Probability Of Fire Spread Research Articles

A Multiagent Mission Coordination System for Continuous Situational Awareness of Bushfires

This paper devises a multi-agent Mission Coordinating Architecture (MCA) to achieve continuous situational awareness (SA) in bushfires, which can help with quick detection and accurate response to the hazards. In this paper, we use Unmanned Aerial Vehicles (UAVs) as instantiations of physical agents. MCA is a scalable architecture and aims to provide the UAVs with parallel mission plans, adopting a fire spread probability map and the Fuzzy C-means method to avoid mission overlap and duplicate information. The architecture is then enhanced by integrating a synchronized communication framework to facilitate UAVs’ adaptive cooperation and total flight time optimization. Furthermore, integrating the communication framework minimizes the number of deployed UAVs to fully cover the same area, saving considerable cost and energy compared to the Parallel Mode. The scalability challenge of the Parallel Mode, determining the required number of UAVs to cover the entire area, and the efficiency of the mission planning algorithm are thoroughly investigated and compared to the performance of the Communication Mode. Finally, the simulation results prove the MCA’s effectiveness in enhancing the UAVs’ exploration capability, resulting in comprehensive monitoring of all affected areas. Note to Practitioners—The proposed architecture in this research could offer flexibility to increase the number of UAVs on demand without requiring a change and adjustment of the parameters. Furthermore, a synchronized communication framework enhances MCA, enabling all UAVs to share their resources and exploit residual battery time to assist each other, manage the overall operation time, and reduce the total operation cost.

Predictive Modelling of Wind-Influenced Dynamic Fire Spread Probability in Tank Farm Due to Domino Effect by Integrating Numerical Simulation with ANN

Pool fires cause immense damage to fuel storage tank farms. Reduced fire escalation risk in tank farms improves fire safety. Computational fluid dynamics (CFD) has proven effective in assessing escalation of fire-related domino effects and is being utilized for pool fire consequences in tank farms. The past CFD-based analysis focused on primary fire effects on secondary targets. This study used fire dynamics simulator (FDS) to model complete evolution of the domino effect under different wind speeds and primary pool fire locations. Dynamic escalation probability (DEP) and fire spread probability of the tank farm were calculated. Offset tank failure increased by 3% and 31%, while inline tank failure dropped by 36% and 90%, at 2 and 8 m/s, respectively. An artificial neural network (ANN) incorporating the Levenberg–Marquardt algorithm is used to predict fire spread probability based on numerical data set. The use of ANNs for this purpose is one of the first attempts in this regard. ANNs can reliably predict dynamic fire spread probability and could be utilized to manage fire-induced domino effects. Moreover, dynamic fire spread probability in tank farms obtained from ANN modelling can be used for safety applications, such as updating mitigation time when fire spread probability is unacceptable for a specific wind speed.

Detecting critical nodes in forest landscape networks to reduce wildfire spread.

Although wildfires are an important ecological process in forested regions worldwide, they can cause significant economic damage and frequently create widespread health impacts. We propose a network optimization approach to plan wildfire fuel treatments that minimize the risk of fire spread in forested landscapes under an upper bound for total treated area. We used simulation modeling to estimate the probability of fire spread between pairs of forest sites and formulated a modified Critical Node Detection (CND) model that uses these estimated probabilities to find a pattern of fuel reduction treatments that minimizes the likely spread of fires across a landscape. We also present a problem formulation that includes control of the size and spatial contiguity of fuel treatments. We demonstrate the approach with a case study in Kootenay National Park, British Columbia, Canada, where we investigated prescribed burn options for reducing the risk of wildfire spread in the park area. Our results provide new insights into cost-effective planning to mitigate wildfire risk in forest landscapes. The approach should be applicable to other ecosystems with frequent wildfires.

INFLUENCE OF FIRE PARTITIONS FOR SPEED FIRE DISTRIBUTION IN CLOSED PREMISES OF PRODUCTION AND STORAGE FACILITIES

Introduction. Fires in closed premises of production and storage facilities are the most dangerous, because they hold large areas with a significant fire load. The current direction of providing a fire safety system at production and storage facilities in closed premises is to eliminate the conditions of the rapid development of fire and minimizing its effect through the use of fire curtains. This method of fire protection is practically not used in closed premises of production and storage facilities at the present stage. In most cases, fire partitions are used in such situations. Therefore, a topic issue today is the research of limiting the development of fires with the use of fire partitions and minimizing fire effects.Purpose. Investigate the process of spreading the fire in closed premises of production and storage facilities by using fire partitions to limit the speed of fire spread. Problem statement and solution. The following tasks must be solved to provide fire protection of production and storage facilities:1. to investigate the process of fire spread in closed premises of production and storage facilities without the use of fire partitions;2. to investigate the impact of fire partitions use on fire rate.Two possible modes of development fire in the premises are considered to solve the first problem: 1) with the presence of sufficient air (oxygen), with fire occurred in regulated fire load; 2) with insufficient air (oxygen), with fire occurred in regulated ventilation.It is necessary to choose the material and fire partition design accordingly to solve the second problem. The results of experimental studies [11] showed that fire partitions vermiculite-silicate plates can be used for various building structures manufacturing. Closed production and storage facilities structure analysis showed that these premises are constructed in most cases with a grid of columns 9Х12 m.Conclusions and proposals:1) There is only the first mode of fire with sufficient oxygen (air) in closed premises of production and storage facilities with a total area of more than 5000 m2 in the process of fire. The fire that occurred is regulated only by the fire load.2) The use of fire partitions between sections of the premises of production and storage facilities reduces the probability of fire spreading in the premises by about 3 times.3) It is necessary to continue research work in this direction to obtain more significant results of the process of development and spread of fire in the premises of production and storage facilities.

Modeling fuel loads dynamics and fire spread probability in the Brazilian Cerrado

Fire events substantially influence biodiversity, carbon cycling, hence climate, human health, and the economy on a global scale. To cope with increasingly widespread fires, we need accurate estimates of the chances of fire occurrence across heterogeneous landscapes. Estimates of risk of fire are fundamental to prevent and fight wildfires. To this end, we developed a monthly fire spread probability model for the Brazilian Cerrado biome based on the historical relation between fuel loads and burned areas. To so, we firstly stratified the biome into 16 climatic regions, given the climate influence on fuel loads. We used historical burned areas and fuel loads from remote sensed data between 2015 and 2018 to build a non-stationary model that estimates fuel loads dynamics across the biome. Climate seasonality is the main factor driving fuel loads dynamics. The correlation between fuel loads and the best predictor (monthly mean precipitation) ranges from 0.27 to 0.88 (mean r = 0.61 and deviation of 0.18) across the Cerrado. The average amplitude of fuel loads is 32% between dry and rainy seasons. Our Bayesian fire risk model uses the burned area as a prior probability and fuel loads to estimate the posterior probability of fire spread. Our results show that the probability of fire spread highly correlates with historical burning events (r = 0.87). The recovery of fuel loads post-fire takes, on average, 2.43 years; however, our results point to a downward pathway of the biome’s vegetation biomass due to frequent recurrent fires. The models we developed provide a useful tool for improving the representation of spatial patterns and seasonality of fires in order to support management practices.

Assessing the Risk of Post-earthquake Fire and Presenting Risk Reduction Strategies in Qazvin and Markazi Provinces

INTRODUCTION: The location of Qazvin and Markazi provinces in high-seismicity regions has increased the probability of earthquake occurrence in these provinces. One of the most serious crises that threaten Qazvin and Markazi provinces is the post-earthquake fire which will be very probable considering the potential hazards. The present study aimed to identify the factors affecting the post-earthquake fire and present some strategies for pre-and post-earthquake preparedness in Qazvin and Markazi provinces. METHODS: In this descriptive-analytical study, the maps were produced using the Geographic Information System (GIS), and data collection sources were books, articles, and documents. Three main maps of risk, vulnerability, and crisis were prepared, and the analyses were performed by SWOT (strengths, weaknesses, opportunities, and threats) table. Thereafter, some practical strategies and policies were presented to achieve the intended goals. Strategies were developed for four programs to mitigate risk likelihood and vulnerability, manage fire, and reconstruct, along with development. FINDINGS: As evidenced by the obtained, the dispersion of some man-made factors, such as power transmission lines, gas stations, and high-risk industries, increases the likelihood of post-earthquake fires in both provinces. Furthermore, such geographical factors as scattered vegetation and location in arid climates increase the probability of fire spread. The final map of the crisis demonstrated that fires are more likely to occur in the center of Qazvin province and the north of Markazi province. CONCLUSION: Based on the results of the present study, the first step in regional planning and policy-making for the mitigation of fire hazards must be based on crisis maps and in harmony with subsequent hazards and damages. In this regard, to mitigate the risk of post-earthquake in these two provinces, the following measures are suggested: increasing safety in infrastructure, networks, facilities, industrial estates, and high-risk industries.

PROPAGATOR: An Operational Cellular-Automata Based Wildfire Simulator

PROPAGATOR is a stochastic cellular automaton model for forest fire spread simulation, conceived as a rapid method for fire risk assessment. The model uses high-resolution information such as topography and vegetation cover considering different types of vegetation. Input parameters are wind speed and direction and the ignition point. Dead fine fuel moisture content and firebreaks—fire fighting strategies can also be considered. The fire spread probability depends on vegetation type, slope, wind direction and speed, and fuel moisture content. The fire-propagation speed is determined through the adoption of a Rate of Spread model. PROPAGATOR simulates independent realizations of one stochastic fire propagation process, and at each time-step gives as output a map representing the probability of each cell of the domain to be affected by the fire. These probabilities are obtained computing the relative frequency of ignition of each cell. The model capabilities are assessed by reproducing a set of past Mediterranean fires occurred in different countries (Italy and Spain), using when available the real fire fighting patterns. PROPAGATOR simulated such scenarios with affordable computational resources and with short CPU-times. The outputs show a good agreement with the real burned areas, demonstrating that the PROPAGATOR can be useful for supporting decisions in Civil Protection and fire management activities.

Full-Scale Informal Settlement Dwelling Fire Experiments and Development of Numerical Models

While fire-related injuries and deaths decreased in the global north over the past few years, they have increased in the global south. With more than one billion people residing in informal settlements (sometimes known as slums, ghettos or shantytowns), it is necessary that greater effort be placed on addressing and developing means for improving fire safety in these areas. As a result of advances made in computer technologies, emerging performance-based regulations and an increase in building complexity in the global north, the use of computer models simulating enclosure fires have increased dramatically. In this work an experimental investigation is presented for (a) a full-scale corrugated steel sheeting clad informal dwelling experiment and (b) a full-scale timber clad informal dwelling experiment. The experimental results are then compared to numerical models consisting of both simple two-zone (OZone) and computational fluid dynamic models. Currently, there is negligible literature available on Fire Dynamic Simulator (FDS) modelling of informal settlement dwellings (sometimes known as shacks or shanties) fires. This paper evaluates the plausibility of using FDS v6.7 and zonal models to predict certain fire parameters (i.e. ceiling temperatures, heat fluxes, etc.) for Informal Settlement Dwellings (ISDs) and to study the plausibility of using FDS to estimate the probability of fire spread. In this paper an introduction to ISDs is given with details pertaining to construction materials and considerations needed for numerical modelling of informal dwellings (i.e. thin permeable boundaries or combustible boundaries). Models are based upon (a) a prescribed heat release rate per unit area in FDS using data obtained from a Fire Propagation Apparatus test, and (b) an empirical two-zone model using OZone. The FDS validation guide was used to quantify the model uncertainties in order to give a critical separation distance at which fire spread between dwellings will not occur. It was found that at 3 m spacing between ISDs there is a 6% chance (based on the model uncertainties) that fire spread can occur. This is an important finding that highlights the danger associated with these closely spaced dwellings and the hope is that it can guide local government and Non-Governmental Organizations in future decision making. Three meters spacing between dwellings, however, may not be possible due to the socio-cultural-political-economic issues associated with informal settlements. This is one of the first papers to demonstrate FDS models against full-scale ISD experiments.

Using a statistical model of past wildfire spread to quantify and map the likelihood of fire reaching assets and prioritise fuel treatments

We present a method to quantify and map the probability of fires reaching the vicinity of assets in a wildfire-prone region, by extending a statistical fire spread model developed on historical fire patterns in the Sydney region, Australia. It calculates the mean probability of fire spreading along sample lines around assets, weights the probability according to ignition probability and also estimates the change in spread probability that fuel reduction in treatment blocks would achieve. We have developed an R package WildfireRisk to implement the analysis and demonstrate it with two case studies in forested eastern Australia. The probability of a fire reaching the vicinity of an asset was highest in the heavily forested parts of each case study, but when weighted for ignition probability, the high probability shifted to the wildland–urban interface. Further, when weighted by asset location, high-priority areas for treatment were in blocks next to the wildland–urban interface. This method is objective, fast and based on the behaviour of real historical fires. We recommend its use in wildfire risk planning, as an adjunct to heuristic methods and simulations. Additional functionality can be incorporated into our method, for instance via a function for building impact.

Assessing the roles of seed bank, seed dispersal and historical disturbances for metapopulation persistence of a pyrogenic herb

Abstract Seed bank, seed dispersal and historical disturbance are critical factors affecting plant population persistence. However, because of difficulties collecting data on these factors they are often ignored. We evaluated the roles of seed bank, seed dispersal and historical disturbance on metapopulation persistence of Hypericum cumulicola, a Florida endemic. We took advantage of long‐term demographic data of multiple populations (22 years; ~11 K individuals; 15 populations) and a wealth of information on burn history (1962–present), and habitat attributes (patch specific location, elevation, area and aggregation) of a system of 92 patches of Florida rosemary scrub. We used previously developed integral projection models to assess the relative ability of simulations with different levels of seed dormancy for recently produced and older seeds and different dispersal kernels (including no dispersal) to predict regional observed occupancy and plant abundance in patches in 2016–2018. We compared a simulation with this model using historical burn history to 500 model simulations with the same average fire regime (using a Weibull distribution to determine the probability of ignition) but with random ignition years. The most likely model had limited dispersal (mean = 0.5 m) and the highest dormancy (field estimates × 1.2 %) and its predictions were associated with observed occurrences (67% correct) and densities (20% of variance explained). Historical burn synchrony among neighbouring patches (skewness in the number of patches burned by year = 1.79) probably explains the higher densities predicted by the simulation with the historical fire regime compared with predicted abundances after simulations using random ignition years (skewness = 0.20 + SE = 0.01). Synthesis. Our findings demonstrate the pivotal role of seed dormancy, dispersal and fire history on population dynamics, distribution and abundance. Because of the prevalence of metapopulation dynamics, we should be aware of the significance of changes in the availability and configuration of suitable habitat associated with human or non‐human landscape changes. Decisions on prescribed fires (or other disturbances) will benefit from our knowledge of consequences of fire frequency, but also of location of ignition and the probability of fire spread.

Probabilistic fire spread forecast as a management tool in an operational setting.

BackgroundAn approach to predict fire growth in an operational setting, with the potential to be used as a decision-support tool for fire management, is described and evaluated. The operational use of fire behaviour models has mostly followed a deterministic approach, however, the uncertainty associated with model predictions needs to be quantified and included in wildfire planning and decision-making process during fire suppression activities. We use FARSITE to simulate the growth of a large wildfire. Probabilistic simulations of fire spread are performed, accounting for the uncertainty of some model inputs and parameters. Deterministic simulations were performed for comparison. We also assess the degree to which fire spread modelling and satellite active fire data can be combined, to forecast fire spread during large wildfires events.ResultsUncertainty was propagated through the FARSITE fire spread modelling system by randomly defining 100 different combinations of the independent input variables and parameters, and running the correspondent fire spread simulations in order to produce fire spread probability maps. Simulations were initialized with the reported ignition location and with satellite active fires. The probabilistic fire spread predictions show great potential to be used as a fire management tool in an operational setting, providing valuable information regarding the spatial–temporal distribution of burn probabilities. The advantage of probabilistic over deterministic simulations is clear when both are compared. Re-initializing simulations with satellite active fires did not improve simulations as expected.ConclusionThis information can be useful to anticipate the growth of wildfires through the landscape with an associated probability of occurrence. The additional information regarding when, where and with what probability the fire might be in the next few hours can ultimately help minimize the negative environmental, social and economic impacts of these fires.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-016-2842-9) contains supplementary material, which is available to authorized users.

A model for slash-and-burn using cellular automata

Slash-and-burn is one of the efficient ways to clear land for fields or increase the soil fertility of established fields, in which farmers intentionally set fires to their field. On the other hand, a cellular automaton is used to simulate fire spread such as forest fire. Therefore, in this paper, we demonstrated fire spread during slash-and-burn using a two-dimensional cellular automata. We proposed and simulated some ways of fire ignition based on principles experimentally derived in Japan using cellular automata models. Our model took in such parameters as bush density, and the probability of fire-spread. We showed that those two parameters are essential for fire-spread. By comparing various firing methods, the number of ignition points effected the time to burn out the field. These results can serve as a prediction for the actual slash-and-burn and a planning firings or creating manuals from the perspective of mathematics.

A Probabilistic Landscape Analysis Supporting the Management of Unplanned Ignitions at Sequoia and Kings Canyon National Parks

Fire management policy in the United States has evolved to encourage fire managers to address the full range of beneficial and detrimental effects of unplanned ignitions. We developed a probability-based fire risk and benefit simulation approach to support wildland fire management at Sequoia and Kings Canyon National Parks (SEKI) in a manner consistent with the SEKI fire management plan. The approach integrated fire behavior, fire spread probability, and resource values to estimate the spatial distribution of expected fire net benefits for any ignition point in a landscape context. We simulated probabilistic fire footprints from each burnable cell and evaluated them for their potential to provide ecosystem benefits or to require risk mitigation. The expected net benefits of igniting a cell were stored in the ignition cell to provide a landscape-level perspective. We provide results that reflect the fire planning weather conditions of concern to demonstrate how the sensitivity of the results can reflect weather influences. The results provided a preprocessed “playbook” type reference guide to fire management. The results can be quickly accessed and intuitively interpreted and were used to promote interagency cooperation in managing the Tehipite fire on northern SEKI and on the Sierra National Forest.

A risk-informed appraisal of prescriptive building separation regulations in Switzerland

In Switzerland, prescriptive requirements apply to minimum separation distances between buildings in order to prevent building-to-building fire spread. These requirements are formulated by the regulatory body, for ease of use and enforcement, in a very simple manner: 10 m minimum separation distance between buildings, if both buildings have combustible exterior linings, 7.5 m if only one building has a combustible exterior lining, and 5 m if both buildings have non-combustible exterior linings. However, no quantitative guidance is given on how to reduce these distances, e.g. in cases where existing buildings are involved. In this paper, an overview on design methods for calculating separation distances in order to prevent fire spread between buildings is given. A model is described to calculate the probability of fire spread between buildings at several distances, taking into account relevant uncertainties. It appears that there is a 1 in 20 chance that a combustible exterior building lining can ignite if exposed to a burning building (room fire conditions) at a distance of 10 m, and a 1 out of 3 chance if at a distance of 5 m. The level of risk implicitly accepted by the Swiss fire codes is discussed, and a method is presented on how to derive separation distances imposing an equal level of risk for different building geometries and occupancies.

Fire safety of EPS insulated facades in residential multi-storey buildings

Effect of EPS ETICS system on fire safety has been studied by using fire safety engineering methods for residential multi-storey buildings up to eight floors. The probabilities of fire spread to apartments above the room-of-fire-origin were assessed by calculating heat exposures and consequences caused by the external flaming both for the EPS ETICS facade and for facade made of at least A2-s1, d0 materials. Concerning consequences for life safety, the fire death probability for EPS ETICS system was found to be within tolerable limits of F-N-curve which illustrates the probability of an event and consequences in terms of number of deaths. Special concern should be paid to fire safety during installation phase when EPS is unprotected without reinforced rendering.

Decreases in Fire Spread Probability with Forest Age Promotes Alternative Community States, Reduced Resilience to Climate Variability and Large Fire Regime Shifts

The generalization that plant communities increase in flammability as they age and invariably lead to resilient self-organized landscape mosaics is being increasingly challenged. Plant communities often exhibit rapidly saturating or even hump-shaped age-flammability trajectories and landscapes often display strong non-linear behaviors, abrupt shifts, and self-reinforcing alternative community states. This plethora of fire-landscape interactions calls for a more general model that considers alternative age-flammability rules. We simulated landscape dynamics assuming communities that (1) increase in flammability with age and (2) gain flammability up to a certain age followed by a slight and moderate loss to a constant value. Simulations were run under combinations of ignition frequency and interannual climatic variability. Age-increasing fire probability promoted high resilience to changes in ignition frequency and climatic variability whereas humpbacked-shaped age-flammability led to strong non-linear behaviors. Moderate (20%) reductions in mature compared to peak flammability produced the least resilient behaviors. The relatively non-flammable mature forest matrix intersected by young flammable patches is prone to break up and disintegrate with slight increases in ignition/climate variability causing large-scale shifts in the fire regime because large fires were able to sweep through the more continuous young/flammable landscape. Contrary to the dominant perception, fire suppression in landscapes with positive feedbacks may effectively reduce fire occurrence by allowing less flammable later stage communities composed of longer lived, obligate seeders to replace earlier stages of light demanding, often more flammable resprouters. Conversely, increases in anthropogenic ignitions, a common global trend of many forested regions may, in synergism with increased climate variability, induce abrupt shifts, and large-scale forest degradation.

A Real-Time Risk Assessment Tool Supporting Wildland Fire Decisionmaking

Abstract Development of appropriate management strategies for escaped wildland fires is complex. Fire managers need the ability to identify, in real time, the likelihood that wildfire will affect valuable developed and natural resources (e.g., private structures, public infrastructure, and natural and cultural resources). These determinations help guide where and when aggressive suppression is required to protect values and when fire may be allowed to burn to enhance ecosystem conditions. This article describes the primary components of the Wildland Fire Decision Support System (WFDSS), a geospatial decision support system developed by the US Forest Service. WFDSS provides state-of-the-art wildfire risk analysis, decision documentation, and long-term implementation planning. In particular, we describe how the two primary decision support analysis components of WFDSS, Fire Spread Probability (fire behavior) and Rapid Assessment of Values at Risk (resource assessment), fit into the current state of risk assessment tools for wildfire suppression decisionmaking.

Dynamic modeling of fire spread in building

Modeling fire spread in a building is a key factor of a fire risk analysis used for fire safety designs of large buildings. In this paper, a dynamic model of fire spread considering fire spread in both horizontal and vertical directions is described. The algorithms for simulating the fire spread process in buildings and calculating dynamic probability of fire spread for each compartment at each time step of simulation are proposed. The formulae used in calculating the input data for the dynamic fire spread model are derived. The dynamic fire spread model can easily be applied for any building including high-rise buildings. A detailed example of calculation of fire spread in a two-storey office building is described.

Stochastic cellular automata model for wildland fire spread dynamics

A stochastic cellular automata model for wildland fire spread under flat terrain and no-wind conditions is proposed and its dynamics is characterized and analyzed. One of three possible states characterizes each cell: vegetation cell, burning cell and burnt cell. The dynamics of fire spread is modeled as a stochastic event with an effective fire spread probability S which is a function of three probabilities that characterize: the proportion of vegetation cells across the lattice, the probability of a burning cell becomes burnt, and the probability of the fire spread from a burning cell to a neighboring vegetation cell. A set of simulation experiments is performed to analyze the effects of different values of the three probabilities in the fire pattern. Monte-Carlo simulations indicate that there is a critical line in the model parameter space that separates the set of parameters which a fire can propagate from those for which it cannot propagate. Finally, the relevance of the model is discussed under the light of computational experiments that illustrate the capability of the model catches both the dynamical and static qualitative properties of fire propagation.

Linking tree-ring and sediment-charcoal records to reconstruct fire occurrence and area burned in subalpine forests of Yellowstone National Park, USA

Reconstructing specific fire-history metrics with charcoal records has been difficult, in part because calibration data sets are rare. We calibrated charcoal accumulation in sediments from three medium (14—19 ha) and one large (4250 ha) lake with a 300 yr tree-ring-based fire-history reconstruction from central Yellowstone National Park (YNP) to reconstruct local fire occurrence and area burned within a 128 840 ha study area. Charcoal peaks most accurately reflected fires within 1.2—3.0 km of coring sites, whereas total charcoal accumulation correlated best with area burned within 6.0—51 km ( r2=0.22—0.62, p<0.05). To reconstruct area burned for the entire study area, we developed a statistical model based on a composite charcoal record. The model explained 64—79% of the variability in area burned from AD 1675 to 1960 and was robust to cross-validation. Reconstructed area burned from AD 1240—1975 was significantly higher during periods including extreme annual drought ( p=0.05), and area burned varied significantly at ~ 60 yr timescales ( p<0.05), similar to the variability in an independent precipitation reconstruction covering the same period. Widespread burning (>10 000 ha) occurred at 150—300 yr intervals, and at the site level, fire probability increased with stand age (composite Weibull c parameter = 1.61 [95% CI 1.36—2.54]), both suggesting that post-fire stand development played an important intermediary role between climate and fire by increasing fuel abundance and probability of fire spread. Our study illustrates the possibility of reconstructing area burned with multiple charcoal records, and results imply that future fire regimes in YNP will be governed by direct impacts of altered moisture regimes and by vegetation dynamics affecting the abundance and continuity of fuels.