Cross-scale controls on carbon emissions from boreal forest megafires

Area of Science:

• Ecology
• Climate Science
• Forestry

Background:

• Boreal forests face increased wildfire risk due to climate change.
• Wildfires significantly impact carbon cycling and climate feedbacks.
• Accurate carbon emission estimates require understanding heterogeneity in combustion.

Purpose of the Study:

• To identify drivers of carbon emissions from boreal forest fires.
• To develop a high-resolution model for scaling carbon emissions.
• To assess the impact of the 2014 NWT fire complex on regional carbon balance.

Main Methods:

• Field plots in Northwest Territories (NWT) boreal forests (black spruce, jack pine).
• Assessment of aboveground and soil organic layer (SOL) combustion.
• Development of a spatial model for emission scaling.

Main Results:

• Average combustion of 3.35 kg C m⁻², with ~90% from SOL.
• Black spruce stands with intermediate drainage were major carbon emitters.
• Total emissions from the 2014 NWT fire complex were 94.3 Tg C.

Conclusions:

• Soil organic layer combustion is the dominant carbon emission source.
• Site-specific factors like drainage are critical for accurate emission modeling.
• Emissions significantly offset Canada's terrestrial carbon sequestration capacity.