Migrating like a herd of cats – climate change and emerging forests in British Columbia

We combine climate preferences of tree species with probable changes in insect, disease, fire and other abiotic factors to describe probable changes in distribution of tree species in British Columbia. Predictions of what British Columbia’s forests will become are rife with uncertainty from three major sources: predicting climate, predicting tree species’ responses and predicting changes in factors modifying the trees’ responses (e.g., pathogens, fires). Challenges in predicting climate result because climate projection models differ and downscaling climate is difficult, particularly where weather stations are sparse. Challenges in predicting responses of individual tree species to climate result because species will be competing under a climate regime we have not seen before and they have not experienced before. That challenge is increased by the differential response of pathogens and effects of changes in fire frequency. We first examine responses of individual species, then consider implications for broad regional forests. Despite the uncertainty, some trends are more likely than others. We present our estimates of the relative species composition of future forests in British Columbia.