Climate change is causing more and bigger wildfires in North American boreal forests, releasing a lot of carbon into the air. Scientists studied burned areas in Canada to figure out where the carbon comes from. They found that most of the carbon emissions come from burning the soil, especially in black spruce forests with medium drainage. Weather and burn date didn't affect emissions much. Overall, the fires in 2014 released a huge amount of carbon, offsetting almost half of Canada's yearly carbon absorption. To predict future carbon emissions accurately, we need to understand how different factors affect carbon release in burned areas.