Johan Eckdahl
Researcher in boreal wildfire
Climatic variation drives loss and restructuring of carbon and nitrogen in boreal forest wildfire
Author
Summary, in English
The boreal forest landscape covers approximately 10% of the earth's land area and accounts for almost 30 % of the global annual terrestrial sink of carbon (C). Increased emissions due to climate-change-amplified fire frequency, size, and intensity threaten to remove elements such as C and nitrogen (N) from forest soil and vegetation at rates faster than they accumulate. This may result in large areas within the region becoming a net source of greenhouse gases, creating a positive feedback loop with a changing climate. Meter-scale estimates of area-normalized fire emissions are limited in Eurasian boreal forests, and knowledge of their relation to climate and ecosystem properties is sparse. This study sampled 50 separate Swedish wildfires, which occurred during an extreme fire season in 2018, providing quantitative estimates of C and N loss due to fire along a climate gradient. Mean annual precipitation had strong positive effects on total fuel, which was the strongest driver for increasing C and N losses. Mean annual temperature (MAT) influenced both pre-and postfire organic layer soil bulk density and C: N ratio, which had mixed effects on C and N losses. Significant fire-induced loss of C estimated in the 50 plots was comparable to estimates in similar Eurasian forests but approximately a quarter of those found in typically more intense North American boreal wildfires. N loss was insignificant, though a large amount of fire-affected fuel was converted to a low C: N surface layer of char in proportion to increased MAT. These results reveal large quantitative differences in C and N losses between global regions and their linkage to the broad range of climate conditions within Fennoscandia. A need exists to better incorporate these factors into models to improve estimates of global emissions of C and N due to fire in future climate scenarios. Additionally, this study demonstrated a linkage between climate and the extent of charring of soil fuel and discusses its potential for altering C and N dynamics in postfire recovery.
Department/s
- Dept of Physical Geography and Ecosystem Science
- BECC: Biodiversity and Ecosystem services in a Changing Climate
Publishing year
2022
Language
English
Pages
2487-2506
Publication/Series
Biogeosciences
Volume
19
Issue
9
Document type
Journal article
Publisher
Copernicus GmbH
Topic
- Climate Research
Status
Published
ISBN/ISSN/Other
- ISSN: 1726-4170