Fire Research » Fire & Climate Change

Direct Carbon Emissions from Forest Fires: An Overview

Although fossil fuel burning contributes most to increasing concentrations of atmospheric greenhouse gases, emissions from global biomass burning (forests, savannas, and agricultural lands) are also a major source of greenhouse gases. Emissions from boreal fires are important because of their location at climatically sensitive northern latitudes, the large fluctuations in annual area burned, and the high energy level of boreal fires, which typically produce smoke columns reaching into the upper troposphere.

Direct emissions of carbon (C) from Canadian forest fires were estimated for all Canada and for each ecozone for the period 1959–1999. The estimates were based on a database (the Large Fire Database) for the country and calculations of fuel consumption for each fire using the Canadian Forest Fire Behaviour Prediction System. This technique used the fire locations and start dates to estimate prevailing fire weather and fuel type for each of about 11 000 fires. An average of 2 million ha per year was burned in this period, ranging from 300 000 ha in 1978 to 7.5 million ha in 1989. Ecozones of the boreal and taiga areas experienced the greatest area burned, releasing most of their C. The mean area-weighted fuel consumption for all fires was 2.6 kg dry fuel per square metre (1.3 kg C per square metre), but ecozones varied from 1.8 to 3.9 kg dry fuel per square metre. The mean annual estimate of direct C emissions was 27 ± 6 Tg (10¹² g) C per year. Individual years ranged from 3 to 115 Tg C per year. These direct fire emissions represent about 18% of the current carbon dioxide emissions from the Canadian energy sector, on average, but vary from 2% to 75% among years. Postfire effects cause an additional loss of C and changes to the forest sink condition.

These results are published in:

• Amiro, B.D.; Flannigan, M.D; Stocks, B.J.; Wotton, B.M. 2002. Perspectives on carbon emissions from Canadian forest fires. Forestry Chronicle 78: 388–390.
• Amiro, B.D.; Todd, J.B.; Wotton, B.M.; Logan, K.A.; Flannigan, M.D.; Stocks, B.J.;Mason, J.A.; Martell, D.L.; Hirsch, K.G. 2001. Direct carbon emissions from Canadian forest fires, 1959 to 1999. Canadian Journal of Forest Research 31:512–525.

See also the following documents on this Web site:

• Annual Carbon Lost Due to Fire, by Ecozone, for 1959–1995
• Carbon Flux from Early Postfire Successional Forests in Saskatchewan