact of climate on SBW outbreaks during the last century and to reconstruct the spatiotemporal patterns in Quebec. For this, we will use the dendrochronological time series, as well as complementary fieldwork, and use the climate datasets to model climate normalized growth. We will extract the rate and the extent of impact of the defoliating insect, and its interaction with climate, on the boreal stands. This study will provide invaluable information to understand major ecological shifts caused by the defoliator and the climate at a spatiotemporal scale.