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.

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.

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.

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.

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

2011 ◽  
Vol 41 (1) ◽  
pp. 215-215
Author(s):  
B. J. Stocks ◽  
M. E. Alexander ◽  
B. M. Wotton ◽  
C. N. Stefner ◽  
M. D. Flannigan ◽  
...  
Keyword(s):  
Black Spruce ◽  
Jack Pine ◽  
Spruce Forest ◽  
Crown Fire ◽  
Fire Behaviour

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.

Time since prior wildfire affects subsequent fire containment in black spruce

2017 ◽  
Vol 26 (11) ◽  
pp. 919 ◽  
Author(s):  
Jennifer L. Beverly
Keyword(s):  
Black Spruce ◽  
Structural Characteristics ◽  
Weather Conditions ◽  
Fire Spread ◽  
Fire Weather ◽  
Weather Index ◽  
Fire Weather Index ◽  
Explanatory Variables ◽  
Time Since Fire ◽  
Crown Fires

In black spruce forests characterised by high-intensity crown fires, early detection and containment of fires while they are small is crucial for averting progression to fire intensities that exceed suppression capabilities. Fire behaviour conditions encountered during initial attack operations are a key determinant of containment success. Conditions will be controlled in part by stand structural characteristics that can be expected to vary as a fire-origin black spruce (Picea mariana (Mill.) B.S.P.) stand ages with increasing time-since-fire. In this study, the influence of time-since-fire on containment outcomes is assessed to explore whether or not prior wildfire exerts a negative feedback on subsequent fires in these ecosystems. Logistic regression analysis using point and polygon fire data for the province of Alberta, Canada, indicated the probability of a containment failure in black spruce increases with time-elapsed since the last fire. Other positive explanatory variables included the size of the fire at the initiation of firefighting and a relative rating of the expected rate of fire spread, the Initial Spread Index (ISI) of the Canadian Forest Fire Weather Index System. Legacy wildfires had a protective effect. When firefighting is initiated at fire sizes ≤1ha, the probability of a containment failure is low during the initial 20–45 years of post-fire stand development, except under the most extreme fire weather conditions.

A conceptual framework for ranking crown fire potential in wildland fuelbedsThis article is one of a selection of papers published in the Special Forum on the Fuel Characteristic Classification System.

2007 ◽  
Vol 37 (12) ◽  
pp. 2464-2478 ◽  
Author(s):  
Mark D. Schaaf ◽  
David V. Sandberg ◽  
Maarten D. Schreuder ◽  
Cynthia L. Riccardi
Keyword(s):  
Conceptual Framework ◽  
Classification System ◽  
Field Observations ◽  
Crown Fire ◽  
Fire Behaviour ◽  
Forest Canopies ◽  
Crown Fires ◽  
Fire Initiation ◽  
Fuel Characteristic ◽  
Selection Of

This paper presents a conceptual framework for ranking the crown fire potential of wildland fuelbeds with forest canopies. This approach extends the work by Van Wagner and Rothermel, and introduces several new physical concepts to the modeling of crown fire behaviour derived from the reformulated Rothermel surface fire modeling concepts proposed by Sandberg et al. (this issue). This framework forms the basis for calculating the crown fire potentials of Fuel Characteristic Classification System (FCCS) fuelbeds (Ottmar et al., this issue). Two new crown fire potentials are proposed (i) the torching potential (TP) and (ii) the active crown potential (AP). A systematic comparison of TP and AP against field observations and Crown Fire Initiation and Spread (CFIS) model outputs produced encouraging results, suggesting that the FCCS framework might be a useful tool for fire managers to consider when ranking the potential for crown fires or evaluating the relative behaviour of crown fires in forest canopies.

scholarly journals A comparison of charcoal reflectance between crown and surface fire contexts in dry south-west USA forests

2018 ◽  
Vol 27 (6) ◽  
pp. 396 ◽  
Author(s):  
Christopher I. Roos ◽  
Andrew C. Scott
Keyword(s):  
Ponderosa Pine ◽  
Fire Severity ◽  
Prescribed Fires ◽  
Crown Fire ◽  
Fire Behaviour ◽  
Surface Fire ◽  
Surface Fires ◽  
South West ◽  
Crown Fires ◽  
Mixed Conifer Forests

The historical and modern importance of crown fires in ponderosa pine and dry mixed-conifer forests of the south-west USA has been much debated. The microscopic reflectance of charcoal in polished blocks under oil shows promise as a semiquantitative proxy for fire severity using charcoal from post-fire landscapes. We measured the reflectance of 33 modern charcoal samples to evaluate (1) whether charcoal reflectance can distinguish between crown fires and surface fires in these forests; and (2) whether surface fires with masticated fuels burn with severities similar to surface fires in grass, litter and duff fuels. The charcoal analysed was primarily collected after wildland fires under two different conditions: (l) wildfires with moderate to high severity and crown fire behaviour (n = 17), and (2) prescribed fires with low to moderate severity but no crown fire behaviour (n = 16). Statistical analysis indicates that charcoal reflectance produced in crown fires significantly differs from surface fire charcoal, particularly surface fire charcoal formed in grass, duff and litter fuels. However, charcoal produced from surface fires in masticated fuels is indistinguishable from crown fire charcoal, suggesting that fires in areas that have experienced in situ mastication may have soil impacts similar to crown fires.

Erratum: Crown fire behaviour in a northern jack pine - black spruce forest

2006 ◽  
Vol 36 (8) ◽  
pp. 2063
Author(s):  
B J Stocks ◽  
M E Alexander ◽  
B M Wotton ◽  
C N Stefner ◽  
M D Flannigan ◽  
...  
Keyword(s):  
Black Spruce ◽  
Jack Pine ◽  
Spruce Forest ◽  
Crown Fire ◽  
Fire Behaviour
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