scholarly journals Examining fuel treatment longevity through experimental and simulated surface fire behaviour: a maritime pine case study

2009 ◽  
Vol 39 (12) ◽  
pp. 2529-2535 ◽  
Author(s):  
Paulo M. Fernandes
Keyword(s):  
Treatment Effectiveness ◽  
Residual Effect ◽  
Fire Spread ◽  
Flame Length ◽  
Maritime Pine ◽  
Fire Behaviour ◽  
Fuel Treatment ◽  
Surface Fire ◽  
Fire Modelling ◽  
The Difference

The adequate prediction of fire behaviour characteristics for both scientific and management objectives is deeply impacted by the performance of fire behaviour models. Both the lack of experimentation and limitations in fire modelling constrain current understanding of fuel treatment effectiveness and longevity. The residual effect of a 10-year-old prescribed fire was quantified by both simulating fire behaviour and observing real-world fire behaviour in treated (T10) and untreated (U25) fuels in a 25-year-old maritime pine ( Pinus pinaster Aiton) stand in Portugal. Fire behaviour characteristics were measured in experimental surface fires (n = 36). Surface-fire behaviour was simulated using BehavePlus with custom fuel models for T10, U25, and U15 (the untreated fuel complex when the stand was 15 years old). The T10 fuel complex had significantly less decomposing litter load and shrub cover and load than the U25 fuel complex. The observed rate of fire spread did not differ between fuel complexes after accounting for the effects of other environmental variables, but flame length in T10 was 25% lower than that in U25. BehavePlus simulations contradicted the difference observed in flame length. Inconsistent and misleading assessments of fuel treatment effectiveness with detrimental impacts on the outcomes of fuel management may result from the generalized practice of solely using simulation in lieu of experimental fires.

Using fuel and weather variables to predict the sustainability of surface fire spread in maritime pine stands

2008 ◽  
Vol 38 (2) ◽  
pp. 190-201 ◽  
Author(s):  
Paulo M. Fernandes ◽  
Hermínio Botelho ◽  
Francisco Rego ◽  
Carlos Loureiro
Keyword(s):  
Moisture Content ◽  
Logistic Model ◽  
Fire Spread ◽  
Maritime Pine ◽  
Fuel Moisture ◽  
Fuel Type ◽  
Weather Variables ◽  
Surface Fire ◽  
Pinus Pinaster Ait ◽  
Fuel Moisture Content

Thresholds for surface fire spread were examined in maritime pine ( Pinus pinaster Ait.) stands in northern Portugal. Fire sustainability was assessed after ignition of 2 m fire lines or in larger burns conducted in 10–15 m wide plots. The experiments were carried out from November to June in three fuel types: litter, litter plus shrubs, and litter with a nonwoody understorey. Moisture content of fine dead fuels, on-site weather variables, and descriptors of the fuel complex all had a highly significant influence on the probability of self-sustaining fire spread. A logistic model based solely on fuel moisture content correctly classified the fire sustainability status of 88% of the observations. Nonetheless, the subjectivity of the moisture of extinction concept was apparent, and further accuracy was achieved by the consecutive addition of fire spread direction (forward or backward), fuel type, and ambient temperature. Fully sustained fire spread, in opposition to marginal burns with broken fire fronts, was similarly dependent on fuel moisture but was affected also by fire spread direction and time since rain. The models can benefit fire research and fire management operations but can be made more practical if integrated in a fire danger rating system.

Sensitivity of a surface fire spread model and associated fire behaviour fuel models to changes in live fuel moisture

2007 ◽  
Vol 16 (4) ◽  
pp. 503 ◽  
Author(s):  
W. Matt Jolly
Keyword(s):  
Fire Spread ◽  
Fuel Moisture ◽  
Fire Behaviour ◽  
Surface Fire ◽  
Fuel Model ◽  
Spread Model ◽  
Fuel Models ◽  
Live Fuel Moisture ◽  
Behaviour Models ◽  
Fire Spread Model

Fire behaviour models are used to assess the potential characteristics of wildland fires such as rates of spread, fireline intensity and flame length. These calculations help support fire management strategies while keeping fireline personnel safe. Live fuel moisture is an important component of fire behaviour models but the sensitivity of existing models to live fuel moisture has not been thoroughly evaluated. The Rothermel surface fire spread model was used to estimate key surface fire behaviour values over a range of live fuel moistures for all 53 standard fuel models. Fire behaviour characteristics are shown to be highly sensitive to live fuel moisture but the response is fuel model dependent. In many cases, small changes in live fuel moisture elicit drastic changes in predicted fire behaviour. These large changes are a result of a combination of the model-calculated live fuel moisture of extinction, the effective wind speed limit and the dynamic load transfer function of some of the fuel models tested. Surface fire spread model sensitivity to live fuel moisture changes is discussed in the context of predicted fire fighter safety zone area because the area of a predicted safety zone may increase by an order of magnitude for a 10% decrease in live fuel moisture depending on the fuel model chosen.

Empirical modelling of surface fire behaviour in maritime pine stands

2009 ◽  
Vol 18 (6) ◽  
pp. 698 ◽  
Author(s):  
Paulo M. Fernandes ◽  
Hermínio S. Botelho ◽  
Francisco C. Rego ◽  
Carlos Loureiro
Keyword(s):  
Wind Speed ◽  
Moisture Content ◽  
Fire Spread ◽  
Fire Intensity ◽  
Fuel Moisture ◽  
Fire Behaviour ◽  
Spread Rate ◽  
Surface Fire ◽  
Rate Of Spread ◽  
Fuel Moisture Content

An experimental burning program took place in maritime pine (Pinus pinaster Ait.) stands in Portugal to increase the understanding of surface fire behaviour under mild weather. The spread rate and flame geometry of the forward and backward sections of a line-ignited fire front were measured in 94 plots 10–15 m wide. Measured head fire rate of spread, flame length and Byram’s fire intensity varied respectively in the intervals of 0.3–13.9 m min–1, 0.1–4.2 m and 30–3527 kW m–1. Fire behaviour was modelled through an empirical approach. Rate of forward fire spread was described as a function of surface wind speed, terrain slope, moisture content of fine dead surface fuel, and fuel height, while back fire spread rate was correlated with fuel moisture content and cover of understorey vegetation. Flame dimensions were related to Byram’s fire intensity but relationships with rate of spread and fine dead surface fuel load and moisture are preferred, particularly for the head fire. The equations are expected to be more reliable when wind speed and slope are less than 8 km h–1 and 15°, and when fuel moisture content is higher than 12%. The results offer a quantitative basis for prescribed fire management.

Effects of salvage logging and pile-and-burn on fuel loading, potential fire behaviour, fuel consumption and emissions

2013 ◽  
Vol 22 (6) ◽  
pp. 757 ◽  
Author(s):  
Morris C. Johnson ◽  
Jessica E. Halofsky ◽  
David L. Peterson
Keyword(s):  
Fuel Consumption ◽  
Field Measurements ◽  
Flame Length ◽  
Pollutant Emissions ◽  
Fire Behaviour ◽  
Treatment Combination ◽  
Fuel Loading ◽  
Fuel Treatment ◽  
Salvage Logging ◽  
Study Results

We used a combination of field measurements and simulation modelling to quantify the effects of salvage logging, and a combination of salvage logging and pile-and-burn fuel surface fuel treatment (treatment combination), on fuel loadings, fire behaviour, fuel consumption and pollutant emissions at three points in time: post-windstorm (before salvage logging), post-salvage logging and post-surface fuel treatment (pile-and-burn). Salvage logging and the treatment combination significantly reduced fuel loadings, fuelbed depth and smoke emissions. Salvage logging and the treatment combination reduced total surface fuel loading (sound plus rotten) by 73 and 77%. All fine woody fuels (<7.6cm) were significantly reduced by salvage logging and the treatment combination. In contrast, there was significant increase in the 1000-h (7.6–22.9cm) fuel loading. Salvage logging and the treatment combination reduced mean fuelbed depth by 38 and 65%. Salvage logging reduced PM2.5 emissions by 19%, and the treatment combination reduced emissions by 27%. Salvage logging and the treatment combination reduced PM10 emissions by 19 and 28%. We observed monotonic changes in flame length, reaction intensity and rate-of-spread after salvage logging and treatment combination. Study results illustrate potential differences between the effects of salvage logging after windstorms and the effects of salvage logging after wildfire.

Interdependencies between flame length and fireline intensity in predicting crown fire initiation and crown scorch height

2012 ◽  
Vol 21 (2) ◽  
pp. 95 ◽  
Author(s):  
Martin E. Alexander ◽  
Miguel G. Cruz
Keyword(s):  
Wildland Fire ◽  
Stem Bark ◽  
Flame Length ◽  
Flame Height ◽  
Crown Fire ◽  
Fire Behaviour ◽  
Surface Fire ◽  
Crown Scorch ◽  
Fire Initiation ◽  
Bark Char

This state-of-knowledge review examines some of the underlying assumptions and limitations associated with the inter-relationships among four widely used descriptors of surface fire behaviour and post-fire impacts in wildland fire science and management, namely Byram’s fireline intensity, flame length, stem-bark char height and crown scorch height. More specifically, the following topical areas are critically examined based on a comprehensive review of the pertinent literature: (i) estimating fireline intensity from flame length; (ii) substituting flame length for fireline intensity in Van Wagner’s crown fire initiation model; (iii) the validity of linkages between the Rothermel surface fire behaviour and Van Wagner’s crown scorch height models; (iv) estimating flame height from post-fire observations of stem-bark char height; and (v) estimating fireline intensity from post-fire observations of crown scorch height. There has been an overwhelming tendency within the wildland fire community to regard Byram’s flame length–fireline intensity and Van Wagner’s crown scorch height–fireline intensity models as universal in nature. However, research has subsequently shown that such linkages among fire behaviour and post-fire impact characteristics are in fact strongly influenced by fuelbed structure, thereby necessitating consideration of fuel complex specific-type models of such relationships.

Corrigendum to: Interdependencies between flame length and fireline intensity in predicting crown fire initiation and crown scorch height

2017 ◽  
Vol 26 (4) ◽  
pp. 345 ◽  
Author(s):  
Martin E. Alexander ◽  
Miguel G. Cruz
Keyword(s):  
Wildland Fire ◽  
Stem Bark ◽  
Flame Length ◽  
Flame Height ◽  
Crown Fire ◽  
Fire Behaviour ◽  
Surface Fire ◽  
Crown Scorch ◽  
Fire Initiation ◽  
Bark Char

This state-of-knowledge review examines some of the underlying assumptions and limitations associated with the inter-relationships among four widely used descriptors of surface fire behaviour and post-fire impacts in wildland fire science and management, namely Byram's fireline intensity, flame length, stem-bark char height and crown scorch height. More specifically, the following topical areas are critically examined based on a comprehensive review of the pertinent literature: (i) estimating fireline intensity from flame length; (ii) substituting flame length for fireline intensity in Van Wagner's crown fire initiation model; (iii) the validity of linkages between the Rothermel surface fire behaviour and Van Wagner's crown scorch height models; (iv) estimating flame height from post-fire observations of stem-bark char height; and (v) estimating fireline intensity from post-fire observations of crown scorch height. There has been an overwhelming tendency within the wildland fire community to regard Byram's flame length–fireline intensity and Van Wagner's crown scorch height–fireline intensity models as universal in nature. However, research has subsequently shown that such linkages among fire behaviour and post-fire impact characteristics are in fact strongly influenced by fuelbed structure, thereby necessitating consideration of fuel complex specific-type models of such relationships.

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.

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.

scholarly journals Modelling and analyzing the surface fire behaviour in Hyrcanian forest of Iran

2014 ◽  
Vol 60 (No. 9) ◽  
pp. 353-362 ◽  
Author(s):  
H. Aghajani ◽  
A. Fallah ◽  
S. Fazlollah Emadian
Keyword(s):  
Forest Floor ◽  
Forest Litter ◽  
Fire Spread ◽  
Burned Area ◽  
Hyrcanian Forest ◽  
Fire Behaviour ◽  
Surface Fire ◽  
Contour Lines ◽  
Slope Wind ◽  
The Impact

The purpose of this study was to assess the forest fire behaviour and investigate the impact of different parameters on the spread of surface fire in the Hyrcanian forest of Iran. Surface fire was simulated using mathematical models in Microsoft Visual Basic 6.0 environment during a 30-minute time period. Several parameters that contributed to the speed of surface fire such as slope, wind velocity and litter thickness in the forest floor and various types of forest litter associated with hornbeam (Carpinus betulus L.), Persian ironwood (Parrotia persica C.A.M), beech (Fagus orientalis L.) and maple (Acer velutinum L.) were investigated. The results indicated that the maximum burned area was associated with beech litter. Forest surface fire demonstrated similar behaviour for the litter types of beech and Ironwood, whereas in the case of maple and hornbeam litters, the fire spread parallelly and perpendicularly to contour lines, respectively. The burned area increased in an irregular pattern as the forest floor slope gradient was increased. Moreover, the skewed pattern of the burned area for the forest floor composed of maple, beech, ironwood andhornbeam litter was described as high, low, moderate and low, respectively. The fire spread angle in forest floor associated with maple and beech litters changed with litter thickness. Finally, litter thickness had a significant effect on the direction of fire spread and this was more prominent with hornbeam litter. &nbsp;

Erratum: Using fuel and weather variables to predict the sustainability of surface fire spread in maritime pine stands

2009 ◽  
Vol 39 (1) ◽  
pp. 198-198
Author(s):  
Paulo M. Fernandes ◽  
Hermínio Botelho ◽  
Francisco Rego ◽  
Carlos Loureiro
Keyword(s):  
Fire Spread ◽  
Maritime Pine ◽  
Weather Variables ◽  
Surface Fire ◽  
Pine Stands
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