bluuebunny/crossref_metadata_2025 huggingface dataset:
Implementing a probabilistic fire modeling system at the pan-European level
Authors: Alcasena Fermín , Rodrigues Marcos , Salis Michele , Resco Víctor , Palaiologou Palaiologos , Ager Alan , Jiménez-Ruano Adrián , Giudice Liliana Del , Gelabert Pere , Cunill Àngel , Vega-García Cristina
Published: October 2022

This research shows the potential use of cross-boundary fire modeling systems at the pan-European level. Despite the growing interest in building fire-resilient cultural landscapes, European Union (EU) level efforts have been reactive and focused on early detection, fire propagation monitoring, and perimeter mapping rather than predicting where the disaster can potentially occur to develop a comprehensive wildfire management strategy. We propose a modeling system that integrates wildfire occurrence models and observed fire-weather scenarios with a fire spread model to generate the probabilistic risk components, i.e., wildfire likelihood and hazard estimates. We selected four NUTS-2 level administrative division pilot sites from different fire-prone countries to implement the modeling system. The European-level pyromes were first delineated based on ecoregions and historical wildfire activity. We then generated human and lightning wildfire occurrence models to display the ignition points. Remote sensing products were used to derive fire spread modeling spatial input data such as surface fuels and canopy metrics. Global atmospheric products were used to calculate the fuel moisture content with physical models and determine the most frequent wind scenarios for each pyrome. We then used the Minimum Travel Time algorithm to model the fire footprints that correspond to 10,000 years or synthetic iterations. This modeling approach accounted for the spatial variation of ignition locations and the changing weather conditions across the different pyromes within each pilot site. The modeling results include the annual burn probability and fire intensity rasters, and fire perimeter vector outputs. Modeled burn patterns showed a close agreement with observed fire size distributions. We compared this modeling system with previous works to explain why stochastic fire modeling is essential to assess wildfire exposure of natural values at risk and human communities. Our results may help predict future catastrophic fires and provide quantitative estimates to identify high-priority management areas within vast regions. The probabilistic predictions generated in this work represent the foundation for developing long-term adaptation strategies to better coexist with fire. This work is also a demonstration of how this modeling system is replicable in any European country.
Influence of tree species on surface fuel structure in Swedish forests
Authors: Plathner Frida Vermina , Sjöström Johan , Granström Anders
Published: October 2022

The highly managed forests of Fennoscandia are dominated by coniferous (Scots pine and Norway spruce) stands with occasional inclusion of deciduous trees (Betula spp, Populus tremula, Quercus robur). Without active pre-commercial thinning, broadleaved deciduous trees would be more common and it is often assumed this would reduce flammability. Generally there is little information on surface fuel structure in Fennoscandia and its relation to the dominant tree species. We therefore evaluated fuel characteristics in a sample of Swedish mature, closed-canopy forest stands dominated by Pinus sylvestris, Picea abies, Quercus robur, Betula pendula, Populus tremula, as well as some mixed-species stands. Stand properties (tree species and basal area of the stand) were measured on site and fuel bed composition was determined by destructive sampling of two 0.25 m2 plots per stand (species, fuel bed depth, live weight, % coverage). Dry weight was evaluated in a laboratory environment. The measured parameters were used as input to the BEHAVE wildfire model, to assess relative fire behaviour for these different fuel assemblies. The results show that the moss/lichen layer was thicker and had a larger dry weight under pure pine stands compared to that under spruce stands, most likely due to better sunlight penetration to the forest floor in pine stands and structural differences of the needle litter. BEHAVE modelling suggested both fireline intensity and rate-of-spread to be substantially higher for pine stands. As for the broadleaved deciduous tree species, even a small inclusion in the coniferous stands severely affected the moss/litter layer. Leaf litter formed horizontal, multi-layered packs that replaced the porous structure and high surface-to-volume ratio of the moss/litter with a more compacted pure litter layer, resulting in reduced flammability. The BEHAVE models presented here are available at https://www.ri.se/sites/default/files/2021-12/SwedishForestFuels_0.zip.
Mulching treatments favour the recovery of ecosystem multifunctionality after a large wildfire in Northwest Spain
Authors: Marcos Elena , Huerta Sara , Fernández-García Víctor , Prieto Iván , Pinto Rayo , Ansola Gemma , Miera Luis Saénz de , Calvo Leonor
Published: October 2022

Wildfires are a widespread phenomenon in forests across the Mediterranean Basin but have increased in severity and extent in recent decades. Post-fire treatments are measures that help recover burned vegetation and their functionality but to what extent they also help recover soil functionality is currently unknown. The main objective of this study was to assess the effect of post-fire treatments on ecosystem multifunctionality after a large wildfire in the Cabrera mountain range in 2017 (NW Spain) where close to 10000 Ha of forest were burnt. At the end of 2017 and during 2018, the administration applied different post-fire treatments in high fire severity affected areas: i) straw mulching, ii) woody debris and iii) subsoiling and iv) mechanical hole afforestation. In each treatment, we established ten 2 x 2 m plots and ten adjacent untreated burned plots and collected a composite soil sample from each plot four years after the fire (2021). We calculated regulating services as the standardized mean of total soil organic C (climate regulation), soil water repellence (water regulation) and soil aggregation (soil protection). Supporting services were measured as the standardized mean of mineral N-NH4+ and N-NO3- and available P (soil fertility), Î²-glucosidase, urease and acid phosphatase (nutrient cycling) and microbial biomass (soil quality). Ecosystem multifunctionality was measured as the standardized mean of all functions measured. Application of straw mulch and woody debris increased regulating ecosystem services in relation to burned control plots. Afforestation with holes had not impact but subsoiling decreased regulating ecosystem services in relation to burned control plots. Post-fire treatments did not have any effect on supporting services. Straw mulch, Woody debris and afforestation with holes improved ecosystem multifunctionality when compared with subsoiling methods. These results show that post-fire stabilisation treatments, in particular straw mulching have a significant positive impact on regulating services and are effective measures in restoring the ecosystem multifunctionality, helping develop effective management based-decisions for the recovery of ecosystem services and functioning after large wildfires.
Observation of Horizontal Smouldering Spread on Layer Thickness of
Tropical Peat
Authors: Mulyasih Hafizha , Putra Randitia Andika , Muhammad Bintang Farhan , Irwansyah Ridho , Nugroho Yulianto Sulistyo
Published: October 2022

Smouldering spread of peat fires has been studied by numerous researchers. This study focus on the development of an adjustable reactor for studying the horizontal spread rate of tropical peat. Experimental work was performed to study the impact of peat layer thickness on horizontal smouldering spread behaviour. The thickness of the peat layer was varied 2 cm, 3 cm, and 4 cm peat thickness. A 3 cm-long coil heater was placed in the centre of the base. For ignition protocol, the coil heater was powered with 100 W of electricity for the first 60 minutes. Smouldering behaviour was observed by the temperature data, that measured using thermocouples and a thermal camera. The thickness of the peat layer and bulk density play important roles in the horizontal spread probability, as it changes the heat balance between the heat generation at the reaction zone and heat loss to the environment. Higher peak temperature was observed for peat 4 cm depth and then decreased by the thickness. The smouldering spread rate increases by peat thickness from 2.21 cm/h to 2.91 cm/h and then reach an asymptotic level. Extinction corresponds to a negative energy balance observed in thickness 2 cm of peat. A self-sustained smouldering front could not be maintained after the igniter was turned off. The detail of the adjustable reactor design and more data analysis will be presented in the full paper.
Present and future fire risk changes in Central Europe
Authors: Billing Maik , Marrs Christopher , Forkel Matthias , Sebode Eike , Thonicke Kirsten
Published: October 2022

Fire risk is projected to increase under future climate change. Most projections focus on fire-prone regions, such as the Mediterranean-type ecosystems, whereas little attention has been paid to regions of low fire risk such as Central Europe. Here, future projections of fire risk which are tailor-made for its specific conditions are scarce. With our study we aim to fill this gap. We use meteorological station data and interpolated climate datasets to compute future fire risk for Central Europe (covering Germany, Poland, the Czech Republic) using the Fire Weather Index. In a next step, we analyse the spatial distribution of reported fire ignitions to identify additional drivers that can explain the spatial pattern of fire ignition and risk, or accelerate fire risk under climate extremes (drought or extreme heat). We analyse how transport infrastructure and proximity to settlements have influenced fire ignition in Central Europe and compare it against relationships known from fire-prone regions. We aim to build on recent adjustments of the FWI to account for respective increased fire risk and apply it to our study area. We conduct high-resolution analysis of fire-risk analysis by computing the FWI along the wildland-urban and wildland-rural interface in individual sites in the study region. In a next step, downscaled future climate scenarios (CMIP6) are applied to compute changes in future fire risk for the entire study area as well as the selected sites in Central Europe. Uncertainty ranges of future fire risk projections will be covered by using several climate scenarios for the entire study region. Detailed analysis will be conducted at the local scale by further refining changes in ignition potentials along the wildland-urban and the wildland-rural interface in selected sites in Central Europe under climate change conditions.
Using simulation and deep learning to derive synthetic high resolution daily fire danger maps
Authors: Filippi Jean-Baptiste , Allaire Frédéric , Vaysse Florence
Published: October 2022

Diagnostic of wildfire danger for the next day typically relies on computation of meteorological indices, usually derived from weather forecast. These indices may represent the danger of ignition, potential rate of spread or droughts, and while it takes into account the vegetation state it do not represent exactly how it will burn, as this is dependent of the fuel distribution and landscape at a scale much finer than weather model allows. On the other hand, overall landscape danger is more and more often evaluated statistically using mass simulation, with a very large number of fire simulated over a variety of weather situation to estimate effective fire area burned (in Ha), reaching a very fine scale at a cost of long computational time. To overcome this computational problem and pinpoint where and when the most critical situation of next day may occurs, We have recently introduced a method, DeepFire, based on deep learning emulation of wildfire simulation to compute these next day fire size distribution an very high temporal and spatial resolution. Nevertheless these simulation comes at a cost, the amount of generated data is large and providing an poses the challenge of creating a synthesis that may actually be helpful in operations. In this study, several approaches are proposed to analyse results and provide fire danger maps and ratings using this new simulation-based prediction system, it is applied to forecasts for 13 relatively large fires that occurred in Corsica and compared to corresponding forecasts using another fire danger index used in operational conditions.
Wildfire rate of spread according to fire isochrones and wind direction in four of the 2019-2020 Black Summer Fires in Australia
Authors: Duane Andrea , Bachfisher Mercedes , Brotons Lluís , Castellnou Marc
Published: October 2022

Wildfires of recent years are unprecedented in terms of fire behavior and impacts all around the world. The wildfire community still needs to better comprehend the physics behind the phenomenon to reduce uncertainty and increase the response capacity during emergencies. Studying past fires becomes crucial for predicting future fire behaviors. However, often the description of fire behavior in past fires has been associated with a high degree of subjectivity according to respondersâ€™ description. Here, we offer a new tool that enables the user to calculate the maximum rate of spread of wildfires according to an isochrones map of the fire. In addition, it includes the possibility to calculate this maximum rate of spread according to wind direction. We apply it to a set of four fires that occurred between the 29 and 31st December 2019 in Australia. Although results are not available in this current version of the paper, we believe this can be a very useful tool for fire analysts to compare and analyze past fires and increase our global understanding of fire behavior.
Assessment of micro-combined heat and power system based on an organic Rankine Cycle coupled to a boiler for residual biomass valorization
Authors: Stasi Christian Di , Torreiro Yarima , Rodríguez-Abalde Ángela
Published: October 2022

Energy from biomass obtained in rural areas provides a sustainable alternative for heat and power production. In particular, the combustion of biomass in boilers represents the most widely used valorization route for the production of thermal energy. Furthermore, cogeneration has proven to be an efficient and clean way of simultaneous production of electricity and useful heat in the place of consumption, with the consequent saving of primary energy and emissions. The specific aim of this experimental work is to study the feasibility of employing forestry wastes as feedstock for microcogeneration (electrical power
Comprehensive Characterization of Pyrolysis and Combustion of Genista Salzmannii Needles (GSN) for Fire Hazard Analysis
Authors: Rahib Yassine , Leroy-Cancellieri Valérie , Cancellieri Dominique , Awad Carmen , Rossi Jean-Louis
Published: October 2022

This article presents a first attempt of implementation of a lab scale methodology proposed to describe the thermal decomposition behavior of vegetative fuels, by using thermogravimetric (TG) methods, with respect to forest fire. Experiments within this method include testing the usual grinded form of samples compared to a continues fuel layer (intact form), which can render reliable and useful information to improve the understanding of the ignitability and combustibility of forest fuels along with predicting fire propagation. Moreover, slow (20 and 40 Â°C/min) and fast (60, 80 and 100 Â°C/min) heating rate were chosen to get close from the actual conditions of wildland fires (preheating/smoldering and flame region, respectively). In this work, we report the thermal decomposition behavior under inert (N2) and oxidative (air) atmospheres of Genista Salzmannii Needles (GSN) involved in fires of Mediterranean forests. TG analyses were performed to assess thermal reactivity and combustion indices (ignition, devolatilization, combustion and burnout indices) of grinded and cut GSN samples at fives heating rates of 20, 40, 60, 80 and 100 Â°C/min. The use of the set of thermal indices practical investigation, ignitability, combustibility and sustainability of forest fuels are important properties to be determined when talking to efficient wildland fire management. Moreover, Activation energy was calculated by means of two iso-conversional methods. The results showed that the cut GSN was characterized by a higher mass loss rate compared to grinded samples. As the heating rate increases, reactivity and combustion indices increase linearly. At low heating rates (20 and 40 Â°C/min), these parameters are quite similar for both samples, while the gap becomes more and more significant at elevated heating rates (60, 80 and 100 Â°C/min). High correlation coefficients (R2 > 0.96) were obtained, which indicate a good degree of fitting reliability between combustion characteristics and the tested heating rates. Furthermore, the variation of activation energy (Ea) with the conversion rate has exhibited a quite similar behavior during the whole pyrolysis and combustion process. Char formation, at the end of an intense devolatilization, was the most complex process. The oxidation of the remaining char was characterized by a significant decrease of Ea, which is not considered as a major event in the combustion process. Finally, the obtained data provide systematic knowledge for understanding the thermal decomposition of forest fuels (considered as the first stage in fire process), while the developed methodology can be used for comparison and classification of vegetative fuels related to fire risk potential.
Numerical Investigation of Crown Fuels Arrangements on Wildfire Behavior Following Fuels Treatments
Authors: Ziegler Justin Paul , Hoffman Chad M. , Parsons Russel A. , Johnson Morris , Menakis James
Published: October 2022

Conventional fuels treatments often simplify forest structure in an attempt to optimize fire hazard reduction. Conversely, forest restoration treatments, aimed at achieving ecological multiple objectives in addition to fire hazard reduction, purposefully retain complex forest structures. The comparative advantage of conventional fuels versus restoration treatments may depend on the severity of the burning environment, residual tree stocking and surface fuel loads. Here, we performed a suite of simulations with the Wildland-urban interface Fire Dynamics Simulator to compare stand-level fire behavior between silvicultural cuttings that either emphasized or reduced forest structural complexity under a range of residual basal areas, surface fuel loads, and burning conditions. These cuttings included distance-based retention, variable retention, and random cuttings, optionally with thinning from below. Rate of spread did increase under more severe burning conditions, and slightly increased after thinning from below or after variable retention cuttings due to the creation of openings. Canopy consumption was lowest when thinning from below and highest after variable retention. While all treatments reduced fire behavior, the differences we observed support the advantage of using conventional fuels treatments where fire hazard reduction is of primary importance. Additionally, the effects of residual basal area, surface fuel load, and burning conditions highlight the multivariate considerations required when planning fuels treatments and assessing performance at stand or landscape scales.
TGA/TDA and Analytical Pyrolysis (Py/GC-MS) of Two Mediterranean Forest Species with Distinctive Flammability Characteristics: Cupressus sempervirens L. and Quercus suber L.
Authors: Jamaladdeen Rawaa , BenBelkacem Imene , Coudour Bruno , Lemée Laurent , Roudaut Christelle , Bouhafsoun Aicha , Djabeur Abderrezak , Wang Hui-Ying , Garo Jean-Pierre
Published: October 2022

The frequencies of wildfires in the Mediterranean climate regions (MCRs) have amplified due to the increased temperatures and drought periods resulting from climate change. Vast areas of forests are consumed by wildfires and certain species are threatened by extinction due to their high flammability and weak thermotolerance to climate change whereas, other species with high thermotolerance are exploited as silviculture measures in forest management strategies. Canopy and litter foliage are the first ignitable structures in a forest fire. In this context, the foliar flammability characteristics of two fire resilient Mediterranean forest species are tested and compared on a laboratory scale; Quercus suber L. (Q.s.L.) and Cupressus sempervirens L (C.s.L). Thermo gravimetric/thermo differential analysis (TGA/TDA) and low- to high- temperature analytical pyrolysis tests and gas chromatography-mass spectrometry (GC-MS) were conducted on live and dry foliar samples of Lebanese C.s.L and Algerian Q.s.L. Branch and cork samples of Q.s.L were also pyrolyzed (Pyr/GC-MS) for their volatile content. The hemicellulose/cellulose degradation temperatures of C.s.L. were in the order of 30 to 50Â°C more than those of Q.s.L. Lignin degradation started later in the Q.s.L. and took place at temperatures higher than those of C.s.L. (ï¾>30Â°C), while the heat release rates (HRR) were greater for the latter than the former in both degradation phases. The pyrolysis tests showed higher volatile content of C.s.L compared to Q.s.L. The high thermotolerance characteristic of C.s.L may be referred to its high terpene content which was negligible in Q.s.L given the fact that it is a non-monoterpene emitter oak species with no terpene storage compartments. The use of C.s.L as a fire barrier could be justified given their thermotolerance characteristic. Q.s.L. fire resilience is justified for their bark characteristics however; their foliage fire resilience should be further experimented.
The role of helicity and fire-atmosphere turbulent energy transfer on potential wildfire behavior
Authors: Zhang Jiawei , Katurji Marwan , Zawar-Reza Peyman , Strand cTara
Published: October 2022

Understanding near surface fire-atmosphere interactions at turbulence scale is fundamental for predicting fire spread behavior. This study investigated the fire-atmosphere interaction and the accompanying energy transport processes within the convective boundary layer. Three groups of large eddy simulations (LES) representing common ranges of convective boundary layer conditions (resulting from land surface heat flux ranging from 120 to 360W/m2) and fire intensities (50 to 150kW/m2) were used to examine how ambient buoyancy-induced atmospheric turbulence can impact fire region heat and momentum transport. In a relatively weak convective boundary layer, the change of near-surface atmospheric turbulence caused by the buoyancy force from the fire heat release is substantial and can cause an anticorrelation of the helicity between the ambient atmosphere and the fire-induced flow. Fire-induced impact becomes much smaller in a relatively strong convective environment with ambient atmospheric flow maintaining coherent structures including vortices across the fire heating region. The helicity also shows strong correlation between the ambient atmosphere and the fire-induced flow. A further energy transport efficiency analysis shows a narrow heat transport zone above the fire line for the weak convective boundary layer scenario. This indicates confined heat release and stronger fire-induced buoyancy force. The high-efficiency heat transport zone becomes much wider in a stronger convective boundary layer which leads to a wider distribution of heat released from fire, the weaker fire-induced buoyancy force and causes less fire-induced flow-field change. The work also found counter-gradient transport zones of both momentum and heat in fire cases in the weak convective boundary layer group. The counter-gradient transport might indicate the existence of strong buoyancy-induced mixing processes.
Effects of wind velocity on predictions of wildland fire rate of spread models: A comparative assessment using surface fuel fire tests
Authors: Kolaitis Dionysios I. , Pallikarakis Christos N. , Founti Maria A.
Published: October 2022

In this work, a collection of ten wildland fire rate of spread prediction models that take into account the effects of wind are reviewed and tested against 166 individual laboratory fire tests, available in the open literature. The investigated models include the well-known semi-empirical models of Rothermel, Wilson and Catchpole et al., the empirical models of Rossa and Fernandes, developed using laboratory fire tests and the empirical models of Burrows et al., Anderson et al., Fernandes et al. and the Canadian Forest Fire Behavior Prediction System, developed using field measurements. The performance of the ten models is evaluated, both qualitatively and quantitatively, by employing a range of dedicated statistical error metrics. It is shown that the performance of each model is affected by their specific characteristics, in conjunction with the characteristics of the experiments against which the models were evaluated. It is found that the model of Catchpole et. al. yields the lowest statistical error metric values. The empirical models that have been developed using field measurements exhibit significant discrepancies against the experimental data, due to the use of specific parameters regarding fuel type, scale and wind speed.
Characteristics of surface litter fires: A systematic experimental study
Authors: Pallikarakis Christos N. , Kolaitis Dionysios I. , Founti Maria A.
Published: October 2022

This work presents the results of laboratory experiments, focused on the characterization of surface wildland fires propagating in a litter fuel bed. A series of fire tests are conducted using an inclinable combustion table, measuring 2 m x 2 m, aiming to identify the effects of several important operational parameters on the characteristics of the developing fire. The parameters studied are the slope angle, the fuel load, the fuel moisture content and the type of ignition. A broad sensor network is installed in the combustion table, including 86 thermocouples, 4 bi-directional velocity probes, 2 Pitot tubes, 3 heat flux sensors, 2 optical cameras and a real-time gas analyser. The obtained measurements are used to determine the time evolution of several characteristic parameters, such as the Rate of Spread and the Heat Release Rate. The construction of a 2D temperature field from the thermocouples that rest on a plane parallel to the propagation axis, illustrates important flame characteristics. It is found that the fireâ€™s Rate of Spread increases with increasing slope angle and fuel load, whereas it decreases with increasing Fuel Moisture Content. The Rate of Spread does not seem to reach a steady state for the fires propagating up-slope. The Heat Release Rate increases with increasing slope and, more intensely, fuel load. As expected, the increase of the Fuel Moisture Content decreases the Heat Release Rate.
Clean Forest – Project concept and preliminary results
Authors: Gomes João , Puna Jaime , Marques António , Gominho Jorge , Lourenço Ana , Galhano Rui , Ozkan Sila
Published: October 2022

The aim of this project is to valorize forest biomass wastes into bioenergy, more precisely, production of 2nd generation synthetic biofuels, such as, biogas, biomethanol, bio-DME, etc., depending on process operating conditions, such as, pressure, temperature and type of solid catalyst used. The valorization of potential forest wastes biomass enhances the reduction of probability of occurrence of forest fires and, presents a major value for local communities, especially, in rural populations. Biogas produced can be burned as biofuel to produce heat and/or electricity, for instance, in cogeneration engines applied for domestic/industrial purposes. After the removal of forest wastes from the forest territory, this biomass is dried, grounded to reduce its granulometry and liquified at temperatures between 100-200 ÂºC. Then, using the electrocracking technology, this liquified biomass is mixed with an alkaline aqueous electrolyte located in an electrolyser (electrochemical reactor which performs an electrolysis process), using a potential catalyst, in order to produce syngas (fuel gas, mainly composed by CO, H2 and CO2). In a second reaction step, this syngas produced can be valorized in the production of synthetic biofuels, in a tubular catalytic reactor. The whole process is easy to implement and energetically, shows significative less costs than the conventional process of syngas gasification, as the energy input in conventional pyrolysis/gasification process is higher than 500 ÂºC, with higher pressures, while, in the electrochemical process, applied in this project, the temperatures are not higher than 70 ÂºC, with 4 bars of pressure, at maximum. Besides that, the input of energy necessary to promote the electrolysis process can be achieved with solar energy, using a photovoltaic panel. In the production of biogas in the catalytic reactor, there is another major value from this process, which is the co-production of water, as Sabatier reaction converts CO2 and H2 into biomethane (CH4) and steam water, at atmospheric pressure, with 300 ÂºC of temperature, maximum, with a high selective solid catalyst. Finally, it is expected to produce a new bio-oil from this kind of biomass, with properties more closer to a fossil fuel than wood bio-oils, which can be used as a fuel or as a diolefins/olefins source and, also, to produce, from forest biomass wastes, pyrolytic bio-oils with complementary properties and valorised characteristics. This can be used in wood treatment or as a phenol source, for several industrial applications. A new and valorised application can be found for forest biomass wastes, which can be incorporated in the biorefinery concept.
Flame Length of Wildland Fires: Effect of Flame Zone Depth
Authors: Finney Mark A. , Grumstrup Torben P.
Published: October 2022

Correlations of flame length L (or height) with the intensity of fires (kW/m2 for area sources or kW/m for line sources) have become foundational to fire behavior science (Byram 1959, Thomas 1963, Nelson and Adkins 1986, among others). Empirical data for these correlations have been based on fires fueled by wood cribs, paper strips, natural gas, and spreading fires at laboratory scales. The data and theory outlined by Thomas (1963, 1967) supported the idea that the horizontal dimension D of an infinite line fire could be neglected if L was much greater than D. Here we report on experiments with line-source fires where the energy release and flame zone dimensions were controlled independently (0.2â‰¤L/Dâ‰¤13.6), finding that increasing D significantly reduced L over the entire range of observations. Our flame length correlation was more similar to that of Thomasâ€™ (1963) than Byram (1959) but the data clearly showed a strong dependency upon D. This finding suggests that fire behavior studies relying on correlations of L and fireline intensity must consider D to have an important effect on physical processes involved in wildfire behavior.
Impact of the bulk density on fire spread through a homogenous vegetation layer
Authors: Awad Carmen , Fayad Jacky , Frangieh Nicolas , Morandini Frédéric , Rossi Jean Louis , Chatelon François Joseph , Marcelli Thierry , Morvan Dominique , Accary Gilbert
Published: October 2022

The bulk density as definition represents the ratio between the packing ratio and the density of the vegetation. Therefore, it is directly related to the fuel load, the height and to the porosity of the vegetation. In fact, the bulk density plays an important role in fire propagation and behavior. Due to its dependence on the fuel porosity, the bulk density influences heat transfers inside the fuel bed, so, it can affect directly the rate of spread. Or, the bulk density influences also the fire intensity and flame characteristics (residence time, height and depth) due to its dependence of the fuel load and fuel bed height. However, despite the important influence of the bulk density on fire propagation, the literature does not clarify its impact on fire behavior, different points of view can be exanimated. So, the aim of this study is to investigate the role played by the bulk density upon both propagation parameters and heat transfer of a surface fire through a homogeneous vegetation layer. Investigations were conducted numerically using â€œFireStar2Dâ€, a complete physical model based on multiphase formulation. Also, experimentally, tests were constructed at the university of Corsica at laboratory scale under no wind and no slope condition. In order to study the elementary effect of the bulk density on fire behavior, three different cases were evaluated: (a) variable fuel load with a constant bulk density, (b) variable fuel load and variable bulk density, (c) variable bulk density with a constant fuel load. Case (a) was only studied numerically, the obtained results are in agreement with the literature: the rate of spread increases with the fuel load until a specific value where the ROS becomes independent of it. Case (b) was evaluated numerically and experimentally using a fix fuel bed height. The numerical and the experimental results showed that the ROS is barely affected by both fuel load and bulk density. Finally, the results of the last case, with a constant fuel load, showed numerically the same tendency proposed by Rothermel: the rate of spread reaches a maximum value at an optimal packing ratio that depends of the surface-volume ratio of the vegetation. Or, experimentally the ROS decreases with the increase of the bulk density. Different variables such as the optical thickness, the fire intensity, the residence time, the radiation and convection heat fluxes have been analyzed.
Numerical simulation of the aerial drops of the Canadair CL-415 and the Dash-8 airtankers
Authors: Calbrix Corentin , Stoukov Alexei , Cadière Axelle , Roig Benoit , Legendre Dominique
Published: October 2022

Fighting wildland fires is a major issue for the protection of populations and environment with a need of more efficient means to fight fires. Airtankers are able to drop volumes of liquid (water or fire retardant) varying from less than 1m3 to several tens of m3, directly on fire or with the objective to form barriers of retardant to stop or reduce the fire propagation. However, the dynamics of a liquid dropped from an airplane has received few attentions in the scientific community, and related studies have mostly focused on Newtonian liquid jets injection in cross flow from millimetric injectors for combustion applications. For firefighting purpose, the liquid can be a retardant (a non Newtonian fluid) and the characteristic size of the delivery systems is of the order of a meter. The objective of this work is to demonstrate that Computational Fluid Dynamics (CFD) can be used to provide a deep understanding of the liquid fragmentation and dispersion when dropped from an aircraft. A numerical investigation is proposed for the analysis of airtanker performance and applied here to the biggest airtankers used in Europe: the Canadair CL-415 and the Dash-8. A numerical approach based on the Volume of Fluid method (VoF) is used to provide an accurate description of the tank discharge as well as to study the liquid ejection, fragmentation and atomization in air. The 3D unsteady resolution of the Navier-Stokes equations for both the liquid and the air allows us to provide a description of the main characteristics of the resulting liquid cloud, characterized by the vertical penetration of the liquid, its lateral expansion and the process of atomization.
Perception of wildfire behaviour and fire suppression tactics among Swedish incident commanders
Authors: Sjöström Johan , Granström Anders , Vylund Lotta
Published: October 2022

Unlike most regions with high-intensity wildfire potential, Sweden lacks specialized wildfire suppression organization. Instead, wildfire suppression is handled by highly decentralized and multitask municipal rescue services. This prompts the question how the incident commanders (ICs) perceive and interpret variation in fire behaviour and how they respond to wildfire incidents with regard to dispatching for initial attack and selecting tactics. To elucidate this, we exposed a spectrum of Swedish ICs to a questionnaire and round-table-exercises of different fire scenarios. The informants had on average 13 years of experience as incident commanders and had on average managed 6 wildfires over the last 5 years. Despite minimal formal wildfire training the respondents showed reasonable consensus in rating of fire behaviour in response to fuels and weather, suggesting that their knowledge was built on personal and group experience. Likewise, they gave estimates on rate of production of hose-lays similar to published expert assessments from Canada. When exposed to a spectrum of fire scenarios, resource dimensioning by ICs was linearly related to the Canadian FWI-index, although most organizations did not have any preordained schemas or rules of initial dispatching resources to guide them. Tactics employed were based mainly on accessing the fire from the nearest road and using direct attack with hose-line laid from the engine and water ferried on trucks. In a scenario where initial attack failed, suppression crews typically fell back on roads, which however would be breached by intense fire, and which also exposed the operation to risk of being outflanked. This response was in fact similar to that employed during a 2014 catastrophic wildfire in central Sweden and may indicate a fundamental flaw in tactics employed for large and intense fires. The present structure of the Swedish wildfire suppression system developed during the second half of the 1900s and depends on rapid access to the fire by a relatively small number of firefighters. The study suggests a relatively high capacity for suppressing forest fires, despite that the organization is primarily rigged for other purposes and that ICs have minimal formal training in this area. Climate change-scenarios suggest longer fire season and more risk days in parts of the country, but the future wildfire scene may be even more sensitive to de-population and diminishing economic resources in heavily forested regions of the country.
Post–fire management for improving soil quality and hydrological process: a case study in a Mediterranean Croatia
Authors: Delač Domina , Kisić Ivica , Pereira Paulo
Published: October 2022

Wildfires in Mediterranean Croatia have increased in recent decades, raising concerns about the adverse effects of fire and the rate of soil and water degradation. Post-fire management techniques, such as mulch application, are commonly used after high to moderate wildfire severity. Local, site-specific solutions are needed to mitigate wildfire effects in this context. This research aims to study the effect of mulches (from on-site sources) on soil and hydrological properties. We hypothesised that mulch application would increase soil quality and reduce erosion and runoff yield. During July 2019, about 900 ha of Pinus halepensins Mil. forest, abandoned grazing and agricultural olive groves (Olea europea L.) were affected by a moderate to high wildfire in the hinterland of Å ibenik City (Croatia, 43Â°45'N 15Â°56'E, 105 m a.s.l.). Twenty-five days after the wildfire occurrence, unmulched (UM, control) and two mulch treatments (Olea europea leaves (OM) and Pinus halepensis needles (PM) were applied for post-fire stabilisation on Cambisols. One treatment covered an ~10 m2 area with 0.5. kg m2 mulch application which was measured on the experimental plots. Prior to mulch application, 15 (5 per treatment) metal rings (0.2 m2) with connected plastic collectors were set up on sloped terrain (~9Â°) to monitor erosion and runoff yield. Soil samples were collected every three months, and erosion and runoff yield after major precipitation events during two years. The studied soil properties were: soil water repetency (SWR), soil hydraulic conductivity (SHC), mean weight diameter (MWD), water stability of aggregates (WSA), soil organic matter (SOM), total carbon (TC), total nitrogen (TN), extractable potassium (K2O), and available (P2O5). Our results showed that both mulch treatments reduce runoff generation in addition to UM treatment. The erosion yield was not occurred due to natural soil conditions. A linear decreasing trend was noted for SWR in all treatments. Overall, PM was showed higher efficiency in increasing soil aggregate stability (MWD and WSA), SHC SOM, and TC. OM has mostly increased soil nutrients such as TN, P2O5, and K2O. Bot mulch treatment increased soil quality, but the effect was variable due to the different chemical compositions of the material. The use of native mulch can be recommended because it improves soil quality and reduces runoff ratio. However, consideration should be given to whether they are available in the areas affected by wildfire.
Research on Application of Forest Fire GS Mark III (Patent Pending) for Peat Fires Extinguishment Methods: A Field Experiment
Authors: Tharima Ahmad Faiz , Lukman Nur Hafizah Mohamad , Abdullah Kamarulzaman Malik , Mukhtar Azfarizal , Razi Mohd Adib Mohammad , Jusoh Wan Nursheila Wan
Published: October 2022

Human-caused intervention and global warming are normally resulting peat fires in Malaysia. In this regard, fire suppression methods and techniques have resulted in increased attention among innovators to put out the fire. In the current study, a series of field experiments have been conducted to quantify the effectiveness of a firefighting equipment invention called Forest Fire GS Mark III. Several hoses and water pumps, and accessories are also integrated with the setting up of GS Mark III. The installation of equipment only considers single hoses line with several lengths from an open water source. In doing so, three field testing have been executed using a single pump, end-to-end pump and serial pump approaches. It was found that the end-to-end pump and serial water pump approach demonstrates significant performance with lengthier spray length and constant water pressure. Conversely, both pressure and length were dropped as the hoses number increase in the serial water pump approach. Compared to the serial water pump, the single pump approach shows performance decrement in spray length and pressure. In addition, the pressure losses increased as increment number of hoses. This study contributes a good input to the fire community in providing the initial design of fire extinguishment methods with better conditions.
Extreme Fire Severity Classification using Clustering and Decision Tree
Authors: Coelho Henrique , Nascimento Susana , Damásio Carlos Viegas , Bugalho Lourdes , Severino Gonçalo
Published: October 2022

With climate change, large, unpredictable and difficult to suppress forest fires are increasingly frequent. To increase the ability to anticipate and respond to these extreme events it is necessary to characterize the meteorological conditions associated with the risk levels of these events. The main objective of this work is to identify those conditions characterizing extreme forest fires in Portugal in the period 2001-2020 with at least 100ha burned area (90% percentile). The conditions characterizing the extreme fires are elicited by applying unsupervised fuzzy clustering and predictive methods to forest fire data and corresponding fire risk indices, namely the Canadian Forest Fire Risk Index (FWI), and subindices, as well as the Continuous Haines Index (CHI), provided by the Portuguese Institute of Sea and Atmosphere (IPMA). The dates and localization of fires are obtained from the shapefiles provided by the Portuguese Institute for Nature Conservation and Forests (ICNF), and complemented with data from the MODIS Global Burned Area Product MCD64A1 downloaded from the University of Maryland repository. The unsupervised fuzzy clustering algorithm (fuzzy c-means) is used for data classification and segmentation, and of the predictive model (decision trees), for weather characterization and extraction of rules. The fuzzy c-means was used to segment the data into 5 or 7 clusters, and to each cluster it is assigned the fire risk scale class of the clusterâ€™s prototype, respectively the EEFIS scale (European-Forest-Fire Information System) for 5 clusters and IPMA fire risk scale for 7 clusters. Using the data from the 2001-2018, decision trees were induced and tested with the data from 2019 and 2020. To ensure the quality of its results, metrics and validation techniques such as cross-validation and bootstrapping are applied. From the experimental study, it is concluded that both the fuzzy c-means algorithm and the decision trees were effective in addressing the problem at hand. From the meteorological conditions, described by the fire risk indices, it was found that these were not always in agreement with the reference forest fire risk prediction scales, revealing the importance of adapting the indices values according to the region in question and taking into account several factors (forest fire risk indices) in the analysis of the conditions associated with the level of risk of an extreme forest fire. The proposed approach proved to be a proof of concept to test the applicability of this type of algorithm in this domain and to compare the results with the two fire risk scales used by IPMA and EEFIS.
Validation of ERA5 fire weather conditions in Greece between 2007 and 2019: A preliminary analysis
Authors: Papavasileiou Georgios , Giannaros Theodore M.
Published: October 2022

Accurate simulations of fire weather conditions for both the past and the future are of great importance for fire management and preparedness. With the advancement of numerical weather prediction models and data assimilation techniques, more accurate reanalysis products have been developed the recent years. Here we validate fire weather conditions in Greece which are computed based on ERA5 reanalysis data using surface observations from the automatic weather station network of the National Observatory of Athens (NOA). We assess the fire weather conditions in an application of the Canadian Forest Fire Weather Index (FWI) System in both datasets. Although, ERA5 FWI archive is available since 1979 here we limit our analysis during the period of 2007 to 2019, due to the limited data availability from the NOA network. The validation of FWI in ERA5 data shows good agreement with the NOA observations with a mean correlation of 0.87. Furthermore, FWI in ERA5 data is overall slightly underestimated compared to NOA observations, which is driven by an underestimation of the three moisture components of FWI, namely the Fine Fuel Moisture Code (FFMC), the Drought Code (DC) and the Duff Moisture Code (DMC). Preliminary results also indicate that the largest errors are found over the eastern and southern parts of Greece, which is the are that experiences the highest FWI values during the summer.
GOLIAT, a project to develop tools for firefighting and land use planning
Authors: Marcelli Thierry , Rossi Lucile , Accary Gilbert , Awad Carmen , Burglin Antoine , Cancellieri Dominique , Cancellieri Valérie , Chatelon François-Joseph , Fayad Jacky , Ferrat Lila , Frangieh Nicolas , Grossi Hugo , Méradji Sofiane , Morandini Frédéric , Morvan Dominique , Pieri Antoine , Wandon Clément , Arobase.fr Agence , Rossi Jean-Louis
Published: October 2022

The GOLIAT project is a consortium of academics and firefighting operators and land-use planning professionals of Corsica. One goal of GOLIAT project is to provide four operational decision support tools. To reach this goal, a survey of past fires occurred in Corsica since the twentieth century beginning is made. This inventory contributes to build up a database with a web display interface easy to use as fire patterns history. A fire behavior and impact simulator prototype for vegetation fires, a geolocation tool for hot spots using UAV images, and a guide of good practices of prescribed fires in the undergrowth are building. At the same time, experimental fires are carried out to improve knowledge about high intensity fire and the experimental results were compared to the predictions provided by a complete physical 3D model, namely FireStar3D.