A radiation-driven model for crown fire spread

2004 ◽  
Vol 34 (8) ◽  
pp. 1588-1599 ◽  
Author(s):  
B W Butler ◽  
M A Finney ◽  
P L Andrews ◽  
F A Albini
Keyword(s):  
Closed Form ◽  
A Priori ◽  
Radiant Energy ◽  
Fire Spread ◽  
Crown Fire ◽  
Spread Rate ◽  
Fire Modelling ◽  
Crown Fires ◽  
Environment Variables ◽  
Fire Front

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.

High-resolution infrared thermography for capturing wildland fire behaviour: RxCADRE 2012

2016 ◽  
Vol 25 (1) ◽  
pp. 62 ◽  
Author(s):  
Joseph J. O'Brien ◽  
E. Louise Loudermilk ◽  
Benjamin Hornsby ◽  
Andrew T. Hudak ◽  
Benjamin C. Bright ◽  
...  
Keyword(s):  
Wildland Fire ◽  
Radiant Energy ◽  
Fire Spread ◽  
Fire Effects ◽  
Fire Behaviour ◽  
Oblique View ◽  
Fire Modelling ◽  
Radiative Power ◽  
Fire Front ◽  
Research Experiment

Wildland fire radiant energy emission is one of the only measurements of combustion that can be made at wide spatial extents and high temporal and spatial resolutions. Furthermore, spatially and temporally explicit measurements are critical for making inferences about fire effects and useful for examining patterns of fire spread. In this study we describe our methods for capturing and analysing spatially and temporally explicit long-wave infrared (LWIR) imagery from the RxCADRE (Prescribed Fire Combustion and Atmospheric Dynamics Research Experiment) project and examine the usefulness of these data in investigating fire behaviour and effects. We compare LWIR imagery captured at fine and moderate spatial and temporal resolutions (from 1 cm2 to 1 m2; and from 0.12 to 1 Hz) using both nadir and oblique measurements. We analyse fine-scale spatial heterogeneity of fire radiant power and energy released in several experimental burns. There was concurrence between the measurements, although the oblique view estimates of fire radiative power were consistently higher than the nadir view estimates. The nadir measurements illustrate the significance of fuel characteristics, particularly type and connectivity, in driving spatial variability at fine scales. The nadir and oblique measurements illustrate the usefulness of the data for describing the location and movement of the fire front at discrete moments in time at these fine and moderate resolutions. Spatially and temporally resolved data from these techniques show promise to effectively link the combustion environment with post-fire processes, remote sensing at larger scales and wildland fire modelling efforts.

Variation in wind and crown fire behaviour in a northern jack pine – black spruce forest

2004 ◽  
Vol 34 (8) ◽  
pp. 1561-1576 ◽  
Author(s):  
S W Taylor ◽  
B M Wotton ◽  
M E Alexander ◽  
G N Dalrymple
Keyword(s):  
Black Spruce ◽  
Flame Temperature ◽  
Fire Spread ◽  
Crown Fire ◽  
Fire Behaviour ◽  
Canopy Layer ◽  
Crown Fires ◽  
Video Observations ◽  
Before And After ◽  
Fire Front

Fire spread and flame temperature were examined in a series of nine experimental crown fires conducted in the Northwest Territories, Canada. Average rates of spread were 17.8–66.8 m·min–1 (0.3–1.1 m·s–1) over burning periods from about 1.5–10 min across 75 m × 75 m to 150 m × 150 m plots. Detailed maps of fire front progression revealed areas with higher rates of spread in the order of tens of metres in horizontal dimension and tens of seconds in duration in several of the fires, which is consistent with the influence of coherent wind gusts. Comparison of open and in-stand wind speed before and after burning suggests that defoliation in the canopy layer during burning would result in the flaming zone having greater exposure to the ambient wind. Estimates of flame front residence from video observations at the surface averaged 34 s; estimates from temperature measurements decreased significantly with height from 74 s at the surface to 31 s below the canopy.

Analysis of the uncertainty of fuel model parameters in wildland fire modelling of a boreal forest in north-east China

2019 ◽  
Vol 28 (3) ◽  
pp. 205 ◽  
Author(s):  
Longyan Cai ◽  
Hong S. He ◽  
Yu Liang ◽  
Zhiwei Wu ◽  
Chao Huang
Keyword(s):  
Monte Carlo ◽  
Wildland Fire ◽  
Time Lag ◽  
Fire Spread ◽  
Model Parameters ◽  
Spread Rate ◽  
North East ◽  
Fire Modelling ◽  
Fuel Model ◽  
Model Parameter Uncertainty

Fire propagation is inevitably affected by fuel-model parameters during wildfire simulations and the uncertainty of the fuel-model parameters makes forecasting accurate fire behaviour very difficult. In this study, three different methods (Morris screening, first-order analysis and the Monte Carlo method) were used to analyse the uncertainty of fuel-model parameters with FARSITE model. The results of the uncertainty analysis showed that only a few fuel-model parameters markedly influenced the uncertainty of the model outputs, and many of the fuel-model parameters had little or no effect. The fire-spread rate is the driving force behind the uncertainty of other fire behaviours. Thus, the highly uncertain fuel-model parameters associated with spread rate should be used cautiously in wildfire simulations. Monte Carlo results indicated that the relationship between model input and output was non-linear and neglecting fuel-model parameter uncertainty of the model would magnify fire behaviours. Additionally, fuel-model parameters have high input uncertainty. Therefore, fuel-model parameters must be calibrated against actual fires. The highly uncertain fuel-model parameters with high spatial-temporal variability consisted of fuel-bed depth, live-shrub loading and 1-h time-lag loading are preferentially chosen as parameters to calibrate several wildfires.

Modelling the rate of fire spread and uncertainty associated with the onset and propagation of crown fires in conifer forest stands

2017 ◽  
Vol 26 (5) ◽  
pp. 413 ◽  
Author(s):  
Miguel G. Cruz ◽  
Martin E. Alexander
Keyword(s):  
Monte Carlo ◽  
Average Rate ◽  
Fire Spread ◽  
Prediction Errors ◽  
Crown Fire ◽  
Conifer Forest ◽  
Fire Behaviour ◽  
Crown Fires ◽  
Deterministic Modelling ◽  
Eastern Australia

Crown fires are complex, unstable phenomena dependent on feedback mechanisms between the combustion products of distinct fuel layers. We describe non-linear fire behaviour associated with crowning and the uncertainty they cause in fire behaviour predictions by running a semiphysical modelling system within a simple Monte Carlo simulation framework. The method was able to capture the dynamics of passive and active crown fire spread regimes, providing estimates of average rate of spread and the extent of crown fire activity. System outputs were evaluated against data collected from a wildfire that occurred in a radiata pine plantation in south-eastern Australia. The Monte Carlo method reduced prediction errors relative to the more commonly used deterministic modelling approach, and allowed a more complete description of the level of crown fire behaviour to expect. The method also provides uncertainty measures and probabilistic outputs, extending the range of questions that can be answered by fire behaviour models.

scholarly journals Quantifying Stand Targets for Silvicultural Prevention of Crown Fires

2002 ◽  
Vol 17 (2) ◽  
pp. 101-109 ◽  
Author(s):  
Christopher R. Keyes ◽  
Kevin L. O'Hara
Keyword(s):  
Stand Structure ◽  
Fire Spread ◽  
Crown Fire ◽  
Fuel Management ◽  
Data Types ◽  
Crown Fires ◽  
Quantitative Basis ◽  
The Relationship ◽  
Stand Conditions ◽  
Forest Managers

Abstract Forest managers are expressing a growing interest in proactively reducing susceptibility to crown fires, but the quantitative basis for defining specific stand targets and prescribing silvicultural regimes for this objective is lacking. A procedure is presented for creating resistant stand structures that exploits the relationship between crown fire development and characteristics of stand structure. The BEHAVE surface fire model was integrated with modified versions of the Van Wagner crown ignition and crown fire spread equations in order to quantify structural targets for mitigative silvicultural practices. The procedure tolerates an array of input data types for weather, site, and surface fuel variables so that hazard-reducing guidelines are tailored to specific site and stand conditions. Suggested strategies for achieving crown fire-resistant stand targets include pruning, low thinning, and surface fuel management. West. J. Appl. For. 17(2):101–109.

The effect of fire front width on surface fire behaviour

1999 ◽  
Vol 9 (4) ◽  
pp. 247 ◽  
Author(s):  
B.M. Wotton ◽  
R.S. McAlpine ◽  
M.W. Hobbs
Keyword(s):  
Forest Litter ◽  
Fire Spread ◽  
Fire Behaviour ◽  
Pine Plantation ◽  
Spread Rate ◽  
Surface Fire ◽  
Flame Radiation ◽  
Surface Fires ◽  
Front Width ◽  
Fire Front

To determine the effect of fire front width on surface fire spread rates, a series of simultaneously ignited experimental fires was carried out in a pine plantation. Fires were ignited in plots with widths ranging from 0.5 m to 10 m and were burned in low wind conditions. Flame lengths were small in all fires, ranging from 20 cm to 60 cm. Since pre-heating of the forest litter from flame radiation is assumed to be an important mechanism in the spread of low intensity, low wind surface fires, it then follows that the width of a flaming front should effect on the heating of the fuel to ignition temperatures. Total flame radiation was also measured at a point 50 cm ahead of the advancing flame front for a number of the fires. Experimental results indicate that a flame radiation measured ahead of the fire stays fairly constant once the flame width is between 2 and 5 m. Theoretical flame radiation calculations confirm this trend. Rates of spread between the 5 and 10 metre width fires also appear to be similar; this indicates that, for the type of fires studied, once flame width is greater than about 2 m, radiation from any extra width of fire front has little effect on spread rate.

Crown fire behaviour in a northern jack pine – black spruce forest

2004 ◽  
Vol 34 (8) ◽  
pp. 1548-1560 ◽  
Author(s):  
B J Stocks ◽  
M E Alexander ◽  
B M Wotton ◽  
C N Stefner ◽  
M D Flannigan ◽  
...  
Keyword(s):  
Black Spruce ◽  
Significant Proportion ◽  
Weather Conditions ◽  
Crown Fire ◽  
Fire Behaviour ◽  
Fire Modelling ◽  
Crown Fires ◽  
Floor Layer ◽  
Prediction Systems ◽  
High Degree

This paper reports on the behaviour of 10 experimental crown fires conducted between 1997 and 2000 during the International Crown Fire Modelling Experiment (ICFME) in Canada's Northwest Territories. The primary goal of ICFME was a replicated series of high-intensity crown fires designed to validate and improve existing theoretical and empirical models of crown fire behaviour. Fire behaviour characteristics were typical for fully developed boreal forest crown fires, with fires advancing at 15–70 m/min, consuming significant quantities of fuel (2.8–5.5 kg/m2) and releasing vast amounts of thermal heat energy. The resulting flame fronts commonly extended 25–40 m above the ground with head fire intensities up to 90 000 kW/m. Depth of burn ranged from 1.4–3.6 cm, representing a 25%–65% reduction in the thickness of the forest floor layer. Most of the smaller diameter (<3.0 cm) woody surface fuels were consumed, along with a significant proportion of the larger downed woody material. A high degree of fuel consumption occurred in the understory and overstory canopy with very little material less than 1.0 cm in diameter remaining. The documentation of fire behaviour, fire danger, and fire weather conditions carried out during ICFME permitted the evaluation of several empirically based North American fire behaviour prediction systems and models.

Modelling logic and the Canadian Forest Fire Behavior Prediction System

1998 ◽  
Vol 74 (1) ◽  
pp. 50-52 ◽  
Author(s):  
C. E. Van Wagner
Keyword(s):  
Forest Fire ◽  
Fire Behavior ◽  
Fire Spread ◽  
Fire Research ◽  
Fire Intensity ◽  
Prediction System ◽  
Behavior Prediction ◽  
Crown Fire ◽  
Fire Modelling ◽  
Semi Empirical

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. Key words: forest fire behavior, Canadian FBP System, fire modelling, crown-fire theory, fire research philosophy

Overview of the International Crown Fire Modelling Experiment (ICFME)

2004 ◽  
Vol 34 (8) ◽  
pp. 1543-1547 ◽  
Author(s):  
B J Stocks ◽  
M E Alexander ◽  
R A Lanoville
Keyword(s):  
Forest Fires ◽  
Model Development ◽  
Western World ◽  
Crown Fire ◽  
Forest Research ◽  
Fire Propagation ◽  
Fire Modelling ◽  
Crown Fires ◽  
The Us ◽  
Modelling Experiment

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.

Corrigendum to: Assessing the effect of foliar moisture on the spread rate of crown fires

2013 ◽  
Vol 22 (6) ◽  
pp. 869 ◽  
Author(s):  
Martin E. Alexander ◽  
Miguel G. Cruz
Keyword(s):  
Radiant Heat ◽  
Fire Spread ◽  
Heat Fluxes ◽  
Fuel Moisture ◽  
Conifer Forests ◽  
Spread Rate ◽  
Rate Of Spread ◽  
Crown Fires ◽  
Wide Range ◽  
Live Fuel Moisture

This paper constitutes a digest and critique of the currently available information pertaining to the influence of live fuel or foliar moisture content (FMC) on the spread rate of crown fires in conifer forests and shrublands. We review and discuss the findings from laboratory experiments and field-based fire behaviour studies. Laboratory experimentation with single needles or leaves and small conifer trees has shown an unequivocal effect of FMC on flammability metrics. A much less discernible effect of FMC on crown fire rate of spread was found in the existing set of experimental crown fires carried out in conifer forests and similarly with the far more robust database of experimental fires conducted in shrubland fuel complexes. The high convective and radiant heat fluxes associated with these fires and the lack of appropriate experimental design may have served to mask any effect of FMC or live fuel moisture on the resulting spread rate. Four theoretical functions and one empirical function used to adjust rate of fire spread for the effect of foliar or live fuel moisture were also concurrently examined for their validity over a wide range of FMC conditions with varying outcomes and relevancy. None of these model functions was found suitable for use with respect to dead canopy foliage.

Sign in / Sign up

Export Citation Format

Share Document