In North American boreal forests, several million hectares can go up in smoke in a single year.During the past 60 years, the area annually affected by forest fires has increased, presumably because of climate change. Or at least that’s part of the explanation. However, to better understand the long-term trends it is important to take a step back. …The results of our research contradict the common wisdom about North American boreal forests — that they burned more in the past than they do today. …We gathered 16 studies that had independently applied the same method to different areas across North American boreal forests, from Alaska to Québec… the results are striking: North American boreal forests burned much more 150 years ago than they do today. In the earliest period covered by our data, between 1700 and 1850, the annual area burned was between two and more than 10 times greater than what has been observed over the past 40 years.