bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of the effect of one-way and two-way fire-wind coupling on the modelling of wildland fire propagation dynamics
Authors: Sadrabadi Mohammad T. , Innocente Mauro S. , Gkanas Evangelos , Papagiannis Ioannis
Published: October 2022

Operational wildland fire propagation models typically are uncoupled from the wind field or rely solely on estimations from an atmospheric model and/or meteorological observations. This leads to a frozen wind field with a high degree of uncertainty, and therefore to results drifting from the ground truth. On the other hand, a fully-coupled model is not viable for operational use due to the enormous computing effort required. This article proposes the use of real-time measurements from a drone swarm to enhance the results of a one-way coupled physics-based model (FireProM-F) to mimic the two-way coupling of fire and atmosphere. In the absence of actual measurements, synthetic data is used at the early stages of this research. The latter is generated using the WFDS levelset model with two-way fire-atmosphere coupling at various phases of the fire. Finally, the 'measured' wind field will be integrated into the target model to determine its effect on the outcomes.
Long-term erosion and the impact of wildfires: two different approaches
Authors: Parente Joana , Nunes João Pedro , Baartman Jantiene , Föllmi Dante
Published: October 2022

Rivers act as a network of channels that carry water, sediment, and energy downstream. On the heterogeneous area of the watershed, some areas might be responsive to disturbance (e.g., wildfires and droughts), while others may be resistant to the change. As a disturbance, fire is usually regarded as a key agent of soil erosion and land degradation. Fires are thought to be responsible for: (i) overland flow and reduction of the capacity of infiltration; (ii) increase of the availability of ash and debris and disruption of the soil nutrient cycle; and (iv) increase of connectivity across the watershed. The potential fire effects on soils and aquatic resources have created a strong demand for a post-fire sediment loss prediction tool. Taking this in mind, this study aims to assess post-fire soil erosion patterns at the decadal scale comparing different approaches. The methodology comprises i) a process-based model that is able to investigate long-term and large-scale spatial landscape evolution, LAPSUS; (ii) an index that represents a connectivity assessment based on local landscape information, the Borselli Index of Connectivity (IC); and (iii) an index that represents the sediment eroded that actually reaches the stream based on local landscape information, combining the IC with the Revised Universal Soil Loss Equation (RUSLE) model. Results include a comparison between the approaches used in the context of specific fire events between 1979 and 2020 for the Agueda watershed in central Portugal. The authors believe that assessing the spatial-temporal evolution of connectivity in the actual landscape with the appropriate tool is extremely important to estimate the probability that a given part of the landscape transfers its sediments downstream.
Mediterranean fire danger classes based on the Canadian Forest Fire Weather Index System, taking into account the Fire Radiative Power products from SEVIRI/MSG satellite
Authors: Silva Mafalda , Durão Rita , Alonso Catarina , Gouveia Célia
Published: October 2022

Fire danger rating systems (FDRS) are widely used across the world for many purposes from planning for daily deployment of fire suppression resources to the evaluation of fire management strategies. FDRS can also be incorporated in different types of models and regions to assess the short and long-term effects of specific fire regimes and fire management policies. The Canadian Forest Fire Weather Index System (FWIS) is a widely known FDR system, being extensively applied for fire danger early warning in several regions around the world, namely over Europe. The FWIS includes a set of six sub-indices, based on meteorological data, to predict fire weather danger and fire behavior over regions under study. In order to have a reliable assessment of the fire danger based on the FWIS it is essential to define the most suitable threshold values for each danger class of the FWIS sub-indices over different regions. To establish those limit values for each class of the FWIS sub-indices, historical percentiles were computed for the period understudy, taking into account the occurred fire events (hotspots), despite the lack of information regarding fire events history and its relation to FWIS sub-indices. To accomplish the proposed validation, our approach is based on Fire Radiative Energy (FRE) released by each fire event that occurred in the Mediterranean region, over the study period. The FRE is computed from Fire Radiative Power (FRP) product as obtained from MSG/SEVIRI, generated and disseminated in near real-time by EUMETSAT in the framework of Land Surface Analysis Satellite Applications Facility (LSA SAF). Since FRP estimates the radiative power emitted by a given fire, it can be linked to local fuel burned amounts and be used as a proxy of fire intensity. By integrating FRP measures emitted during the lifetime of the fires that occurred over the regions under study, an estimate of the total FRE released can be easily obtained for each event. To obtain the FRE data for this work, it was considered the period of available FRP/SEVIRI data, from March 2010 to October 2021. Thresholds values of each defined danger class for the FWI, FFMC and ISI indices were calculated considering the total FRE hotspots registered, in agreement with the different fire regimes of the Mediterranean region. Since extreme wildfire patterns in Southern Mediterranean countries have been increasing over the last years, FRP/FRE products are a key tool to monitor and to improve fire managing activities, preparedness-including planning for deployment of fire suppression resources, over affected regions.
Modeling daily natural-caused ignition probability in the Iberian Peninsula
Authors: Jiménez-Ruano Adrián , Gelabert Pere Joan , Dios Victor Resco de , Vega-García Cristina , Torres Luis , Ribalaygua Jaime , Rodrigues Marcos
Published: October 2022

In the European Mediterranean region natural-caused wildfires are a small fraction of total ignitions. Lightning strikes are the most common source of non-human fires, being strongly tied to specific synoptic conditions and patterns associated with atmospheric instability, such as dry thunderstorms. Likewise, lightning-related ignitions often associate with dry fuels and dense vegetation layers. In the case of Iberian Peninsula, the confluence of these factors favors recurrent lightning fires in the eastern Mediterranean mountain ranges and the. However, under appropriate conditions lightning fires can start elsewhere, holding the potential to propagate over vast distances. In this work, we assessed the likelihood of ignition leveraging a large dataset of lightning strikes and historical fires available in Spain. We trained and tested a machine learning model to evaluate the probability of ignition provided that a lightning strikes the ground. Our model was calibrated in the period 2009-2015 using data for mainland Spain plus the Balearic Islands. To build the binary response variable we classified lightning strikes between that triggered a fire event. For each lightning strike we extracted a set of covariates relating fuel moisture conditions, the presence and density of the vegetation layer and the shape of the relief. The final model was subsequently applied to forecast daily probabilities at 1x1 km resolution for the entire Iberian Peninsula. Although the model was originally calibrated in Spain, we extended the predictions to the entire Iberian Peninsula. By doing so we were able to validate in the future our outputs against the Portuguese dataset of recent natural-caused fires (bigger than 1 ha) from 2001 to 2021. Overall, the model attained a great predictive performance with a median AUC of 0.82. Natural-caused ignitions triggered mainly in low dead (dFMC 250) fuel moisture conditions. Lightning strikes with negative polarity seem to trigger fires more frequently when the mean density of discharger was greater than 5. Finally, natural wildfires usually started at higher elevations (above 500 m.a.s.l.).
On the vertical profiles of temperature, relative humidity and wind in the nighttime period in central mainland Portugal
Authors: Rio João , Lopes Manuel , Silva Pedro , Novo Ilda , Monteiro Maria
Published: October 2022

In the framework of the Firestorm project, four portable weather stations were installed in the LousÃ£-Estrela mountainous ridge. The data observed with this equipment, along with two other stations from IPMAâ€™s surface network, allows the monitoring of the vertical profile of temperature, relative humidity and wind in the region. Many forest fires in mainland Portugal affect areas with complex terrain, with hills or mountains in the 400-1200m asl range, where weather conditions strongly influence the fire propagation and lifetime. Therefore, it becomes even more pertinent to study the vertical profiles of temperature, humidity and wind as they often exhibit large variability, namely in the night-time period. This paper provides the first study of the available observations by providing statistics for the summer 2021 and winter 2021/22. It has also allowed the identification of some periods in which significant temperature inversions with very dry air at medium levels or even the valley have occurred. Further details of the vertical profile and the weather pattern that led to these events are shown in three selected events.
Persistent Underground Smouldering Fire in Deep Peat Layer
Authors: Qin Yunzhu , Musa Dayang Nur Sakinah , Lin Shaorun , Huang Xinyan
Published: October 2022

Peatlands are important terrestrial carbon pools. Due to climate change and human activities, peatlands are more prone to large-scale fires than ever before, especially deep underground fires. However, most current smouldering researches focus on small-scale smouldering behaviour in relatively shallow layers, which poses a research gap. This work explores in-depth (up to 60 cm) smouldering behaviour, such as persistence, propagation and emission. Experimental results demonstrate that underground smouldering fires can sustain in deep soil layers for more than a week without any additional oxygen supply. Because of the competition of oxygen supply and heat losses, a critical depth of 55 cm for smouldering propagation was obtained, below which smouldering cannot self-sustained propagate. This work will help better connect lab-scale experiments with real underground smouldering peat fires and understand smouldering dynamics in deep soil layers.
Spatial estimates of fire risk in Victoria, Australia considering ignition likelihood and containment probability through Bayesian Network Analysis
Authors: Marshall Erica , Penman Trent
Published: October 2022

Accounting for multiple changing systems in environmental decision making is challenging and requires balancing several competing priorities. In fire risk, one approach which is increasingly used to capture uncertainty within multiple systems and to prioritise management efforts is Bayesian Network analysis. Here, we have used a Bayesian Network to understand the interactions between ignition likelihood, containment probability, fire behaviour, and fire weather, alongside the subsequent risks to people and property. We developed, populated and tested a Bayesian Network (BN) which classifies the likelihood of outcomes for each of these systems. We then apply this BN to grid of 72,000 potential ignition locations accross Victoria to predict house and life loss values under conditions capturing the top ten worst ranked weather days in the history of each location. We use Phoenix fire behaviour simulations and landscape scale raster data to populate the parent nodes for each ignition and extract the expected values for predicted nodes under different weather scenarios and varying levels of suppression. We found values predicted by the BN broadly matched the spatial patterns of risk produced in Phoenix i.e., areas where risk was highest and lowest in terms of fire area and house loss aligned. However, the values are rescaled by the BN as it takes into account the influence of ignition likelihood and containment probability on risk estimates. The BN is also able to capture uncertainty around the values presented from across the top ten Phoenix simulations, so the recorded values represent the likely outcome for each node given the range of potential weather conditions in those scenarios. We show that BNs can be a useful management tool for estimating fire risks across a range of weather scenarios and locations while still considering ignition likelihood and suppression effectiveness.
SurEau-Ecos-FMC: mechanistic modelling of fuel moisture content (FMC) at leaf and canopy scale under extreme drought
Authors: Ruffault Julien , Limousin Jean-Marc , Pimont François , Dupuy Jean-Luc , Cochard Hervé , Martin-StPaul Nicolas
Published: October 2022

Understanding and predicting fuel moisture content (FMC) is a crucial prerequisite to increase our knowledge of forestâ€™s vulnerability to fires in a changing climate. While live fuel moisture content (LFMC) is a main driver of fire behavior and activity in crown fires in forests and shrublands, it remains poorly understood and predicted, especially under extreme drought. A major reason for that is that LFMC sensitivity to climate is mediated by a range of location-specific factors, including soil characteristics and plant response to drought. Another reason is that LFMC is often simulated at the leaf scale while, from a fire danger perspective, canopy scale fuel moisture content (CFMC) is more relevant. Here we introduced a FMC module in the plant-hydraulic SurEau-Ecos model to simulate the dynamics of both LFMC and CFMC as a function of leaf water potential (psi_{Leaf}). CFMC integrates the impacts on moisture content of foliage mortality that can occur under extreme drought because of leaf embolism. SurEau-Ecos-FMC relies on two main mechanisms. The relationship between psi_{Leaf} and leaf relative water content of the symplasm is modeled through pressure volume curves. Percent loss of leaf conductance (PLC) is derived from psi_{Leaf} through vulnerability curves to cavitation and affects the dynamics of fuel moisture content in two different ways. At the leaf level, PLC dictates the dynamics of the leaf apoplasmic reservoir. At the canopy level, PLC drives the proportion of dead fuel within the canopy. SurEau-Ecos-FMC captured relatively well the temporal dynamics of LFMC measured in a Quercus ilex stand at the PuÃ©chabon site over a three-years period. The model explained 69 % (RMSE = 4.27) and 74 % (RMSE = 4.92) of the variance in the minimum and maximum daily observed LFMC, respectively. The model was also able to capture the dynamics in CFMC resulting from leaf mortality during the summer drought. Indeed, we showed that the years when SurEau-Ecos-FMC predicted leaf mortality were the ones with the highest anomaly in NDVI. Multi-model projections of fire danger indices based on CFMC showed a general increase of fire danger over the next century. Under RCP8.5, the averaged minimum CFMC reached during the year is expected to decrease from 65 % to 32 % and the fire season length (number of day when CFMC
The Flames Catalogue: an engineering tool to predict flame geometry
Authors: Muñoz Juan Antonio , Pastor Elsa , Fernandes Paulo M. , Cruz Miguel , Planas Eulàlia
Published: October 2022

Flames can be geometrically described from a simplified perspective by means of their length (or height), angle and depth. These parameters are key for fire safety calculations, to prevent injuries during entrapments or to design preventive infrastructures. Most methods to estimate flame geometry require information on fire behaviour (i.e. rate of spread or fireline intensity), which are not always available or straightforward. Within this context, we are developing a tool to estimate flame geometry only from environmental parameters (fuel, weather and terrain) and without the need of fire behaviour predictions beforehand. To achieve this, we have gathered data on field-scale fires and used them to fit binary logistic regressions, to obtain the probability of occurrence of a certain flame geometry for specific fuel structures. We have already modelled flame length probability from fuel consumption in different fuel structures and flame angle probability from fuel consumption and wind speed in grasslands. We are currently working to fit binary logistic regressions with fuel load (easier to estimate than fuel consumption) and to extend the dataset to cover a wider range of fuel structures and conditions.
The role of the fuel moisture content on the prediction of large wildfires using the Fire Weather Index system
Authors: Alves Daniela , Viegas Domingos Xavier , Almeida Miguel , Reis Luís , Raposo Jorge , Ribeiro Carlos
Published: October 2022

Fuel moisture content is one of the fundamental parameters in forest fire research and management given its implications for many aspects of fire danger systems. In Portugal, such as in many other countries, to classify the days with more favourable conditions for wildfires it is common to use the Canadian Forest Fire Weather Index System (CFFWIS) which is based on the estimation of moisture content of several fuel components. The mathematical structure of CFFWIS requires as input the daily meteorological parameters which are used to estimate the moisture content of the soil for different layers that are the primary outputs of the system â€“ the fire moisture codes. The final output parameter of the system is the Fire Weather Index (FWI) which represents a measure of the fire danger due to meteorological conditions. The temporal scale of the study is from 2018 and 2021 and the study area is in LousÃ£, a central region of Portugal. In this work, in addition to the meteorological data, we will use as input the direct measurements of dead fuels in the CFFWIS and analyse its influence on the FWI. The fuel moisture content (mf) is determined through the sample collection of dead pine needles in LousÃ£. For this temporal scale, mf by sampling is significantly lower than the modelled mf using meteorological parameters. An advantage of using the mf measurements is to increase the range of FWI variation, giving a higher sensitivity to the index to more easily discriminate the days with high fire danger and large burned areas. Two methods are addressed: â€œFWI aâ€ which represents the traditionally FWI determined only by meteorological parameters, and the â€œFWI bâ€ which is determined with fuel moisture content measurements and with meteorological data for the days that we did not have measurements. The original FWI, based only meteorological parameters, is compared with the FWI determined using mf measurements. The different methods will be related with the number of fires and burned area to analyse their performance. The results show a good fit between mf and FWI for days with extreme weather conditions (mf<5%).
Deep Learning for High-Resolution Wildfire Modeling
Authors: Finney Mark A. , Forthofer Jason M. , Liu Xinle , Burge John , Ihme Matthias , Sha Fei , Chen Yi-Fan , Hickey Jason , Anderson John
Published: October 2022

We demonstrate the use of a deep learning (DL) approach for representing the behavior of a high-resolution physics-based wildland fire spread model. The ultimate objective is being able to efficiently use the DL model for intensive simulations of large fires while retaining fidelity to the fine-scale physical processes. We begin with a fire model that reduces the spatial domain of the fire spread problem to one dimension (1D). The 1D model explicitly resolves cm-scale fuel variations, heat transfer and heating/drying dynamics of individual fuel particles and burning behavior of the bed. We then ran the fire model for 78,125 factorial combinations of fuel, weather, and topographic conditions as training data for the DL algorithm. The results of the DL analysis show overall agreement of 96% of the variation in fire behavior as represented by steady state rate of spread, flame length and flame zone depth. Exceptions to the DL regression indicate areas where more work is required in refining the resolution in training cases and use of advanced methods of embedding the fire model inside the DL algorithm loop.
Autonomous fire containment tool
Authors: Hofmann Martin , Zenz David
Published: October 2022

The destructive effect of wildfires on biodiversity and infrastructure is compounded by an increasing frequency and intensity and the scarcity of water as an extinguishing agent. We therefore propose a methodology to assess the efficiency of water-based extinguishing strategies and propose a novel autonomous tool designed to contain an advancing fire front. To that end, the distribution of water is analysed and correlated to the successful containment of firelines of increasing intensities. A scaling law for the critical amount of water is proposed. We make use of laboratory-scale equipment to reproduce realistic behavior in presence of wind, before scaling up fire intensities up to 2500 kW/m in field tests. The novel apparatus, dubbed Papageno module, could replace aerial drops, characterized by low containment efficiency, high running costs and considerable risk for personnel. Destined to communities in all geographical areas threatened by wildfires, the Papageno module reduces the destructive impact of these phenomena on infrastructures in the wildland urban interface and can equally serve as a protective equipment for areas with valuable biodiversity. The Papageno module is the missing tool for safe and efficient containment of wildfires on a ZIP-code level. Thanks to this simple-to-use apparatus, public entities, such as communities and civil protection agencies, will be capable of shielding critical infrastructure from an advancing fire front with a minimal amount of water. Thanks to its autonomous operating mode, practitioners are not exposed to the risk and can attend other duties meanwhile.
Experimental evaluation of bench-scale flammability of Ulex europaeus using a cone calorimeter
Authors: Melnik Katharine O. , Valencia Andres , Pau Dennis , Park Andy , Katurji Marwan , Nilsson Daniel , Baker Greg , Melnik Oleg M. , Pearce6 Grant , Strand Tara
Published: October 2022

Wildfires have been causing considerable damage worldwide, and improving the ability to predict wildfire behaviour will ensure effective emergency response and keep ecosystems and communities safe. Increasing the understanding of factors affecting vegetation flammability is necessary for improving fire behaviour prediction models. This work investigates the influence of moisture content on the flammability of live and dead needles (0-3mm), twigs (3.1-6mm) and stems (6.1-10mm) of gorse (Ulex europaeus L.). Gorse is a shrub invasive in New Zealand, Chile and Western United States. In these countries, gorse poses a fire risk to nearby communities, as it contains flammable volatile resins, accumulates a substantial amount of elevated dead material, and grows in large masses, all of which promote fire ignition and growth. Gorse flammability was quantified with a bench-scale oxygen consumption calorimeter (cone calorimeter) with a focus on heat release rate. Supporting tests were performed on small sub-samples using simultaneous thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) to assess material-scale pyrolysis dynamics, providing fine scale information on the thermal degradation of each tissue type at the particle level. The experimental methodology included investigation of the maximum moisture content at which each tissue type can ignite at 50 kW/m2, which is a reasonable approximation of the heat flux at the vegetation surface during fire front arrival in a shrub fire. Six moisture content levels from zero to the highest ignitable moisture content were then selected, and samples were placed into a climate chamber to set the moisture content of the samples to the desired level. Three replicates of each tissue type were tested in a cone calorimeter at each moisture content. Flammability was assessed based on the heat release rate, effective heat of combustion, mass loss rate, time to ignition and flaming duration. Additionally, a small sub-sample of fresh live and dead needles, twigs and stems was analysed in the TGA/DSC apparatus. TGA/DSC results showed a different thermal degradation mechanism between dried live and dead fuel, with live tissue being more flammable than dead. However, the pyrolysis dynamics were not substantially affected by particle size, suggesting that the differences in flammability attributes measured in the cone calorimeter are likely driven by physical characteristics such as surface-area-to-volume ratio rather than chemical composition. The results of this work contribute to the understanding of gorse flammability and the effect of moisture content and fuel structure on fire behaviour.
Impact of prescribed burning on soil organism communities in a Pinus laricio forest.
Authors: Longeard Pauline , Belliard Pauline , Nadarajah Sugahendni , Massaiu Antonella , Pieri Antoine , Morandini Frederic , Andrei-Ruiz Marie-Cécile , Ferrat Lila
Published: October 2022

The objective of this preliminary study is to highlight the potential impacts of prescribed fire on soil organism communities in Pinus laricio forests, a species endemic to Corsica. For this purpose, a control plot, and a plot burned on 10th November 2020, were delimited in Bavella (South Corsica). The intensity of the burning was characterized using K-Type thermocouples at different depths in the soil. Soil organisms were collected with pitfall trap and BerlÃ¨se method, then identified to the order. Results show a decrease of all orders on the burned plot, with important potential of survival of the organisms in the soil, since heat transfer is weak (+10Â°C max at 3cm depth) and the burned surfaces heterogeneous. A rapid recolonization is indeed observed in the spring. The contribution of organic matter, minerals, and free ecological niches could encourage this phenomenon. In order to better understand the heterogeneity of the plots and to highlight the specificities of Pinus laricio forests, a study at the sub-plot level is in progress, as well as an identification of organisms up to the family level.
Moisture content of live forest fuel of Holm oak (Quercus ilex L.) related with forest fires in Mediterranean part of Croatia
Authors: Rosavec Roman , Barčić Damir , Mikac Stjepan , Ugarković CDamir
Published: October 2022

Due to its biological diversity and preservation, the Mediterranean area is an extremely valuable area on Earth. In recent years, the Mediterranean region has been frequently affected by fires. An increasing number of fires are certainly degrading the Mediterranean ecosystem and disrupting its stability, leading to a reduction in biodiversity and an increase in devastated areas. In addition to understanding and knowing the biological and ecological consequences of forest fires and methods of remediation and restoration of burned areas, knowledge of factors that cause forest fires and factors that cause the initial spread of fire is important to reduce burned areas and prepare and conduct preventive activities. The moisture content of living forest fuel is an extremely important factor for the spread of forest fires. It is a factor that is very sensitive and depends on local microclimatic conditions. The practice is that some very significant variables for forest fires, such as the moisture content of potential fuels, are sought to be obtained by applying various models, although it is known that these models cannot determine the true values of required variables unlike actual, empirical research. The most important climatic factors that are taken into account when it comes to forest fires are temperature and humidity or water (precipitation). It is a climazonal species in the forest ecosystems of the Mediterranean part of Croatia. The research was conducted at two locations; the island of Rab and Makarska. The results show differences in the influence of climatic conditions depending on the location of the research. The obtained results confirm that the understanding of climatic conditions and vegetation characteristics in terms of moisture content of living fuels and their relationship can contribute to improving knowledge about firefighting issues and identify critical periods of high risk of forest fires.
Ecoregion based attribution analysis of the influence of several fire danger indices on the amount of burned area at a global scale by means of pseudo transfer entropy
Authors: Pérez Antonio , Silini Riccardo , Sánchez Iván , Bedia Joaquín
Published: October 2022

Understanding the current fire-climate relationships is of utmost importance in order to assess the potential impacts that projected climate may exert in the near future. However, the many factors involved in fire activity often prevent a proper attribution of the observed variability. Unlike the many previous correlative studies, here we address this problem using a 'causality' measure known as â€œpseudo transfer entropyâ€ (pTE), relating three widely used fire danger indices to the global observed burned areas (namely the Canadian Fire Weather Index, the Fire Danger Index from the Australian McArthur Mark 5 Rating System and the Burning Index from the U.S. Forest Service National Fire-Danger Rating System). The study has been performed at an spatial aggregation level defined by the RESOLVE ecoregions, attending to their homogeneous fuel and climatic properties, and considering different spatial and temporal aggregation statistics (mean, 90th percentile, 95th percentile and sum). We present an open, web-based interactive tool to explore and compare the results derived from the causality of these different fire danger indices with the observed burned area. Our results unveil some consistent patterns and three main conclusions can be drawn: 1) in the overall, all indices exhibit a similar performance in explaining observed burned areas, although regional differences may justify the selection of one index over another in regional studies, 2) the aggregation method used at the ecoregion level affects the causality results, with higher percentiles being better explained by pTE than the mean state and 3) the interactive tool designed may serve as a valuable method of intercomparison and analysis for the vulnerability and impact assessment community involved in fire research.
The application of a genetic algorithm to estimate fuel bed properties from bench-scale testing
Authors: Walker-Ravena Carlos , Campbell-Lochrie Zakary , Gallagher Michael R. , Skowronski Nicholas S. , Mueller Eric V. , Hadden Rory M.
Published: October 2022

A methodology based on an automated optimisation technique is applied to interrogate the relationship between fuel bed structure and effective heat transfer properties. The methodology uses optimisation of the heat equation coupled with thermogravimetric data to reproduce mass data. The mass data is provided from Fire Propagation Apparatus ignition tests conducted on pinus rigida fuel beds with solid fractions ranging from 0.03 to 0.51. The fuel bed structure is represented by the solid fraction and the effective fuel bed properties are posed as a function of the fuel bed structure. This relationship between the two is optimised using the a genetic algorithm. In this way a methodology for interrogating the relationship between the fuel bed structure and the effective properties is presented.
A study of fire and plume dynamics for static pool fires and their interaction with vegetation
Authors: Muniraj Navya , Gong Weixuan , Selvaraj Muthu Kumaran , Simeoni Albert
Published: October 2022

Prescribed burns are an essential tool of fire management to reduce the impact and occurrence of wildfires. While managing prescribed burns, the smoke trajectory and downwind exposure to smoke are intimately coupled with the smoke production dynamics and the development of the fire plume in the vicinity of the fire front. In turn, the fire plume development is strongly coupled to fire behavior and the flow environment near the fire. This work aims at understanding fire behavior and plume development while interacting with vegetation at the large laboratory scale through experiments and modeling. In order to investigate these coupled processes, initially, flame and plume behavior from a static fire source will be characterized. A rectangular pool fire fueled by diesel is used and point measurements of flow, temperature and heat flux will be conducted. The burning rate will be measured using a load cell. K-type thermocouples and bi-directional pressure probes will be used for measuring the temperature and velocity, respectively in the flame and plume zones. These data will be used for validating a numerical model for simulating pool fires and the model will be subsequently used for predicting the plume interaction with vegetation. A Douglas fir tree, whose properties are well defined in the literature, will be used as vegetation. The Lagrangian particle model available in the Fire Dynamics Simulator (FDS) will be used to model the tree. The tree will be of regular shape and size with foliage and different classes of wood segregated based on typical size (diameter) range. The bulk density of the tree will be varied to replicate the systematic and controlled variation of the flow obstruction encountered by the plume and gives a realistic prediction of velocity, temperature, and heat flux within the vegetation. In the future, experiments with vegetation located in the plume region will be conducted to validate the numerical predictions.
A systematic study of the reliability of fire pattern indicators used in wildland fire investigation
Authors: Cuevas Juan I. , Gallagher Michael R. , Cole Jason , Patterson Matthew , Skowronski Nicholas S. , Simeoni Albert
Published: October 2022

This work presents the preliminary results obtained from the first set of six field experiments conducted within the scope of a project focused on the systematic evaluation of the reliability of fire pattern indicators used in wildland fire investigation. The field experiments were conducted in the Pinelands National Reserve (NJ, USA), during the conduction of prescribed burns. This allowed to study the generation of fire pattern indicators in a realistic scenario and under controlled conditions. During the experiments, a series of sensors were used to determine the heat exposure that induces the appearance of fire pattern indicators over planted supporting elements. The preliminary results obtained restate the fact that fire pattern indicators are a useful and valid tool for the determination of the area of origin of a fire, if they are used in a holistic manner. Further results and analysis to be presented in the full version of this work include fire spread, and the characterization of the heat exposure that generate the fire pattern indicators observed in the complete experimental campaign.
Assessing Potential Safety Zone Suitability using the Safe Separation Distance Evaluator (SSDE)
Authors: Jimenez Daniel , Campbell Michael , Dennison Philip , Thompson Matthew , Butler Bret
Published: October 2022

Safety zones are fundamental tools that can be used by wildland firefighters to avoid injury or fatality when engaging in wildland fire operations. The National Wildfire Coordinating Group (NWCG) recommends that a safety zone be defined as a pre-planned area of sufficient size and suitable location that is expected to prevent injury to fire personnel from known hazards without using fire shelters. Currently, safety zones are primarily designated by fireline personnel as part of daily fire management operations. Though critical to safety zone assessment, the effectiveness of this approach is inherently limited by the individualâ€™s ability to accurately and consistently interpret vegetation conditions, topography, burning conditions and spatial characteristics of potential safety zones (e.g. area and geometry of a forest clearing). Regardless, effective safety zones provide safe separation distance (SSD) from surrounding flames, ensuring that the surrounding heat cannot cause burn injury. We introduce a new online tool for mapping SSD based on vegetation height, terrain, wind speed, and burning conditions: the Safe Separation Distance Evaluator (SSDE). The new tool allows users to draw a potential safety zone polygon and estimate SSD and the extent to which that safety zone polygon may be suitable, given the local landscape, weather, and fire conditions. The SSDE tools calculates separation distance based on vegetation height, wind and slope adjustment factors and burning conditions. Fuels layers are imported for LANDFIRE Existing Vegetation Height. Slope is calculated from the Shuttle Radar Topography Mission (STRM) digital elevation model. Winds are derived from the local fire weather forecast. Burning conditions are based on fuel moisture, relative humidity, and temperature. The Safe Separation Distance Evaluator (SSDE) algorithm is built and applied in Google Earth Engine (GEE), a cloud-based platform for processing and analyzing GIS and remotely sensed data, using JavaScript application programming interface. SSDE is a tool that can provide valuable safety information to wildland fire personnel who are charged with the critical responsibility of protecting the public and landscapes from increasingly intense and frequent fires in a changing climate.
High Resolution Wildfire Fuel Mapping for Community Directed Forest Management Planning
Authors: Robinson Patrick , Elkin Che , Green Scott
Published: October 2022

Climate change and institutional forest management practices are leading to more frequent and severe wildfire events around the world, a trend that is projected to increase in coming years. Wildfire plays an important role in maintaining ecological systems, but wildfires also pose threats to health, safety, infrastructure, and important ecosystem services. Reactionary response to these threats has predominantly informed management decisions in recent decades and greater focus on mitigation and adaptation is needed. Through a community directed consultation process, the goal of this work has been to provide direct, operational information to aid in local management decision making for a First Nations community in British Columbia, Canada. Here we use a combination of field sampling and high-resolution Airborne Laser Scanning (ALS) data to assess vertical and horizontal fuel loading at fine resolution (~10m2). Our analysis found a high degree of fuel loading heterogeneity in areas characterized as homogeneous using coarser fuel layers and provided a means of identifying high fire risk areas that may be targeted for ecosystem rehabilitation aimed at reducing current and future fire risk. We discuss how this spatially explicit data can be used to evaluate feedback between forest dynamics and fuel loading; information critical for managing forests for multiple objectives into the future. Following our analysis, we compiled our results for the community into an interactive decision support web mapping platform designed with the goal of user friendly, accessible land managment planning, avoiding the need for technical expertise and internal capacity.
Influence of combined hydric and thermal stresses on Rosmarinus officinalis and Cistus albidus
Authors: Jamaladdeen Rawaa , Coudour Bruno , Dédaldéchamp Fabienne , Lemée Laurent , Garo Jean-Pierre , Wang Hui-Ying
Published: October 2022

Wildfires are a growing threat, especially in Mediterranean climate areas during periods of drought. Wildfire research community continues to investigate propagation mechanisms on a large scale considering the thermal and fluid mechanics effects, or the main fire emissions (CO, CO2, H2O, H2, CH4). However, research on the effect of abiotic stresses on the plant emission during wildfires remains lacking, despite the fact that Mediterranean are considered important BVOC emitting and storing species. This article addresses the effect of combined hydric and thermal stresses on the volatileâ€™s emission behaviours of two important Mediterranean shrub species; Rosmarinus officinalis and Cistus albidus that are largely consumed in wildfires. Different levels of hydric stress were applied on plants of the two species in a greenhouse of the EBI laboratories of the University of Poitiers. Thermal stress was executed by placing the water stressed plants inside a hermetic enclosure equipped with a radiant panel of maximal radiant heat flux of 84kW.m-2 and a fire-resistant glazed window for visualisation. The gaseous emissions of the plants under thermal stresses were collected and analysed by two complementary devices: an instantaneous gas analyser for CO, CO2, H2 and CH4, and adsorbent tubes by using the techniques of adsorption and desorption (by pyrolysis) for emission collection and analyses, respectively. Simultaneous Py/GC-MS experiments were realised at IC2MP on a foliar scale of the water stressed plants in order to gain more control and precision in emission analyses. The heating tests showed a good reproducibility for pyrolyses of leaf samples and interesting variations between the monoterpene emissions of stressed and unstressed plants. At plant scale, number of tests for each plant species at a given hydric stress level were insufficient to give trends and strong results because of some imposed technical problems and the constraints of public health crisis. However, these tests allowed us to adapt experimental protocols and devices for further testing such as: plant location and fixation, heat flux ramp, sampling location, use of adsorbent tubes, hydric stress duration and normalisation of measured concentrations according to the plant size.
Logistics challenges of approaching the wildfires with different fire vehicles
Authors: Bodnár László
Published: October 2022

In order to protect human life, property and the environment from the wildfires, professional and voluntary fire departments are the first interveners in Hungary. One of the major challenges of firefighting against wildfires is the logistics. Such a logistic challenge is the migration to the fire site with different fire vehicles. The logistic challenges of wildfires usually develope in rural areas, on dirt roads of the forest, away from the residential areas. These areas are difficult to approach with some fire trucks that are not specifically designed for these purposes. These difficulties affect the efficiency of firefighting. In the paper, the Author draw conclusions from the logistical difficulties of firefighting against wildfires that are suitable for proving the time loss of migration and to determine how the time loss affects the spread of a fire and the effectiveness of firefighting. The Author shows how the frontline (Tfrontline) of a fire can change due to time loss (Î”t) at 1 m/min, 5 m/min and 9 m/min fire propagation (Vfire propagation). By using a formula, the Author also calculate the size of the frontline fire. As a result of the paper he determines the amount of time loss with a new method, which is related to the increase of the fire frontline.
Low cost protection system of infrastructures against forest fires
Authors: Vaz Gilberto , Raposo Jorge , Reis Luís , Monteiro Pedro , Viegas Domingos Xavier
Published: October 2022

Forest fires are one of the main disasters that devastate many countries every year. The destruction caused by these phenomena generates social impacts putting at risk the population lives, environmental impacts due to the extreme deforestation and the high number of pollutants that are released to the atmosphere but also extremely important economic impacts caused by the destruction of a wide range of infrastructures and essential goods. Therefore, as it is impossible to remove all the infrastructures from the forest and from the wildland-urban interface, the development and installation of protection systems is essential. The main objective of this work is the development of a low cost protection system, with rigid panels, requiring a simple and easy installation, to protect outdoor infrastructures such as telecommunications stations, shelters, roadside enclosures, power cabinets, and other structures. A study was carried out on panels that could be used for the protection in order to determine whether the protective material would be more appropriate. Taking into account the fire resistance behaviour, thermal and structural properties and cost, the panels selected were the magnesium oxide fibreglass reinforced. The protection was constructed, installed on a telecommunication cabinet and experimentally laboratory tested in a wind combustion tunnel. To collect the data InfraRed and video cameras, heat flux sensors and sheathed thermocouples were used to determine the fire propagation, heat flux and temperatures, respectively. The data obtained in the experimental tests show clearly that the simple low cost protection is effective for the protection of telecommunication cabinets and other similar infrastructures against forest fires.
Numerical study of high intensity experimental field fires across Corsican shrubland vegetation
Authors: Fayad Jacky , Rossi Lucile , Frangieh Nicolas , Awad Carmen , Accary Gilbert , Chatelon François-Joseph , Morandini Frédéric , Marcelli Thierry , Cancellieri Valérie , Cancellieri Dominique , Morvan Dominique , Pieri Antoine , Planelles Gilles , Costantini René , Briot Patrice , Meradji Sofiane , Rossi Jean-Louis
Published: October 2022

Field-scale experiments have been conducted on steep sloped terrains in Speluncatu and Letia, north-western and southern regions of Corsica. This work lies within the GOLIAT project framework and it was provided by the Fire and Rescue Service of North Corsica and the Corsican DFCI (DÃ©fense de la ForÃªt Contre lâ€™Incendie) Group. This work reported high intensity fires propagating through shrub vegetation areas (Genista Salzmannii) lying between 60 cm and 85 cm. These sites were selected because of the density of the vegetation, the high slope angle values with a wind direction aligned with the main slope, which can generate a fire close to wildfire behaviour. A detailed experimental protocol is used in order to determine the propagation conditions and the fire behaviour using UAV cameras and heat flux gauges. In order to investigate the different phenomena encountered in these types of fires, numerical simulations were conducted using a complete physical fire model, based on multiphase formulation, namely FireStar2D. Numerical predictions were used to examine the fire front dynamics related to the fireâ€™s rate of spread and fireline intensity. Despite the unfavourable wind and humidity conditions, experimental results analysis showed that the fireline intensity was higher than 7 MW/m, which means that these fires fall into the category of the very high fire severity. Numerical results predicting the fireâ€™s rate of spread, fireline intensity and fire impact were in good agreement with the experimental data.