North American boreal forests are a large carbon source due to wildfires from 1986 to 2016
Abstract Wildfires are a major disturbance to forest carbon (C) balance through both immediate combustion emissions and post-fire ecosystem dynamics. Here we used a process-based biogeochemistry model, the Terrestrial Ecosystem Model (TEM), to simulate C budget in Alaska and Canada during 1986–2016,...
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| Format: | Article |
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Nature Portfolio
2021-04-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-021-87343-3 |
| _version_ | 1818978122792435712 |
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| author | Bailu Zhao Qianlai Zhuang Narasinha Shurpali Kajar Köster Frank Berninger Jukka Pumpanen |
| author_facet | Bailu Zhao Qianlai Zhuang Narasinha Shurpali Kajar Köster Frank Berninger Jukka Pumpanen |
| author_sort | Bailu Zhao |
| collection | DOAJ |
| description | Abstract Wildfires are a major disturbance to forest carbon (C) balance through both immediate combustion emissions and post-fire ecosystem dynamics. Here we used a process-based biogeochemistry model, the Terrestrial Ecosystem Model (TEM), to simulate C budget in Alaska and Canada during 1986–2016, as impacted by fire disturbances. We extracted the data of difference Normalized Burn Ratio (dNBR) for fires from Landsat TM/ETM imagery and estimated the proportion of vegetation and soil C combustion. We observed that the region was a C source of 2.74 Pg C during the 31-year period. The observed C loss, 57.1 Tg C year−1, was attributed to fire emissions, overwhelming the net ecosystem production (1.9 Tg C year−1) in the region. Our simulated direct emissions for Alaska and Canada are within the range of field measurements and other model estimates. As burn severity increased, combustion emission tended to switch from vegetation origin towards soil origin. When dNBR is below 300, fires increase soil temperature and decrease soil moisture and thus, enhance soil respiration. However, the post-fire soil respiration decreases for moderate or high burn severity. The proportion of post-fire soil emission in total emissions increased with burn severity. Net nitrogen mineralization gradually recovered after fire, enhancing net primary production. Net ecosystem production recovered fast under higher burn severities. The impact of fire disturbance on the C balance of northern ecosystems and the associated uncertainties can be better characterized with long-term, prior-, during- and post-disturbance data across the geospatial spectrum. Our findings suggest that the regional source of carbon to the atmosphere will persist if the observed forest wildfire occurrence and severity continues into the future. |
| first_indexed | 2024-12-20T16:38:37Z |
| format | Article |
| id | doaj.art-ab3e5226bef94ab09a223d270321a2e6 |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-12-20T16:38:37Z |
| publishDate | 2021-04-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-ab3e5226bef94ab09a223d270321a2e62022-12-21T19:33:06ZengNature PortfolioScientific Reports2045-23222021-04-0111111410.1038/s41598-021-87343-3North American boreal forests are a large carbon source due to wildfires from 1986 to 2016Bailu Zhao0Qianlai Zhuang1Narasinha Shurpali2Kajar Köster3Frank Berninger4Jukka Pumpanen5Department of Earth, Atmospheric, and Planetary Sciences, Purdue UniversityDepartment of Earth, Atmospheric, and Planetary Sciences, Purdue UniversityProduction Systems - Milk Production Unit, Natural Resources Institute Finland (Luke)Department of Forest Sciences, University of HelsinkiDepartment of Environmental and Biological Sciences, University of Eastern FinlandDepartment of Environmental and Biological Sciences, University of Eastern FinlandAbstract Wildfires are a major disturbance to forest carbon (C) balance through both immediate combustion emissions and post-fire ecosystem dynamics. Here we used a process-based biogeochemistry model, the Terrestrial Ecosystem Model (TEM), to simulate C budget in Alaska and Canada during 1986–2016, as impacted by fire disturbances. We extracted the data of difference Normalized Burn Ratio (dNBR) for fires from Landsat TM/ETM imagery and estimated the proportion of vegetation and soil C combustion. We observed that the region was a C source of 2.74 Pg C during the 31-year period. The observed C loss, 57.1 Tg C year−1, was attributed to fire emissions, overwhelming the net ecosystem production (1.9 Tg C year−1) in the region. Our simulated direct emissions for Alaska and Canada are within the range of field measurements and other model estimates. As burn severity increased, combustion emission tended to switch from vegetation origin towards soil origin. When dNBR is below 300, fires increase soil temperature and decrease soil moisture and thus, enhance soil respiration. However, the post-fire soil respiration decreases for moderate or high burn severity. The proportion of post-fire soil emission in total emissions increased with burn severity. Net nitrogen mineralization gradually recovered after fire, enhancing net primary production. Net ecosystem production recovered fast under higher burn severities. The impact of fire disturbance on the C balance of northern ecosystems and the associated uncertainties can be better characterized with long-term, prior-, during- and post-disturbance data across the geospatial spectrum. Our findings suggest that the regional source of carbon to the atmosphere will persist if the observed forest wildfire occurrence and severity continues into the future.https://doi.org/10.1038/s41598-021-87343-3 |
| spellingShingle | Bailu Zhao Qianlai Zhuang Narasinha Shurpali Kajar Köster Frank Berninger Jukka Pumpanen North American boreal forests are a large carbon source due to wildfires from 1986 to 2016 Scientific Reports |
| title | North American boreal forests are a large carbon source due to wildfires from 1986 to 2016 |
| title_full | North American boreal forests are a large carbon source due to wildfires from 1986 to 2016 |
| title_fullStr | North American boreal forests are a large carbon source due to wildfires from 1986 to 2016 |
| title_full_unstemmed | North American boreal forests are a large carbon source due to wildfires from 1986 to 2016 |
| title_short | North American boreal forests are a large carbon source due to wildfires from 1986 to 2016 |
| title_sort | north american boreal forests are a large carbon source due to wildfires from 1986 to 2016 |
| url | https://doi.org/10.1038/s41598-021-87343-3 |
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