The contribution of wildland fire emissions to deposition in the U S: implications for tree growth and survival in the Northwest.
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ABSTRACT:
SUBMITTER: Koplitz SN
PROVIDER: S-EPMC7970516 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Recent wildfire events, in the United States (USA) and around the world, have resulted in thousands of homes destroyed and many lives lost, leaving communities and policy makers, once again, with the question as to how to manage wildfire risk. This is particularly important given the prevalent trend of increased fire frequency and intensity. Current approaches to managing wildfires focus on fire suppression and managing fuel build-up in wildlands. However, reliance on these strategies alone has clearly proven inadequate. As such, focus should be shifted towards minimizing potential losses to communities. Achieving this goal, however, requires detailed understanding of the factors that contribute to community vulnerability and the interplay between probability of ignition, vulnerability and calculated risk. In this study, we evaluate wildfire risk for four different communities across the USA for the duration of May to September to communicate a different perspective of risk assessment. We show, for the first time, that community risk is closely related to wind speed and direction, pattern of surrounding wildland vegetation, and buildings layout. The importance of the findings lies in the need for exploring unique viable solutions to reduce risk for every community independently as opposed to embracing a generalized approach as is currently the case.
| S-EPMC7481699 | biostudies-literature
Project description:IntroductionSurface soil microbial communities are directly exposed to the heat from wildland fires. Due to this, the microbial community composition may be stratified within the soil profile with more heat tolerant microbes near the surface and less heat tolerant microbes, or mobile species found deeper in the soil. Biological soil crusts, biocrusts, are found on the soil surface and contain a diverse microbial community that is directly exposed to the heat from wildland fires.MethodsHere, we used a simulated fire mesocosm along with a culture-based approach and molecular characterization of microbial isolates to understand the stratification of biocrust and bare soil microbes after low severity (450°C) and high severity (600°C) fires. We cultured and sequenced microbial isolates from 2 to 6 cm depth from both fire types.ResultsThe isolates were stratified along the soil depth. Green algal isolates were less thermotolerant and found in the deeper depths (4-6 cm) and the control soils, while several cyanobacteria in Oscillatoriales, Synechococcales, and Nostocales were found at 2-3 cm depth for both fire temperatures. An Alphaproteobacteria isolate was common across several depths, both fire types, and both fire temperatures. Furthermore, we used RNA sequencing at three depths after the high severity fire and one control to determine what microbial community is active following a fire. The community was dominated by Gammaproteobacteria, however some Cyanobacteria ASVs were also present.DiscussionHere we show evidence of stratification of soil and biocrust microbes after a fire and provide evidence that these microbes are able to survive the heat from the fire by living just below the soil surface. This is a steppingstone for future work on the mechanisms of microbial survival after fire and the role of soil insulation in creating resilient communities.
| S-EPMC10064808 | biostudies-literature
Project description:Identifying communities vulnerable to adverse health effects from exposure to wildfire smoke may help prepare responses, increase the resilience to smoke and improve public health outcomes during smoke days. We developed a Community Health-Vulnerability Index (CHVI) based on factors known to increase the risks of health effects from air pollution and wildfire smoke exposures. These factors included county prevalence rates for asthma in children and adults, chronic obstructive pulmonary disease, hypertension, diabetes, obesity, percent of population 65 years of age and older, and indicators of socioeconomic status including poverty, education, income and unemployment. Using air quality simulated for the period between 2008 and 2012 over the continental U.S. we also characterized the population size at risk with respect to the level and duration of exposure to fire-originated fine particulate matter (fire-PM2.5) and CHVI. We estimate that 10% of the population (30.5 million) lived in the areas where the contribution of fire-PM2.5 to annual average ambient PM2.5 was high (>1.5 ?g/m3) and that 10.3 million individuals experienced unhealthy air quality levels for more than 10 days due to smoke. Using CHVI we identified the most vulnerable counties and determined that these communities experience more smoke exposures in comparison to less vulnerable communities.
| S-EPMC6372951 | biostudies-literature
Project description:Atmospheric deposition of nitrogen (N) influences forest demographics and carbon (C) uptake through multiple mechanisms that vary among tree species. Prior studies have estimated the effects of atmospheric N deposition on temperate forests by leveraging forest inventory measurements across regional gradients in deposition. However, in the United States (U.S.), these previous studies were limited in the number of species and the spatial scale of analysis, and did not include sulfur (S) deposition as a potential covariate. Here, we present a comprehensive analysis of how tree growth and survival for 71 species vary with N and S deposition across the conterminous U.S. Our analysis of 1,423,455 trees from forest plots inventoried between 2000 and 2016 reveals that the growth and/or survival of the vast majority of species in the analysis (n = 66, or 93%) were significantly affected by atmospheric deposition. Species co-occurred across the conterminous U.S. that had decreasing and increasing relationships between growth (or survival) and N deposition, with just over half of species responding negatively in either growth or survival to increased N deposition somewhere in their range (42 out of 71). Averaged across species and conterminous U.S., however, we found that an increase in deposition above current rates of N deposition would coincide with a small net increase in tree growth (1.7% per ? kg N ha-1 yr-1), and a small net decrease in tree survival (-0.22% per ? kg N ha-1 yr-1), with substantial regional and among-species variation. Adding S as a predictor improved the overall model performance for 70% of the species in the analysis. Our findings have potential to help inform ecosystem management and air pollution policy across the conterminous U.S., and suggest that N and S deposition have likely altered forest demographics in the U.S.
| S-EPMC6193662 | biostudies-other
Project description:BackgroundThe increasing size and frequency of wildland fires are leading to greater potential for cardiopulmonary disease and cancer in exposed populations; however, little is known about how the types of fuel and combustion phases affect these adverse outcomes.ObjectivesWe evaluated the mutagenicity and lung toxicity of particulate matter (PM) from flaming vs. smoldering phases of five biomass fuels, and compared results by equal mass or emission factors (EFs) derived from amount of fuel consumed.MethodsA quartz-tube furnace coupled to a multistage cryotrap was employed to collect smoke condensate from flaming and smoldering combustion of red oak, peat, pine needles, pine, and eucalyptus. Samples were analyzed chemically and assessed for acute lung toxicity in mice and mutagenicity in Salmonella.ResultsThe average combustion efficiency was 73 and 98% for the smoldering and flaming phases, respectively. On an equal mass basis, PM from eucalyptus and peat burned under flaming conditions induced significant lung toxicity potencies (neutrophil/mass of PM) compared to smoldering PM, whereas high levels of mutagenicity potencies were observed for flaming pine and peat PM compared to smoldering PM. When effects were adjusted for EF, the smoldering eucalyptus PM had the highest lung toxicity EF (neutrophil/mass of fuel burned), whereas smoldering pine and pine needles had the highest mutagenicity EF. These latter values were approximately 5, 10, and 30 times greater than those reported for open burning of agricultural plastic, woodburning cookstoves, and some municipal waste combustors, respectively.ConclusionsPM from different fuels and combustion phases have appreciable differences in lung toxic and mutagenic potency, and on a mass basis, flaming samples are more active, whereas smoldering samples have greater effect when EFs are taken into account. Knowledge of the differential toxicity of biomass emissions will contribute to more accurate hazard assessment of biomass smoke exposures. https://doi.org/10.1289/EHP2200.
| S-EPMC6039157 | biostudies-literature
Project description:Fire agencies across the United States must make complex resource allocation decisions to manage wildfires using a national network of shared firefighting resources. Firefighters play a critical role in suppressing fires and protecting vulnerable communities. However, they are exposed to health and safety risks associated with fire, smoke inhalation, and infectious disease transmission. The COVID-19 pandemic further complicated these risks, prompting fire agencies to propose resource management adaptations to minimize COVID-19 exposure and transmission. It is unclear if and how the pandemic may have operationally influenced wildland firefighting personnel resource use given compounding wildfire and COVID-19 risks. Therefore, we developed generalized linear mixed models that were fit using multiple integrated datasets to detect changes in personnel resource use for years prior to and during the COVID-19 pandemic, while controlling for historical fire and landscape conditions, societal risks, and management objectives. Analyses of observed and predicted firefighting resource use revealed reductions in the mean personnel resources used per wildfire per day during the pandemic for models developed across the western U.S. and for various western U.S. fire regions. Notably, the Northern California and the Great Basin Coordination Centers showed statistically significant reductions in ground personnel use during the COVID-19 pandemic. Learning from wildland fire management strategies and resource use trends that occurred during the COVID-19 pandemic, fire agencies can better anticipate resource constraints that may arise during the compounding threats of severe wildland fire activity and infectious disease outbreaks to proactively prepare and adapt suppression management strategies.
| S-EPMC11358158 | biostudies-literature
Project description:In less than 15?years, the Amazon region experienced three major droughts. Links between droughts and fires have been demonstrated for the 1997/1998, 2005, and 2010 droughts. In 2010, emissions of 510?±?120?Tg?C were associated to fire alone in Amazonia. Existing approaches have, however, not yet disentangled the proportional contribution of multiple land cover sources to this total. We develop a novel integration of multisensor and multitemporal satellite-derived data on land cover, active fires, and burned area and an empirical model of fire-induced biomass loss to quantify the extent of burned areas and resulting biomass loss for multiple land covers in Mato Grosso (MT) state, southern Amazonia-the 2010 drought most impacted region. We show that 10.77% (96,855?km2) of MT burned. We estimated a gross carbon emission of 56.21?±?22.5?Tg?C from direct combustion of biomass, with an additional 29.4?±?10?Tg?C committed to be emitted in the following years due to dead wood decay. It is estimated that old-growth forest fires in the whole Brazilian Legal Amazon (BLA) have contributed to 14.81?Tg of C (11.75?Tg?C to 17.87?Tg?C) emissions to the atmosphere during the 2010 fire season, with an affected area of 27,555?km2. Total C loss from the 2010 fires in MT state and old-growth forest fires in the BLA represent, respectively, 77% (47% to 107%) and 86% (68.2% to 103%) of Brazil's National Plan on Climate Change annual target for Amazonia C emission reductions from deforestation.
| S-EPMC4994379 | biostudies-literature
Project description:ObjectivesDue to accelerating wildland fire activity, there is mounting urgency to understand, prevent, and mitigate the occupational health impacts associated with wildland fire suppression. The objectives of this review of academic and grey literature were to: 1. Identify the impact of occupational exposure to wildland fires on physical, mental, and emotional health; and 2. Examine the characteristics and effectiveness of prevention, mitigation, or management strategies studied to reduce negative health outcomes associated with occupational exposure to wildland fire.MethodsFollowing established scoping review methods, academic literature as well as government and industry reports were identified by searching seven academic databases and through a targeted grey literature search. 4679 articles were screened using pre-determined eligibility criteria. Data on study characteristics, health outcomes assessed, prevention or mitigation strategies studied, and main findings were extracted from each included document. The results of this scoping review are presented using descriptive tables and a narrative summary to organize key findings.ResultsThe final sample was comprised of 100 articles: 76 research articles and 24 grey literature reports. Grey literature focused on acute injuries and fatalities. Health outcomes reported in academic studies focused on respiratory health (n = 14), mental health (n = 16), and inflammation and oxidative stress (n = 12). The identified studies evaluated short-term outcomes measuring changes across a single shift or wildland fire season. Most research was conducted with wildland firefighters and excluded personnel such as aviation crews, contract crews, and incident management teams. Five articles reported direct study of mitigation strategies, focusing on the potential usage of masks, advanced hygiene protocols to reduce exposure, fluid intake to manage hydration and core temperature, and glutamine supplementation to reduce fatigue.ConclusionsWhile broad in scope, the evidence base linking wildland fire exposure to any one health outcome is limited. The lack of long-term evidence on changes in health status or morbidity is a clear evidence gap and there is a need to prioritize research on the mental and physical health impact of occupational exposure to wildland fire.
| S-EPMC8725416 | biostudies-literature
Project description:INTRODUCTION:Wildland fires degrade air quality and adversely affect human health. A growing body of epidemiology literature reports increased rates of emergency departments, hospital admissions and premature deaths from wildfire smoke exposure. OBJECTIVE:Our research aimed to characterize excess mortality and morbidity events, and the economic value of these impacts, from wildland fire smoke exposure in the U.S. over a multi-year period; to date no other burden assessment has done this. METHODS:We first completed a systematic review of the epidemiologic literature and then performed photochemical air quality modeling for the years 2008 to 2012 in the continental U.S. Finally, we estimated the morbidity, mortality, and economic burden of wildland fires. RESULTS:Our models suggest that areas including northern California, Oregon and Idaho in the West, and Florida, Louisiana and Georgia in the East were most affected by wildland fire events in the form of additional premature deaths and respiratory hospital admissions. We estimated the economic value of these cases due to short term exposures as being between $11 and $20B (2010$) per year, with a net present value of $63B (95% confidence intervals $6-$170); we estimate the value of long-term exposures as being between $76 and $130B (2010$) per year, with a net present value of $450B (95% confidence intervals $42-$1200). CONCLUSION:The public health burden of wildland fires-in terms of the number and economic value of deaths and illnesses-is considerable.
| S-EPMC6117838 | biostudies-literature
Project description:The environmental sources of microbial aerosols and processes by which they are emitted into the atmosphere are not well characterized. In this study we analyzed microbial cells and biological ice nucleating particles (INPs) in smoke emitted from eight prescribed wildland fires in North Florida. When compared to air sampled prior to ignition, samples of the air-smoke mixtures contained fivefold higher concentrations of microbial cells (6.7 ± 1.3 × 104 cells m-3) and biological INPs (2.4 ± 0.91 × 103 INPs m-3 active at temperatures ≥ -15 °C), and these data significantly positively correlated with PM10. Various bacteria could be cultured from the smoke samples, and the nearest neighbors of many of the isolates are plant epi- and endophytes, suggesting vegetation was a source. Controlled laboratory combustion experiments indicated that smoke emitted from dead vegetation contained significantly higher numbers of cells, INPs, and culturable bacteria relative to the green shrubs tested. Microbial viability of smoke aerosols based on formazan production and epifluorescent microscopy revealed no significant difference in the viable fraction (~80%) when compared to samples of ambient air. From these data, we estimate each fire aerosolized an average of 7 ± 4 × 109 cells and 2 ± 1 × 108 biological INPs per m2 burned and conclude that emissions from wildland fire are sources of viable microbial aerosols to the atmosphere.
| S-EPMC8027831 | biostudies-literature