How will climate change and forest harvesting influence the habitat quality of two culturally salient species?

Boreal landscapes face increasing disturbances which can affect cultural keystone species, i.e. culturally salient species that shape in a major way the cultural identity of a people. Given their importance, the fate of such species should be assessed to be able to act to ensure their perennity. We assessed how climate change and forest harvesting will affect the habitat quality of Rhododendron groenlandicum and Vaccinium angustifolium, two cultural keystone species for many Indigenous peoples in eastern Canada. We used the forest landscape model LANDIS-II in combination with species distribution models to simulate the habitat quality of these two species on the territories of three Indigenous communities according to different climate change and forest harvesting scenarios. Climate-sensitive parameters included wildfire regimes as well as tree growth. Moderate climate change scenarios were associated with an increased proportion of R. groenlandicum and V. angustifolium in the landscape, the latter species also responding positively to severe climate change scenarios. Harvesting had a minimal effect, but slightly decreased the probability of presence of both species where it occurred. According to the modeling results, neither species is at risk under moderate climate change scenarios. However, under severe climate change, R. groenlandicum could decline as the proportion of deciduous trees would increase in the landscape. Climate change mitigation strategies, such as prescribed fires, may be necessary to limit this increase. This would prevent the decrease of R. groenlandicum, as well as contribute to preserve biodiversity and harvestable volumes.

Fire deaths in Cape Town, South Africa: A retrospective review of medico-legal and toxicological findings (2006 - 2018)

BACKGROUND

In South Africa, fire-related deaths are common, particularly within dense informal housing settlements. Published data on deaths from fire incidents in Cape Town is sparse. Additionally, little emphasis has been placed on the role of toxicological investigations in these deaths, despite the known risk of alcohol and drug impairment to burn injury.

METHODS

A retrospective, descriptive analysis of post-mortem case reports from Salt River Mortuary was conducted to investigate all deaths in which fires were involved in the west metropole of Cape Town, between 2006 to 2018. Demographic, circumstantial, and toxicological data were analyzed using R software.

RESULTS

In total 1370 fire deaths occurred over 13 years, with a mean of 106 (SD ± 18) cases per annum (≈3% of the annual caseload and a mortality rate of 5.5 per 100,000). Males (70.4%), adults (mean=30.7 years), and toddlers (1-4 years old) were notably at risk. Deaths typically occurred in the early morning (00h00 - 06h00) (45.7%), during winter (32.1%), and in lower socioeconomic areas with highly dense informal settlements (65.6%), with 29% of deaths occurring in multi-fatality incidents. Ethanol was detected (≥0.01 g/100 mL) in 55.1% of cases submitted for analysis (71.5%), with a mean of 0.18 g/100 mL, and with 93.8% of positive cases > 0.05 g/100 mL. Carboxyhaemoglobin (COHb) analysis was requested in 76.4% of cases, with 57% of cases having a %COHb of ≥ 20%. Toxicology results (for drugs other than ethanol) from the national laboratory were outstanding in 34.4% of the cases at the conclusion of the study. BAC and %COHb were significantly higher in deaths from burns and smoke inhalation (usually accidents) than deaths from combined trauma and burns (typically homicides). Fire deaths with high COHb levels were more likely to display cherry-red discoloration (OR=3.1) and soot in the airways (OR=2.7) at autopsy.

CONCLUSION

This article provides an updated description of fire deaths in the west metropole of Cape Town. The importance of BAC and COHb testing in these cases was noted, and the authors call for an investigation of the role of drug impairment (specifically frequently misused drugs methamphetamine and methaqualone) as a risk factor in these deaths. Areas of high-density informal settlements, where open flames are used to heat, light, and cook, were noted as high risk.

Siting of fuel stations within residential areas in Ghanaian cities: Perceptions of residents in Wa on fire disaster risks

This paper responds to the limited literature on perceptions of fire disaster risks associated with the siting of fuel stations in dense residential areas in African cities. We address three interrelated research objectives regarding fire disaster risk and safety behaviours. First, we explore residents' perception of the reasons for the siting of fuel stations in residential areas. Second, we examine their sociodemographic characteristics and perception of fire disaster risks associated with fuel stations; and third, we examine residents' fire safety behaviours around fuel stations. We address these objectives by engaging with risk perception theory and protection motivation theory as well as an empirical review of literature worldwide. We also draw evidence from Wa in Ghana using a mixed research approach involving 182 participants. Through a questionnaire, observation checklist, a camera, and an in-depth interview guide, we elicited data from residents and relevant stakeholders to address our research questions. The quantitative data were analysed using descriptive statistics and a chi-square test, while thematic analysis was used to analyse the responses obtained from the interviews. We found that ease of access and competition motivated the siting of fuel stations in residential areas. Although residents knew the risk of living near fuel stations, measures were not implemented to reduce their vulnerability to fire disasters. People living near fuel stations should be encouraged to invest in equipment and take measures to reduce their vulnerability to fire disasters.

Experimental study to compare the strength of concrete with different amounts of polypropylene fibers at high temperatures

It is widely known that adding fibers to concrete improves the properties of concrete, which has a brittle behavior. Although concrete has high compressive strength but poor tensile strength, this has led researchers to offer a variety of ways to deal with this weakness. The use of fibers is one of the methods used to enhance concrete behavior. Fire is one of the most important cases in structures; if the temperature is high or its duration is long, it will cause serious damage to the structure. The present study is an experimental study in which different concrete samples with different amounts of polypropylene fibers and different cement content are exposed once at a normal temperature of 25 °C and again at high temperatures, including 250 °C and 500 °C. The effect of temperature on the compressive and tensile strengths of concrete containing 0.5%, 1.5%, and 2% polypropylene fibres and with cement contents of 200 kg/m3, 260 kg/m3, and 320 kg/m3. The compressive and tensile strength was evaluated at curing 28 days of strength. The results showed a severe strength loss for all concretes after exposure to 500 °C. The relative compressive strengths of concretes containing PP fibers were higher than those of concretes without PP fibers. The tensile strength of concrete was more sensitive to high temperatures than the compressive strength. Based on the test results, it can be concluded that adding 2% PP fibers can significantly promote the residual mechanical properties of concrete during heating. The compressive strength at 25 °C with 2% PP fibres decreases by 43% with cement contents of 200 kg/m3 and 64% with cement contents of 260 kg/m3, and 37% with cement contents of 320 kg/m3, respectively. Also, the compressive strength at 500 °C with 2% PP fibres decreases by 61% with 200 kg/m3, 59% with 260 kg/m3, and 42% with cement contents of 320 kg/m3, respectively.

Polycyclic aromatic compounds in a northern freshwater ecosystem: Patterns, sources, and the influences of environmental factors

Polycyclic aromatic compounds (PACs) - a large group of organic chemicals naturally present in petroleum deposits (i.e., petrogenic) or released into the environment by incomplete combustion of organic materials (i.e., pyrogenic) - represent a potential risk to the health of aquatic ecosystems. In high latitude freshwater ecosystems, concentrations of PACs may be increasing, yet there are limited studies in such systems to assess change and to understand threats. Using 10 years of contemporary data from passive samplers deployed across five regions (n = 43 sites) in the Mackenzie River Basin, we (i) describe baseline levels of PACs, (ii) assess spatiotemporal patterns, and (iii) evaluate the extent to which environmental factors (fire, snowmelt, and proximity to oil infrastructure) influence concentrations in this system. Measured concentrations were low, relative to those in more southern systems, with mixtures primarily being dominated by non-alkylated, low molecular weight compounds. Concentrations were spatially consistent, except for two sites near Norman Wells (an area of active oil extraction) with increased levels. Similarly, observed annual variation was minimal, with 2014 having generally higher levels of PACs. We did not detect effects of fire, snowmelt, or oil infrastructure on concentrations. Taken together, our findings suggest that PACs in the Mackenzie River are currently at low levels and are primarily petrogenic in origin. They further indicate that ongoing monitoring and testing of environmental drivers (especially at finer spatial scales) are needed to better predict how ecosystem change will influence PAC levels in the basin and in other northern systems.

Pregnancy exposure to PM2.5 from wildland fire smoke and preterm birth in California

BACKGROUND

Wildfires in the Western United States are a growing and significant source of air pollution that is eroding decades of progress in air pollution reduction. The effects on preterm birth during critical periods of pregnancy are unknown.

METHODS

We assessed associations between prenatal exposure to wildland fire smoke and risk of preterm birth (gestational age < 37 weeks). We assigned smoke exposure to geocoded residence at birth for all live singleton births in California conceived 2007-2018, using weekly average concentrations of particulate matter ≤ 2.5 µm (PM2.5) attributable to wildland fires from United States Environmental Protection Agency's Community Multiscale Air Quality Model. Logistic regression yielded odds ratio (OR) for preterm birth in relation to increases in average exposure across the whole pregnancy, each trimester, and each week of pregnancy. Models adjusted for season, age, education, race/ethnicity, medical insurance, and smoking of the birthing parent.

RESULTS

For the 5,155,026 births, higher wildland fire PM2.5 exposure averaged across pregnancy, or any trimester, was associated with higher odds of preterm birth. The OR for an increase of 1 µg/m3 of average wildland fire PM2.5 during pregnancy was 1.013 (95 % CI:1.008,1.017). Wildland fire PM2.5 during most weeks of pregnancy was associated with higher odds. Strongest estimates were observed in weeks in the second and third trimesters. A 10 µg/m3 increase in average wildland fire PM2·5 in gestational week 23 was associated with OR = 1.034; 95 % CI: 1.019, 1.049 for preterm birth.

CONCLUSIONS

Preterm birth is sensitive to wildland fire PM2.5; therefore, we must reduce exposure during pregnancy.

A European-scale analysis reveals the complex roles of anthropogenic and climatic factors in driving the initiation of large wildfires

Analysing wildfire initiation patterns and identifying their primary drivers is essential for the development of more efficient fire prevention strategies. However, such analyses have traditionally been conducted at local or national scales, hindering cross-border comparisons and the formulation of broad-scale policy initiatives. In this study, we present an analysis of the spatial variability of wildfire initiations across Europe, focusing specifically on moderate to large fires (> 100 ha), and examining the influence of both human and climatic factors on initiation areas. We estimated drivers of fire initiation using machine learning algorithms, specifically Random Forest (RF), covering the majority of the European territory (referred to as the "ET scale"). The models were trained using data on fire initiations extracted from a satellite burned area product, comprising fires occurring from 2001 to 2019. We developed six RF models: three considering all fires larger than 100 ha, and three focused solely on the largest events (> 1000 ha). Models were developed using climatic and human predictors separately, as well as both types of predictors mixed together. We found that both climatic and mixed models demonstrated moderate predictive capacity, with AUC values ranging from 79 % to 81 %; while models based only on human variables have had poor predictive capacity (AUC of 60 %). Feature importance analysis, using Shapley Additive Explanations (SHAP), allowed us to assess the primary drivers of wildfire initiations across the European Territory. Aridity and evapotranspiration had the strongest effect on fire initiation. Among human variables, population density and aging had considerable effects on fire initiation, the former with a strong effect in mixed models estimating large fires, while the latter had a more important role in the prediction of very large fires. Distance to roads and forest-agriculture interfaces were also relevant in some initiation models. A better understanding of drivers of main fire events should help designing European forest fire management strategies, particularly in the light of growing importance of climate change, as it would affect both fire severity and areas at risk. Factors of fire initiation should also be part of a comprehensive approach for fire risk assessment, reduction and adaption, contributing to more effective wildfire management and mitigation across the continent.

An uncut copy of Scleromyceti Sueciae: lost and then found

BACKGROUND

A copy of Scleromyceti Sueciae, a work on which the nomenclature of many fungi is based was known to occur in Scotland's Glasgow University Botany Department but the buildings were devastated by fire in 2001 and the whereabouts of this important work, if it existed, was lost. Its re-finding is reported herein.

RESULTS

The Glasgow copy of Scleromyceti Sueciae, an uncut first edition of Fries' work, was located in the Glasgow Museums in its original cabinet being transferred there years before the fire and its specimens being now databased. It is one of the few existing uncut copies of this important scientific work and one of the best-preserved copies of the first edition.

CONCLUSION

The discovery of this first edition of Scleromyceti Sueciae emphasizes the significance to reserve special conservation for important collections by early mycologists. It also allows interested mycologists world-wide to know of the existence in Glasgow of an uncut, first edition copy.

The utility of blow fly (Diptera: Calliphoridae) evidence from burned human remains

Burning of human remains is a common method to conceal or destroy evidence associated with homicides and illegal activities. However, data regarding blow fly colonization of burned remains are scarce, with all previously published empirical studies focusing only on non-human animals. It is critically important to obtain basic data on blow fly colonization patterns of burned human remains as such evidence may represent the only feasible method for PMI estimation in cases of burning. In this study, we thermally altered six human donors to a Crow-Glassman Scale Level 3 (CGS-3) and placed them at the Anthropology Research Facility at the University of Tennessee in Summer 2021, Spring 2022, and Summer 2022. Six unburned human donors were used as controls. Observations for insect activity began within 24 h of placement and continued twice weekly through decomposition. Age estimations were performed with immature blow flies to estimate the time of colonization (TOC), and accuracy was assessed against the time of placement for each donor. All burned donors examined in this study were colonized by blow flies. No significant difference in species composition was determined between treatments, though TOC estimations from burned donors were slightly (but significantly) less accurate than TOC estimations from unburned donors (80% vs. 83% accuracy; χ2 = 0.041, df = 1, P = 0.840). These results indicate that blow flies can successfully colonize human remains burned to CGS-3 and that accurate TOC estimations can still be generated from larval specimens. Though several limitations to this study exist (e.g., inconsistent donor BMI, lack of donor temperature data), our results underscore the utility of entomological evidence in cases of burned human remains.

Exposure Assessment Study on Lithium-Ion Battery Fire in Explosion Test Room in Battery Testing Facility

A lithium-ion battery is a rechargeable battery that uses the reversible reduction of lithium ions to store energy and is the predominant battery type in many industrial and consumer electronics. The lithium-ion batteries are essential to ensure they operate safely. We conducted an exposure assessment five days after a fire in a battery-testing facility. We assessed some of the potentially hazardous materials after a lithium-ion battery fire. We sampled total suspended particles, hydrogen fluoride, and lithium with real-time monitoring of particulate matter (PM) 1, 2.5, and 10 micrometers (μm). The area sampling results indicated that primary potential hazardous materials such as dust, hydrogen fluoride, and lithium were below the recommended limits suggested by the Korean Ministry of Labor and the American Conference of Governmental Industrial Hygienists Threshold Limit Values. Based on our assessment, workers were allowed to return to work.

Research on the evacuation of people from a road tunnel fire based on a mathematical model

A mathematical model for the evacuation of people from a road tunnel is created, taking into account various factors such as the speed at which people move, the density of the flow of people, and the outcome of the fire. This model allows for the precise calculation of the evacuation time and the optimization of the evacuation route in a fire scenario. The constructed mathematical model was used to determine how long it would take for people to evacuate this road tunnel, and the findings of the Pathfinder simulation were compared. The findings demonstrate a relationship between the model's evacuation time and the human flow density, movement velocity, and fire product characteristics. The evacuation time is closer to the outcome of the actual fire scene when the impact of the fire environment on the speed of evacuation is quantified. The mathematical model of human evacuation's calculation of the evacuation time is essentially accurate when compared to the Pathfinder simulation's calculation, with an error of only 0.77 %. The model provides recommendations for optimizing the evacuation of people from a road tunnel in the case of a fire by not only predicting where the crowding would occur but also by calculating the duration of the crowding.

Using high-resolution land cover data to assess structure loss in the 2018 Woolsey Fire in Southern California

There are growing concerns about increases in the size, frequency, and destructiveness of wildfire events. One commonly used mitigation strategy is the creation and maintenance of defensible space, a zone around buildings where vegetation is managed to increase potential for structures to survive during wildfires. Despite widespread acceptance and advocacy of defensible space, few studies provide empirical evidence documenting the efficacy of different fuel modification practices under real wildfire conditions. The 2018 Woolsey Fire in Los Angeles County, California, occurred a short time after high-resolution (0.07 m2) land cover data were created, providing a unique opportunity to quantify vegetation before the fire. We integrated measurements from this high-resolution land cover data with parcel data, building attributes, and environmental context. We then used Random Forests models to analyze the extent to which these factors predicted structure loss in the wildfire. Variable importance scores showed vegetation around buildings was not a strong predictor of building-level damage outcomes compared to building materials and landscape features such as paved land cover per parcel, elevation, building density, and distance to road networks. Among building materials, multi-paned windows and enclosed eaves were most highly associated with building survival. These results are consistent with other studies that conclude building materials and environmental context are more related to survivorship than defensible space.

Wildfire and cattle legacies on gradients of soil nitrogen underlie patterns of annual brome invasion

Human activities are increasing wildfires and livestock activity in arid ecosystems with potential implications for the spread of invasive grasses. The objective of this study was to test whether fire history and cattle activity alter soil resource gradients, thereby affecting patterns of Bromus rubens L. (red brome) invasion. Six paired burned and unburned transect lines (1-km long) were established in the northeast Mojave Desert along the boundaries of four independent wildfire scars. At 100-m transect increment points, we measured the distance to the two nearest cowpats, and two random points and measured the density, height, biomass, and seed production of red brome, soil moisture and inorganic nitrogen (N). Cattle activity was 29% greater along burned transects compared to unburned transects (P < 0.05). Red brome height, density, and seed production were 11-34% greater along burned transects than unburned transects (P < 0.05). Red brome height, biomass, density, and seed production were twofold to tenfold greater next to cowpats compared to random points (P < 0.05). Soils along burned transects and beneath cowpats had greater soil inorganic N (P < 0.05), which was positively correlated with red brome density, height, biomass, and seed production (R2 = 0.60-0.85, P < 0.0001). Transgenerational effects were evident as seeds from red brome next to cowpats had 27% higher germination than seeds collected from random points. Positive responses of red brome to increased inorganic N related to fire and cattle activity may contribute fine fuel infill that drives invasive grass-fire cycles in deserts.

Spatio-temporal assessment of soil properties immediately and eight months after a high intensity-controlled burn in the south of Spain

In recent years, the use of fire as a means by which to manage forest ecosystems has become more frequent in Europe. Fire has a significant impact on the soil, and it is therefore necessary to understand how controlled burns affect this invaluable resource. The purpose of this study was to evaluate the main alterations in the physical-chemical and biological properties of the soil because of a high intensity-controlled burn in "Los Boquerones" area (Villaviciosa de Córdoba, Spain). Additionally, we assessed the spatial heterogeneity of the alterations of different soil properties. A grid of 12 points was established on a hillside in Sierra Morena (Córdoba). Thermocouples were placed at each point, and soil samples were collected at two depths (0-2 cm and 2-5 cm) before burning, immediately after burning and eight months later. Soil pH, electrical conductivity, nutrient content and/or availability, among others, and their spatio-temporal variations were analysed. Soil pH, increased in the first centimetres of the soil (0-2 cm) immediately after burning up to >2 units, and the increase was maintained eight months following the burn. Additionally, the high-intensity burn had a positive short-term effect on some of the soil properties, such as nutrient availability for plants, which was considerably increased. The magnitude of the alterations in the soil indicators assessed was spatially explained by the behaviour of the fire during the controlled burning. The burn also had both direct and indirect effects on soil microorganisms. In conclusion, the possible immediate and short-term effects of burning on the soil resource should be considered for a more holistic management of fire in forest ecosystems, as its functionality and capacity to provide ecosystem services is largely altered by these events as a function of their intensity.

Surface coated ZnO powder as flame retardant for wood: A short communication

In the present study, the ability of a coating of zinc oxide (ZnO) powder to improve the fire-safety of wood exposed to radiative heat flux was examined, focusing on the ignition time of the wood. To test ZnO's efficiency on the wood substrate, two different amounts of ZnO (0.5 and 1 g ZnO per dm2) were applied to the wood surface and exposed to radiative heat from a cone calorimeter wherein a pristine piece of wood with no ZnO treatment was taken as control. The experiments were conducted at three different irradiation levels i.e., 20, 35, and 50 kWm-2. The results showed that applying ZnO on the surface of the wood significantly increased the ignition time (TTI). For the three different heat fluxes, using 0.5 g ZnO per dm2 coating on the wood surface increased the TTI by 26-33 %. Furthermore, the application of 1 g of ZnO per dm2 generated a TTI increment of 37-40 %. All three irradiation levels showed similar trends in TTI. The micrographs taken before and after combustion showed no significant disparity in the morphology of ZnO. The agglomerated ZnO particles on the wood surface remained intact after combustion. This study demonstrates a facile method of using ZnO to delay the ignition of wood. This could potentially impart fire-safety to wooden structures/façades in wildland-urban interfaces and elsewhere by reducing flame spread.

Managing high-risk behaviours and challenges to prevent housing loss in permanent supportive housing: a rapid review

Permanent supportive housing is an effective intervention for stably housing most people experiencing homelessness and mental illness who have complex support needs. However, high-risk behaviours and challenges are prevalent among this population and have the potential to seriously harm health and threaten housing tenures. Yet, the research on the relationship between high-risk issues and housing stability in permanent supportive housing has not been previously synthesized. This rapid review aimed to identify the housing-related outcomes of high-risk behaviours and challenges in permanent supportive housing settings, as well as the approaches used by agencies and residents to address them. A range of high-risk behaviours and challenges were examined, including risks to self (overdose, suicide/suicide attempts, non-suicidal self-injury, falls/fall-related injuries), and risks to multiple parties and/or building (fire-setting/arson, hoarding, apartment takeovers, physical/sexual violence, property damage, drug selling, sex trafficking). The search strategy included four components to identify relevant academic and grey literature: (1) searches of MEDLINE, APA PsycINFO, and CINAHL Plus; (2) hand searches of three journals with aims specific to housing and homelessness; (3) website browsing/searching of seven homelessness, supportive housing, and mental health agencies and networks; and (4) Advanced Google searches. A total of 32 articles were eligible and included in the review. Six studies examined the impacts of high-risk behaviours and challenges on housing tenancies, with overdose being identified as a notable cause of death. Twenty-six studies examined approaches and barriers to managing high-risk behaviours and challenges in PSH programs. These were categorized into eight types of approaches: (1) clinical, (2) relational/educational, (3) surveillant, (4) restrictive, (5) strategic, (6) design-based, (7) legal, and (8) self-defence. Consistent across all approaches was a lack of rigorous examination of their effectiveness. Further, some approaches that are legal, restrictive, surveillant, or strategic in nature may be used to promote safety, but may conflict with other program objectives, including housing stability, or resident empowerment and choice. Research priorities were identified to address the key evidence gaps and move toward best practices for preventing and managing high-risk behaviours and challenges in permanent supportive housing.

Characterization of global fire activity and its spatiotemporal patterns for different land cover types from 2001 to 2020

Fire is a widespread phenomenon that plays an important role in Earth's ecosystems. This study investigated the global spatiotemporal patterns of burned areas, daytime and nighttime fire counts, and fire radiative power (FRP) from 2001 to 2020. The month with the largest burned area, daytime fire count, and FRP presented a bimodal distribution worldwide, with dual peaks in early spring (April) and summer (July and August), while the month with the largest nighttime fire count and FRP showed a unimodal distribution, with a peak in July. Although the burned area showed decline at the global scale, a significant increase occurred in temperate and boreal forest regions, where nighttime fire occurrence and intensity have consistently increased in recent years. The relationships among burned area, fire count, and FRP were further quantified in 12 typical fire-prone regions. The burned area and fire count exhibited a humped relationship with FRP in most tropical regions, whereas the burned area and fire count constantly increased when the FRP was below approximately 220 MW in temperate and boreal forest regions. Meanwhile, the burned area and FRP generally increased with the fire count in most fire-prone regions, indicating an increased risk of more intense and larger fires as the fire count increased. The spatiotemporal dynamics of burned areas for different land cover types were also explored in this study. The results suggest that the burned areas in forest, grassland, and cropland showed dual peaks in April and from July to September while the burned areas in shrubland, bareland, and wetlands usually peaked in July or August. Significant increases in forest burned area were observed in temperate and boreal forest regions, especially in the western U.S. and Siberia, whereas significant increases in cropland burned area were found in India and northeastern China.

In vitro effect of burned pasture soil on eggs and free-living larvae of ruminant gastrointestinal nematodes

Gastrointestinal nematodes are the most expensive agent of disease currently facing the livestock production industry. Spending the beginning of their life cycle as eggs and free-living larvae, nematodes are vulnerable to a multitude of external environmental factors. Fire is a naturally occurring force of nature that has both destructive and reconstructive effects on soil characteristics which nematode stages rely on for survival. The aim of this project was to evaluate in vitro the effect of burned pasture soil (200 °C and 500 °C) on the free-living stages of ruminant nematodes. We tested the effect of burned soil on the ability of eggs to hatch and produce infective larvae, and then tested survival of infective larvae within burned soil. Adding burned soil (500 °C) to larval cultures improved larval yield compared to larval cultures containing raw soil or soil burned at a lower heat (200 °C), and raw soil improved longer term survival of infective larvae. We were able to recover significantly more larvae from samples with low soil content either as raw or soil burned at 200 °C, when compared with samples with soil burned at 500 °C. This study has shown that the survival of gastrointestinal nematodes at the L3 stage is negatively impacted by the addition of soil burned at 500 °C. Although this temperature is closest to that of a medium intensity wildfire, which is a typically destructive process in agriculture, it reduces the number of infective GIN larvae available for animals to ingest. These experiments enable us to address in vitro if post-fire soil conditions alter the number of infective larvae available on pasture, and thus the infectivity of the pasture to livestock.

Optode-based chemical imaging of laboratory burned soil reveals millimeter-scale heterogeneous biogeochemical responses

Soil spatial responses to fire are unclear. Using optical chemical sensing with planar 'optodes', pH and dissolved O₂ concentration were tracked spatially with a resolution of 360 μm per pixel for 72 h after burning soil in the laboratory with a butane torch (∼1300 °C) and then sprinkling water to simulate a postfire moisture event. Imaging data from planar optodes correlated with microbial activity (quantified via RNA transcripts). Post-fire and post-wetting, soil pH increased throughout the entire ∼13 cm × 17 cm × 20 cm rectangular cuboid of sandy loam soil. Dissolved O₂ concentrations were not impacted until the application of water postfire. pH and dissolved O₂ both negatively correlated (p < 0.05) with relative transcript expression for galactose metabolism, the degradation of aromatic compounds, sulfur metabolism, and narH. Additionally, dissolved O₂ negatively correlated (p < 0.05) with the relative activity of carbon fixation pathways in Bacteria and Archaea, amoA/amoB, narG, nirK, and nosZ. nifH was not detected in any samples. Only amoB and amoC correlated with depth in soil (p < 0.05). Results demonstrate that postfire soils are spatially complex on a mm scale and that using optode-based chemical imaging as a chemical navigator for RNA transcript sampling is effective.

Silvicultural Practices in the Management of Diospyros melanoxylon (Tendu) Leaf Production: Options and Trade-offs

Non-timber forest products (NTFPs) are known to provide livelihoods for forest-based communities across the world. While ensuring the sustainability of NTFP harvests is a key challenge, optimizing the production of NTFPs through appropriate silvicultural practices is also critical for forest-based economies. In Central India, the suitability of fire or pruning practices for enhancing the production of leaves of the tendu tree (Diospyros melanoxylon) has been much debated. While villagers commonly adopt annual litter fires, the state Forest Department urges leaf collectors to adopt the more labor-intensive practice of pruning. On the other hand, conservationists recommend completely hands-off management (no fire or pruning). In this study, we compared leaf production from the competing practices of litter fire, pruning, pruning-with-fire, and hands-off management, that are experimented with in community-managed forests. We checked for confounding factors such as tree canopy cover, presence of tendu trees, and inherent differences in forest type. We conducted the study during the pre-harvest season from March to May 2020 in villages in the northern Gadchiroli district of Maharashtra, India. We found that pruning and pruning-with-fire lead to higher root sprout production and, in turn, higher leaf production per unit area when compared to litter fire and the control (no pruning or fire). Fire alone led to a negative impact on leaf production. Implementing pruning instead of litter fire, however, comes with labor costs. Its adoption is therefore linked with the institutional arrangements for tendu management and marketing that shape community perception of costs. गौण वन उत्पादने जगभरातील वन-आधारित समुदायांसाठी उपजीविका म्हणून महत्त्वाची आहेत. त्यांच्या शाश्वत उपलब्धतेसाठी तसेच त्यांच्यावर अवलंबून आजीविकांच्या दृष्टीने वन उपजाच्या नियोजन पद्धतींचा वनवृक्षशास्त्राच्या दृष्टीने अभ्यास होणे गरजेचे आहे. मध्य भारतातील वन-आधारित समुदाय अनेक वर्ष तेंदू वृक्षाच्या पानांना (म्हणजे बिडी-पत्त्याला) निरनिराळ्या पद्धतीने संकलित करीत आहेत व त्याकरिता निरनिराळ्या पद्धतीने नियोजन करीत आहेत. झाडाची झुडपी वाढ करून, पाने हाता जवळ वाढवणे हा त्यातील मुख्य उद्देश आहे. यामध्ये झाडाच्या रोपांची मुळाशी छाटणी करणे (खुट/बेल कटाई) किंवा, जंगलातील पाचोळा पेटवणे, किंवा या दोन्ही पद्धती एकत्रित वापरणे ('छाटणी-व-आग') अशा पद्धतींचा समावेश आहे. अलीकडे काही लोक तेंदू संवर्धनासाठी झाडाची विना-नियोजन वाढ होऊ देतात (म्हणजे विना आग आणि विना खुट कटाईने). यातील कोणत्या पद्धतीने प्रती हेक्टरी सर्वात जास्त तेंदू पाने तयार होतात याचा अभ्यास आम्ही केला. यासाठी आम्ही उत्तर गडचिरोली, महाराष्ट्र येथील काही गावांच्या सामुहिक वन क्षेत्रात मार्च ते मे २०२० मध्ये वेगवेगळ्या नियोजन पद्धतीमध्ये होणाऱ्या तेंदूपत्ता उत्पन्नाचा पद्धतशीर अभ्यास केला. एकूण आम्हाला असे दिसले की, आग वापरण्यापेक्षा तेंदूच्या रोपांची मुळाशी केलेली छाटणी व 'छाटणी-व-आग' या पद्धती अधिक पानांचे उत्पन्न देतात. आम्ही पाहिले की स्थानिक जंगल प्रकार, त्याची दाटी, व तेंदू वृक्षाची निकटता या निकषांमुळे पानांच्या उत्पन्नात नियोजन पद्धतीपेक्षा जास्त परिणाम होत नाही. परंतु यातील कोणतीही पद्धत वापरताना व वन-आधारित उपजीविका सांभाळत, तसेच सामुहिक वन नियोजन करताना काही व्यावहारिक अडचणी आहेत. त्यांचावरही आम्ही या अभ्यासात विचार केला आहे.

Fire-induced geochemical changes in soil: Implication for the element cycling

Soils play an essential role in supporting and sustaining life on this planet. In fire-impacted environments, fire causes considerable changes to the soil, especially in the various elements. The present work provides a comprehensive and up-to-date review of the effect of fire on soil geochemistry, and its impact on the cycling of different biogenic, major, minor, and trace elements in the soil. Results from both natural and experimental fires (field-scale and lab-scale) are considered in this review. The temperature at which mineral transformation occurs in the soil during fires is summarised. The review suggests that fires can significantly alter mobility and hence, the cycling of many elements in fire-affected regions. Change in speciation of elements following fires risks formation and/or increased availability of the toxic forms of elements in the soil. The unique physical, chemical, and biological conditions observed during fires make many unlikely reactions more likely. However, the information available in the literature is often fire, vegetation, and element specific. More studies on this topic by changing these three variables will improve our understanding of changes in the soil caused by fire. Hence, with fires being touted to increase global presence in the coming years, more studies on understanding their effects on soils are recommended.

Fire Safety in Informal Settlements: A Gendered Framework of Fire Justice

People living in informal settlements, whether in urban or tented environments, face daily risks of injury and loss of life or property due to preventable fires. Currently, research and practice in the field of fire risk and prevention within informal settlements centres on technical interventions and solutions. While developments in materials, response and urban planning, for example, are an important aspect of reducing the effects of fire, the gendered framework for fire justice presented in this paper challenges the dominance of such technical solutions which neglect social dimensions of vulnerability to fire risk. Rethinking fire risk through gender can ensure strategies and systems of fire safety are situated, and informed by the range of people who experience fire and burns risk. The multidisciplinary framework engages with critical feminist approaches to disaster, vulnerability analysis and education, arguing for a gendered framework of fire justice that presents new possibilities for how fire risk and safety are understood and responded to by the range of stakeholders and actors who seek to reduce the instances and impact of fire on already marginalised populations, including those living in informal settlements.

Years After a Fire, Biocrust Microbial Communities are Similar to Unburned Communities in a Coastal Grassland

Microbial communities are integral for ecosystem processes and their taxonomic composition and function may be altered by a disturbance such as fire. Biocrusts are composed of macroscopic and microscopic organisms and are important for a variety of ecosystem functions, such as nutrient cycling and erosion control. We sought to understand if biocrust community composition and function were altered 1 year after a prescribed fire and 6 years after a wildfire in a coastal California grassland on San Clemente Island. We used shotgun metagenomic sequencing and measurements of chlorophyll content, exopolysaccharide production related to soil stability, and nitrogen fixation. There were no differences in the community composition between unburned samples and the samples burned in the prescribed fire and wildfire. Chlorophyll content differed between the prescribed fire and the controls; however, there were no measured differences in exopolysaccharide production, and nitrogen fixation. However, the wildfire and their respective unburned samples had different functions based on the gene annotations. We compiled one Actinobacteria metagenome-assembled genome from the shotgun sequences which had genes for oxidative and heat stress tolerance. These results suggest that the biocrust community can reach a community composition and function similar to the unburned biocrusts within a year after a prescribed burn and 6 years after a wildfire. However, legacy effects of the wildfire may present themselves in the differences between functional gene sequences. Due to their ability to match the undisturbed community composition and function within years and without intervention, future restoration work should consider the biocrusts in their restoration plans as they may provide valuable ecosystem functions after a disturbance.

The verification of wildland-urban interface fire evacuation models

This paper introduces a protocol for the verification of multi-physics wildfire evacuation models, including a set of tests used to ensure that the conceptual modelling representation of each modelling layer is accurately implemented, as well as the interactions between different modelling layers and sub-models (wildfire spread, pedestrian movement, traffic evacuation, and trigger buffers). This work presents a total of 24 verification tests, including (1) 4 tests related to pedestrians, (2) 15 tests for traffic evacuation, (3) 5 tests concerning the interaction between different modelling layers, along with 5 tests for wildfire spread and trigger buffers. The evacuation tests are organized in accordance with different core components related to evacuation modelling, namely Population, Pre-evacuation, Movement, Route/destination selection, Flow constraints, Events, Wildfire spread and Trigger buffers. A reporting template has also been developed to facilitate the application of the verification testing protocol. An example application of the testing protocol has been performed using an open wildfire evacuation modelling platform called WUI-NITY and its associated trigger buffer model k-PERIL. The verification testing protocol is deemed to improve the credibility of wildfire evacuation model results and stimulate future modelling efforts in this domain.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11069-023-05913-2.

Analyses of physical factors that contribute to the blood carboxyhemoglobin saturation in autopsy cases of house fire fatalities

The authors analyzed data from forensic autopsies of 75 patients who died as a result of house fires to clarify the physical factors that affect blood carboxyhemoglobin (COHb) saturation. Blood COHb saturation levels were significantly lower in patients who survived in the hospital. No significant differences were found in the blood COHb saturation levels between patients who died immediately at the scene and those who were pronounced dead at the receiving hospital without heartbeat being restored. The COHb saturation levels were significantly different among the groups of patients classified by the amount of soot. Although age, coronary artery stenosis, and blood alcohol concentration did not significantly affect blood COHb saturation, on comparing patients who died in the same fire, lower COHb saturation was observed in two patients, one with severe coronary artery stenosis and other with severe alcohol intoxication. To accurately interpret blood COHb saturation during forensic autopsy, the heartbeat status (present or absent) at the time of the rescue and the amount of soot in the trachea must be determined. Low levels of COHb saturation may be observed in fatalities with severe coronary atherosclerosis or severe alcohol intoxication.

Land sharing complements land sparing in the conservation of disturbance-dependent species

Alteration of natural disturbances in human-modified landscapes has resulted in many disturbance-dependent species becoming rare. Conservation of such species requires efforts to maintain or recreate disturbance regimes. We compared benefits of confining efforts to habitats in protected areas (a form of land sparing) versus integrating them with general management of production land (a form of land sharing), using two examples: fire in forests and grazing in semi-natural grasslands. We reviewed empirical studies from the temperate northern hemisphere assessing effects of disturbances in protected and non-protected areas, and compiled information from organisations governing and implementing disturbances in Sweden. We found advantages with protection of areas related to temporal continuity and quality of disturbances, but the spatial extent of disturbances is higher on production land. This suggests that an approach where land sparing is complemented with land sharing will be most effective for preservation of disturbance-dependent species in forests and semi-natural grasslands.

Effect of fire on characteristics of dissolved organic matter in forested catchments in the Mediterranean biome: A review

Fires in forested catchments pose a water contamination risk from fire-derived dissolved organic matter (DOM). Fire events are expected to increase under a projection of warmer and drier climatic conditions; therefore, understanding the consequences of fire-derived DOM is critical for water supply and management of drinking water and catchments. This paper addresses how fire regime - the intensity, severity and frequency of fires - influences DOM quantity and composition in surface waters in forested catchments, and how long it takes for water quality to recover to pre-fire levels. A review of post-fire studies in Mediterranean regions reporting on DOM related parameters has been conducted. The literature shows that post-fire DOM composition and reactivity is different from DOM generated under processes of biological degradation, and hence our reliance on DOM 'bulk properties' and surrogate DOM bulk parameters may not provide sufficient information to deal with the potential complexity of the organic compounds produced by a catchment fire. Appropriate measures are important to adequately operate conventional water treatment facilities, for example. Critical parameters for the effects of burning include the alteration of DOM composition, aromaticity, and the relative amounts of labile/recalcitrant organic components. The literature shows mixed information for the influence of both burn severity and fire intensity, on these parameters, which indicates DOM response to fire is highly variable. For fire frequency, the evidence is more unequivocal, indicating that frequent fires change the composition of DOM to components that are less bioavailable, and elevate the degree of aromaticity, which may be detrimental to water quality. In addition, and in general terms, the more recent the fire, the more aromatic and humified DOM components are found, and vice versa. The recovery of surface water quality to pre-fire conditions was variable, with no safe temporal thresholds suggested in the literature. In some cases, fire-induced changes in DOM composition were observable up to 16 years post-fire. The lack of clearly observed trends in post-fire DOM with fire regimes could be attributed to numerous factors such as limited long-term and event-based observations, experimental design challenges, and site-specific biological, physical and hydrological factors. The application of terminologies used to describe fire regimes such as burn severity and fire intensity also creates challenges in comparing the outcomes and results from numerous studies.

Influence of prescribed burning on reindeer winter pastures at landscape scale in northern Sweden: A modelling approach

Whilst the re-introduction of fire can contribute to biodiversity conservation in Fennoscandian forests, the effects on reindeer herding remain uncertain. To assess the short- and long-term effects of prescribed burning on lichen supply in a productive forest landscape, we developed a model simulating lichen biomass available for reindeer grazing, covering 300 years and 1500 pine stands, under different soil preparation scenarios, including different prescribed burning regimes and mechanical scarification. Our simulations revealed that burning 25-50% of yearly clear-cuts has the potential to stop, or even reverse, reindeer lichen decline at landscape scale after 70 years, greatly surpassing the short-term losses caused by burning. No burning or burning 5% of yearly clear-cuts, as required by the FSC certification, compounded the negative effects of fire suppression and scarification on lichen. Compared to the scenario with no soil preparation, all our simulations resulted in a continuous decrease of lichen supply in Lichen-type stands, indicating that any form of disturbance in these habitats can strongly limit future gains.

Direct and indirect pathways of land management effects on wetland plant litter decomposition

Litter decomposition is a fundamental process underpinning multiple ecosystem services. Despite a long history of research on decomposition, direct and indirect effects of multiple interactive land management on wetland decomposition yet remain less well understood. Here, we used a long-term whole-ecosystem wetland experiment in south-central Florida to investigate interactive effects of land-use intensification, cattle grazing and prescribed fire on in situ wetland plant litter decomposition. We further examined the direct and indirect pathways of land management effects on litter decomposition through changes in associated litter traits, soil properties, and soil microbial attributes using structural equation models. We used the litterbag technique that quantifies decomposition rates (k-values) and recalcitrant fractions (A-values). Our results showed that land-use intensification increased k-values in ungrazed wetlands and decreased k-values in grazed wetlands, but consistently reduced A-values regardless of other treatments. Prescribed fire individually suppressed litter decomposition by reducing k and increasing A. Further, these effects occurred through altering litter, soil, and microbial properties. Our results revealed that litter traits and soil properties were the first two strongest factors in determining wetland decomposition processes. Particularly, litter P and Mg contents and soil P and K contents were the best predictors for k, while litter Ca and lignin contents and soil pH, N and water content best predicted A. Moreover, microbial traits exhibited interactive effects with litter and soil properties to affect wetland litter decomposition. Our research suggests that cattle grazing could buffer against stimulating effect of land-use intensification on decomposition rates and thus avoid nutrient releases pulses. Our study further indicates that land-use intensification and fire suppression in subtropical wetlands could promote organic matter depletion and thus nutrient loss, highlighting the need to reduce anthropogenic disturbances to natural wetlands to maintain their capacity for providing associated regulating and supporting services.

Season and prey identity mediate the effect of predators on parasites in rodents: a test of the healthy herds hypothesis

The healthy herds hypothesis (HHH) suggests that predators decrease parasitism in their prey. Repeated tests of this hypothesis across a range of taxa and ecosystems have revealed significant variation in the effect of predators on parasites in prey. Differences in the response to predators (1) between prey taxa, (2) between seasons, and (3) before and after catastrophic disturbance are common in natural systems, but typically ignored in empirical tests of the HHH. We used a predator exclusion experiment to measure the effect of these heterogeneities on the tri-trophic interaction among predators, parasites and prey. We experimentally excluded mammalian predators from the habitats of hispid cotton rats (Sigmodon hispidus) and cotton mice (Peromyscus gossypinus) and measured the effect of exclusion on gastrointestinal parasites in these rodents. Our experiment spanned multiple seasons and before and after a prescribed burn. We found that the exclusion of the same predators had opposite effects on the parasites of small mammal prey species. Additionally, we found that the effect of mammal exclusion on parasitism differed before versus after fire disturbance. Finally, we saw that the effect of predator exclusion was highly dependent on prey capture season. Significant effects of exclusion emerged primarily in the fall and winter months. The presence of so many different effects in one relatively simple system suggests that predator effects on parasites in prey are highly context dependent.

Inflammatory and psychological consequences of chronic high exposure firefighting

OBJECTIVES

This study aimed to examine the impact of extreme heat exposure frequency on inflammation and well-being in UK Fire Service personnel.

METHODS

136 Fire personnel and 14 controls (CON) were recruited [92 Firefighters (FF), 44 Breathing Apparatus Instructors (BAI)]. BAI were split into low (LBAI; ≤15 exposures per month) and high (HBAI; ≥20 exposures per month) categories. Measures of inflammation, mood and fatigue were collected at 0, 3 and 6 month times points. These variables were analysed for differences between groups and association with frequency of exposure.

RESULTS

HBAI exhibited raised IL-1β, IL-6, IL-10, IgE and lower IgM (p < 0.05). In addition, IL-1β, IL-6, IL-10 and IgM were associated with monthly exposure number, with exposures accounting for 15.4% of the variance in IL-6, 11.8% of IL-1β and 25.2% of IL-10. No differences in mood or fatigue were reported (p > 0.05).

CONCLUSION

High exposure firefighting consistently causes systemic inflammation without perceptual recognition of potential health risks.

The complexity of biological disturbance agents, fuels heterogeneity, and fire in coniferous forests of the western United States

Forest biological disturbance agents (BDAs) are insects, pathogens, and parasitic plants that affect tree decline, mortality, and forest ecosystems processes. BDAs are commonly thought to increase the likelihood and severity of fire by converting live standing trees to more flammable, dead and downed fuel. However, recent research indicates that BDAs do not necessarily increase, and can reduce, the likelihood or severity of fire. This has led to confusion regarding the role of BDAs in influencing fuels and fire in fire-prone western United States forests. Here, we review the existing literature on BDAs and their effects on fuels and fire in the western US and develop a conceptual framework to better understand the complex relationships between BDAs, fuels and fire. We ask: 1) What are the major BDA groups in western US forests that affect fuels? and 2) How do BDA-affected fuels influence fire risk and outcomes? The conceptual framework is rooted in the spatiotemporal aspects of BDA life histories, which drive forest impacts, fuel characteristics and if ignited, fire outcomes. Life histories vary among BDAs from episodic, landscape-scale outbreaks (bark beetles, defoliators), to chronic, localized disturbance effects (dwarf mistletoes, root rots). Generally, BDAs convert aboveground live biomass to dead biomass, decreasing canopy fuels and increasing surface fuels. However, the rate of conversion varies with time-since-event and among BDAs and forest types, resulting in a wide range of effects on the amount of dead fuels at any given time and place, which interacts with the structure and composition of the stand before and subsequent to BDA events. A major influence on fuels may be that BDAs have emerged as dominant agents of forest heterogeneity creation. Because BDAs play complex roles in fuels and fire heterogeneity across the western US which are further complicated by interactions with climate change, drought, and forest management (fire suppression), their impacts on fuels, fire and ecological consequences cannot be categorized simply as positive or negative but need to be evaluated within the context of BDA life histories and ecosystem dynamics.

Heatwaves and fire in Pantanal: Historical and future perspectives from CORDEX-CORE

The Pantanal biome, at the confluence of Brazil, Bolivia and Paraguay, is the largest continental wetland on the planet and an invaluable reserve of biodiversity. The exceptional 2020 fire season in Pantanal drew particular attention due to the severe wildfires and the catastrophic natural and socio-economic impacts witnessed within the biome. So far, little progress has been made in order to better understand the influence of climate extremes on fire occurrence in Pantanal. Here, we evaluate how extreme hot conditions, through heatwave events, are related to the occurrence and the exacerbation of fires in this region. A historical analysis using a statistical regression model found that heatwaves during the dry season explained 82% of the interannual variability of burned area during the fire season. In a future perspective, an ensemble of CORDEX-CORE simulations assuming different Representative Concentration Pathways (RCP2.6 and RCP8.5), reveal a significant increasing trend in heatwave occurrence over Pantanal. Compared to historical levels, the RCP2.6 scenario leads to more than a doubling in the Pantanal heatwave incidence during the dry season by the second half of the 21st century, followed by a plateauing. Alternatively, RCP8.5 projects a steady increase of heatwave incidence until the end of the century, pointing to a very severe scenario in which heatwave conditions would be observed nearly over all the Pantanal area and during practically all the days of the dry season. Accordingly, favorable conditions for fire spread and consequent large burned areas are expected to occur more often in the future, posing a dramatic short-term threat to the ecosystem if no preservation action is undertaken.

Building a small fire database for Sub-Saharan Africa from Sentinel-2 high-resolution images

Coarse resolution sensors are not very sensitive at detecting small fire patches, making current estimations of global burned areas (BA) very conservative. Using medium or high-resolution sensors to generate BA products becomes then a priority, particularly in areas where fires tend to be small and frequent. Building on previous work that developed a small fire dataset (SFD) for Sub-Saharan Africa for 2016, this paper presents a new version of the dataset for 2019 using the two Sentinel-2 satellites (A and B) and VIIRS active fires. Total estimated BA was 4.8 Mkm². This value was much higher than estimations from two global, coarser-spatial resolution BA products based on MODIS data for the same area and period: 80 % greater than estimates from FireCCI51 (based on MODIS 250 m bands) and 120 % larger than MCD64A1 (based on MODIS 500 m bands). The main differences were observed in those months with higher fire occurrence (November to January for the Northern Hemisphere regions and June to September for the Southern Hemisphere ones). Accuracy assessment of the SFD product was based on a novel sampling strategy designed to obtain independent fire reference perimeters. Validation results showed remarkable high accuracy values comparing to existing global BA products. Overall omission errors (OE) were estimated as 8.5 %, commission errors (CE) as 15.0 %, with a Dice Coefficient of 87.7 %. All of these estimations implied significant improvements over the global, coarser spatial resolution BA products (OE > 50 % and CE > 20 % for the same area and period), as well as over the previous SFD product for 2016 of the same area, generated from a single Sentinel-2 satellite and MODIS active fires (OE = 26.5 % and CE = 19.3 %). Temporal accuracies greatly increased as well with the new product, with 92.5 % of fires detected within the first 10 days of occurrence.

Smoke pollution must be part of the savanna fire management equation: A case study from Darwin, Australia

Savanna fire management is a topic of global debate, with early dry season burning promoted as a large-scale emissions reduction opportunity. To date, discussions have centred on carbon abatement efficacy, biodiversity and cultural benefits and/or risks. Here we use a case study of Darwin, Australia to highlight smoke pollution as another critical consideration. Smoke pollution from savanna fires is a major public health issue, yet absent so far from discussions of program design. Here, we assess the likely impacts of increased early dry season burning on smoke pollution in Darwin between 2004 and 2019, spanning the introduction and expansion of carbon abatement programs. We found increased smoke pollution in the early dry season but little change in the late dry season, contributing to a net annual increase in air quality standard exceedances. Geospatial analysis suggests this relates to increased burning in the path of early dry season trade winds. This study highlights the complex health trade-offs involved with any large-scale prescribed burning, including for carbon abatement.

The interaction between administrative jurisdiction and disturbance on public lands: Emerging socioecological feedbacks and dynamics

Disturbance is one of the fundamental shapers of ecological communities, redistributing resources and resetting successional pathways. Human activities including resources management can influence disturbance regimes and trajectories by actively imposing or suppressing disturbance events or shaping ecosystem recovery via disturbance response. Furthermore, different management objectives may drive different disturbance responses. This suggests that the management jurisdiction to which a land parcel is assigned is likely to influence disturbance management and therefore ecological conditions within that parcel. Here, we combined two exploratory approaches to investigate this linkage. First, we used a systematic literature review to develop a typology of reported disturbance response types and strategies by federal land management agencies in the US. Second, we used Forest Inventory and Analysis (FIA) plot data in five multi-jurisdictional ecosystems containing national parks to investigate the relationship between land ownership and large disturbance occurrence and between disturbance and tree growth rate. We found that agencies vary in the diversity of disturbance response tactics they are reported to employ, and disturbance types vary in the diversity of responses reported in the literature. Disturbance occurrence varied by land ownership type across the FIA dataset, and the direction of tree growth rate was influenced by the interaction between ownership type and disturbance occurrence in two of five examined ecosystems. Although our mixed methods approach was purely exploratory and not mechanistic, our findings suggest that disturbance response is one possible route by which management regimes may influence ecological conditions. Efforts to understand and predict ecological heterogeneity across large landscapes must consider variation in the social system as a potential contributor to such patterns.

Anthropogenic fire patterns affect niche breadth and niche overlap in sympatric songbird species

The severity of wildfires increases globally, and return intervals decrease. Fires can benefit biodiversity, as post-burn early successional stages provide diverse habitats and niches for many species. How fire disturbance affects niche use and niche overlap of species is poorly understood so far. We studied the effect of anthropogenic fire on breeding habitat use, niche breadth and niche overlap of five sympatric bunting species breeding in wetlands of the Amur River floodplain (Russian Far East). Fire frequency, measured as the time an area burnt in the period 2000 to 2017, was mapped from Landsat imagery and related to the presence or absence of the species. Niche breadth and niche overlap were calculated separately for occurrences in burned (within the study year) and unburned patches. Fire frequency characterized differences in niche use among the species, but the probability of presence was not affected by recent fire in four of five species. Niche breadth was significantly lower in recently burned patches, but we found no increase in niche overlap between species after fire. Instead, the studied species seemed to occupy similar patches before and after fire, possibly because of a high site fidelity. Our results clearly show that fire frequency is a major determinant for the niche separation in the five studied species, while recent fire does not affect niche overlap.

Fire/flames mortality in Australian children 1968-2016, trends and prevention

INTRODUCTION

Mortality attributed to fire and flame for children (0-14 years) over a fifty-year period has not been previously analyzed in Australia. The literature has focused on these deaths over a shorter time period or disaggregated with other causes of burns or deaths in one burns center. However, mortality associated with fire/flames affects this age group the greatest. The aims of this study are to: (1) develop a trends analysis of fire and flames mortality between1968 to 2016, using the Australian Bureau of Statistics (ABS) mortality database and, (2) determine the association of interventions with fire and flames mortality using the Haddon's categorical intervention framework.

METHODS

International Classification of Disease (ICD) codes were extracted and code equivalencies between ICD 8, 9, 10 and the Australian Bureau of Statistics for fire/flames data between 1968--2016 were assessed. To determine whether population changes affected the risks of mortality, the frequency and, rates per 100,000 were used. A literature review was conducted that summarized the current knowledge of interventions associated with the major decreases in the fire and flames mortality rate.

RESULTS

In Australia, we found was a downward trend for the period although with significant variation from year to year when compared to external cause mortality. Additionally, there were multiple successful interventions associated with a sustained decrease in mortality. After 2016, child fire-related mortality remains a problem particularly in low socioeconomic groups and indigenous peoples. A combination of research, public awareness, engineering, legal enforcement, advancements in burns care and, evidence-based policy development all have a role to play in future injury prevention initiatives. Although direct causation to an individual is not possible, associations can be drawn from interventions on a population level to decreases in mortality.

CONCLUSION

We found was a steady decline in both rates and frequency of childhood fire and flames mortality from 1968 to 2016 associated with multiple interventions.

Discovering Graphical Heuristics on Fire-Induced Spalling of Concrete Through Explainable Artificial Intelligence

Fire-induced spalling of concrete continues to be an intriguing and intricate research problem. A deep dive into the open literature highlights the alarming discrepancy and inconsistency of existing theories, as well as the complexity of predicting spalling. This brings new challenges to creating fire-safe concretes and primes an opportunity to explore modern methods of investigation to tackle the spalling phenomenon. Thus, this paper leverages the latest advancements in explainable Artificial Intelligence (XAI) to vet existing theories on fire-induced spalling and to discover solutions/heuristics to predict spalling of concrete mixtures. The developed heuristics are in the form of graphs and nomograms. The proposed solutions allow interested researchers and engineers to graphically identify the propensity of a given concrete mixture to spalling directly and with ease. For example, we report that concrete mixtures with a combination of moderate water/binder ratio (of about 0.3), low heating rate (less than 2.5°C/min), moderate rise in temperature (less than 500°C), and have moisture content (less than 3%) are expected to be less prone to spalling. Further, findings from this research showcase the potential for developing simple (i.e., one-shot) and graphical (coding-free and formula-free) XAI-based solutions and web applications to address decades-long problems in the area of concrete research.

Fire and summer temperatures interact to shape seed dormancy thresholds

BACKGROUND AND AIMS

In Mediterranean ecosystems, the heat shock of wildfire disrupts physical seed dormancy in many plant species. This triggers germination in the post-fire environment where seedling establishment is optimal due to decreased competition and increased resource availability. However, to maintain the soil seed bank until a fire occurs, the minimum heat capable of breaking seed dormancy (i.e. the lower heat threshold) must be above the maximum temperatures typically observed in the soil during the summer. We therefore hypothesized that summer temperatures have shaped heat requirements for physical dormancy release. Specifically, we predicted that seeds from populations growing under warmer summers will have higher values of the lower heat threshold.

METHODS

To evaluate this prediction, we collected seeds from two Cistus species in 31 populations (20 Cistus albidus and 11 Cistus salviifolius) along a climate gradient of summer temperatures on the eastern coast of Spain. For each population, seeds were treated to 10 min heat shocks, from 30 to 120 °C in 5 °C increments (19 treatments), to simulate increasing heat doses from summer to fire-related temperatures. Seeds were then germinated in the lab.

KEY RESULTS

For all populations, maximum germination was observed when applying temperatures associated with fire. Lower heat thresholds varied among populations, with a positive relationship between summer temperatures at seed population origin and the heat dose required to break dormancy.

CONCLUSIONS

Our results suggest that fire drives maximum dormancy release for successful post-fire germination, while summer temperatures determine lower heat thresholds for ensuring inter-fire seed bank persistence. Significant among-population variation of thresholds also suggests that post-fire seeder species have some potential to modify their dormancy release requirements in response to changing climate.

Crop residue burning in South Asia: A review of the scale, effect, and solutions with a focus on reducing reactive nitrogen losses

This paper reviews the literature on crop residue burning - a widespread practice in many regions in South Asia. Specifically, we examine evidence from studies highlighting the scale of the practice in South Asia, the environmental implications, the drivers of the practice and the remedies to the problem. The studies provide evidence that the Indo-Gangetic Plain (IGP) is a hot-spot for atmospheric pollutants, with seasonal crop residue burning being a major contributor. The burning of crop residue is reported to degrade the soil, increase the risk of erosion, and increase the soil temperature, consequently decimating soil microorganisms. This subsequently impacts the monetary cost involved in recovering the soil fertility and the potential for further pollution through the increased use of fertilizer. The review shows that farmers' reasons for burning crop residues are mainly the high cost of incorporating, collecting, transporting, and processing crop residues in South Asia. Labour shortages, the marketability of the crop residue and the short time interval between harvest and next cropping seasons also influence farmers decision to burn crop residue. To address this problem, there is the need to encourage the use of agricultural machines capable of sowing crops in standing stubble, adopting in-situ practices and changing crop varieties to those with short duration. In addition, education and awareness are needed to change beliefs and perceptions on crop residue burning. Crucially, when promoting alternative sustainable uses of crop residue, the economic benefits should be prioritized, and support towards initial investments that accompany the adoption of alternative practices should be provided.

How can the analysis of reserve dynamics after fire support the phenological insight of Bulbostylis paradoxa (Spreng.) Lindm (Cyperaceae)?

Carbohydrate reserves are an essential key to plant survival from disturbance. Therefore, studying the different storage organs and types of reserves makes it possible to understand the dynamics of singular plants such as Bulbostylis paradoxa (Spreng.) Lindm, which presents flowering triggered by fire in the Cerrado. Physiological response to fire frequency is detailed by measuring the plant's reserves after a fire disturbance and which carbohydrates are more available for its use. It was measured the concentrations of starch, amino acids, total soluble carbohydrates and soluble proteins in leaves (control), flowers (burning) and caudex of B. paradoxa, in unburned individuals (control), and burned individuals (annually and biennially, obtained 48 h and 15 days after fire). Starch concentrations increased at both fire frequencies in all parts of the plant, as did carbohydrate concentrations. In amino acids, an increase in the concentration of flowers from individuals burned biennially 48 h after fire was observed. The protein concentration showed a decrease in burned plants. Furthermore, the two burning frequencies and the days following the fire can influence the storage of such reserves.

Fire frequency and type regulate the response of soil carbon cycling and storage to fire across soil depths and ecosystems: A meta-analysis

Fire is a very common disturbance in terrestrial ecosystems and can give rise to significant effects on soil carbon (C) cycling and storage. Here, we conducted a global meta-analysis on the response of soil C cycling and storage across soil profiles (organic layer, 0-5 cm, 0-10 cm, 0-20 cm, and 20-100 cm) to fire reported in 308 studies across 383 sites and examined the role of fire frequency, fire type, soil type, ecosystem type, and post-fire time in regulating the response of soil C dynamics to fire. Overall, we found soil C cycling and storage were more responsive to one fire and wildfire as compared to frequent fire and prescribed fire, respectively. Soil respiration significantly decreased by 22 ± 9% by one fire, but was not significantly affected by frequent fire across ecosystems. One fire significantly reduced soil C content in the organic, 0-10 cm, and 20-100 cm layers by 27 ± 16%, 10 ± 9%, and 33 ± 18%, respectively, while frequent fire significantly reduced soil C content at a depth of 0-5 cm and 0-20 cm by 29 ± 8% and 16 ± 12%, respectively. Soil C cycling and storage showed little response to frequent prescribed fire. In addition, the response of soil C cycling and storage varied among different soil and ecosystem types, with a stronger response being observed in forest than in grassland. Within 20 years post-fire, soil C cycling and storage tended to recover only after one fire but not after frequent fire. We also found that soil physicochemical properties and microbial communities were more responsive to one fire than frequent fire, which could indirectly affect the effects of fire on soil C cycling and storage. The results of our study have filled some critical gaps in previous meta-analyses in fire ecology.

Firefighters' urinary concentrations of VOC metabolites after controlled-residential and training fire responses

INTRODUCTION

Firefighters are exposed to volatile organic compounds (VOCs) during structural fire responses and training fires, several of which (e.g., benzene, acrolein, styrene) are known or probable carcinogens. Exposure studies have found that firefighters can absorb chemicals like benzene even when self-contained breathing apparatus (SCBA) are worn, suggesting that dermal absorption contributes to potentially harmful exposures. However, few studies have characterized VOC metabolites in urine from firefighters.

OBJECTIVES

We quantified VOC metabolites in firefighters' urine following live firefighting activity across two field studies.

METHODS

In two separate controlled field studies, spot urine was collected before and 3 h after firefighters and firefighter students responded to simulated residential and training fires. Urine was also collected from instructors from the training fire study before the first and 3 h after the last training scenario for each day (instructors led three training scenarios per day). Samples were analyzed for metabolites of VOCs to which firefighters may be exposed.

RESULTS

In the residential fire study, urinary metabolites of xylenes (2MHA), toluene (BzMA), and styrene (MADA) increased significantly (at 0.05 level) from pre- to post-fire. In the training fire study, MADA concentrations increased significantly from pre- to post-fire for both firefighter students and instructors. Urinary concentrations of benzene metabolites (MUCA and PhMA) increased significantly from pre- to post-fire for instructors, while metabolites of xylenes (3MHA+4MHA) and acrolein (3HPMA) increased significantly for firefighter students. The two highest MUCA concentrations measured post-shift from instructors exceeded the BEI of 500 μg/g creatinine.

CONCLUSIONS

Some of the metabolites that were significantly elevated post-fire are known or probable human carcinogens (benzene, styrene, acrolein); thus, exposure to these compounds should be eliminated or reduced as much as possible through the hierarchy of controls. Given stringent use of SCBA, it appears that dermal exposure contributes in part to the levels measured here.

Monitoring post-fire neighborhood competition effects on pine saplings under different environmental conditions by means of UAV multispectral data and structure-from-motion photogrammetry

In burned landscapes, the recruitment success of the tree dominant species mainly depends on plant competition mechanisms operating at fine spatial scale, that may hinder resource availability during the former years after the disturbance. Data acquisition at very high spatial resolution from unmanned aerial vehicles (UAV) have promoted new opportunities for understanding context-dependent competition processes in post-fire environments. Here, we explored the potentiality of UAV-borne data for assessing inter-specific competition effects of understory woody vegetation on pine saplings, as well as intra-specific interactions of neighboring saplings, across three burned landscapes located along a climatic/productivity gradient in the Iberian Peninsula. Geographic object-based image analysis (GEOBIA), including multiresolution segmentation and support vector machine (SVM) classification, was used to map pine saplings and understory shrubs at species level. Input data were, on the one hand, multispectral (11.31 cm·pixel^-1) and Structure-from-Motion (SfM) canopy height model (CHM) data fusion, hereafter MS-CHM, and, on the other, RGB (3.29 cm·pixel^-1) and CHM data fusion, hereafter RGB-CHM. A Random Forest (RF) regression algorithm was used to evaluate the effects of neighborhood competition on the relative growth in height of 50 pine saplings randomly sampled across the MS-CHM classified map. Circular plots of 3 m radius were set from the centroid of each target pine sapling to measure percentage cover, mean height of all individuals in the plot and mean height of individuals contacting the target sapling. Competing shrub species were differentiated according to their fire-adaptive traits (i.e. seeders vs resprouters). Object-based image classification applied on MS-CHM yielded higher overall accuracy for the three sites (83.67% ± 3.06%) than RGB-CHM (74.33% ± 3.21%). Intra-specific competitive effects were not detected, whereas increasing cover and height of shrub neighbors had a significant non-linear impact on the growth on pine saplings across the study sites. The strongest competitive effects of seeder shrubs occurred in open areas with low vegetation cover and fuel continuity, following a gap-dependent model. The non-linear relationships evidenced in this study between the structure of neighboring shrubs and the growth of pine seedlings/saplings have profound implications for considering possible competing thresholds in post-fire decision-making processes. These results endorse the use of UAV multispectral and SfM photogrammetry as a valuable post-fire management tool for measuring accurately the effect of competition in heterogeneous burned landscapes.

Seasonal impoundment management reduces nitrogen cycling but not resilience to surface fire in a tidal wetland

Hydrology and salinity regimes of many impounded wetlands are manipulated to provide seasonal habitats for migratory waterfowl, with little-known consequences for ecosystem structure and function. Managed hydrology can alter ecosystems by directly changing soil properties and processes and by influencing plant community dynamics. Additionally, management history may influence ecosystem response to disturbance, including fires. To better understand how wetland management regime influences ecosystem response to disturbance, we quantified elevation, soil nitrogen concentrations and process rates, and plant community structure and diversity in a natural experiment following the 2018 Branscombe Fire. We measured paired burned-unburned patches in both tidally-influenced and managed, seasonally-impounded wetlands in Suisun Marsh, California, USA. Unburned ecosystem structure and nutrient cycling differed by wetland management history; unburned impounded wetlands were ∼1 m lower in elevation and plant community composition was dominated by succulents whereas the unburned tidal wetland was dominated by graminoids. Unburned impounded wetland soil nitrogen cycling (potential nitrification and denitrification) rates were <28% of those measured in unburned tidal wetland soils and soil extractable nitrate, ammonium, and dissolved inorganic phosphorus concentrations were also substantially lower in unburned impounded than unburned tidal wetlands. Despite these differences in pre-disturbance (i.e., unburned) conditions, all soil processes recovered to baseline levels within 6 months after surface fire, and we found no evidence of plant community change 1 year after fire in either wetland management type. Overall, water management history exerted stronger control on ecosystem processes and structure than surface fire disturbance. Low extractable soil nitrate and potential denitrification rates may indicate limitation of soil nitrogen removal in impounded wetlands, with implications for downstream environmental quality and eutrophication across managed landscapes.

Effect of fire on the palatability of plants in an African woodland savanna: varying impacts depending on plant functional groups

Fire and herbivores are two important drivers of changes in vegetation composition, quality and dynamics and both are highly related to each other. Herbivores are known to respond to fire both in terms of foraging decisions and distribution. However, little is known about the actual changes in plant chemistry following a fire event and how long these changes will last. We investigated the effect of fire on two different plant functional groups (grasses and woody species) in a woodland savanna of southern Africa. We studied chemical compounds known to be important for palatability of five perennial grass and seven woody species (trees and shrubs) common in the woodland savanna and known to be utilized by herbivores. We wanted to know if plant chemistry differs between a recently burned site (burned 2 years ago) and a control site, burned 16 years ago, and if grasses and woody species show similar relative differences between sites (i.e., the plants' response to fire). We found a clear difference in chemical composition patterns between the plant functional groups, with an almost homogenous response to fire among woody species, but higher variability in response among grass species. Furthermore, we found that woody species maintained a higher nutritional value even 2 years after burning, whereas grasses did not show clear differences among the two investigated sites. Hence, few years after burning, woody plants might still serve as an attraction for herbivores, especially browsers, in contrast to grasses. The knowledge about these differences between the two functional groups in response to fire is beneficial for the development of management strategies for large herbivores whether domestic or wild.

Effects of fire on soil organic carbon, soil total nitrogen, and soil properties under rotational shifting cultivation in northern Thailand

Fire has been used for land clearing under rotational shifting cultivation (RSC) in Northern Thailand for a long time. However, the effects of fire on soil organic carbon (SOC), soil total nitrogen (STN), and soil properties are not well understood. We determined SOC, STN, and soil properties of the topsoil layer (0-30 cm) along a fallow chronosequence under RSC and assessed how fire affects SOC, STN, and soil properties. Eight fields at Ban Mae Pok, Mae Chaem District, Chiang Mai Province, Northern Thailand, were investigated. The levels of SOC, STN, and soil properties were observed at three time points: pre-burning, post-burning (5 minutes after burning), and post-harvest (nine months after burning). The highest SOC and STN stocks, organic matter (OM), and clay content were observed for the longest fallow period (7 years fallow), whereas the shortest period (1 year fallow) resulted in the lowest SOC and STN stocks. Fire caused no significant changes in SOC, STN, and some soil properties (soil texture, available P, exchangeable K, exchangeable Ca, exchangeable Mg, bulk density, and OM) because of the low fire intensity and short fire duration. Only pH and electrical conductivity were significantly increased (p ≤ 0.05) after burning due to the demobilization of base cations in burnt vegetation and incorporation into the soil with ashes and wood charcoal. Although fire may still be necessary for RSC, maintaining the fire intensity below 380 °C to reduce SOC losses and appropriate post-fire management strategies to reduce STN losses are crucial.

Fire mitigates bark beetle outbreaks in serotinous forests

Bark beetle outbreaks and forest fires have imposed severe ecological damage and caused billions of dollars in lost resources in recent decades. The impact of such combined disturbances is projected to become more severe, especially as climate change takes its toll on forest ecosystems in the coming years. Here, we investigate the impact of multiple disturbances in a demographically heterogeneous tree population, using an age-structured difference equation model of bark beetle outbreaks and forest fires. We identify two dynamical regimes for beetle and fire dynamics. The model predicts that fire helps dampen beetle outbreaks not only by removing host trees but also by altering the demographic structure of forest stands. We show that a stand thinning protocol, which reduces the population size of the largest few juvenile classes by a small percentage, is able to significantly reduce beetle-induced tree mortality. Our research demonstrates one approach to capturing compound disturbances in a mathematical model.

The effect of proximity to protected areas on community adaptation to environmental change

The consequences of protected areas for proximal human communities are diverse. Protected areas can alleviate poverty by providing a range of economic opportunities for people that live and work within them. Equally, however, they may also disempower and disposes local communities. For communities adapting to systemic environmental change, proximity to protected areas can act to limit potential adaptive pathways. Here, we employ social science methods to explore the impact of an internationally significant protected area on adjacent communities in the Tonle Sap Lake basin, Cambodia. Semi-structured interviews, informed by a scenario framework, reveal an awareness of declining fish yields and a perceived lack of economic alternatives. Vulnerability to hydroclimatic extremes, particularly storms, flood, drought and - increasingly - fire, are exacerbated as a result of proximity to the protected area. We conclude that the impact of protected areas on local communities is heterogenous, and that the development of adaptive and effective management policies requires sensitivity to local conditions and impacts.