Wildfire Containment Research Articles

The cost of operational complexity: A causal assessment of pre-fire mitigation and wildfire suppression

Pre-fire mitigation efforts that include the installation and maintenance of fuel breaks are integral to wildfire suppression in Southern California. Fuel breaks alter fire behavior and assist in fire suppression at strategic locations on the landscape. However, the combined effectiveness of fuel breaks and wildfire suppression is not well studied. Using daily firefighting personnel to proxy the quantity and diversity of potential fire suppression operations (i.e., operational complexity), we examined 15 wildfires from 2017 to 2020 in the Los Padres, Angeles, San Bernardino, and Cleveland National Forests to assess how weather and site-specific fuel break characteristics influenced wildfire containment when leveraged during suppression operations. After removing effects of fuel treatments, wildfire and aerial firefighting, we estimated that expanding fuel break width in grass-dominant systems from 10 to 100 m increased the average success rate against a heading fire from 31 % to 41 %. Likewise, recently cleared fuel breaks had higher success rates compared to poorly maintained fuel breaks in both grass (25 % to 45 %) and shrub systems (20 % to 45 %). Combined, grass and shrub systems exhibited an estimated success rate of 80 % under mild weather conditions (20th percentile) and 19 % under severe weather (80th percentile). Other significant determinants included forb and grass production, adjacent tree canopy cover and terrain. Consistent with complexity theory and previous suppression effectiveness research, our analysis showed signs of suppression effectiveness declining as firefighter personnel increased. Future work could better account for the role of suppression with improved data on firefighting resource types, actions, locations, and timing.

Hierarchical Framework for Optimizing Wildfire Surveillance and Suppression Using Human-Autonomous Teaming

The integration of manned and unmanned aircraft can help improve wildfire response. Wildfire containment failures occur when the resources available to first responders, who execute the initial stages of wildfire management referred to as the initial attack, are ineffective or insufficient. Initial attack surveillance and suppression models have linked action spaces and objectives, making their optimization computationally challenging. The initial attack may be formulated as a multi-agent partially observable Markov decision process (MPOMDP). We divide the initial attack MPOMDP into surveillance and suppression processes with their respective planners operating on different, but constant, time scales. A hierarchical framework iterates between surveillance and suppression planners while also providing collision avoidance. This framework is exemplified by a set of multirotor unmanned aircraft surveying an initial attack fire while a manned helicopter suppresses the fire with a water bucket. Wildfire-specific solver extensions are formulated to reduce the otherwise vast action spaces. The hierarchical framework outperforms firefighting techniques and a myopic baseline by up to 242% for moderate wildfires and 60% for rapid wildfires when simulated in abstracted and actual case studies. We also validate the early dispatching of additional suppression assets using regression models to ensure wildfire containment within thresholds established by wildfire agencies.

Vegetation, fuels, and fire-behavior responses to linear fuel-break treatments in and around burned sagebrush steppe: are we breaking the grass-fire cycle?

BackgroundLinear fuel breaks are being implemented to moderate fire behavior and improve wildfire containment in semiarid landscapes such as the sagebrush steppe of North America, where extensive losses in perennial vegetation and ecosystem functioning are resulting from invasion by exotic annual grasses (EAGs) that foster large and recurrent wildfires. However, fuel-break construction can also pose EAG invasion risks, which must be weighed against the intended fire-moderation benefits of the treatments. We investigated how shrub reductions (mowing, cutting), pre-emergent EAG-herbicides, and/or drill seedings of fire-resistant perennial bunchgrasses (PBGs) recently applied to create a large fuel-break system affected native and exotic plant abundances and their associated fuel loading and predicted fire behavior.ResultsIn heavily EAG-invaded areas, herbicides reduced EAG and total herbaceous cover without affecting PBGs for 2–3 years and reduced predicted fire behavior for 1 year (from the Fuel Characteristic Classification System). However, surviving post-herbicide EAG cover was still > 30%, which was sufficient fuel to exceed the conventional 1.2-m-flame length (FL) threshold for attempting wildfire suppression with hand tools. In less invaded shrubland, shrub reduction treatments largely reduced shrub cover and height by ~ half without increasing EAGs, but then redistributed the wood to ground level and increased total herbaceous cover. Herbicides and/or drill seeding after shrub reductions did not affect EAG cover, although drill seedings increased PBG cover and exotic forbs (e.g., Russian thistle). Fire behavior was predicted to be moderated in only one of the many yearly observations of the various shrub-reduction treatment combinations. Over all treatments and years, FLs were predicted to exceed 1.2 m in 13% of simulations under average (11 km h−1) or high (47 km h−1) wind speed conditions and exceed the 3.4-m threshold for uncontrollable fire in 11% of simulations under high-wind speeds only.ConclusionsPredicted fire-moderation benefits over the first 4 years of fuel break implementation were modest and variable, but, generally, increases in EAGs and their associated fire risks were not observed. Nonetheless, ancillary evidence from shrublands would suggest that treatment-induced shifts from shrub to herbaceous fuel dominance are expected to improve conditions for active fire suppression in ways not readily represented in available fire models.

Local community participation and volunteerism in wildfire area management: A systematic review

Wildfires have caused considerable economic, ecological, and social damage in recent years. For this reason, decision-makers in wildfire management (WFM) have face increasingly difficult challenges. While decision support systems help decision-makers, it is clear that some deficiencies still persist. In this context, it is thought that the active role of local people involved in wildfire management can eliminate these deficiencies because they have experience and direct knowledge about fighting wildfires in Wildland Urban Interface (WUI) areas. Hence, their expertise can be utilized in future wildfire containment efforts. In this study, the author presents some general information about WUI, public participation, and the decision-making process and its relation to wildfires. In addition, the author will also examine previous studies on the participation of local people in wildfire management and investigate the decision-making processes regarding this issue by using Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) technique. The results of this study suggest that there should be a widespread adoption of the community-based integrated fire management (CBIFM) approach, instead of the top-down management approach commonly employed in wildfire management. The results strongly suggest that decision-makers should reach a consensus as to how the principle of participation in fire management should work by reviewing the socio-economic interests of the local community.

Mitigating Source Water Risks with Improved Wildfire Containment

In many fire-prone watersheds, wildfire threatens surface drinking water sources with eroded contaminants. We evaluated the potential to mitigate the risk of degraded water quality by limiting fire sizes and contaminant loads with a containment network of manager-developed Potential fire Operational Delineations (PODs) using wildfire risk transmission methods to partition the effects of stochastically simulated wildfires to within and out of POD burning. We assessed water impacts with two metrics—total sediment load and frequency of exceeding turbidity limits for treatment—using a linked fire-erosion-sediment transport model. We found that improved fire containment could reduce wildfire risk to the water source by 13.0 to 55.3% depending on impact measure and post-fire rainfall. Containment based on PODs had greater potential in our study system to reduce total sediment load than it did to avoid degraded water quality. After containment, most turbidity exceedances originated from less than 20% of the PODs, suggesting strategic investments to further compartmentalize these areas could improve the effectiveness of the containment network. Similarly, risk transmission varied across the POD boundaries, indicating that efforts to increase containment probability with fuels reduction would have a disproportionate effect if prioritized along high transmission boundaries.

Sustainable Land Management, Wildfire Risk and the Role of Grazing in Mediterranean Urban-Rural Interfaces: A Regional Approach from Greece

Mediterranean regions are likely to be the most vulnerable areas to wildfires in Europe. In this context, land-use change has promoted land abandonment and the consequent accumulation of biomass (fuel) in (progressively less managed) forests and (non-forest) natural land, causing higher fire density and severity, economic damage, and land degradation. The expansion of Wildland-Urban Interfaces (WUIs) further affects fire density by negatively impacting peri-urban farming and livestock density. Assuming the role of grazing in controlling fuel accumulation in forests and non-forest natural land as an indirect measure of wildfire containment around large Mediterranean cities, our work focuses on the role of nomadic livestock, i.e., sheep and goats—the most abundant and traditional farm species in the area. The present study (i) investigates the relationship between fire frequency/extent and livestock decline at the regional level in Greece, (ii) explores changes over time in regional wildfire regimes, comparing Attica, a particularly vulnerable peri-urban region which includes Athens (the Greek capital city), with the rest of the country, and (iii) quantifies trends over time in livestock characteristics (population structure and dynamics) over a sufficiently long time interval (1961–2017) at the same spatial scale, with the aim to document the progressive reduction of nomadic livestock in peri-urban districts. A comprehensive analysis of statistical data, corroborated with a literature review, outlined the relationship between livestock decline over time and changes in specific wildfire characteristics at the regional scale, evidencing peculiar environmental conditions in Attica. In this region, a rapid decline of nomadic livestock was observed compared to in the rest of Greece, leading to a higher wildfire risk. The results of this study suggest that nomadic livestock contributes to sustainable management of peri-urban land, stimulating grazing that may prevent fuel accumulation in fringe woodlands.

Suppressing the thermal decomposition of forest fuel using the different water spraying schemes

This article presents the main findings of the experimental research into the fire suppression by continuous spraying of water over the combustion zone and by pulsed liquid aerosol delivery according to two schemes. The test samples con-tained either birch leaves only or mixed of (leaves, twigs, and needles). We monitored the temperature in the fuel bed and used thermocouple readings to determine the conditions and characteristics of suppressing the combustion and thermal decomposition of the material. Using optical methods and high speed recording, we obtained the parameters of sprayed liquid-flow as well as the processes involved in the interaction between liquid aerosol and the decomposing forest fuel. The experimental study helped us establish how much time and quenching liquid is sufficient to suppress the forest fuel combustion. Furthermore, we determined the influence of the forest fuel volume on the conditions and characteristics of the processes under study. Finally, we identified the main physical principles of the thermal decomposition of forest fuel when using the proposed approaches to spraying water into the combustion zone. The research findings enable the optimization of aerial firefighting in terms of wildfire containment and suppression.

What are the drivers of dangerous fires in Mediterranean France?

Wildfire containment is often very challenging for firefighters, especially for large and rapidly spreading fires where the risk of firefighter entrapment is high. However, the conditions leading to these ‘dangerous’ fires are poorly understood in Mediterranean Europe. Here, we analyse reports and interviews of firefighters over the last 40 years in four regions of south-eastern France and investigate the weather conditions that induce large fires, fast-growing fires and fires that are conducive to entrapment. We adopt a quantile regression model to test the effect of weather conditions across different fire sizes and growth rates. The results show that strong winds drive the largest fires everywhere except in Corsica, the southernmost region, where high temperature is the main driver. Strong winds also drive entrapments whereas high temperatures induce rapidly spreading fires. This emphasises that wind-driven fire is the dominant pattern of dangerous fires in France, but it reveals that large ‘convective’ fires can also present considerable danger. Beyond that, the Fire Weather Index appears to be a good predictor of large fires and fires conducive to entrapments. Identifying weather conditions that drive ‘dangerous’ wildfires will provide useful information for fire agencies to better prepare for adverse fire behaviours.

Calibration and Validation of Immediate Post-Fire Satellite-Derived Data to Three Severity Metrics

AbstractSince 2007, the USDA Forest Service’s Remote Sensing Applications Center (RSAC) has been producing fire severity data within the first 30 to 45 days after wildfire containment (i.e., initial assessments [IA]), for wildfires that occur on USDA Forest Service managed lands, to support post-fire management actions. Satellite image-derived map products are produced using calibrations of the relativized differenced normalized burn ratio (RdNBR) to the Composite Burn Index (CBI), percent change in tree basal area (BA), and percent change in canopy cover (CC). Calibrations for extended assessments (EA) based upon one-year post-fire images have previously been published. Given that RdNBR is sensitive to ash cover, which declines with time since fire, RdNBR values that represent total mortality can be different immediately post fire compared with one year post fire. Therefore, new calibrations are required for IAs. In this manuscript, we describe how we modified the EA calibrations to be used for IAs using an adjustment factor to account for changes in ash cover computed through regression of IA and EA RdNBR values. We evaluate whether the accuracy of IA and EA maps are significantly different using ground measurements of live and dead trees, and CBI taken one year post fire in 11 fires in the Sierra Nevada and northwestern California. We compare differences between error matrices using Z-tests of Kappa statistics and differences between mean plot values in mapped categories using Generalized Linear Models (GLM). We also investigate whether map accuracy is dependent upon plot distance from boundaries delineating mapped categories. The IAs and EAs produced similarly accurate broad-scale estimates of tree mortality. Between IAs and EAs of each severity metric, the Kappa statistics of error matrices were not significantly different (P > 0.674) nor were mean plot values within mapped categories (P > 0.077). Plots <30 m (one Landsat pixel) distance from mapped polygon boundaries were less accurate than plots ≥30 m inside mapped polygons (P < 0.001). As land managers concentrate most post-fire management actions where tree mortality is high, it is desirable for map accuracy of severely burned areas to be high. Plots that were ≥30 m inside polygons depicting ≥75 % or ≥90 % BA mortality were correctly classified (producer’s accuracy) >92.3 % of the time, regardless of IA or EA.

Criteria and methodology for evaluating aerial wildfire suppression

Aircraft are often used to drop suppressants and retardants to assist wildfire containment. Drop effectiveness has rarely been measured due to the difficulties in collecting data from wildfires and running field experiments and the absence of definitions and measures. This paper presents a set of criteria and methodologies for evaluating the effectiveness of aerial suppression drops. These consider drop placement, coverage and effect on fire behaviour. This paper also details drop site and delivery conditions that are required for determining causal factors that influence drop effectiveness and allow drops to be compared. Examples of drop impact evaluations made during experimental fires are used to demonstrate these methodologies. The main methods proposed are based on the analysis of orthorectified airborne infrared imagery of drops, which can be used to measure drop dimensions, proximity to fire perimeter and their effect on fire spread. These evaluations can be used to compare tactics, suppressants and delivery systems and to inform cost–benefit analyses of aerial suppression.

A stochastic programming standard response model for wildfire initial attack planning

Wildfires are responsible for several civilians deaths and millions of dollars in property losses every year, on average. Wildfire containment is the result of an effectively performed initial attack. We formulate a two-stage stochastic integer programming standard response model for initial attack. The model assumes a known standard response needed to contain a fire of given size. The goal of the model is to contain as many fires as possible while minimizing the fixed rental and travel costs and the expected future operational costs. We report on a study based on district TX12, which is one of the fire planning units of the Texas Forest Service (TFS) in East Texas, involving seven operations bases and up to 28 dozers. We use our methodology to position the dozers based on 30- and 60-min maximum travel time restrictions and evaluate each deployment in terms of the number of fire-fighting resources positioned at each operations base and the expected number of escaped (contained) fires. We also consider deploying additional resources to operations bases that need them the most. The deployments made by our methodology provide several insights and show that the original distribution of resources in TX12 at the time of this study was not optimal. For example, more dozers were initially located at operations bases in areas of low density of fires while fewer dozers were located at bases in areas of high density of fires.

Integrated simulation and optimization for wildfire containment

Wildfire containment is an important but challenging task. The ability to predict fire spread behavior, optimize a plan for firefighting resource dispatch and evaluate such a plan using several firefighting tactics is essential for supporting decision making for containing wildfires. In this article, we present an integrated framework for wildfire spread simulation, firefighting resource optimization and wildfire suppression simulation. We present a stochastic mixed-integer programming model for initial attack to generate firefighting resource dispatch plans using as input fire spread scenario results from a standard wildfire behavior simulator. A new agent-based discrete event simulation model for fire suppression is used to simulate fire suppression based on dispatch plans from the stochastic optimization model, and in turn provides feedback to the optimization model for revising the dispatch plans if necessary. We report on several experimental results, which demonstrate that different firefighting tactics can lead to significantly different fire suppression results for a given dispatch plan, and simulation of these tactics can provide valuable information for fire managers in selecting dispatch plans from optimization models before actual implementation in the field.

Impacts of conservation easements for threat abatement and fire management in a rural oak woodland landscape

Rural residential development can impact habitat and complicate fire management. Conservation easements are created to prevent development but are rarely assessed for their influence on development patterns. In the Lassen Foothills, California, The Nature Conservancy (TNC) holds over 37,000 ha of mostly public-funded conservation easements on ranchland dominated by blue oak ( Quercus douglasii) woodland. For this region we modeled land use through 2050 under two scenarios, with and without conservation easements, using a rule-based growth model. We mapped development footprints on 760 rural residential parcels through automated remote sensing. From calculated footprint sizes we projected site-level habitat loss for each scenario. We also projected the influence of development patterns on fire management. With easements present the Lassen Foothills would gain about 184 new homes, compared with 223 homes if easements were absent. With an average residential footprint size of 0.34 ± 0.25 ha (mean ± SD), we found that easements slightly reduce vegetation conversion, protecting an additional 16.8 ha than were protected by the general plan alone. Without easements, scattered development may alter fire management on 12,370 ha (17.5% of undeveloped wildfire containment areas) by requiring more fire suppression and reducing options for prescribed burning. Low development pressure and county land use policies maintain very low residential densities in the Lassen Foothills. The easement program may increase options for fire management by preserving large landscapes. This case illustrates the limited effectiveness of land acquisition in preventing development in a low-threat landscape, and demonstrates the utility of growth models for prioritizing conservation investments.

DEVS-FIRE: Towards an Integrated Simulation Environment for Surface Wildfire Spread and Containment

Simulating wildfire spread and containment remains a challenging problem due to the complexity of fire behavior. In this paper, the authors present an integrated simulation environment for surface wildfire spread and containment called DEVS-FIRE. DEVS-FIRE is based on the discrete event system specification (DEVS) and uses a cellular space model for simulating wildfire spread and agent models for simulating wildfire containment. The cellular space model incorporates real spatial fuels data, terrain data and temporal weather data into the prediction of wildfire behavior across both time and space. DEVS-FIRE is designed to be integrated with stochastic optimization models that use the scenario results from the simulation to determine an optimal mix of firefighting resources to dispatch to a wildfire. Preliminary computational experiments with fuel, terrain and weather data for a real forest demonstrate the viability of the integrated simulation environment for wildfire spread and containment.

Meteorologically influenced wildfire impacts on urban particulate matter and visibility in Tucson, Arizona, USA

Fire managers must consider air-quality impacts when planning prescribed burns or devising wildfire containment strategies. Particulate matter (PM) is the primary pollutant of concern: it is the major component of smoke and has known detrimental influences on human health and the environment. The present study examines wildfire–weather–PM interactions and the resulting impacts on urban air quality and visibility in Tucson, Arizona, USA. Few violations of air-quality standards were recorded during large wildfire events in the study area. When examined at a higher-resolution time scale, the impacts of the fires on urban air quality are apparent. The present study also found that extreme PM values were linked to humid and windy conditions, wildfires appear to have a greater impact on PM10 concentrations than PM2.5 concentrations, and PM10 is more closely tied to visibility degradation during fire events than PM2.5. Comparison of actual PM concentrations to those predicted by a regulatory model indicates that the model overestimates standard exceedances, with resulting implications for prescribed burn planning.

An Integer Programming Model to Optimize Resource Allocation for Wildfire Containment

Abstract Determining the specific mix of fire-fighting resources for a given fire is a necessary condition for identifying the minimum of the Cost Plus Net Value Change (C+NVC) function. Current wildland fire management models may not reliably do so. The problem of identifying the most efficient wildland fire organization is characterized mathematically using integer-programming techniques. This mathematical exposition is then solved using the LINGO optimization language. Sensitivity analysis is conducted on model inputs to demonstrate the flexibility of the model architecture. Further, the model is used to model budget constraints commonly faced by fire managers. FOR. SCI. 49(2):331–335.

Simulating Wildfire Containment with Realistic Tactics

Abstract Existing simulation models for fire protection planning rely on a containment algorithm which fails to account for the interaction between the production of containment line and a fire's capacity to spread. This paper describes a technique for simulating wildland fire containment which explicitly accounts for this interaction by extending, generalizing, and, in some cases, simplifying methods reported earlier (Anderson 1983, Albini et al. 1978, Mees 1985, Anderson 1989). Representing the containment boundary in parametric form [i.e., expressing its Cartesian (x, y) or polar (r, ) coordinates as functions of a dimensionless parameter instead of specifying y as a function of x or r as a function of ], leads to a formalism with two significant advantages: (1) it allows a free choice for the shape of the free burning fire boundary, and (2) it is appropriate for simulations of parallel (indirect) attack as well as direct head and tail attack. In general, the technique requires solution of a first-order, nonlinear, differential equation, a task easily accomplished using numerical methods. The dependence of final fire size and containment time on the line-building rate and eccentricity of the free burning fire boundary are illustrated with the special case of an expanding ellipse and constant line-building rate, for which the containment boundary can be obtained by a simple quadrature. Our General Formulation algorithm is demonstrated with a series of simulations that span the range of likely parameters for fire spread and fireline production. Comparisons made on representative fires between predictions of the General Formulation and models currently in use indicate that current models almost always overestimate fire size, sometimes by as much as an order of magnitude. For. Sci. 42(3):267-281.