Carbon Emissions From Fires in Eastern Siberian Larch Forests

Area of Science:

• Ecology
• Forestry
• Climate Science

Background:

• Siberian boreal forests, particularly larch ecosystems, are crucial carbon sinks.
• Recent increases in fire extent and intensity threaten these vital ecosystems.
• Limited field data exists on carbon combustion in Siberian larch forests.

Purpose of the Study:

• To estimate pre-fire carbon stocks and combustion in Cajander larch forests.
• To identify key drivers of carbon emissions from Siberian larch forest fires.
• To assess the impact of these fires on the regional carbon balance.

Main Methods:

• Field sampling of 41 burned plots in Cajander larch forests (Larix cajanderi) in Yakutia, Russia.
• Estimation of pre-fire aboveground and belowground carbon stocks.
• Measurement of carbon combustion, with a focus on organic soil layers.

Main Results:

• Pre-fire carbon stocks averaged 3.12 kg C m⁻² (aboveground) and 3.50 kg C m⁻² (belowground).
• Average carbon combustion was 3.20 kg C m⁻², with 78% originating from organic soil layers.
• Combustion rates were comparable to North American boreal forests and higher than previously reported for other Siberian forests.

Conclusions:

• Severe fires in Cajander larch forests lead to substantial carbon combustion, primarily from soils.
• Fire weather and landscape variables, especially organic soil depth, drive carbon emissions.
• Accurate accounting of Siberian larch forest fires is critical for understanding the global carbon balance, particularly with projected climate change impacts.