Low Fire Research Articles

Heat Analysis and Fire Prevention of Timber Buildings in Southwest China Based on Fractal and Seepage Theory

In traditional settlements in Southwest China, there are many timber historical buildings and residential buildings, which feature a low fire resistance rating. The preservation and inheritance of these timber buildings are mainly threatened by fire. However, the existing research has not explored the deep correlation between the spatial structure of settlements and fire. To make up for the gap, this paper aims to find the ideas and measures that effectively prevent the fire from occurring in timber buildings of traditional settlements in Southwest China, based on fractal and seepage theory. Firstly, the fractal features were extracted from the spatial structure of these settlements. Then, the authors identified the factors affecting the spread of fire in buildings, and analyzed the mechanism of fire propagation between the timber buildings of traditional settlements. On this basis, a fire prevention scheme was proposed, which integrates the “targeted control of overall structure” with “comprehensive synergy between multiple local elements”. The research results provide a reference for applying fractal and seepage theory in the fire prevention of other buildings with special structures.

Geology and taphonomy of a unique tyrannosaurid bonebed from the upper Campanian Kaiparowits Formation of southern Utah: implications for tyrannosaurid gregariousness.

Tyrannosaurids are hypothesized to be gregarious, possibly parasocial carnivores engaging in cooperative hunting and extended parental care. A tyrannosaurid (cf. Teratophoneus curriei) bonebed in the late Campanian age Kaiparowits Formation of southern Utah, nicknamed the Rainbows and Unicorns Quarry (RUQ), provides the first opportunity to investigate possible tyrannosaurid gregariousness in a taxon unique to southern Laramidia. Analyses of the site’s sedimentology, fauna, flora, stable isotopes, rare earth elements (REE), charcoal content and taphonomy suggest a complex history starting with the deaths and transport of tyrannosaurids into a peri-fluvial, low-energy lacustrine setting. Isotopic and REE analyses of the fossil material yields a relatively homogeneous signature indicating the assemblage was derived from the same source and represents a fauna living in a single ecospace. Subsequent drying of the lake and fluctuating water tables simultaneously overprinted the bones with pedogenic carbonate and structurally weakened them through wet-dry cycling. Abundant charcoal recovered from the primary bone layer indicate a low temperature fire played a role in the site history, possibly triggering an avulsion that exhumed and reburied skeletal material on the margin of a new channel with minimal transport. Possible causes of mortality and concentration of the tyrannosaurids include cyanobacterial toxicosis, fire, and flooding, the latter being the preferred hypothesis. Comparisons of the RUQ site with other North American tyrannosaur bonebeds (Dry Island-Alberta; Daspletosaurus horneri-Montana) suggest all formed through similar processes. Combined with ichnological evidence, these tyrannosaur mass-burial sites could be part of an emerging pattern throughout Laramidia reflecting innate tyrannosaurid behavior such as habitual gregariousness.

Useful Life of Prescribed Fires in a Southern Mediterranean Basin: An Application to Pinus pinaster Stands in the Sierra Morena Range

Prescribed fire is a globally relevant fuel treatment for surface fuel management and wildfire hazard reduction. However, Mediterranean ecosystems are adapted to low and moderate fires; hence, the useful life of prescribed fires is limited. Useful life is defined as the effective rotation length of prescribed fires to mitigate fire spread based on critical surface intensity for crown combustion. In this sense, the useful life of a prescribed fire focuses on surface fuel dynamics and its potential fire behavior. In Pinus pinaster stands, the useful life can be established between 0 and 4 years. Canopy base height, time elapsed from the burning, postfire precipitation, and fine fuel moisture content during the burning were identified as the most important variables in postburn fuel dynamics. Other stand characteristics and postfire precipitation can improve the fine fuel and live fuel dynamics models. Our findings support prescribed fires as an effective fuel treatment in the medium term for forest fire prevention, according to stand characteristics and burning implementation conditions. In this sense, forest managers can use the proposed decision tree to identify the useful life of each prescribed fire based on fine fuel moisture content during burning implementation.

Synergetic integration of thermal conductivity and flame resistance in nacre‐like nanocellulose composites

Highly thermally conductive and flame resistant nanocellulose-based composites can synchronously achieve efficient thermal dissipation and low fire hazards of electronic devices, which shows great promise in next-generation green and flexible electronics. However, it has long been intractable to optimize the high thermal conductivity (TC) and flame resistance simultaneously. Herein, synergetic integration of high TC and flame resistance in nacre-like nanocellulose composites has been successfully achieved by the vacuum-assisted filtration of cellulose nanofibers (CNFs) and functionalized boron nitride nanosheets (BNNS-p-APP). Benefiting from the highly oriented hierarchical microstructure, strong hydrogen-bonding interaction, and successful immobilization of ammonium polyphosphate (APP), the as-obtained CNFs/BNNS-p-APP composite film achieves a high in-plane TC of 9.1 W m−1 K−1 and outstanding flame resistance. Meantime, this eco-friendly nanocellulose-based composite also exhibits remarkable flexibility, folding endurance, and mechanical robustness, robustness, which may open up a new opportunity for the thermal management of flexible electronics.

Controls and Hardware Development of Multi-Level Miller Cycle Dynamic Skip Fire (mDSF) Technology

<div class="section abstract"><div class="htmlview paragraph">mDSF is a novel cylinder deactivation technology developed at Tula Technology, which combines the torque control of Dynamic Skip Fire (DSF) with Miller cycle engines to optimize fuel efficiency at minimal cost. mDSF employs a valvetrain with variable valve lift plus deactivation and novel control algorithms founded on Tula’s proven DSF technology. This allows cylinders to dynamically alternate among 3 potential states designated as: High Fire, Low Fire, and Skip (deactivation). The Low Fire state is achieved through an aggressive Miller cycle with Early Intake Valve Closing (EIVC). The three operating states in mDSF can be used to simultaneously optimize engine efficiency and driveline vibrations. Acceleration performance is retained using the all-cylinder, High Fire mode. mDSF can be implemented cost-effectively using an asymmetric intake valve lift strategy, with one high-flow power charging port and one high-efficiency Miller port.</div><div class="htmlview paragraph">Prototype mDSF cylinder heads were based on the EA888 Gen 3B engine by retrofitting the valvetrain with asymmetric intake cams, deactivatable roller finger followers and two oil control valves per cylinder. Event-based engine controls were developed to enable for each cylinder dynamic selection of the three mDSF operating modes: High Fire, Low Fire and Skip. Appropriate air estimation, fuel control and ignition control techniques were employed to ensure acceptable torque delivery and tailpipe emissions.</div><div class="htmlview paragraph">Engine dynamometer tests showed a 23% reduction in engine fuel consumption at 1500 rpm, 2 bar NMEP. Maximum torque and power from the baseline production engine up to 5000 rpm were also achieved. mDSF vehicle tests on the WLTC demonstrated a 6% reduction in CO<sub>2</sub> from Miller 2-step. Euro 6d compliant emissions were also reported. Further improvements in fuel economy, drivability and NVH may be possible by leveraging mixed firing densities more extensively.</div></div>

Transition from subsistence grazing to nature-based recreation: A nuanced view of land abandonment in a mountain social-ecological system, southwestern Cape, South Africa

Over the last 50 years, studies have shown a decline in the use of mountain lands, a phenomenon termed land abandonment. We investigate the causal mechanisms of land use change in a mountain catchment important for regional water supplies in the southwestern Cape of South Africa. Uniquely, we include nature-based recreational land use types typically excluded from land abandonment studies. We repeated a structured questionnaire originally conducted with landowners 38 years previously and analysed orthoimages from 1948, 1972 and 2014. To identify and contextualise causal mechanisms of change we used thematic analysis and generated narratives from in-depth interviews with landowners. The land use system in 1948 and 1972 was dominated by livestock-based, subsistence agriculture and small-scale farming. This transitioned to agricultural intensification on the lowlands and small portions of the mountains and the utilisation of mountains for non-economic nature-based recreation and ecotourism. The use of frequent small, low intensity-controlled fires was prevalent in the past. More recently, fires have been actively suppressed resulting in the build-up of biomass and the development of infrequent, extensive, high-intensity wildfires. Land use change in the mountains was driven primarily by socio-economic drivers, including socio-economic benefits related to globalisation and economic growth, and not by concerns over land degradation or resource depletion. Our findings support evidence that shows that people’s responses to economic opportunities drive local determinants of land use change and highlights the importance of perceptions in driving land use transitions. We show that existing models of land abandonment are likely overly deterministic in that they do not consider social and cultural factors that may cause a landowner to continue using their land for semi-economic or non-economic reasons. While there is merit in large-scale remote sensing studies, we emphasise the importance of using mixed remote sensing and social science methods for informing models of land use change.

Simulation and Sustainability Assessment Of H2S Utilization from Acid Gas on Haldor Topse Wet Gas Sulfuric Acid and Claus

Claus process is a widely adopted process to reduce emissions from refineries by converting H2S into elemental sulfur. On the other hand, Haldor Topsoe’s Wet Gas Sulfuric Acid (WSA) is an alternative to convert H2S directly into sulfuric acid. The purpose of this project was to simulate both of these state-of-the-art technologies and evaluate their suitability for various acid gas capacity and H2S concentrations. Three sustainability pillars of people (safety), planet (environment), and profit were used as the comparison metrics. The developed simulation (1st principle) models were used to generate lots of data as the basis for subsequent development of regression models. The latter models were used in the comparisons for they are much faster in calculations than the 1st principle models. The results showed that the WSA process was safer (lower Fire and Explosion Damage Index), more environmentally friendly (lower Global Warming Potential), and more profitable (higher annual profit) in most of the evaluated operating conditions.

Measuring a Fire. The Story of the January 2019 Fire Told from Measurements at the Warra Supersite, Tasmania

Non-stand-replacing wildfires are the most common natural disturbance in the tall eucalypt forests of Tasmania, yet little is known about the conditions under which these fires burn and the effects they have on the forest. A dry lightning storm in January 2019 initiated the Riveaux Road fire. This fire burnt nearly 64,000 ha of land, including tall eucalypt forests at the Warra Supersite. At the Supersite, the passage of the fire was recorded by a suite of instruments measuring weather conditions and fluxes (carbon, water and energy), while a network of permanent plots measured vegetation change. Weather conditions in the lead-up and during the passage of the fire through the Supersite were mild—a moderate forest fire danger index. The passage of the fire through the Supersite caused a short peak in air temperature coinciding with a sharp rise in CO2 emissions. Fine fuels and ground vegetation were consumed but the low intensity fire only scorched the understorey trees, which subsequently died and left the Eucalyptus obliqua canopy largely intact. In the aftermath of the fire, there was prolific seedling regeneration, a sustained reduction in leaf area index, and the forest switched from being a carbon sink before the fire to becoming a carbon source during the first post-fire growing season.

Assemblages of myxomycetes associated with three different substrates affected by forest wildfires

Background and aims – In late November and early December of 2016, forest wildfires occurred over portions of the Great Smoky Mountains National Park (USA) and more than 4 000 ha were affected. Previous studies have shown that myxomycete assemblages can be greatly impacted as a result of this type of disturbance; after which, the recovery of the forest determines the availability of substrates for new colonisation. The objective of the project reported herein was to assess the impact of wildfires on the recovery of the assemblages of myxomycetes associated with three different substrates (forest floor leaf litter, the bark of living trees, and woody twigs) in two areas with different fire intensity.Material and methods – Two study areas subjected to different fire intensity were selected and sampled 30 months after the wildfires. Myxomycetes were studied using the moist chamber culture technique as it applies to these organisms. Satellite imagery was used to determine forest recovery and similarity indices were used to compare experimental myxomycete assemblages among study areas and substrates. Historical data were used as a reference to contextualise the results.Key results – A total of 38 species of myxomycetes representing 17 different genera were recorded from the two study areas. Samples from the lower intensity burn area yielded more myxomycetes than samples from the higher intensity burn area, with values of 84% and 59%, respectively. This same pattern was also observed for the number of recorded specimens (133 and 93, respectively). The comparison of experimental assemblages with previous data suggested that ground litter assemblages were still in early stages of recovery, whereas the assemblages associated with bark and twigs had recovered much faster.Conclusion – The relatively higher intensity fire had more of an effect on myxomycetes than the relatively lower intensity fire. Myxomycete assemblages are resilient to wildfires and they recover differentially depending on the substrate they grow on.

Study on Flame Retardancy and Mechanism of Talc Composite Foams

Under high temperature, aqueous film forming foam extinguishing agent has poor flame retardancy and low fire efficiency. In order to solve this problem, talc was introduced into foam to form composite foam. The fire resistance and fire extinguishing properties of the composite foam were studied. The results showed that talc composite foam had good flame retardant resistance. when the concentration of talc reached 40 g/100 ml, the 50% liquid separation time of the composite foam was 21.1 min. The fuel burning in the anti burning tank did not ignite the gasoline in the oil pan, and burned out at 51.5 min. It was related to the structure of composite foam and the properties of talc. Due to the introduction of talc, the viscosity of the composite foam increased. The network structure of composite foam was important to the improved stability of foam. Talc powder formed a dense layer covering the oil surface, which effectively isolated the oil from the air.

Unburnt habitat patches are critical for survival and in situ population recovery in a small mammal after fire

Abstract Fire drives animal population dynamics across many ecosystems. Yet, we still lack an understanding of how most species recover from fire and the effects of fire severity and patchiness on recovery processes. This information is crucial for fire‐mediated biodiversity conservation, particularly as fire regimes change globally. We conducted an experiment to test whether post‐fire recovery is driven by in situ survival or recolonisation, and to determine whether this varies with fires of increasing percentage area burnt (burn cover) and severity. We used the pale field rat Rattus tunneyi as a model, because it represents the extinction process for a suite of mammal species suffering population collapse across Australia's northern savannas. Our treatments spanned a gradient from patchy, low severity fires (simulating early dry season management burns) to thorough, high severity fires (simulating wildfires). We performed capture–mark–recapture, vegetation and aerial surveys before, 6 weeks after and 1 year after fire. Six weeks after fire, pale field rats were only captured in unburnt patches of vegetation, and capture rates were proportional to the amount of unburnt habitat. One year later, both vegetation and pale field rat populations recovered across all sites. However, population recovery after low severity fires was likely achieved through in situ survival and reproduction in unburnt micro‐refuges, compared to recolonisation driving recovery after high severity fires. Synthesis and applications. Pale field rat persistence is strongly dependent on the retention of unburnt habitat patches within fire‐affected areas. Management strategies that increase micro‐refugia within burnt areas may facilitate pale field rat population recovery. Globally, building recovery mechanisms into fire management will be vital for supporting the long‐term persistence of fire‐affected species.

Stand boundary effects on obligate seeding Eucalyptus delegatensis regeneration and fuel dynamics following high and low severity fire: Implications for species resilience to recurrent fire

AbstractIncreased fire frequency can result in a decline of obligate seeding plants, which rely on re‐seeding for population persistence following canopy scorching fire. The resilience of obligate seeding plants to fire at any point in time depends on plant maturity and the size of plants in relation to potential fire scorch height. We investigated variation in the resilience of post‐fire regenerating Eucalyptus delegatensis subsp. delegatensis (alpine ash) to a short inter‐fire interval at its boundaries with E. fastigata (brown barrel) stands. The resilience of post‐fire E. delegatensis regeneration was modelled across these stand boundaries as a function of the height of the plants, their reproductive maturity and predicted fire behaviour derived from local fuel characteristics. We measured these attributes 14 years following the Canberra 2003 wildfires and stratified study sites by fire severity. The height and reproductive maturity of post‐fire E. delegatensis saplings decreased at stand boundaries with E. fastigata, while fuel was uniformly abundant and capable of supporting canopy scorching fire under mild fire weather conditions. This suggests that E. delegatensis is less resilient to frequent fire in the presence of interspecific competition and other environmental conditions that occur at stand boundaries, which represent the edge of the species’ realised niche. With forecasts for increased fire frequency in south eastern Australia, persistence of E. delegatensis may be greatest in pure stands corresponding to the core of the species’ realised niche, and in moist and sheltered topographic areas that are less prone to frequent canopy scorching fire. Our findings suggest the importance of considering fine‐scale spatial variation in important obligate seeding plant traits when predicting and managing the response of obligate seeding species to frequent fire.

Experimental Study on the Effect of Basalt Fiber and Sodium Alginate in Polymer Concrete Exposed to Elevated Temperature

Polymer concrete contains aggregates and a polymeric binder such as epoxy, polyester, vinyl ester, or normal epoxy mixture. Since polymer binders in polymer concrete are made of organic materials, they have a very low heat and fire resistance compared to minerals. This paper investigates the effect of basalt fibers (BF) and alginate on the compressive strength of polymer concrete. An extensive literature review was completed, then two experimental phases including the preliminary phase to set the appropriate mix design, and the main phase to investigate the compressive strength of samples after exposure to elevated temperatures of 100 °C, 150 °C, and 180 °C were conducted. The addition of BF and/or alginate decreases concrete compressive strength under room temperature, but the addition of BF and alginate each alone leads to compressive strength increase during exposure to heat and increase in the temperature to 180 °C showed almost positive on the compressive strength. The addition of BF and alginate both together increases the rate of strength growth of polymer concrete under heat from 100 °C to 180 °C. In conclusion, BF and alginate decrease the compressive strength of polymer concretes under room temperature, but they improve the resistance against raised temperatures.

Attribution of the accelerating increase in atmospheric methane during 2010–2018 by inverse analysis of GOSAT observations

Abstract. We conduct a global inverse analysis of 2010–2018 GOSAT observations to better understand the factors controlling atmospheric methane and its accelerating increase over the 2010–2018 period. The inversion optimizes anthropogenic methane emissions and their 2010–2018 trends on a 4∘×5∘ grid, monthly regional wetland emissions, and annual hemispheric concentrations of tropospheric OH (the main sink of methane). We use an analytical solution to the Bayesian optimization problem that provides closed-form estimates of error covariances and information content for the solution. We verify our inversion results with independent methane observations from the TCCON and NOAA networks. Our inversion successfully reproduces the interannual variability of the methane growth rate inferred from NOAA background sites. We find that prior estimates of fuel-related emissions reported by individual countries to the United Nations are too high for China (coal) and Russia (oil and gas) and too low for Venezuela (oil and gas) and the US (oil and gas). We show large 2010–2018 increases in anthropogenic methane emissions over South Asia, tropical Africa, and Brazil, coincident with rapidly growing livestock populations in these regions. We do not find a significant trend in anthropogenic emissions over regions with high rates of production or use of fossil methane, including the US, Russia, and Europe. Our results indicate that the peak methane growth rates in 2014–2015 are driven by low OH concentrations (2014) and high fire emissions (2015), while strong emissions from tropical (Amazon and tropical Africa) and boreal (Eurasia) wetlands combined with increasing anthropogenic emissions drive high growth rates in 2016–2018. Our best estimate is that OH did not contribute significantly to the 2010–2018 methane trend other than the 2014 spike, though error correlation with global anthropogenic emissions limits confidence in this result.

Environmental changes during MIS6-3 in the Basin of Mexico: A record of fire, lake productivity history and vegetation

The responses of lake productivity, vegetation, and fire events in the Basin of Mexico to orbital changes from late MIS 6 to MIS 3 (146–35 ka) have been studied based on geochemical (Ti, TIC, TOC, C/N), charcoal (CHAR) and pollen data of the sediment core CHA08 from Lake Chalco. The paleoenvironmental reconstruction identifies the MIS 6 as a wetter period with episodes of dry conditions, low forest cover and low fire activity. A sudden change from wetter to dry environments with low to high forest cover and fire activity episodes characterized the end of the MIS 6 (132–130 ka) coincident with high spring insolation. Variations in vegetation composition, with a tendency towards higher forest cover, fire-activity, runoff, and organic matter availability, are recorded during the MIS 5, MIS 4, and MIS 3. However, a reduction in the fire-activity was recorded for the cold and dry MIS 4. Spectral analysis based on the titanium concentration record of Lake Chalco suggests a precessional forcing on runoff variations. We explored the impact of the Intertropical Convergence Zone latitudinal migrations which have been related to the summer insolation at 65° N by comparing runoff data with other sedimentary records from North and Central America. Our results highlight the sensitivity of the high altitude tropical basin to climate variations.

Monitoring of the Fire in Muli County on March 28, 2020, based on high temporal-spatial resolution remote sensing techniques

Wildfires are serious natural disasters, and fire monitoring has become an important task for the protection of forest resources. Remote sensing technology has become one of the most commonly used tools for wildfire monitoring and fire point identification. However, single-source remote sensing data cannot meet the fire monitoring requirements of temporal resolution and spatial resolution simultaneously, which affects the efficiency and timeliness of monitoring. With the wildfire in Wakeliangzi, Xiangjiao township, Muli county, Liangshan Yi Autonomous Prefecture, Sichuan Province, China, on March 28, 2020 as the study object, fire monitoring was carried out based on a collaboration of multi-source remote sensing data acquired by the Sentinel-2 satellite, Landsat-8 satellite and the GF-4 satellite. Based on the integrated shortwave and infrared bands of the Sentinel-2 satellites, which were sensitive to fire information, the fire patch was analyzed. The normalized differential vegetation indexes (NDVIs) and normalized burn ratios (NBRs) were calculated before and after the fire, and then, the burned area and fire severity were calculated based on the obtained NDVIs and NBRs. We performed time series monitoring of the fire points based on the remote sensing data acquired by the GF-4 satellite with a high temporal resolution. Moreover, according to the remote sensing data in the medium-wave infrared band, which is sensitive to fire information, the wildfire point was located based on the smoke screen and temperature. Lastly, we calculated the vegetation coverage based on the data from the Sentinel-2 satellites and analyzed the relationship between vegetation coverage and fire severity. With the remote sensing data acquired by the Landsat-8 satellites in the integrated shortwave and infrared bands, the spatial distribution of the fire patch was quickly and effectively obtained. The total burned area reached 180.37Km2, 117.24Km2 of which had a low fire severity, 27.05Km2 featured a medium fire severity and 45.09Km2 had a high fire severity. Compared with the results of manual visual interpretation and cross validation of published results, the recognition accuracy of different fire areas is better. The multispectral data and medium-wave infrared band data acquired by the GF-4 satellite enabled us to locate the fire point and monitor the dynamic time series of the fire. The linear regression showed that the vegetation fractional cover (VFC) was significantly correlated with the relative differenced normalized burn ratio (dNBR). By combining the high temporal-spatial resolution remote sensing data acquired by the Sentinel-2 satellites and the GF-4 satellite, wildfires can be dynamically monitored and quantitatively analyzed, thereby achieving precise, macro-level fire monitoring. The findings in this study not only provide information for the Muli fire, but the results also offer a technical reference for wildfire remote sensing monitoring and emergency response.

Fire and montane vegetation dynamics through successive phases of human occupation in the northern Drakensberg, South Africa

Palaeoecological evidence is compared with the existing archaeological record to understand how changing human activity, over the past two millennia, impacted fire regimes and vegetation dynamics in the Drakensberg Mountains, South Africa. Sediment cores from two wetland sites in the Cathedral Peak area of the northern Drakensberg, KwaZulu-Natal are dated using accelerator mass spectrometry to chronologically support biological proxy data. Fossil pollen analysis is used to detect changes in vegetation composition, and macroscopic charcoal to reconstruct changing fire regimes. Charcoal accumulation rates (CHAR) are used as a proxy for burned biomass, and charcoal width-to-length ratio (W/L) as a proxy for dominant fuel type, whether grassy or woody. Results indicate an increase in CHAR, coincident with the appearance of cereal-type grasses (>40 μm) c. 550 cal BP, suggesting a change in fire regimes associated with the arrival of early agropastoralists. A notable decline in charcoal W/L at this time indicates a shift towards a more grassy fuel type. This is consistent with a seasonal shift in the timing of ignitions from high intensity late season lightning fires to low intensity early season anthropogenic fires. The latter are less damaging to woody vegetation explaining an overall shift to a more grassy fuel type. Large scale ecosystem change is evident in the colonial period, including decreased forest pollen taxa such as Podocarpus, which may be linked to colonial period logging. The increased dominance of Pteridium spores documents the invasion trajectory of bracken fern into montane grasslands in the area, which is attributed to ecosystem disturbance in the form of colonial fire suppression. The subalpine wetland clearly documents woody encroachment of the surrounding open grassland landscape during the agropastoral and subsequent colonial periods. By contrast, at the montane wetland site, these trends appear to be overprinted by local forest dynamics and recent deforestation, likely an elevation effect. Palaeoecological evidence demonstrates how changes in fire regimes and vegetation composition in the northern Drakensberg are closely tied to human activity over the past two millennia.

Modeling Low Intensity Fires: Lessons Learned from 2012 RxCADRE

Coupled fire-atmosphere models are increasingly being used to study low-intensity fires, such as those that are used in prescribed fire applications. Thus, the need arises to evaluate these models for their ability to accurately represent fire spread in marginal burning conditions. In this study, wind and fuel data collected during the Prescribed Fire Combustion and Atmospheric Dynamics Research Experiments (RxCADRE) fire campaign were used to generate initial and boundary conditions for coupled fire-atmosphere simulations. We present a novel method to obtain fuels representation at the model grid scale using a combination of imagery, machine learning, and field sampling. Several methods to generate wind input conditions for the model from eight different anemometer measurements are explored. We find a strong sensitivity of fire outcomes to wind inputs. This result highlights the critical need to include variable wind fields as inputs in modeling marginal fire conditions. This work highlights the complexities of comparing physics-based model results against observations, which are more acute in marginal burning conditions, where stronger sensitivities to local variability in wind and fuels drive fire outcomes.

Effect of fire severity on soil properties in a seasonally dry forest ecosystem of Central India

Forest fire monitoring, assessment, and management are important aspects of the tropics because of their significant ecological, economic, and social impact. Soil is considered one of the most important natural resources. Wildfire alters the soil nutrient status and pool through volatilization, erosion, leaching, oxidation, and ash transport. Little information is available on how soil properties, carbon stock, nitrogen stock, and soil microbial biomass carbon vary along depth and fire severity (high, medium, low, and no fire). In order to address this question, soil was sampled from 0–10 to 10–20 cm depths from different fire zones (high, medium, low, and no fire zone) of Bhoramdeo Wildlife Sanctuary of Chhattisgarh, India. The level of macronutrients, carbon stock, nitrogen stock, and microbial biomass carbon was higher at no-fire zone than in the rest of the sites (high, medium, and low severity fire zones). Total soil carbon stock (0–20 cm soil depth) was highest in no-fire zone (69.51 ton ha−1) followed by medium (66.55 ton ha−1) or low fire severity (53.69 ton ha−1). The total soil nitrogen stock across the sites ranged between 2.60 and 4.08 ton ha−1, and it was higher in the no-fire zone followed by the medium or high fire severity. Soil microbial biomass carbon reflected a similar trend with higher values in no-fire zone followed by the medium fire severity, high fire severity and low fire severity zones. Such information on wildfire and soil attributes is essential for the preparation of better management and action plan to regulate the forest soil quality.

Holocene fire history reconstruction of a mid-elevation mixed-conifer forest in the Eastern Cascades, Washington, USA

Fire histories of mid-elevation mixed-conifer forests are uncommon in the eastern Cascades, limiting our understanding of long-term fire dynamics in these environments. The purpose of this study was to reconstruct the fire and vegetation history for a moist mid-elevation mixed-conifer site, and to determine whether Holocene fire activity in this watershed was intermediate to fire regimes observed at higher and lower elevations in the eastern Cascades. Fire activity and vegetation change was reconstructed using macroscopic charcoal and pollen analysis of sediment core from Long Lake. This site is located ~45 km west of Yakima, WA, and exists in a grand fir-dominated, mixed-conifer forest. Results show low fire activity from ca. 9870 to 6000 cal yr BP, after which time fire increased and remained frequent until ca. 500 cal yr BP. A woodland environment existed at the site in the early Holocene, with the modern coniferous forest establishing ca. 6000–5500 cal yr BP. A mixed-severity fire regime has existed at the site for the past ~6000 years, with both higher- and lower-severity fire episodes occurring on average every ~80–100 years. However, only one fire episode occurred in the Long Lake watershed during the past 500 years, and none within the past ~150 years. Based on a comparison with other eastern Cascade sites, Holocene fire regimes at Long Lake, particularly during the late Holocene, appear to be intermediate between those observed at higher- and lower elevation sites, both in terms of fire severity and frequency.