The country’s forests are so huge that for decades policymakers assumed that human activity would make little impact. “The rationale was that it will all come out in the wash: the trees will recover, the forests will grow back, and we’ll all be fine,” Simard says, speaking on a video call from Vancouver. But deforested areas do not fully recover, and thanks to logging, the wildfires and a devastating pine beetle outbreak, Canada’s forests, once a vast carbon sink, have since 2001 been a net emitter of carbon.