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ABSTRACT Siberian boreal forests have experienced increases in fire extent and intensity in recent years, which may threaten their role as carbon (C) sinks. Larch forests (Larixspp.) cover approximately 2.6 million km2across Siberia, yet little is known about the magnitude and drivers of carbon combustion in these ecosystems. To address the paucity of field‐based estimates of fuel load and consumption in Siberian larch forests, we sampled 41 burned plots, one to two years after fire, in Cajander larch (Larix cajanderi) forests in the Republic of Sakha (Yakutia), Russia. We estimated pre‐fire carbon stocks and combustion with the objective of identifying the main drivers of carbon emissions. Pre‐fire aboveground (trees and woody debris) and belowground carbon stocks at our study plots were 3.12 ± 1.26 kg C m−2(mean ± standard deviation) and 3.50 ± 0.93 kg C m−2. We found that combustion averaged 3.20 ± 0.75 kg C m−2, of which 78% (2.49 ± 0.56 kg C m−2) stemmed from organic soil layers. These results suggest that severe fires in Cajander larch forests can result in combustion rates comparable to those observed in North American boreal forests and exceeding those previously reported for other forest types and burning conditions in Siberia. Carbon combustion was driven by both fire weather conditions and landscape variables, with pre‐fire organic soil depth being the strongest predictor across our plots. Our study highlights the need to better account for Siberian larch forest fires and their impact on the carbon balance, especially given the expected climate‐induced increase in fire extent and severity in this region.
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Fire‐Induced Carbon Loss and Tree Mortality in Siberian Larch Forests
Climate change is intensifying the fire regime across Siberia, with the potential to alter carbon combustion and post‐fire carbon re‐accumulation trajectories. Few field‐based estimates of fire severity (e.g., carbon combustion and tree mortality) exist in Siberian larch forests (Larixspp.), which limits our ability to project how an intensified fire regime will affect regional and global climate feedbacks. Here, we present field‐based estimates of fire‐induced tree mortality and carbon loss in eastern Siberian larch forests. Our results suggest that fires in this region result in high tree mortality (means of 83% and 76% at Arctic and subarctic sites, respectively). In both absolute and relative terms, aboveground carbon loss following fire is higher in Siberian larch forests than in North America, but belowground carbon loss is considerably lower. This suggests fundamental differences in wildfire behavior and carbon dynamics between dominant vegetation types across the boreal biome.
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- Award ID(s):
- 1708129
- PAR ID:
- 10544703
- Publisher / Repository:
- Geophysical Research Letters
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 51
- Issue:
- 1
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1029/2023GL105216
