Warming and Earlier Spring Increase Western U.S. Forest Wildfire Activity

Westerling, A. L.; Hidalgo, Hugo G.; Cayan, Daniel R.; Swetnam, Thomas W.

doi:10.1126/science.1128834

Cited by 4,421 publications

(3,638 citation statements)

References 31 publications

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“…Wildfire season in North America has increased in intensity and duration, resulting in a greater population at high risk of wildfire smoke exposure 1, 2, 3. Exposure to wildfire smoke is already contributing to substantial clinical, public health, and economic societal burdens, and yet, large‐scale wildfire events are projected to increase through the end of the century in many regions, including in California 2, 4, 5…”

Section: Introductionmentioning

confidence: 99%

Cardiovascular and Cerebrovascular Emergency Department Visits Associated With Wildfire Smoke Exposure in California in 2015

Wettstein

Hoshiko

Fahimi

et al. 2018

JAHA

183

146

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BackgroundWildfire smoke is known to exacerbate respiratory conditions; however, evidence for cardiovascular and cerebrovascular events has been inconsistent, despite biological plausibility.Methods and ResultsA population‐based epidemiologic analysis was conducted for daily cardiovascular and cerebrovascular emergency department (ED) visits and wildfire smoke exposure in 2015 among adults in 8 California air basins. A quasi‐Poisson regression model was used for zip code‐level counts of ED visits, adjusting for heat index, day of week, seasonality, and population. Satellite‐imaged smoke plumes were classified as light, medium, or dense based on model‐estimated concentrations of fine particulate matter. Relative risk was determined for smoky days for lag days 0 to 4. Rates of ED visits by age‐ and sex‐stratified groups were also examined. Rates of all‐cause cardiovascular ED visits were elevated across all lags, with the greatest increase on dense smoke days and among those aged ≥65 years at lag 0 (relative risk 1.15, 95% confidence interval [1.09, 1.22]). All‐cause cerebrovascular visits were associated with smoke, especially among those 65 years and older, (1.22 [1.00, 1.49], dense smoke, lag 1). Respiratory conditions were also increased, as anticipated (1.18 [1.08, 1.28], adults >65 years, dense smoke, lag 1). No association was found for the control condition, acute appendicitis. Elevated risks for individual diagnoses included myocardial infarction, ischemic heart disease, heart failure, dysrhythmia, pulmonary embolism, ischemic stroke, and transient ischemic attack.ConclusionsAnalysis of an extensive wildfire season found smoke exposure to be associated with cardiovascular and cerebrovascular ED visits for all adults, particularly for those over aged 65 years.

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Section: Introductionmentioning

confidence: 99%

Cardiovascular and Cerebrovascular Emergency Department Visits Associated With Wildfire Smoke Exposure in California in 2015

Wettstein

Hoshiko

Fahimi

et al. 2018

JAHA

183

146

View full text Add to dashboard Cite

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“…It has been predicted the frequency and intensity of wildfire would increase under global warming (Bradstock, 2002;Cary, 2002;Westerling et al, 2006). Fire influences the population and species diversity of the aboveground plants (Bond and Van Wilgen, 1996) and belowground soil properties (Certini, 2005) as well as microorganisms (Vázquez et al, 1993).…”

Section: Introductionmentioning

confidence: 99%

Shifts in the abundance and community structure of soil ammonia oxidizers in a wet sclerophyll forest under long-term prescribed burning

Long

Chen

et al. 2014

Science of The Total Environment

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• We examined how fires affected the abundances and communities of soil AOB and AOA.• A long-term repeated forest fire experiment was investigated.• Fires increased the abundance of bacterium amoA genes, but not archaeal amoA genes.• Fire also modified the composition of AOA and AOB communities.• AOB genotype was affected by soil pH and DOC, while AOA by nitrate-N and DOC. a b s t r a c t a r t i c l e i n f o Fire shapes global biome distribution and promotes the terrestrial biogeochemical cycles. Ammonia-oxidizing bacteria (AOB) and archaea (AOA) play a vital role in the biogeochemical cycling of nitrogen (N). However, behaviors of AOB and AOA under long-term prescribed burning remain unclear. This study was to examine how fire affected the abundances and communities of soil AOB and AOA. A long-term repeated forest fire experiment with three burning treatments (never burnt, B0; biennially burnt, B2; and quadrennially burnt, B4) was used in this study. The abundances and community structure of soil AOB and AOA were determined using quantitative PCR, restriction fragment length polymorphism and clone library. More frequent fires (B2) increased the abundance of bacterium amoA gene, but tended to decrease archaeal amoA genes. Fire also modified the composition of AOA and AOB communities. Canonical correspondence analysis showed soil pH and dissolved organic C (DOC) strongly affected AOB genotypes, while nitrate-N and DOC shaped the AOA distribution. The increased abundance of bacterium amoA gene by fires may imply an important role of AOB in nitrification in fire-affected soils. The fire-induced shift in the community composition of AOB and AOA demonstrates that fire can disturb nutrient cycles.

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“…Atmosphere-Ocean General Circulation Models (AOGCMs) predict mean annual temperature in the SW US to increase between 2 °C and 5 °C in conjunction with an overall decrease in annual precipitation, thus resulting in increased severity and duration of drought-like conditions [4,7]. Warmer, drier conditions in the SW US have been linked to an increased frequency of catastrophic wildfires [4,8,9], bark-beetle outbreaks [4,10], and widespread mortality events [1][2][3][4][5][6]11]. These amplified rates of tree mortality and extensive mortality events result in large pulses of stored carbon being released into the atmosphere [1,12].…”

Section: Introductionmentioning

confidence: 99%

Carbon Stocks and Climate Change: Management Implications in Northern Arizona Ponderosa Pine Forests

Bagdon

Huang

2014

Forests

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Abstract:Researchers have observed climate-driven shifts of forest types to higher elevations in the Southwestern US and predict further migration coupled with large-scale mortality events proportional to increases in radiative forcing. Range contractions of forests are likely to impact the total carbon stored within a stand. This study examines the dynamics of Pinus ponderosa stands under three climate change scenarios in Northern Arizona using the Climate Forest Vegetation Simulator (Climate-FVS) model to project changes in carbon pools. A sample of 90 stands were grouped according to three elevational ranges; low-(1951 to 2194 m), mid-(2194 to 2499 m), and high-(2499 to 2682 m.) elevation stands. Growth, mortality, and carbon stores were simulated in the Climate-FVS over a 100 year timespan. We further simulated three management scenarios for each elevational gradient and climate scenario. Management included (1) a no-management scenario, (2) an intensive-management scenario characterized by thinning from below to a residual basal area (BA) of 18 m 2 /ha in conjunction with a prescribed burn every 10 years, and (3) a moderate-management scenario characterized by a thin-from-below treatment to a residual BA of 28 m 2 /ha coupled with a prescribed burn every 20 years. Results indicate that any increase in aridity due to climate change will produce substantial mortality throughout the elevational range of ponderosa pine stands, with lower elevation stands projected to experience the most devastating effects. Management was only effective for the intensive-management scenario; stands receiving this treatment schedule maintained moderately consistent levels of basal area and demonstrated a higher level of resilience to climate change relative to the two other management scenarios. The results of this study indicate that management can improve OPEN ACCESSForests 2014, 5 621 resiliency to climate change, however, resource managers may need to employ more intensive thinning treatments than currently proposed to achieve the best results.

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Warming and Earlier Spring Increase Western U.S. Forest Wildfire Activity

Cited by 4,421 publications

References 31 publications

Cardiovascular and Cerebrovascular Emergency Department Visits Associated With Wildfire Smoke Exposure in California in 2015

Cardiovascular and Cerebrovascular Emergency Department Visits Associated With Wildfire Smoke Exposure in California in 2015

Shifts in the abundance and community structure of soil ammonia oxidizers in a wet sclerophyll forest under long-term prescribed burning

Carbon Stocks and Climate Change: Management Implications in Northern Arizona Ponderosa Pine Forests

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