Trends and causes of severity, size, and number of fires in northwestern California, USA
Abstract
Research in the last several years has indicated that fire size and frequency are on the rise in western U.S. forests. Although fire size and frequency are important, they do not necessarily scale with ecosystem effects of fire, as different ecosystems have different ecological and evolutionary relationships with fire. Our study assessed trends and patterns in fire size and frequency from 1910 to 2008 (all fires > 40 ha), and the percentage of high-severity in fires from 1987 to 2008 (all fires > 400 ha) on the four national forests of northwestern California. During 1910-2008, mean and maximum fire size and total annual area burned increased, but we found no temporal trend in the percentage of high-severity fire during 1987-2008. The time series of severity data was strongly influenced by four years with region-wide lightning events that burned huge areas at primarily low-moderate severity. Regional fire rotation reached a high of 974 years in 1984 and fell to 95 years by 2008. The percentage of high-severity fire in conifer-dominated forests was generally higher in areas dominated by smaller-diameter trees than in areas with larger-diameter trees. For Douglas-fir forests, the percentage of high-severity fire did not differ significantly between areas that re-burned and areas that only burned once (10% vs. 9%) when re-burned within 30 years. Percentage of high-severity fire decreased to 5% when intervals between first and second fires were > 30 years. In contrast, in both mi…
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Wildfires in the United States have increased in frequency since the mid-1980s.
“Wildfires in the United States (U.S.) have increased in frequency since the mid-1980s (Dennison et al., 2014; Miller et al., 2012; Singleton et al., 2019).”
From Wildfire Induces Changes in Receiving Waters: A Review With Considerations for Water Quality Management (2022) · cites this paper as Miller et al., 2012
Beyond changes in fire frequency and area burned, other changing components of fire regimes have been identified, including changing spatial patterns of fire severity and the lengthening of wildfire seasons.
“Beyond changes in fire frequency and area burned, other changing components of fire regimes have been identified in recent years, including changing spatial patterns of fire severity (Harvey, Donato, & Turner, 2016b;Miller, Skinner, Safford, Knapp, & Ramirez, 2012;Steel, Koontz, & Safford, 2018) and the lengthening of wildfire seasons (Jolly et al., 2015).”
From Fire as a fundamental ecological process: Research advances and frontiers (2020) · cites this paper as Miller, Skinner, Safford, Knapp, & Ramirez, 2012
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References 72 · Cited by 227
- Authors
- Miller, J. D., Skinner, C. N., Safford, H. D., Knapp, E. E., & Ramirez, C. M.
- Affiliations
- US Forest Service (US)
- Corresponding author
- Miller, J. D.
- Venue
- Ecological Applications
- Publisher
- Wiley
- Published
- 2012-01
- Volume
- 22
- Issue
- 1
- Pages
- 184-203
- ISSN
- 1051-0761 (ISSN-L)
- 1939-5582
- OpenAlex
- W2133795721
- Cited by
- 227
- References
- 72
- Citations by year
- 2026: 6 · 2025: 10 · 2024: 14 · 2023: 14 · 2022: 17 · 2021: 14 · 2020: 18 · 2019: 14 · 2018: 16 · 2017: 15 · 2016: 17 · 2015: 26 · 2014: 17 · 2013: 21 · 2012: 6
- FWCI
- 12.52
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Ecological Applications (publishedVersion)
- PubMed (publishedVersion)
- Funders
- Northwestern University
- Topics
- Physical Sciences › Environmental Science › Global and Planetary Change › Fire effects on ecosystems
- Physical Sciences › Environmental Science › Global and Planetary Change › Forest Management and Policy
- Physical Sciences › Environmental Science › Ecology › Rangeland and Wildlife Management
- Keywords
- fire size, fire frequency, high-severity fire, fire rotation, lightning fires, Douglas-fir forests, fire return interval, precipitation, prescribed burning, national forests, northwestern California
- MeSH terms
- California, Environmental Monitoring, Fires, Human Activities, Lightning, Time Factors, Trees, Ecosystem
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