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Wu X, Sverdrup E, Mastrandrea MD, Wara MW, Wager S. Low-intensity fires mitigate the risk of high-intensity wildfires in California's forests. SCIENCE ADVANCES 2023; 9:eadi4123. [PMID: 37948522 PMCID: PMC10637742 DOI: 10.1126/sciadv.adi4123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 10/12/2023] [Indexed: 11/12/2023]
Abstract
The increasing frequency of severe wildfires demands a shift in landscape management to mitigate their consequences. The role of managed, low-intensity fire as a driver of beneficial fuel treatment in fire-adapted ecosystems has drawn interest in both scientific and policy venues. Using a synthetic control approach to analyze 20 years of satellite-based fire activity data across 124,186 square kilometers of forests in California, we provide evidence that low-intensity fires substantially reduce the risk of future high-intensity fires. In conifer forests, the risk of high-intensity fire is reduced by 64.0% [95% confidence interval (CI): 41.2 to 77.9%] in areas recently burned at low intensity relative to comparable unburned areas, and protective effects last for at least 6 years (lower bound of one-sided 95% CI: 6 years). These findings support a policy transition from fire suppression to restoration, through increased use of prescribed fire, cultural burning, and managed wildfire, of a presuppression and precolonial fire regime in California.
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Affiliation(s)
- Xiao Wu
- Department of Biostatistics, Columbia University, New York, NY, USA
| | - Erik Sverdrup
- Graduate School of Business, Stanford University, Stanford, CA, USA
| | | | - Michael W. Wara
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA
| | - Stefan Wager
- Graduate School of Business, Stanford University, Stanford, CA, USA
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Steel ZL, Jones GM, Collins BM, Green R, Koltunov A, Purcell KL, Sawyer SC, Slaton MR, Stephens SL, Stine P, Thompson C. Mega-disturbances cause rapid decline of mature conifer forest habitat in California. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2023; 33:e2763. [PMID: 36264047 DOI: 10.1002/eap.2763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/25/2022] [Accepted: 08/30/2022] [Indexed: 06/16/2023]
Abstract
Mature forests provide important wildlife habitat and support critical ecosystem functions globally. Within the dry conifer forests of the western United States, past management and fire exclusion have contributed to forest conditions that are susceptible to increasingly severe wildfire and drought. We evaluated declines in conifer forest cover in the southern Sierra Nevada of California during a decade of record disturbance by using spatially comprehensive forest structure estimates, wildfire perimeter data, and the eDaRT forest disturbance tracking algorithm. Primarily due to the combination of wildfires, drought, and drought-associated beetle epidemics, 30% of the region's conifer forest extent transitioned to nonforest vegetation during 2011-2020. In total, 50% of mature forest habitat and 85% of high density mature forests either transitioned to lower density forest or nonforest vegetation types. California spotted owl protected activity centers (PAC) experienced greater canopy cover decline (49% of 2011 cover) than non-PAC areas (42% decline). Areas with high initial canopy cover and without tall trees were most vulnerable to canopy cover declines, likely explaining the disproportionate declines of mature forest habitat and within PACs. Drought and beetle attack caused greater cumulative declines than areas where drought and wildfire mortality overlapped, and both types of natural disturbance far outpaced declines attributable to mechanical activities. Drought mortality that disproportionately affects large conifers is particularly problematic to mature forest specialist species reliant on large trees. However, patches of degraded forests within wildfire perimeters were larger with greater core area than those outside burned areas, and remnant forest habitats were more fragmented within burned perimeters than those affected by drought and beetle mortality alone. The percentage of mature forest that survived and potentially benefited from lower severity wildfire increased over time as the total extent of mature forest declined. These areas provide some opportunity for improved resilience to future disturbances, but strategic management interventions are likely also necessary to mitigate worsening mega-disturbances. Remaining dry mature forest habitat in California may be susceptible to complete loss in the coming decades without a rapid transition from a conservation paradigm that attempts to maintain static conditions to one that manages for sustainable disturbance dynamics.
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Affiliation(s)
| | - Gavin M Jones
- USFS Rocky Mountain Research Station, Albuquerque, New Mexico, USA
- University of New Mexico, Albuquerque, New Mexico, USA
| | - Brandon M Collins
- University of California, Berkeley, California, USA
- USFS Pacific Southwest Research Station, Davis, California, USA
| | - Rebecca Green
- Sequoia & Kings Canyon National Park, Three Rivers, California, USA
| | - Alexander Koltunov
- USFS Pacific Southwest Region, McClellan, California, USA
- University of California, Davis, California, USA
| | - Kathryn L Purcell
- USFS Pacific Southwest Research Station, Coarsegold, California, USA
| | | | | | | | - Peter Stine
- Stine Wildland Resources Science, Sacramento, California, USA
| | - Craig Thompson
- USFS Pacific Southwest Research Station, Fresno, California, USA
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Baijnath-Rodino JA, Li S, Martinez A, Kumar M, Quinn-Davidson LN, York RA, Banerjee T. Historical seasonal changes in prescribed burn windows in California. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 836:155723. [PMID: 35523328 DOI: 10.1016/j.scitotenv.2022.155723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/01/2022] [Accepted: 05/01/2022] [Indexed: 06/14/2023]
Abstract
Prescribed (Rx) burns are conducted on days when the meteorological thresholds of maximum air temperature, relative humidity, and wind speeds are all met (burn window) in order to ensure safe Rx burn practices. Limited burn windows have been consistently identified as one of the most important constraints for conducting Rx burns in California. We investigate whether burn windows across California can be extended from the typical fall season to include other opportune seasons for facilitating specific management objectives. We quantify the seasonal Rx burn efficiencies by assessing the frequency and burned areas using an aggregate of Rx datasets, and we compute the seasonal spatiotemporal trends in the number of days the set of meteorological parameters are met over thirty-five years (1984 to 2019), using the gridMET 4 km dataset. Our results indicate that while fall burns are most frequently executed (40% of the time), the spring (and to a lesser extent winter) seasons yield efficient Rx burns similar to fall because greater acres are being consumed with less burns. In addition, winter and spring seasons experience burn window opportunities (70-90% of the time) over larger areas than the other seasons, and this is predominantly over forested regions in Northern California. Our results also indicate that burn windows in the winter and spring are decreasing at a rate of one day per year over a larger spatial area than that of summer and fall. This decrease is primarily driven by changes in the number of days the relative humidity thresholds are met. Policymakers recognize the critical importance that Rx burns have on a multitude of ecosystem restoration factors, fire behavior dynamics, and firefighter safety. Therefore, there is a need to capitalize on these additional burn windows before these opportunities become less feasible in the future.
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Affiliation(s)
- Janine A Baijnath-Rodino
- University of California Irvine, Department of Civil and Environmental Engineering, Irvine, CA, United States.
| | - Shu Li
- University of California Irvine, Department of Civil and Environmental Engineering, Irvine, CA, United States
| | - Alexandre Martinez
- University of California Irvine, Department of Civil and Environmental Engineering, Irvine, CA, United States
| | - Mukesh Kumar
- University of California Irvine, Department of Civil and Environmental Engineering, Irvine, CA, United States
| | - Lenya N Quinn-Davidson
- University of California, Davis, Agriculture and Natural Resources, Eureka, United States
| | - Robert A York
- University of California, Berkeley, Department of Environmental Science, Policy, and Management, Georgetown, United States
| | - Tirtha Banerjee
- University of California Irvine, Department of Civil and Environmental Engineering, Irvine, CA, United States
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Park J, Choi W, Jung SU. Exploring Trends in Environmental, Social, and Governance Themes and Their Sentimental Value Over Time. Front Psychol 2022; 13:890435. [PMID: 35837641 PMCID: PMC9275432 DOI: 10.3389/fpsyg.2022.890435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 05/02/2022] [Indexed: 11/13/2022] Open
Abstract
Environmental, social, and governance (ESG) is an indicator that measures a company's non-financial performance. Many firms have recently emphasized the importance of ESG. Ascertaining what topics are being discussed around ESG and how they change over time will contribute significantly to gaining insight into ESG. Using 73,397,870 text data scraped and refined from publicly available Twitter data, this study applied Latent Dirichlet Allocation (LDA) and the dynamic topic model (DTM) to ascertain the hidden structure of the ESG-related document collection and the topics being discussed. The study further conducts a sentiment analysis to examine the sentiment of the general public regarding ESG. Topic modeling shows that various topics regarding ESG are being discussed and evolve over time. Sentiment analysis shows that many people have neutral or positive sentiments toward ESG-related issues. This study contributes to exploring insights into ESG among the public and understanding public reactions toward ESG. We further conclude the study with a discussion of managerial implications and potential future research.
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Affiliation(s)
- Joonbeom Park
- Graduate School of Information, Yonsei University, Seoul, South Korea
| | - Woojoo Choi
- Graduate Business School, Hankuk University of Foreign Studies, Seoul, South Korea
| | - Sang-Uk Jung
- Graduate Business School, Hankuk University of Foreign Studies, Seoul, South Korea
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