bluuebunny/crossref_metadata_2025 huggingface dataset:
Systematizing experts' risk perception on rural fires resulting from traditional burnings in Portugal: A Mental Model approach
Authors: Souza Mayara Emilia Barbosa , Pacheco Abílio Pereira , Teixeira Jorge Grenha
Published: October 2022

Fire is a traditional method used for the elimination of residual materials from agricultural and forestry activities, but its improper and negligent use increases the risk to cause significant social, economic, and environmental impacts. Translating the nature and magnitude of the risk, a mental model approach has been used for a deeper understanding of what can be done to reduce future socioeconomic and environmental impacts. Considering the rural fire risk context, in this study we applied the mental model approach to (1) explore the different perspectives of experts on rural fire risks, focusing on the burning problem, and (2) systematize the aggregated knowledge of experts on the subject. Semi-structured interviews that included real-time interactions with the proposed mental model on the MURAL platform were remotely conducted with twenty-eight experts with in-depth involvement and experience in fire and forest management in Portugal, including actors from industry, academics, third sector, and public entities. The experts' contributions were periodically validated by the research team and included in the reference mental model to translate the aggregated knowledge of the expert community. The data collected was transcribed, coded, and analyzed following a thematic analysis approach with NVivo software support. After nine iterations, the expert's mental model was concluded encompassing the burning motivators, alternative solutions, associated risks before and during the burning, underlying causes, natural elements and factors, and impacts. Overall, the study provides an in-depth and holistic understanding of rural fire risks, focusing on burning, which is essential for identifying incorrect beliefs and existing risk factors that are often neglected. The participatory and dynamic process of actors' knowledge systematization on burning risks through a mental model allowed the identification of divergent perspectives between expert groups, especially concerning the effectiveness of the current legislation on the use of fire, indicating the need to improve the dialogue between experts. Moreover, the study shows how risk communication campaigns do not replace technical monitoring closer to the population and recognize the importance and need of sensitization and communication actions to disseminate the use of available alternatives to overcome traditional habits of rural communities. Still, it indicates that successful alternative solutions of burning may be achieved with strong local and sectoral involvement. Finally, this research provides a baseline to help decision-makers and stakeholders identify the most relevant variables about rural fire risks to build effective risk communications strategies and mitigate social and environmental impacts in the future.
A comparative study of the combustion dynamics and flame properties of dead forest fuels
Authors: Sahila Adel , Boutchiche Hanane , Viegas Domingos Xavier , Reis Luis , Zekri Nouredine
Published: October 2022

The combustion properties of several dead Mediterranean forest fuels were investigated experimentally. Samples of straw, eucalyptus, shrubs, and Pinus Pinaster with the same load were placed in cylindrical containers of the same size and were ignited from the perimeter of the container's bottom. A pitot tube and a thermocouple are placed one meter above the fuel surface to measure the airflow induced by the flame and the flame temperature. The main combustion parameters (mass-loss rate, flame height and temperature, and the induced air velocity) seem to evolve according to the same trend regardless of the fuel type. They increase rapidly in the growth phase of the flame then they decrease over a relatively long period characterizing the decay phase. In the crossover period between these two burning phases, the flame is fully developed with a maximum height and burning rate. The time required for the burning rate to attain its maximum value seems to vary only slightly with the fuel type. The maximum flame height and burning rate are found to be the largest for shrubs and the lowest for straw. The flame temperature and airflow are found to depend on the position in the flame with maximum values near the continuous zone of the flame.
Critical heat flux for ignition of dead and live Pinus halepensis needles. Influence of moisture content
Authors: Sabi Fatima Z. , Zekri Nouredine , Terrah Sidi M. , Mosbah Omar , Boutchiche Hanane , Kaiss Ahmed
Published: October 2022

Wildland fire spread has been shown to exhibit unexpected behaviors depending on the fuel roughness, wind and land topography. Fire outbreak has attracted for a long time both wildland fire scientists and operational. The critical heat flux for ignition is one of the most important parameters used in fire safety. For example, it is used for the fuel breaks estimation at Wildland Urban Interface. The critical heat flux for ignition of dead and live Pinus Halepensis needles (moist and dry) is investigated using a cone calorimeter. It is determined by using a recently developed method based on the phase transition theory where ignition time follows a power-law trend near threshold. Compared to the usual deterministic methods, this method accounts for the probabilistic ignition behavior observed for porous fuels. Within the errors, the determined critical heat flux for ignition seems to be independent of the state of the fuel (live or dead) and of its moisture content. A heat transfer analysis is realized using the steady temperature which is related to the absorbed incident heat flux. From this analysis it is concluded that surface temperature at ignition does not change for fresh or dry live and dead fuels.
Ground water as water source opportunity at the fire front – case study at Bács-Kiskun County, Hungary
Authors: Restás Ágoston , Kristóf András , Bodnár László
Published: October 2022

Almost without exceptions, in case of long time wildfires, the continuous water supply is always a logistic problem. One of the several reasons is obviously that most of the wildfires occur during droughts, when there is no rainfall and the natural water sources have low flows. Another problem with the water supply is that the frontline of fire and the water source are usually quite far apart from each other. In this case, firefighters are facing a logistical problem, where not only the limited number of fire trucks, but also the slow movement of these vehicles or even blocks have to be taken into account. The Hungarian example presented in the paper shows the use of local opportunities, just as the imaginative use of groundwater can provide a suitable water source at the fire site. With regard to the effective water transport, the question arises as to whether the average water flow that can be provided during a conventional long-distance water transport can also be provided by the water flow of wells drilled on the fire site. The research shows that, under certain conditions, the groundwater provided by drilled wells can be an alternative solution to the logistical difficulties of long-distance water transport.
Influence of fuel load on the flammability of live Pinus Halepensis needles
Authors: Mosbah O. , Sabi F. Z. , Terrah S.M. , Boutchiche H. , Hamamousse N. , Sahila A. , Kaiss A. , Zekri N.
Published: October 2022

The fuel flammability, combustibility and fire spread properties depend on several parameters. Among these parameters the heat flux, moisture content, wind and the fuel load. Flammable ignition occurs when the emitted organic volatile components flow mixed with air reaches to a minimum rate corresponding to the lower flammability limit. The gas flow of these components depends on the fuel quantity (load) and its temperature. Therefore, ignition time depends on the fuel load. In this work the effect of the load on ignition time of live Pinus Halepensis needles is investigated using a cone calorimeter (providing three incident heat flux intensities). The average fuel moisture content is around 50% in wet basis. Ignition time exhibits an exponential trend for all the incident heat flux intensities considered with a correlation coefficient R^2>0.96. The exponent corresponds to a characteristic load m Ì…_0 around 1 kg/mÂ² slightly dependent on the incident flux within statistical errors. For very small loads compared to m Ì…_0 ignition time is nearly independent of load, because the time required for water evaporation is neglected compared to that required for volatiles mixture with air to reach the lower flammability limit. For larger loads (in the range 0.38 kg/mÂ² to 1.27 kg/mÂ²), the time required for water evaporation introduces a shift in ignition time which increases linearly with load. Finally, for large loads compared to m Ì…_0, the fuel bed thickness becomes larger than the optical length, and only its top layer is heated, transmitting thus heat to the internal layers by conduction. Therefore, the internal layers evaporate water and cool the upper one, leading to exponential of ignition time with the load. For dry fuels, ignition time appears independent of load.
Mitigating rural fires through transformative service research: value cocreation with forest-related rural communities
Authors: Souza Mayara Emilia Barbosa , Teixeira Jorge Grenha , Pacheco Abílio Pereira
Published: October 2022

Socioeconomic changes have caused profound transformations in forest landscapes and increased abandonment of rural areas, leading to fuel accumulation and higher landscape homogeneity, and consequently, raising the rural fires risk. Rural fires risk is also fueled by climate change, due to heat waves and lack of precipitation. In this context, rural communities inhabiting forest areas are those who suffer the most, because rural fires, land degradation and climate change can disturb their food and economic strategy. These communities already suffer from underdeveloped rural infrastructure, and services, lack of labor and education opportunities, that trigger poverty and migration. Given this accelerating pace of change and increasing uncertainty, many fields of knowledge have been dedicated to contributing towards a more sustainable and inclusive future. In service research, transformative service research (TSR) literature plays a central role on understanding problems and finding solutions that improve well-being and create uplifting change through services. Similarly, the fire research field highlights the need for an integrated perspective to analyze all the aspects involved in rural fires occurrence, whether they are of an environmental or economic nature, or a sociological or demographic nature. This study aims to explore new services to cocreate value with forest-related rural communities, thus helping to manage forest areas and mitigate rural fires risks. A qualitative methodology was employed involving 28 participants related to fire management and forest areas and communities, including actors from industries, public entities, academics, the third sector. The data collected through individual interviews were transcribed, coded, and analyzed following a thematic analysis approach, with NVivo software support. Overall, the study emphasizes the need for an endogenous and adapted set of services to cocreate value with vulnerable communities in forest areas, which consequently enable rural fires mitigation. Given the high level of land abandonment and accumulation of residual materials that increases the risk of rural fires, the development of valuing and recovery solutions is a priority. Finally, this research can also help decision-makers and stakeholders to generate and support services that cocreate value with rural communities to a sustainable, safe and inclusive future.
Exploring atmospheric evaporative demand in relation to wildland fire
Authors: Brown Timothy , McEvoy Daniel , Andrade Andrew , Parker Britt
Published: October 2022

Evaporative demand, the upper limit of actual evapotranspiration (ET) that could occur given unlimited surface water supply, has a strong connection to drought and wildfire potential in the western United States and globally. A physically based evaporative demand formulation incorporates temperature, wind speed, humidity, and incoming shortwave radiation â€“ components that drive land surfaceâ€atmosphere interactions and drying. These are also the primary physically based components in the U.S. National Fire Danger Rating System as well as inputs to other fire danger systems. Thus, correspondence between evaporative demand and fire danger can be expected and this has previously been demonstrated such as via the Evaporative Demand Drought Index (EDDI) indicator. For example, EDDI can be decomposed to examine the weighted physical factors over time leading up to a fire event. Utilizing evaporative demand for monitoring and prediction can serve as an early warning of significant fire potential weeks to possibly months in advance. Similarly, evaporative demand can inform prescribed burn planning. Based on the exploration of EDDI indicators prior to fire events, this presentation will discuss analyses of evaporative demand in the context of both wildfire and prescribed fire with an ultimate goal to better understand if and how evaporative demand can be used to inform wildland fire management decisions.
Usage of pouches with phase change materials (PCMs) to increase the thermal performance of a firefighter jacket - development and thermal behaviour evaluation of the multilayer system
Authors: Silva Margarida , Ribeiro J. , Moreira A. , Fernandes P. , Santos Gilda , Marques Rita , Campos João B. L. M. , Neves Soraia F.
Published: October 2022

The growth in size and duration of wildland fires in recent years and the increasingly demand for high-performance protective clothing, has led Thermal Protective Clothing (TPC) research and development to seek solutions to minimise firefighter thermal load and skin burns. In this context, the present work was developed under the framework of the DIF-Jacket project (https://difjacketproject.fe.up.pt), with the main goal being the development of a new multilayer system with phase change materials (PCMs) to be used in a jacket of wildland firefighters and the subsequent development of an experimental procedure to evaluate its transient behaviour. For that purpose, a small-scale multilayer system was developed. It consisted of three layers: an outer textile layer, a pouch with PCMs (intermediate layer) and an inner textile layer. The pouch with PCMs was incorporated into the multilayer system to absorb the incoming heat from the environment, to increase the time that a firefighter can be exposed to it. Subsequently, an experimental set-up was then developed to evaluate the transient behaviour of the solution with PCMs, simulating the different phases to which a firefighter is exposed to (i.e., direct exposure to a radiative heat flux followed by a post-fire period). Therefore, the effect of some pouch-related parameters on the multilayer system thermal behaviour was studied, namely different geometries of the pouches (square and rectangular) and two types of PCMs. As main conclusions, similar tendencies were obtained with the square and rectangular pouches. The best temperature homogeneity of the PCM pouches was obtained with the macroencapsulated PCM. The incorporation of PCMs in the multilayer system significantly delays its heating. Further research must be conducted to delay even more the increase of temperature during exposure time. Nevertheless, the described set-up can be used to analyse several opposing requirements of a multilayer system with PCM pouches integrated, allowing the correlation of geometrical features, and properties of the system components (either textiles or PCM pouches) with the system transient temperature behaviour.
Fire images classification using high order statistical features
Authors: Harkat Houda , Nascimento Jose , Bernardino Alexandre , Ahmed Hasmath Farhana Thariq
Published: October 2022

Wildfires and forest fires have devastated millions of hectares of forest across the world over the years. Computer vision-based fire classification, which classifies fire pixels from non-fire pixels in image or video datasets, has gained popularity as a result of recent innovations. A conventional machine learning-based approach or a deep learning-based approach can be used to distinguish fire pixels from an image or video. Deep learning is currently the most prominent method for detecting forest fires. Although deep learning algorithms can handle large volumes of data, typically ignore the differences in complexity among training samples, limiting the performance of training models. Moreover, in real-world fire scenarios, deep learning techniques with little data and features underperform. The present study utilizes a machine learning-based approach for extracting features of higher-order statistical methods from pre-processed images from publicly available datasets: Corsican and FLAME, and a private dataset: Firefront Gestosa. It should be noted that handling multidimensional data to train a classifier in machine learning applications is complex. This issue is addressed through feature selection, which eliminates duplicate or irrelevant data that has an effect on the model's performance. A greedy feature selection criterion is adopted in this study to select the most significant features for classification while reducing computational costs. The Support Vector Machine (SVM) is a conventional machine classifier that works on discriminative features input obtained using the MIFS, feature selection technique. The SVM uses a Radial Basis Function (RBF) kernel to classify fire and non-fire pixels, and the model's performance is assessed using assessment metrics like overall accuracy, sensitivity, specificity, precision, recall, F-measure, and G-mean.
Fireline production rate assessment under Mediterranean conditions
Authors: Ortega Macarena , Silva Francisco Rodríguez y , Molina Juan Ramón
Published: October 2022

Global change is raising the occurrence and simultaneity of large wildfires. However, increasing the number of suppression resources is not necessarily the way to manage it and even less if suppression resource assignment is determined based on the experience of the incident commander or incident management team. This research focuses on the estimation of fire line production rate in wildfires of different size under Mediterranean conditions. Fire line production rate was defined as the expected length of fire line that can be built by a firefighting crew in a period. Their most important explanatory variables were fuel model type, attack type, fire size, working time and support of aerial resources. Fuel models with the highest fire line production rate are those corresponding to grassland. Fire line production rate in indirect attack is lower than in direct attack regardless of fuel model. Fire line production rate decreased with increasing wildfire size. Firefighter production rate was decreased by 41.79% after three hours of work, due to fatigue in stress conditions next to the fire front. Aerial support increased fire line production rate between 8.14% and 20.63%. Finally, according to the findings obtained, the most efficient crew is made up of 7-9 firefighters. The assessment of the average firefighter production rates based on easily identifiable variables from an incident command post, provides objective information for decision making about the type and number of resources required in wildfires suppression activities. An efficient allocation of suppression resources would reduce crew fatigue and increase the effectiveness of operational plans.
Influence of a sea-breeze front over a fire plume, Pedrogão Grande wildfires (20 June 2017)
Authors: Pinto Paulo , Silva Álvaro , Viegas Domingos Xavier , Almeida Miguel , Ribeiro Luís Mário
Published: October 2022

During the afternoon of 20 June 2017, two massive wildfires were ongoing more than 30 km to the east-southeast of the city of Coimbra, central Portugal. There were no clouds over the location and surrounding areas. As these fires were progressing, smoke plumes were observed with their tops at around 6-7 km a.m.s.l. However, as a sea-breeze front arrived at the buoyancy sources it was observed an outstanding vertical growth of the plumes. One of these developments was particularly analyzed and it was found that the plume topped at nearly double that altitude in less than 60 min. As a result of this interaction, an impressive pyroCumulus cloud formed. This process was analyzed using weather radar with Dual polarization capabilities.
Large eddy simulations of the structure of spreading line fires at flame scale
Authors: Ahmed Mohamed M. , Trouvé Arnaud , Forthofer Jason M. , Finney Mark A.
Published: October 2022

Our general objective in the present study is to develop tools to better describe the coupling between solid phase and gas phase processes that control the dynamics of flame spread in wildland fire problems. We focus on a modelling approach that resolves processes occurring at flame scales, i.e., the formation of flammable vapors from the biomass vegetation due to pyrolysis, the subsequent combustion of these fuel vapors with ambient air, the establishment of a turbulent flow because of heat release and buoyant acceleration, and the thermal feedback to the solid biomass through radiative and convective heat transfer. The modelling capability is based on a general-purpose Computational Fluid Dynamics (CFD) library called OpenFOAM and an in-house Lagrangian particle model that treats drying, thermal pyrolysis, oxidative pyrolysis and char oxidation using a one-dimensional porous medium formulation that allows descriptions of thermal degradation processes occurring during both flaming and smoldering combustion. The modelling capability is calibrated for pine wood and is first applied to simulations of fire spread across a surrogate vegetation bed corresponding to thin, monodisperse, cylindrical-shaped sticks of pine wood with prescribed particle and environmental properties (i.e., bed height, surface-to-volume ratio, packing ratio, moisture content, and wind velocity). While the model can be used in sloped terrain, the present simulations are limited to a flat ground surface. The current emphasis is on determining threshold conditions for successful spread, differences between the plume-dominated and wind-driven flame regimes, possible transitions to a steady or time-dependent flame structure, and differences in the relative weights of the flaming and smoldering regions.
Predicting fire severity in Montana using a random forest classification scheme
Authors: Johnson Jesse V. , Marcozzi Anthony , Bunt Frederick , Bova Jacob , Hogland John
Published: October 2022

Fire managers often make decisions about wildfire incidents on a landscape scale. While several well developed models can predict fire behaviour at these scales, the paucity of data they draw upon can limit their range of validity. Other models explicitly represent the physical complexities of a fire environment, but at increased computational costs and increased sensitivity to boundary conditions. In this paper, we explore a middle ground between landscape level, data-driven fire behaviour predictions and physics-based, computationally expensive models. As a first step, we employ machine learning to predict fire severity from a set of well recognized covariates such as weather, fuel, and topography. A gradient boosted regression tree is used for the classification task, and sets of model hyperparameters tested to determine their role in the classification. The model demonstrates skill in prediction of the burn severity, but is limited by the dynamically evolving set of features; especially the weather. Results were found to be biassed towards under-predicting the severity of wildfires. We conclude with a discussion of approaches available to improve model performance and future applications of the predicted burn severity.
QUIC-Fire: Initial capabilities of a fast-running simulation tool for prescribed fire applications
Authors: Linn Rodman , Goodrick Scott , Brambilla Sara , Robinson David , Brown Michael , Sieg Carolyn , O’Brien Joseph , Parsons Russell , Hiers John Kevin
Published: October 2022

Prescribed fire is increasingly being looked to as a tool that can support land and fire managers in their efforts towards ecological sustainability and wildfire risk management. As prescribed fire use is considered for treatment of more acres and in more complex settings, practitioners are having to work harder to meet their expanding treatment goals in a safe and environmentally responsible manner. In the context of a prescribed fire, the role of multiple ignitions and complex fire geometries depends heavily on feedbacks between the fire and atmosphere and accentuates the need for explicit representation of these processes in any modeling tools that are to be used to support prescribed fire managers. Computational fluid dynamics models like FIRETEC and WFDS are inherently capable of representing this interaction, but they are too computationally expensive for widespread uses by practitioners for exploration and analysis. We have developed a new simulation tool called QUIC-Fire to capture these fire/atmosphere feedbacks while being orders of magnitude less computationally expensive by coupling the fast-running 3-D rapid wind solver QUIC-URB to a physics-based cellular automata fire spread model Fire-CA. Here we describe some of the model basics and provide initial demonstration capabilities of a new fast-running modeling tool, QUIC-Fire, that can be applied to prescribed fire planning. QUIC-Fire provides a self-determining fire prediction capability that represents the critical coupled fire/atmosphere feedbacks at scales relevant for prescribed fire. Although, the development of this model is in the nascent stages, initial results show an encouraging capability to capture basic trends in fire behavior, response of fire spread to size of fire, consumption of canopy fuels in prescribed fire scenarios, interaction between multiple firelines and response to heterogeneity in vegetation. Its ability to model response to both ignition patterns and a temporally and spatially variable fire environment without computational expense of CFD solutions is encouraging.
Sensitivity of LIDAR Derived Fuel Cells to Fire Modeling at Laboratory Scale
Authors: Marcozzi Anthony , Johnson Jesse , Parsons Russell , Downs Jacob
Published: October 2022

Computer models of wildfires are an important tool for fire managers and scientists. However, fuel inputs to wildfire models can be difficult to represent with sufficient detail in a computationally efficient manner. Recent advances in fuel mapping with airborne and terrestrial laser scanning (LIDAR) techniques present new opportunities to capture variation in fuels within a tree canopy and on a landscape. In this paper, we develop a technique for building 3D representations of vegetation from point clouds created by Terrestrial Laser Scans (TLS). Our voxel based approach is capable of representing heterogeneous crown fuels as collections of fuel cells in modern 3D Computational Fluid Dynamics wildfire models such as FDS, QUIC-Fire, or FIRETEC. We evaluated the effectiveness of our technique at different fuel cell resolutions by using the DAKOTA optimization toolkit to compare simulated fire behavior in FDS with observed burn data collected during a series of experiments at the Missoula Fire Sciences Laboratory. The difference between simulated and observed fire behavior was quantified by taking the Root Mean Square Error between the observed and simulated mass curves over time. Our primary finding was that the point cloud derived fuel cells accurately describe observed fire behavior when evaluated over fuel moisture content and dry foliage mass. We also found that the global minimum RMSE persists across fuel cells at each resolution. However, the RMSE gradient increases with fuel cell size. This result implies that while both low and high resolution fuel cells are capable of accurately representing complex fuel distributions in 3D fire models, low resolution fuel cells are more sensitive to changes in fuel moisture content and dry foliage mass. The results of this paper offer fire managers and scientists responsible for simulating fire behavior guidelines for how best to translate LIDAR data to 3D fire models, and what fuel cell resolution can best capture accurate fire behavior. With these best practices in mind, fire managers will be able to generate improved fire behavior predictions for prescribed burns, forest thinning plans, and suppression activities.
Towards real-time predictions of large-scale wildfire scenarios using a fully coupled atmosphere-fire physical modelling framework
Authors: Wang Qing , Ihme Matthias , Chen Yi-fan , Yang Vivian , Sha Fei , Anderson John
Published: October 2022

With the changing climate, fire-exclusion, and expansion of wildland-urban interfaces, the frequency and severity of wildfires are expected to increase, putting substantial stress on fire management and authorities to mitigate the risk of wildfires. Improved physical models in conjunction with advanced high-performance computing resources offer new opportunities for operational use in examining potential fire-spread scenarios and planning. This work presents an open-source, high-fidelity modelling framework for simulating large-scale wildfire scenarios, taking into consideration atmospheric/fire coupling, complex terrain, and heterogeneous fuel loading. The framework is implemented using the TensorFlow programming environment on tensor processing units (TPUs). TPUs are a dedicated high-performance computing architecture to accelerate machine-learning applications and high-performance scientific computing. This framework solves the Favre-filtered reacting Navier-Stokes equations and the unclosed terms describing turbulence/chemistry interaction and turbulence transport are modelled using large-eddy simulation (LES) closures. Wildfire dynamics is described by a one-step solid-fuel pyrolysis/combustion model that is coupled to atmospheric flow dynamics using a Boussinesq-type approximation. A second-order finite-difference discretization is employed in a variable-density, low-Mach number formulation to discretize the governing equations, and an immersed-boundary method is adapted to represent complex terrain. In conjunction with the coupled atmosphere/fire model and physical models for turbulence/atmosphere/fire interaction, the resulting simulation framework enables high-resolution simulations (with spatial resolution below 2m) of large-scale fires that cover up to ~100,000 acres. Following the summary of validation results against a prescribed fire experiment to assess the overall accuracy at well-controlled conditions, we employ this coupled atmosphere/fire modelling framework to simulate a large-scale wildfire scenario that is representative of the 2017 California Tubbâ€™s fire. To this end, we extract the terrain of the North Bay region of Calistoga and Santa Rosa, spanning an area of 20Ã—20 km2, and consider a North-Eastern wind. The simulation results illustrate the rapid fire-spread dynamics and the coupling of the fire with the terrain and atmosphere. With relevance to operational and research applications that include parametric studies to examine effects of wind, fuel-density, other environmental factors, and fire-management strategies, we discuss the scalability and further extensions of the physical fidelity towards enabling real-time applications on TPU-compute architectures.
Validation of operational fire spread models in California
Authors: Cardil Adrián , Monedero Santiago , Navarrete Miguel Ángel , de-Miguel Sergio , Silva Carlos A. , Quilez Raúl , Purdy Scott , Ramirez Joaquin
Published: October 2022

The use of wildfire simulators allows estimating fire spread and behaviour in diverse and complex fire environments, supporting fire planning and analysis of incidents in operational environments. However, uncertainty derived from the spatio-temporal estimation of input variables and modelâ€™s inherent inaccuracies related to its limitations and assumptions may undermine the utility of such predictions. Here, we assessed the performance of well-known operational surface and crown fire spread models used in California through the analysis of the rate of spread (ROS) of 1,853 wildfires occurring in the State from 2019 to 2021. For each detected wildfire, we retrieved the observed fire progression using the FireGuard (FG) database which provides the fire progression through geo-spatial polygons every 15 minutes approximately. Based on this data, we developed an algorithm that characterises the ROS for each FG polygon and the average ROS in the first 8 hours of the fire. Also, we ran a fire simulation for each wildfire with Wildfire Analyst Enterprise using high-resolution fuel and weather data to estimate the rate of spread. Then, we assessed 1) the accuracy of the fire simulations by comparing the real and simulated ROS based on the Mean Absolute Error (MAE), Mean Bias Error (MBE) and Mean Absolute Percentage Error (MAPE); 2) the most important factors influencing the accuracy of fire simulations, including the wind speed, and fuel types. Although the models clearly underestimated ROS in timber fuels, especially when no crown fire behaviour was predicted, most of the fire simulations had an acceptable error to be used in operational environments given the new techniques to adjust and calibrate the fires with field data. Finally, we used this analysis to present new approaches to optimise the fire predictions, including the optimisation of new custom fuels through genetic algorithms and enhancement of crown fire spread models.
A Comparison of Particulate Morphology of Wildland Fuels and Human-Made Fuels at the Wildland-Urban Interface
Authors: Manzello Samuel L. , Suzuki Sayaka
Published: October 2022

Improved knowledge of large outdoor fire particulate emissions is needed at the laboratory-scale. Here, samples of oriented strand board (OSB), a common human-made fuel abundant cities, were ignited using a radiant heater coupled to a spark igniter. Particulate samples were taken to begin to look at the morphology of the generated particulates. Using a simple experimental setup affords the capability to investigate particulates produced from smoldering combustion as well as those collected from flaming combustion. As the nature of particulate samples were expected to be sensitive to the voltage of the electron beam for smoldering combustion in particular, scanning electron microscopy (SEM) was used as first step to investigate the morphology. Transmission electron microscopy (TEM) operates at higher acceleration voltages and this is expected to influence the samples. As a direct comparison to the results from the engineered cellulosic based material experiments, branches from conifer trees, a natural vegetative fuel, were also exposed to a radiant heater and particulate samples were collected using similar experimental protocols. morphology of the generated particulates is greatly influenced by the state of combustion for both the engineered cellulosic based material (OSB) as well as those collected for natural vegetation. Results of this study will be presented
Anatomy of the Las Máquinas wildfire using remote sensing tools
Authors: Valdivia Jorge , Avila Israel , Auat-Cheein Fernando , Fuentes Andrés , Reszka Pedro
Published: October 2022

The Las Máquinas wildfire took place in central Chile in the austral summer season of 2017 has becomes the most severe event in Chilean history, causing loss of life, property and the destruction of native forest, crops, large areas of commercial plantations and biodiverse habitats. Since this event has no precedent in Chilean wildfire history, it was used as an example to carry out a detailed analysis of the conditions before (pre-), during (per-) and after (post-) the fire from a remote sensing perspective. The goal of this work is to develop a framework to carry out detailed analyses of catastrophic fires for forensic and public policy purposes, making use of the advantages posed by Earth Observation satellites, including the simultaneous imaging of large areas with a good spatial resolution, and an ever-increasing temporal resolution, coupled with a sophisticated suite of instruments which allow measuring many parameters simultaneously. This study examines the biophysical, meteorological and physical variables like the evolution of the Normalized Difference Vegetation Index (NDVI), weather conditions, maximum temperature evolution, the Canadian Fire Weather Index, the burned area, the maximum fire radiative power, among others, for the five municipalities that were affected by the fire: Cauquenes, Chanco, Empedrado, ConstituciÃ³n and San Javier, all of which are located in the Maule Region. The results indicate that Las Maquinas wildfire took place under exceptional meteorological conditions. In particular, the conditions before the night when Santa Olga was destroyed were characterized by record values of the FWI, which caused a significant increase in the burned area and overwhelmed any response by the fire brigades.
Impact of forest gaps on wind turbulence and potential wildfire behavior at the rural-urban interface
Authors: Zhang Jiawei , Katurji Marwan , Brasington James , Hilton James , Zawar-Reza Peyman , Strand Tara
Published: October 2022

Forest canopy can impact fire behavior through modulating both subcanopy atmospheric turbulence and wake turbulence at the forest edge. The 2020 Lake ÅŒhau fire happened at a rural-urban interface where the heavily fire-damaged village was surrounded by a heterogeneous forest canopy. Evidence shows that high wind speeds with strong gusts were present throughout the fire outbreak, indicating a strong wind-driven wildfire. Since the village was surrounded by complex terrain including a forest canopy, the forest canopy might play an important role in modifying the wind conditions within the village which could impact the fire spread behavior. This research uses Large Eddy Simulation (LES) to study wind gusts and other near-surface wind characteristics in the Lake ÅŒhau area under the weather conditions of the 2020 Lake ÅŒhau fire. The work especially focuses on how the forest canopy around the village could change the wind gust within and around the village area. To do so, a LiDAR field campaign was also undertaken to obtain ultra-high resolution (grid resolution < 10m) forest canopy and other geoinformation. Results also show that the village was impacted by two mesoscale wind systems - an offshore westerly downslope wind from west of the village and a northerly wind coming down over Lake ÅŒhau. The LES results were also used to further explore how simulated forest gap orientation might impact the downstream wind. Previous studies have shown that creating forest gaps or firebreaks can significantly change the wind characteristics within and at the edge of the forest. Three additional scenarios were studied by modifying the forest canopy around the village, including one without any forest canopy, one with horizontal (West-East orientation) forest gaps and one with vertical (North-South orientation) forest gaps. Total removal of the forest canopy increased the average wind gust in almost all areas within the village while the changes were spatially more heterogeneous in the horizontal and vertical gap scenarios. Differences of the spatial wind gust distribution might be related to how different forest gap alignments change the dominant inflow wind component. Next steps of this work will utilize passive tracers and temporal analysis to identify the processes driving these differences.
Impact of the WUI vegetation management on damage to building: comparing post-fire damage assessment and CFD modelling results.
Authors: Ganteaume Anne , Guillaume Bruno , Girardin Bertrand
Published: October 2022

In most Wildland-Urban Interface (WUI) fires, damage to building can result from poor vegetation management, comprising a lack of mandatory brush-clearing around building or an unwise location of trees (e.g. too close to building or overhanging the roof). It was interesting to check if post fire damage can be predicted by CFD fire modelling in different scenarios of vegetation management (treated vs untreated) according to different past-fire events. Ultimately, this work will help to assess if the fuel treatment regulation in the framework of fire prevention is efficient and to pinpoint possible limitations. Different scenarios of vegetation treatments were tested on four study cases of dwellings surrounded by gardens juxtaposed to wildland vegetation (therefore submitted to the regulation on fuel management in WUI) that were affected by the Vidauban fire in 2003 or the Rognac fire in 2016 (SE France). In each case, comparisons of modeled and observed fire behaviour and impacts on buildings were performed using the Fire Dynamic Simulator model (FDS) and very accurate georeferenced ornamental vegetation mapping, especially around buildings. Despite problems to adapt FDS modelling to the high fuel moisture content (FMC) of some species, results showed that overall brush-clearing mitigated fire intensity and propagation and therefore damage to building and ornamental vegetation, sometimes highlighting that this fuel management measure could be softened (decreasing the radius treated) or, on the contrary, strengthened according to the topography and wind. The fuel biomass treatment involving vegetation residues left on site was also found as deleterious as the lack of treatment. Overall, the modelling using FDS, at the WUI scale and taking into account a very refined vegetation distribution, was mostly successfully validated by post-fire damage recorded during the past-fire events, which was rarely attempted in the complex environment of forest fires in the French Mediterranean area. The current scientific limitations of the model did not allowed obtaining realistic results in terms of heat flux received by the building, even if they were coherent in global intensity comparing treated and untreated vegetation, and have to be addressed in future improvements of the model.
Investigating Conifer Tree Flame Spread Under an Applied Wind Field
Authors: Suzuki Sayaka , Manzello Samuel L.
Published: October 2022

In this study, discrete fuel packages, manifested as conifer trees, were spaced apart, and the flame spread processes through these fuel packages were observed under an applied wind field. The experiments were conducted using wind facilities at the National Research Institute of Fire and Disaster (NRIFD) in Japan. Three ignition sources were utilized. The first considered a custom propane burner, the second made use of firebrand showers using a custom firebrand generator, and the third utilized one tree to ignite another tree. During the subsequent flame spread processes through the discrete fuel packages, mass loss profiles, and attendant firebrand production was quantified. Results of this study will be presented.
Curriculum Framework for the Sustainable Development Goals
Authors: Secretariat Commonwealth
Published: October 2022

In September 2015, the 2030 Agenda for Sustainable Development and the Sustainable Development Goals (SDGs) detailed therein were formally adopted at the United Nations (UN) Sustainable Development Summit. The SDGs succeed the Millennium Development Goals (MDGs) and guide the global path of sustainable development after 2015.
The 2030 Agenda for Sustainable Development is a plan of action for people, planet and prosperity, with countries and all stakeholders acting in collaborative partnership to implement this plan. The Agenda also seeks to strengthen universal peace and provides a common vision for peaceful societies.
Use of Benzodiazepines and Z-Drugs in Inflammatory Bowel Disease
Authors: Bernstein Charles N. , Fisk John D. , Walld Randy , Bolton James M. , Sareen Jitender , Patten Scott B. , Singer Alexander , Lix Lisa M. , Hitchon Carol A. , El-Gabalawy Renée , Graff Lesley A. , Katz Alan , Witges Kelcie , Marriott James J. , Marrie Ruth Ann ,   for the CIHR Team in Defining the Burden and Managing the Effects of Psychiatric Comorbidity in Chronic Immunoinflammatory Disease
Published: October 2022

INTRODUCTION:

We estimated the incidence and prevalence of benzodiazepine and Z-drug (separately and jointly as BZD) use in the inflammatory bowel disease (IBD) population compared with matched controls without IBD and examined the association of mood/anxiety disorders (M/ADs) with the use of BZD from 1997 to 2017.

METHODS:

Using administrative data from Manitoba, Canada, we identified 5,741 persons with incident IBD who were matched in a 1:5 ratio to controls on sex, birth year, and region. Validated case definitions were used to identify M/AD. Dispensations of BZD were identified. Multivariable generalized linear models were used to assess the association between IBD, M/AD, and BZD use.

RESULTS:

In 2016, the incident age/sex-standardized benzodiazepine use rates per 1,000 were 28.06 (95% confidence interval [CI] 26.41–29.81) in the IBD cohort and 16.83 (95% CI 16.28–17.39) in controls (adjusted rate ratio = 1.69 [95% CI 1.56–1.79]). Benzodiazepine incidence rates were higher for women with IBD than men, but the RR between cases and controls were similar for men and women. The incident age/sex-standardized Z-drug use rate per 1,000 was 21.07 (95% CI 19.69–22.41) in the IBD cohort. This was 1.87-fold higher than in controls (95% CI 1.73–2.01). In 2017, approximately 20% of persons with IBD used benzodiazepines and 20% used Z-drugs. There was a subadditive effect of both benzodiazepine and Z-drug uses between IBD and M/AD after adjusting for covariates.

DISCUSSION:

The use of BZD is more common in people with IBD than in population controls. Strategies to reduce the use of BZDs in persons with IBD and to offer alternative management strategies for M/ADs, sleep disorders, and other symptomatic concerns are needed.
Comparable Mortality Between Asian Patients with Chronic Hepatitis B Under Long-Term Antiviral Therapy vs Matched Control: A Population-Based Study
Authors: Yun Byungyoon , Oh Juyeon , Ahn Sang Hoon , Yoon Jin-Ha , Kim Beom Kyung
Published: October 2022

INTRODUCTION:

Antiviral therapy (AVT) substantially improved the prognosis for patients with chronic hepatitis B (CHB). Head-to-head comparisons of prognosis between treated patients with CHB and the general population are scarce. We directly compared the prognosis between Asian patients with CHB receiving AVT and the general population.

METHODS:

From the South Korean National Health Insurance Service database, patients with CHB receiving AVT ≥3 years, aged 40–64 years, who underwent health examinations between 2011 and 2012 (AVT-CHB group) were recruited. As a control, propensity score–matched general population was chosen among patients without CHB. The primary outcome was all-cause mortality; secondary outcomes were cardiovascular disease (CVD), hepatocellular carcinoma (HCC), and all types of non-HCC malignancies.

RESULTS:

During follow-up (median 7.2 years), 26,467 and 75,469 individuals in the AVT-CHB group and matched general population were analyzed. The 5- and 7-year cumulative all-cause mortality rates were 0.40% and 1.0% for the AVT-CHB group vs 0.50% and 1.0% for the matched general population (adjusted hazard ratio [aHR] 0.96, 95% confidence interval [CI] 0.83–1.10; P = 0.51). The AVT-CHB group had a lower risk of CVD than the matched general population (aHR 0.70, 95% CI: 0.62–0.79; P < 0.001). Although the AVT-CHB group was more likely to develop HCC than the matched general population (aHR 13.16, 95% CI: 10.90–15.89; P < 0.001), the non-HCC malignancy risks in the AVT-CHB group were comparable to the matched general population (aHR 1.05, 95% CI 0.98–1.13; P = 0.137).

DISCUSSION:

The AVT-CHB group had a similar risk of all-cause mortality and non-HCC malignancies and a lower risk of CVD than the matched general population.