Forest wildfires as a recent source of CO₂ at northern latitudes

Abstract

Since 1977, the extent of forest wildfires in the boreal and western regions of North America increased 6- to 9-fold over long-term trends, and an estimated 132 × 106 ha of temperate and boreal forest burned across the northern hemisphere. Emissions during and after burning may have been a significant feedback to global warming. Simulated carbon budgets indicated a hemispheric release of 1.4 Pg C during burning and 4.1 Pg C gross from CO2 fluxes postfire. The total release (5.5 Pg C) was 43% of the biospheric CO2 release to the atmosphere, 1977–1990. Over the next century (1991–2090), continuing emissions from wood and soil decomposition will release an additional 6.9 Pg C gross. A large CO2 release was contrary to assumptions of little net carbon flux in the temperate and boreal forests. The pattern of attenuated CO2 release in northern forests also contrasted with sharp emission peaks in tropical deforestation. A simulation experiment indicated that the CO2 pulse from direct emissions per unit area was 10-fold larger in tropical deforestation than in northern forest wildfires on average; postfire release in the northern systems, however, was about 10 times longer in duration and only slightly less overall than in tropical deforestation fires.

Effect of fire on soil‐atmosphere exchange of methane and carbon dioxide in Canadian boreal forest sites

“…0148-0227/97/97JD-01331509.00 times the amount directly released during burning in the boreal region [Auclair and Carter, 1993].…”

Carbon Storage on Landscapes with Stand-replacing Fires

“…If climate change significantly increases the area burned over the next centuryand it may Drapek 1998, Dale et al 2001)-these short-term effects are likely to influence atmospheric CO 2 concentration. Short-term effects of fire on carbon storage are regulated by the amount of carbon lost in combustion (Tinker and Knight 2000, Schuur et al 2002, by the rate and amount of regeneration , and by the amount of material from the prior stand that is decomposing (AuClair and Carter 1993, Turner et al 1995, Kurz and Apps 1999. Fire severity affects combustion losses, especially for surface fuels , and may also affect the rate and amount of vegetation recovery (Wirth et al 2002).…”

Sequestration of carbon in the Finnish boreal forest ecosystem managed for timber production

“…region, however, forest fires could have a significant effect on the C balance (Auclair and Carter 1993; see also Chapters 8, Stocks et al, and 14, Kurz and Apps). Regular forest management and the dense network of forest roads have led to a decrease in forest fires in Finland.…”