Intensified burn severity in California’s northern coastal mountains by drier climatic condition
The severity of wildfire burns in interior lands of western US ecosystems has been increasing. However, less is known about its coastal mountain ecosystems, especially under extreme weather conditions, raising concerns about the vulnerability of these populated areas to catastrophic fires. Here we e...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2020-01-01
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| Series: | Environmental Research Letters |
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| Online Access: | https://doi.org/10.1088/1748-9326/aba6af |
| _version_ | 1827870413833633792 |
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| author | Yuhan Huang Yufang Jin Mark W Schwartz James H Thorne |
| author_facet | Yuhan Huang Yufang Jin Mark W Schwartz James H Thorne |
| author_sort | Yuhan Huang |
| collection | DOAJ |
| description | The severity of wildfire burns in interior lands of western US ecosystems has been increasing. However, less is known about its coastal mountain ecosystems, especially under extreme weather conditions, raising concerns about the vulnerability of these populated areas to catastrophic fires. Here we examine the fine-scale association between burn severity and a suite of environmental drivers including explicit fuel information, weather, climate, and topography, for diverse ecosystems in California’s northern coastal mountains. Burn severity was quantified using Relative difference Normalized Burn Ratio from Landsat multispectral imagery during 1984–2017. We found a significant increasing trend in burned areas and severity. During low-precipitation years, areas that burned had much lower fuel moisture and higher climatic water deficit than in wetter years, and the percentage of high-severity areas doubled, especially during the most recent 2012–2016 drought. The random forest (RF) machine learning model achieved overall accuracy of 79% in classifying categories of burn severity. Aspect, slope, fuel type and availability, and temperature were the most important drivers, based on both classification and regression RF models. We further examined the importance of drivers under four climatic conditions: dry vs. wet years, and during two extended drought periods (the 2012–2016 warmer drought vs. the 1987–1992 drought). During warm and dry years, the spatial variability of burn severity was a mixed effect of slope, long-term minimum temperature, fuel amount, and fuel moisture. In contrast, climatic water deficit and short-term weather became dominant factors for fires during wetter years. These results suggest that relative importance of drivers for burn severity in the broader domain of California’s northern coastal mountains varied with weather scenarios, especially when exacerbated by warm and extended drought. Our findings highlight the importance of targeting areas with high burn severity risk for fire adaptation and mitigation strategies in a changing climate and intensifying extremes. |
| first_indexed | 2024-03-12T15:56:30Z |
| format | Article |
| id | doaj.art-31b5907817ed4f30ad8b61ac0d35bdd8 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T15:56:30Z |
| publishDate | 2020-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-31b5907817ed4f30ad8b61ac0d35bdd82023-08-09T14:52:44ZengIOP PublishingEnvironmental Research Letters1748-93262020-01-01151010403310.1088/1748-9326/aba6afIntensified burn severity in California’s northern coastal mountains by drier climatic conditionYuhan Huang0https://orcid.org/0000-0001-7478-1442Yufang Jin1Mark W Schwartz2James H Thorne3Department of Land, Air and Water Resources, University of California , Davis, CA, United States of AmericaDepartment of Land, Air and Water Resources, University of California , Davis, CA, United States of AmericaDepartment of Environmental Science and Policy, University of California , Davis, CA, United States of AmericaDepartment of Environmental Science and Policy, University of California , Davis, CA, United States of AmericaThe severity of wildfire burns in interior lands of western US ecosystems has been increasing. However, less is known about its coastal mountain ecosystems, especially under extreme weather conditions, raising concerns about the vulnerability of these populated areas to catastrophic fires. Here we examine the fine-scale association between burn severity and a suite of environmental drivers including explicit fuel information, weather, climate, and topography, for diverse ecosystems in California’s northern coastal mountains. Burn severity was quantified using Relative difference Normalized Burn Ratio from Landsat multispectral imagery during 1984–2017. We found a significant increasing trend in burned areas and severity. During low-precipitation years, areas that burned had much lower fuel moisture and higher climatic water deficit than in wetter years, and the percentage of high-severity areas doubled, especially during the most recent 2012–2016 drought. The random forest (RF) machine learning model achieved overall accuracy of 79% in classifying categories of burn severity. Aspect, slope, fuel type and availability, and temperature were the most important drivers, based on both classification and regression RF models. We further examined the importance of drivers under four climatic conditions: dry vs. wet years, and during two extended drought periods (the 2012–2016 warmer drought vs. the 1987–1992 drought). During warm and dry years, the spatial variability of burn severity was a mixed effect of slope, long-term minimum temperature, fuel amount, and fuel moisture. In contrast, climatic water deficit and short-term weather became dominant factors for fires during wetter years. These results suggest that relative importance of drivers for burn severity in the broader domain of California’s northern coastal mountains varied with weather scenarios, especially when exacerbated by warm and extended drought. Our findings highlight the importance of targeting areas with high burn severity risk for fire adaptation and mitigation strategies in a changing climate and intensifying extremes.https://doi.org/10.1088/1748-9326/aba6affire behaviorextreme weatherdroughtclimate changeremote sensingartificial intelligence |
| spellingShingle | Yuhan Huang Yufang Jin Mark W Schwartz James H Thorne Intensified burn severity in California’s northern coastal mountains by drier climatic condition Environmental Research Letters fire behavior extreme weather drought climate change remote sensing artificial intelligence |
| title | Intensified burn severity in California’s northern coastal mountains by drier climatic condition |
| title_full | Intensified burn severity in California’s northern coastal mountains by drier climatic condition |
| title_fullStr | Intensified burn severity in California’s northern coastal mountains by drier climatic condition |
| title_full_unstemmed | Intensified burn severity in California’s northern coastal mountains by drier climatic condition |
| title_short | Intensified burn severity in California’s northern coastal mountains by drier climatic condition |
| title_sort | intensified burn severity in california s northern coastal mountains by drier climatic condition |
| topic | fire behavior extreme weather drought climate change remote sensing artificial intelligence |
| url | https://doi.org/10.1088/1748-9326/aba6af |
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