Chapter

Crown Fire

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Definition: A crown fire is defined as a fire that has ascended from the ground into the forest canopy and is spreading through it, usually in conjunction with the surface fuels. Introduction: Live vegetation and dead vegetative fuel in forests, woodlands, and shrublands is generally distributed in layers along a vertical vegetation profile from the surface of the ground to the top of the trees. The higher layer of this profile, the canopy layer, includes the crowns of tall trees and, in some cases, the crowns of tall shrubs. When wildfires spread through a forest, they do not necessarily burn all fuel layers. As a rule, they start on dead fuels on the forest floor, and they are classified according to the tallest fuel layer that they burn as ground fires, surface fires, and crown fires. Depending on the conditions, the layers that burn may change during the evolution of a fire. Crown fires are less common than surface fires in most forest ecosystems, but because of...

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... Using custom fuel models generated an appear the crown fire with moderate accuracy, in contrast, in simulation using standard fuel models, the simulated crown fire was active and mainly observed in cover land by Pinus brutia stand. This due to the high crown fuel load as well as the high value of CBD (i.e greater than of 0.2) in this type (Xanthopoulos & Athanasiou, 2020), in addition, the fuel load from live wood classes increases the fuel bed depth and, as a result, increases the flame length and facilitates the transfer of fire from the surface to the crown (Stratton, 2004). While the Cupressus stand has a very low fuel load from shrubs and therefore no crown fire inside it, the simulated map showed that there is a passive crown fire in part of this stand. ...
Article
Full-text available
Aim of study: Forest fuel classification and characterization is a critical factor in wildfire management. The main purpose of this study was to develop custom fuel models for accurately mapping wildfire spread compared to standard models. Area of study: The study was conducted at a replanted forest dominated by coniferous species, in the Arabdagh region, Golestan Province, northern Iran. Materials and methods: Six custom fuel models were developed to characterize the main vegetation types in the study area. Fuel samples were collected from 49 randomly selected plots. In each plot, the fuel load of 1-hr, 10-hr, 100-hr, 1000-hr, live herbs, live woody plants, surface area volume ratio, and fuel depth were estimated using the Fuel Load (FL) sampling method along three transects. Canopy fuel load was calculated for each fuel model. The performance of the custom fuel models versus standard fuel models on wildfire behavior simulations was compared using the FlamMap MTT simulator. Main results: The results showed that, despite the similarity in the burned area between observed and modeled fires, the custom fuel models produced an increase in simulation accuracy. Compared to the observed fire, simulation results did not give realistic results to the crown fire. The simulation using standard fuel models did not result in crown fire, while the simulation using custom fuel models showed a moderate rate of crown fire with a Kappa coefficient of 0.54. Research highlights: The results demonstrated the importance of developing custom fuel models to simulate wildfire maps with higher accuracy for wildfire risk management. Keywords: custom fuel model; FlamMap; replantation; vegetation type; wildfire behavior.
Article
Full-text available
Wildfire occurrence frequency is increasing worldwide, generating more and more concern, especially in Wildland-Urban interfaces (WUI) and Wildland-Industrial Interfaces (WII) areas. Wildfires approaching WII can cause severe damage to people and industrial assets. In these scenarios, storage tanks present in industrial installations are among the most vulnerable pieces of equipment, since they are usually located in the proximity of the plant boundary. If hazardous substances are stored, tank damage caused by the fire can lead to loss of containment and trigger technological accident scenarios, escalating the consequences. Preserving the integrity of this type of equipment in case of wildfires is of paramount importance. The present study proposes a stepwise methodology for the evaluation of safety distances between storage tanks and vegetation that may be affected by a wildfire. According to the available data on the wildfire, on the lay-out and on the tanks that are likely to be affected, the methodology provides safety distances that may be applied to design fuel-reduced fringes around the industrial facility. The methodology proposed represents a quantitative tool for the calculation of safety distances that can guide industrial managers and assist regulators in the definition of more reliable standards. The comparison of the safety distances resulting from the present study with regulations and guidelines currently in use in different countries rises concern about the possible underestimation of required safety distances in the case of severe wildfires.
Article
Full-text available
Aims of study: To conduct the first full-scale crown fire experiment carried out in a Mediterranean conifer stand in Spain; to use different data sources to assess crown fire initiation and spread models, and to evaluate the role of convection in crown fire initiation. Area of study: The Sierra Morena mountains (Coordinates ETRS89 30N: X: 284793-285038; Y: 4218650-4218766), southern Spain, and the outdoor facilities of the Lourizán Forest Research Centre, northwestern Spain. Material and methods: The full-scale crown fire experiment was conducted in a young Pinus pinea stand. Field data were compared with data predicted using the most used crown fire spread models. A small-scale experiment was developed with Pinus pinaster trees to evaluate the role of convection in crown fire initiation. Mass loss calorimeter tests were conducted with P. pinea needles to estimate residence time of the flame, which was used to validate the crown fire spread model. Main results: The commonly used crown fire models underestimated the crown fire spread rate observed in the full-scale experiment, but the proposed new integrated approach yielded better fits. Without wind-forced convection, tree crowns did not ignite until flames from an intense surface fire contacted tree foliage. Bench-scale tests based on radiation heat flux therefore offer a limited insight to full-scale phenomena. Research highlights: Existing crown fire behaviour models may underestimate the rate of spread of crown fires in many Mediterranean ecosystems. New bench-scale methods based on flame buoyancy and more crown field experiments allowing detailed measurements of fire behaviour are needed.
Conference Paper
Full-text available
In this paper the assignment and theoretical investigations of the problems of crown forest fire initiation and spread in windy condition were carried out. Mathematical model of forest fire was based on an analysis of known experimental data and using concept and methods from reactive media mechanics. The investigation takes in to account the mutual interaction of the forest fires and three dimensional atmosphere flows. The research is done by means of mathematical modeling of physical processes. It is based on numerical solution of Reynolds equations for chemical components and equations of energy conservation for gaseous and condensed phases. It is assumed that the forest during a forest fire can be modeled as a two-temperature multiphase non-deformable porous reactive medium. A discrete analog for the system of equations was obtained by means of the finite volume method. The developed model of forest fire initiation and spreading would make it possible to obtain a detailed picture of the variation in the velocity, temperature and chemical species concentration fields with time. Mathematical model and the result of the calculation give an opportunity to evaluate critical conditions of the forest fire initiation and spread which allows applying the given model for of means for preventing fires.
Conference Paper
Full-text available
The objective of the study was the development of an empirical model to predict when a surface fire may ignite the forest crown and become a crown fire. Through an extensive literature review candidate variables for inclusion in the model were identified. The importance of these variables and their quantitative relationships were examined experimentally. The effect of water stress on ignitability of tree branches was examined by exposing branches of water stressed and unstressed seedlings to a hot air convection column (513 °C) and measuring the time required for ignition. The data did not provide column air temperature and live needle moisture content on ignitability of tree branches was quantified by exposing branches of three conifer species to a hot air convection column, at temperatures between 400 and 640 °C, and measuring time-to- ignition. Three multiple regression equations for the prediction of time-to-ignition with temperature and moisture as the independent variables were developed. Experimental burns in a wind tunnel provided temperature profiles obtained by thermocouples at four different heights above the fuel beds. A series of regression equations were developed to predict time-temperature profiles at any height above moving fires. A crown fire initiation model was developed based on the equations from the last two experiments. It is based on calculation of an ignition score. The threshold value of the score above which ignition is predicted was determined experimentally through additional burns in the wind tunnel and in the field, by exposing tree branches or small trees to moving fires, obtaining temperature profiles at their bottom, and calculating the corresponding ignition score.
Technical Report
Full-text available
This report documents a number of changes to the 1992 release of the Canadian Forest Fire Behavior Prediction (FBP) System, and addresses several mathematical and physical inconsistencies in its underlying models that have been identified over the last 15 years of its operational use throughout Canada. Several additional equations are included to allow calculations of a few elements not included in the original release of the system. However, these updates and revisions do not represent significant changes to the structure of the FBP System, but are largely modifications and clarifications of some of the models within the system. The implementation of these mathematical changes to the FBP System into existing technology transfer products (e.g., field guides and aids, software products), should be virtually transparent to most users. Finally, 20 formal test cases are presented to allow the developers of applications based on the FBP System to test their products against known benchmarks. It is important to understand that this document does not represent a new version of the Canadian FBP System (described in ST-X-3 “The Development and Structure of the Canadian Forest Fire Behavior System”), but is rather a supplement to that publication. A correct and up-to-date implementation of the FBP System must rely on the information contained in both these reports.
Article
Full-text available
The initiation of crown fires in conifer stands was modelled through logistic regression analysis by considering as independent variables a basic physical descriptor of the fuel complex structure and selected components of the Canadian Forest Fire Weather Index (FWI) System. The study was based on a fire behaviour research database consisting of 63 experimental fires covering a relatively wide range of burning conditions and fuel type characteristics. Four models were built with decreasing input needs. Significant predictors of crown fire initiation were: canopy base height, wind speed measured at a height of 10 m in the open, and four components of the FWI System (i.e., Fine Fuel Moisture Code, Drought Code, Initial Spread Index and Buildup Index). The models predicted correctly the type of fire (i.e., surface or crown) between 90% and 66% of the time. The C index, a statistical measure, varied from 0.94 to 0.71, revealing good concordance between predicted probabilities and observed events. A comparison between the logistic models and Canadian Forest Fire Behaviour Prediction System models did not show any conclusive differences. The results of a limited evaluation involving two independent experimental fire data sets for distinctly different fuel complexes were encouraging. The logistic models built may have applicability in fire management decision support systems, allowing for the estimation of the probability of crown fire initiation at small and large spatial scales from commonly available fire environment and fire danger rating information. The relationships presented are considered valid for free-burning fires on level terrain in coniferous forests that have reached a pseudo steady-state and are not deemed applicable to dead conifer forests (i.e., insect-killed stands).
Article
Full-text available
The relative variation in predicted fireline intensity and the wind speed thresholds for the onset of crowning and active crown fire spread in a lodgepole pine (Pinus contorta Dougl. ex Loud.) stand subjected to a commercial thinning operation were examined. This involved seven distinct scenarios, each with different assumptions regarding fine dead fuel moisture contents and fire behavior models. This case study illustrates that widely varying results can be expected, depending on how the environmental inputs are handled and which fire behavior characteristic is analyzed.
Article
Full-text available
The Forest Service of the U.S. Department of Agriculture is dedicated to the principle of multiple use management of the Nation's forest resources for sustained yields of wood, water, forage, wildlife, and recreation. Through forestry research, cooperation with the States and private forest owners, and management of the national forests and national grasslands, it strives—as directed by Congress—to provide increasingly greater service to a growing Nation. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 1400 Independence Avenue, SW, Washington, DC 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer.
Article
Full-text available
The rate of spread of crown fires advancing over level to gently undulating terrain was modeled through nonlinear regression analysis based on an experimental data set pertaining primarily to boreal forest fuel types. The data set covered a significant spectrum of fuel complex and fire behavior characteristics. Crown fire rate of spread was modeled separately for fires spreading in active and passive crown fire regimes. The active crown fire rate of spread model encompassing the effects of 10-m open wind speed, estimated fine fuel moisture content, and canopy bulk density explained 61% of the variability in the data set. Passive crown fire spread was modeled through a correction factor based on a criterion for active crowning related to canopy bulk density. The models were evaluated against independent data sets originating from experimental fires. The active crown fire rate of spread model predicted 42% of the independent experimental crown fire data with an error lower then 25% and a mean absolute percent error of 26%. While the models have some shortcomings and areas in need of improvement, they can be readily utilized in support of fire management decision making and other fire research studies.
Article
Full-text available
Allometric equations for the estimation of crown fuel weight of Aleppo pine (Pinus halepensis Mill.) trees in the Mediterranean Basin were developed. Forty trees were destructively sampled and their crown fuels were weighed separately for each fuel category. Crown fuel components, both living and dead, were separated into size classes and regression equations that estimate crown fuel load by diameter class were derived. The allometric equation y ≤ ax b with diameter at breast height as the single predictor was chosen, because the addition of other parameters did not decrease the residual sum of squares significantly. The adjusted coefficient of determination (R 2adj) values were high (R2adj ≤ 0.82-0.88) in all cases. Diameter at breast height was the most significant determinant of crown fuel biomass. The aerial fuels that are consumed during crown fires (i.e. needles and twigs with diameter less than 0.63 cm) comprised 29.3% of the total crown weight. Live fuels constituted ∼96.3% of total crown biomass, distributed as follows: needles 16.7% (average load 12.07 kg), branches with 0.0-0.63-cm diameter 12.6% (average load 9.18 kg), 0.64-2.5-cm diameter 37.3% (27.99 kg), 2.51-7.5-cm diameter 25.4% (18.59 kg), and >7.5-cm diameter 3.7% (2.65 kg). The equations provide quantitative fuel biomass attributes for use in crown fire behaviour models, fire management and carbon assessment in Aleppo pine stands.
Article
Full-text available
A model,was developed to predict the ignition of forest crown fuels above a surface fire based on heat transfer theory. The crown fuel ignition model (hereafter referred to as CFIM) is based on first principles, integrating: (i) the characteristics of the energy source as defined by surface fire flame front properties; (ii) buoyant plume dynamics; (iii) heat sink as described by the crown fuel particle characteristics; and (iv) energy transfer (gain and losses) to the crown fuels. Fuel particle temperature increase is determined through an energy balance relating heat absorption to fuel particle temperature. The final model output is the temperature of the crown fuel particles, which upon reaching ignition temperature are assumed to ignite. CFIM predicts the ignition of crown fuels but does not determine the onset of crown fire spread per se. The coupling of the CFIM with models determining the rate of propagation of crown fires allows for the prediction of the potential for sustained crowning. CFIM has the potential to be implemented,in fire management,decision support systems. Additional keywords: crown fire initiation; fire behavior; heat transfer; modeling.
Article
Full-text available
Fire managers are increasingly concerned about the threat of crown fires, yet only now are quantitative methods for assessing crown fire hazard being developed. Links among existing mathematical models of fire behavior are used to develop two indices of crown fire hazard-the Torching Index and Crowning Index. These indices can be used to ordinate different forest stands by their relative susceptibility to crown fire and to compare the effectiveness of crown fire mitigation treatments. The coupled model was used to simulate the wide range of fire behavior possible in a forest stand, from a low-intensity surface fire to a high-intensity active crown fire, for the purpose of comparing potential fire behavior. The hazard indices and behavior simulations incorporate the effects of surface fuel characteristics, dead and live fuel moistures (surface and crown), slope steepness, canopy base height, canopy bulk density, and wind reduction by the canopy. Example simulations are for western Montana Pinus ponderosa and Pinus contorta stands. Although some of the models presented here have had limited testing or restricted geographic applicability, the concepts will apply to models for other regions and new models with greater geographic applicability.
Article
Full-text available
The International Crown Fire Modelling Experiment (ICFME), carried out between 1995 and 2001 in Canada's Northwest Territories, involved 18 experimental high-intensity crown fires, with more than 100 participants representing 30 organizations from 14 countries. ICFME has provided valuable new data and insights into the nature and characteristics of crowning forest fires, which will assist in addressing fire management problems and opportunities affecting both people and ecosystems in future decades. ICFME evolved as the result of a number of converging issues: the recognition that the US and Canada could not continue separate approaches to fire behaviour model development, the opening of Russia to the western world, increased communication, and the formation of international associations to facilitate collaboration. While the initial impetus for ICFME was the desire to improve the physical modeling of crown fire propagation and spread, the project also created the opportunity to examine many other aspects and impacts of crown fires. This special issue of the Canadian Journal of Forest Research devoted to ICFME is intended to summarize most of the major research results from the project.
Article
Full-text available
We describe the development of a model system for the prediction over the full range in fire behaviour in exotic pine plantation fuel types in relation to environmental conditions. The proposed system integrates a series of sub-models describing surface fire characteristics and crowning potential properties (e.g., onset of crowning, type of crown fire and associated rate of spread). The main inputs are wind speed, fine dead fuel moisture content, and fuel complex structure, namely surface fuel bed characteristics, canopy base height and canopy bulk density. The detail with which the model system treats surface and crown fire behaviour allows users to quantify stand "flammability" with stand age for particular silvicultural prescriptions. The application of the model to a radiata pine plantation thinning treatment case study in Victoria is presented. The results highlight the complex interactions that take place between fire behaviour and attendant fuel and weather conditions. The structural changes introduced in the fuel complex by the treatment altered fire behaviour, but no definite reduction and/or increase in rate of fire spread was identified. The results illustrate the role that simulation models can play in support of silvicultural and fuel management decision making.
Article
Full-text available
The unknowns in wildland fire phenomenology lead to a simplified empirical model approach for predicting the onset of crown fires in live coniferous forests on level terrain. Model parameterization is based on a data set (n = 71) generated from conducting outdoor experimental fires covering a significant portion of the spectrum of burning conditions associated with the initiation of crown fires. A logistic model is developed to predict the likelihood of crown fire occurrence based on three fire environment variables, namely the 10-m open wind speed, fuel strata gap (equivalent to live crown base height in some stands), estimated moisture content of fine dead fuels, and one fire-behavior descriptor–surface fuel consumption. The model correctly predicts 85% of the cases in the data set used in its development, and the receiver operating characteristic statistic is 0.94. The model is evaluated for its sensitivity to its inputs, and its behavior is compared with other models used in decision support systems to operationally predict crown fire initiation. The results of a limited test of the model against two independent experimental fire data sets for distinctly different fuel complexes is encouraging. FOR. SCI. 50(5):640–658.
Article
Full-text available
Application of crown fire behavior models in fire management decision-making have been limited by the difficulty of quantitatively describing fuel complexes, specifically characteristics of the canopy fuel stratum. To estimate canopy fuel stratum characteristics of four broad fuel types found in the western United States and adjacent areas of Canada, namely Douglas-fir, ponderosa pine, mixed conifer, and lodgepole pine forest stands, data from the USDA Forest Service's Forest Inventory and Analysis (FIA) database were analysed and linked with tree-level foliage dry weight equations. Models to predict canopy base height (CBH), canopy fuel load (CFL) and canopy bulk density (CBD) were developed through linear regression analysis and using common stand descriptors (e.g. stand density, basal area, stand height) as explanatory variables. The models developed were fuel type specific and coefficients of determination ranged from 0.90 to 0.95 for CFL, between 0.84 and 0.92 for CBD and from 0.64 to 0.88 for CBH. Although not formally evaluated, the models seem to give a reasonable characterization of the canopy fuel stratum for use in fire management applications. Additional keywords: canopy base height; canopy bulk density; canopy fuel load; crown fire behavior; crown fuel dynamics.
Article
Full-text available
Numerical calculations of the transition of a downstream (surface) forest fire into an upstream (crown) forest fire based on a general mathematical model of forest fires are presented. It is found that the ignition of the forest canopy is a gas-phase phenomenon. Critical conditions for the transition of a downstream into an upstream forest fire are determined. The numerical calculations are compared with experimental data.
Article
Full-text available
To control and use wildland fires safely and effectively depends on creditable assessments of fire potential, including the propensity for crowning in conifer forests. Simulation studies that use certain fire modelling systems (i.e. NEXUS, FlamMap, FARSITE, FFE-FVS (Fire and Fuels Extension to the Forest Vegetation Simulator), Fuel Manage- ment Analyst (FMAPlus!), BehavePlus) based on separate implementations or direct integration of Rothermel’s surface and crown rate of fire spread models with Van Wagner’s crown fire transition and propagation models are shown to have a significant underprediction bias when used in assessing potential crown fire behaviour in conifer forests of western North America. The principal sources of this underprediction bias are shown to include: (i) incompatible model linkages; (ii) use of surface and crown fire rate of spread models that have an inherent underprediction bias; and (iii) reduction in crown fire rate of spread based on the use of unsubstantiated crown fraction burned functions. The use of uncalibrated custom fuel models to represent surface fuelbeds is a fourth potential source of bias. These sources are described and documented in detail based on comparisons with experimental fire and wildfire observations and on separate analyses of model components. The manner in which the two primary canopy fuel inputs influencing crown fire initiation (i.e. foliar moisture content and canopy base height) is handled in these simulation studies and the meaning of Scott and Reinhardt’s two crown fire hazard indices are also critically examined.
Article
Full-text available
The effect of convection column air temperature and live needle moisture content on the flammability of tree branches was verified and quantified by exposing sample branches of three conifer species (Pinus ponderosa, P. contorta and Pseudotsuga menziesii var. glauca) to a hot-air convection column in the laboratory, at temperatures from 400 to 640C, and measuring time to ignition. The experiment was repeated monthly over the course of a year using branches collected early in the morning from the crown base of trees in 2 areas near Missoula, Montana, thus taking advantage of the natural fluctuation of live needle moisture content. Three multiple regression equations for the prediction of time to ignition with air temperature and needle moisture as the independent variables were developed.
Article
Full-text available
A crown fuel ignition model (CFIM) describing the temperature rise and subsequent ignition of the lower portion of tree crowns above a spreading surface fire was evaluated through a sensitivity analysis, comparison against other models, and testing against experimental fire data. Results indicate that the primary factors influencing crown fuel ignition are those determining the depth of the surface fire burning zone and the vertical distance between the ground/surface fuel strata and the lower boundary of the crown fuel layer. Intrinsic crown fuel properties such as fuel particle surface area-to-volume ratio and foliar moisture content were found to have a minor influence on the process of crown fuel ignition. Comparison of model predictions against data collected in high-intensity experimental fires and predictions from other models gave encouraging results relative to the validity of the model system.
Article
This article outlines the flexible semi-empirical philosophy used throughout six decades of fire research by the Canadian Forest Service, culminating in the development of the Forest Fire Behavior Prediction System. It then describes the principles involved when spread rate and fuel consumption are estimated separately to yield fire intensity, and the anomaly that has resulted from the omission of a foliar-moisture effect on crown-fire spread. Judged on its results so far, this Canadian approach has held its own against any other, and holds full promise for the future as well.
Article
Forest fire danger rating research in Canada was initiated by the federal government in 1925. Five different fire danger rating systems have been developed since that time, each with increasing universal applicability across Canada. The approach has been to build on previous danger rating systems in an evolutionary fashion and to use field experiments and empirical analysis extensively. The current system, the Canadian Forest Fire Danger Rating System (CFFDRS), has been under development by Forestry Canada since 1968. The first major subsystem of the CFFDRS, the Canadian Forest Fire Weather Index (FWI) System, provides numerical ratings of relative fire potential based solely on weather observations, and has been in use throughout Canada since 1970. The second major subsystem, the Canadian Forest Fire Behavior Prediction (FBP) System, accounts for variability in fire behavior among fuel types (predicting rate of spread, fuel consumption, and frontal fire intensity), was issued in interim form in 1984 with final production scheduled for 1990. A third major CFFDRS subsystem, the Canadian Forest Fire Occurrence Prediction (FOP) System, is currently being formulated. This paper briefly outlines the history and philosophy of fire danger rating research in Canada discussing in detail the structure of the current CFFDRS and its application and use by fire management agencies throughout Canada. Key words: fire danger, fire behavior, fire occurrence prediction, fuel moisture, fire danger rating system, fire management.
Article
The software package Prometheus is Canada’s only operational wildfire growth modelling simulator. The program calculates accurate, fast, multi-day forecasts of moving fire fronts and is currently used in fire fighting situations, in fire risk analysis and in the design of “fire-safe” communities and forests. At the core of Prometheus is an algorithm that calculates the evolution of the fire front in an empirical manner, assuming locally elliptic fire spread and Huygens’ principle in a Lagrangian description of the evolution. This report describes progress made on a set of problems that Prometheus developers brought to the 10th Pacific Institute for the Mathematical Sciences (PIMS) Industrial Problem Solving Workshop held in June 2006 at Simon Fraser University. In particular, we investigate the mathematical background behind the Prometheus code and suggest a new method (the “outer hull” approach) to remove tangles from the evolving front. Other methods that can reduce tangles and crossings are “smoothing” of data and parameters, and redistribution of vertices on the evolving front. We investigate the use of de Boor’s algorithm as an automated procedure for redistributing vertices along the front. Finally, we investigate the level set method as a new tool for forest fire spread simulations and show in some simple test cases the excellent potential of this method.
Article
The objective of this study is to investigate the capability of a physical two-phase model to predict the ignition of crown fuels by a surface fire and then to determine the degree of crowning. The model considers the hydrodynamic aspects of the flow and accounts for the basic physicochemical processes resulting from the thermal degradation of organic matter. Turbulence, soot formation, and its impact on radiation are considered in order to improve the physical insight. Calculations have been performed to investigate the effects of crown base height and aerial fuel moisture content on the onset of crowning. Numerical results are found to be consistent with experimental observations and the widely used Canadian Fire Behavior Prediction System classification by crown fraction burned. This model may be used to extend the domain of application of semiphysical theories, e.g., Van Wagner's theory, where fuel and environmental factors are generally determined from empirical observations of previous fires. It provides a means of adjusting these factors in other fire situations without requiring additional experiments.
Article
This paper reports on the,structure of a fire growth simulation model, FARSITE, and its performance under simplified test conditions. FARSITE incorporates existing models of surface fire, crown fire, point-source fire acceleration, spotting, and fuel moisture. This documentation of how the simulation was constructed, and how the individual fire behavior models perform, will be useful to researchers and managers who use FARSITE or are interested in fire growth simulation. The models were integrated using a vector propagation technique for fire perimeter expansion that controls for both space and time resolution of fire growth over the landscape. The model produces vector fire perimeters (polygons) at specified time intervals. The vertices of these polygons contain information on the fire's spread rate and intensity, which are interpolated to produce raster maps of fire behavior. Because fire behavior at each vertex is assumed independent of the others, the simulation outputs illustrate the strict spatial consequences to fire behavior of incorporating the models into a two-dimensional simulation. Simplified test conditions show that surface fire growth and intensity conform to idealized patterns. Similarities also exist between simulated crown fires and observed patterns of extreme wind-driven fires. Complex patterns of fi re growth and behavior result from the spatial and temporal dependencies in the model. The limitations and assumptions of this approach are discussed.
Article
Some theory and observations are presented on the factors governing the start and spread of crown fire in conifer forests. Crown fires are classified in three ways according to the degree of dependence of the crown phase of the fire on the ground surface phase. The crown fuel is pictured as a layer of uniform bulk density and height above ground. Simple criteria are presented for the initiation of crown combustion and for the minimum rates of spread and heat transfer into the crown combustion zone at which the crown fire will spread. The theory is partially supported by some observations in four kinds of conifer forest.
Article
A numerical model for the prediction of the spread rate and intensity of forest crown fires has been developed. The model is the culmination of over 20 years of previously reported fire modeling research and experiments; however, it is only recently that it has been formulated in a closed form that permits a priori prediction of crown fire spread rates. This study presents a brief review of the development and structure of the model followed by a discussion of recent modifications made to formulate a fully predictive model. The model is based on the assumption that radiant energy transfer dominates energy exchange between the fire and unignited fuel with provisions for convective cooling of the fuels ahead of the fire front. Model predictions are compared against measured spread rates of selected experimental fires conducted during the International Crown Fire Modelling Experiment. Results of the comparison indicate that the closed form of the model accurately predicts the relative response of fire spread rate to fuel and environment variables but overpredicts the magnitude of fire spread rates.
Article
Published data on two sets of experimental fires in jack pine (Pinusbanksiana Lamb.) forest were subjected to two forms of analysis. The first was a classification into surface fires and two kinds of crown fire, passive and active. In the second, the data were used to develop a model to predict both the spread rate of fire and the degree of crown consumption. The model consists mainly of two limiting equations for spread rate, one for surface fires and the other for full crowning fires; the independent variable is the Canadian Initial Spread Index. A critical surface intensity is first used to distinguish surface fires from crowning fires. A further process then estimates the degree of crowning and places the calculated final spread rate somewhere in the space between the limiting equations. The model inputs include six physical stand properties plus a pre-estimate of surface fuel consumption. It is a blend of physical theory and empirical observation.
Article
The problem of spread of upper crown fires in homogeneous forests and along various openings (roads, motorways, power lines, etc.), which are potential fire hazardous areas, was formulated mathematically and solved numerically. Key words: mathematical modeling, crown forest fire front, front precursors.
Article
Describes BURN subsystem, Part 1, the operational fire behavior prediction subsystem of the BEHAVE fire behavior prediction and fuel modeling system. The manual covers operation of the computer program, assumptions of the mathematical models used in the calculations, and application of the predictions.
Article
Describes methods for approximating behavior and size of a wind-driven crown fire in mountainous terrain. Covers estimation of average rate of spread, energy release from tree crowns and surface fuel, fireline intensity, flame length, and unit area power of the fire and ambient wind. Plume-dominated fires, which may produce unexpectedly fact spread rates even with low ambient windspeeds, are covered and supplemental methods suggested for estimating their occurrence. The spread information can be used to estimate and map fire area and perimeter.
Article
This manual documents procedures for estimating the rate of forward spread, intensity, flame length, and size of fires burning in forests and rangelands. Contains instructions for obtaining fuel and weather data, calculating fire behavior, and interpreting the results for application to actual fire problems.
Crown fire behavior characteristics and prediction in conifer forests: a state-of-knowledge synthesis
  • M E Alexander
  • M G Cruz
  • N M Vaillant
  • D L Peterson
Alexander ME, Cruz MG, Vaillant NM, Peterson DL (2013) Crown fire behavior characteristics and prediction in conifer forests: a state-of-knowledge synthesis. Joint Fire Science Program, Boise. JFSP 09-S-03-1 Final Report. p 39
USDA forest service general technical report INT-122, p 22. Intermountain Forest and Range Experiment Station
  • H E Anderson
Anderson HE (1982) Aids to determining fuel models for estimating fire behavior. USDA forest service general technical report INT-122, p 22. Intermountain Forest and Range Experiment Station, Ogden, 84401
BehavePlus fire modeling system, version 4.0: user's guide. USDA Forest Service, Rocky Mountain Research Station, general technical report RMRS-GTR-106WWW revised
  • P L Andrews
  • C D Bevins
  • R C Seli
Andrews PL, Bevins CD, Seli RC (2008) BehavePlus fire modeling system, version 4.0: user's guide. USDA Forest Service, Rocky Mountain Research Station, general technical report RMRS-GTR-106WWW revised. (Fort Collins)
Forest fire: control and use, 2nd edn. The Bark Beetles, Fuels, and Fire Bibliography
  • A A Brown
  • K P Davis
Brown AA, Davis KP (1973) Forest fire: control and use, 2nd edn. The Bark Beetles, Fuels, and Fire Bibliography. Paper 140
Atmospheric conditions related to blowup fires
  • G M Byram
Byram GM (1954) Atmospheric conditions related to blowup fires. Stn. Pap. No. 35. Asheville: USDA Forest Service, Southeastern Forest Experiment Station. (Reprinted as: National Fire Equipment System Publication NFES 2565 by the National Wildfire Coordinating Group, Boise)
Combustion of forest fuels; Forest fire behavior
  • G M Byram
Byram GM (1959) Combustion of forest fuels; Forest fire behavior. In: Davis KP (ed) Forest fire: control and use, vol 61-89. McGraw-Hill, New York, pp 90-123
Canadian forest fire danger rating system -users' guide. Agric. Can., Canadian Forestry Service. Fire Danger Group, Ottawa. Three-ring binder
Canadian Forestry Service (1987) Canadian forest fire danger rating system -users' guide. Agric. Can., Canadian Forestry Service. Fire Danger Group, Ottawa. Three-ring binder (unnumbered publication)
Fuels Management Analyst Plus software, version 3 (Fire Program Solutions LLC: Estacada)
  • D Carlton
Carlton D (2005) Fuels Management Analyst Plus software, version 3 (Fire Program Solutions LLC: Estacada). Available at http://www.fireps.com/fmanal yst3/index.htm (Verified 8 Nov 2009)
USDA Forest Service Research Paper PNW 1970
  • G R Fahnestock
Fahnestock GR (1970) Two keys for appraising forest fire fuels. USDA Forest Service Research Paper PNW 1970. p 26
An overview of FlamMap fire modeling capabilities. Fuels management-how to measure success: conference proceedings
  • M Finney
Finney M (2006) An overview of FlamMap fire modeling capabilities. Fuels management-how to measure success: conference proceedings
Mathematical modeling of forest fires and new methods of fighting them
  • A M Grishin
Grishin AM (1997) Mathematical modeling of forest fires and new methods of fighting them. In: Albini F (ed) (trans: Czuma M, Chikina L, Smokotina L). Tomsk State University, Tomsk, p 390
Validación y ajustes de los modelos de propagación de fuego de copa en la ordenación del paisaje forestal
  • J R Molina
Molina JR (2015) Validación y ajustes de los modelos de propagación de fuego de copa en la ordenación del paisaje forestal. In: Lecciones aprendidas en los incendios forestales; Rodríguez y Silva F (Ed). SECF-Universidad de Córdoba-MAGRAMA -Junta de