Tree rings provide a window into Quebec's 19th century climate for researchers / In tree rings, Concordia researchers peer into Quebec's 19th century climate / Tree rings from Canada's Gaspesie mountains reveal effects of global warming dating back almost a century / Tree rings, climate change and the rainy season / Tree rings show last northern summer was the warmest since year 1 / Hot history: Tree rings show that last northern summer was the warmest since year 1 / Unlocking the climate secrets of North China with ancient tree rings