Examining fire behavior in mesquite - acacia shrublands

2005 ◽  
Vol 14 (2) ◽  
pp. 131 ◽  
Author(s):  
Tamara J. Streeks ◽  
M. Keith Owens ◽  
Steve G. Whisenant
Keyword(s):  
Flame Temperature ◽  
Fire Behavior ◽  
Fire Spread ◽  
Flame Length ◽  
South Texas ◽  
Fire Intensity ◽  
Rate Of Spread ◽  
Vegetation Shift ◽  
Naturally Occurring ◽  
Behavior Systems

The vegetation of South Texas has changed from mesquite savanna to mixed mesquite–acacia (Prosopis–Acacia) shrubland over the last 150 years. Fire reduction, due to lack of fine fuel and suppression of naturally occurring fires, is cited as one of the primary causes for this vegetation shift. Fire behavior, primarily rate of spread and fire intensity, is poorly understood in these communities, so fire prescriptions have not been developed. We evaluated two current fire behavior systems (BEHAVE and the CSIRO fire spread and fire danger calculator) and three models developed for shrublands to determine how well they predicted rate of spread and flame length during three summer fires within mesquite–acacia shrublands. We also used geostatistical analyses to examine the spatial pattern of net heat, flame temperature and fuel characteristics. The CSIRO forest model under-predicted the rate of fire spread by an average of 5.43 m min−1 and over-predicted flame lengths by 0.2 m while the BEHAVE brush model under-predicted rate of spread by an average of 6.57 m min−1 and flame lengths by an average of 0.33 m. The three shrubland models did not consistently predict the rate of spread in these plant communities. Net heat and flame temperature were related to the amount of 10-h fuel on the site, but were not related to the cover of grasses, forbs, shrubs, or apparent continuity of fine fuel. Fuel loads were typical of South Texas shrublands, in that they were uneven and spatially inconsistent, which resulted in an unpredictable fire pattern.

scholarly journals COMPORTAMENTO DO FOGO, EM CONDIÇÕES DE LABORATÓRIO, EM COMBUSTÍVEIS PROVENIENTES DE UM POVOAMENTO DE Pinus elliottii L.

FLORESTA ◽  
2004 ◽  
Vol 34 (2) ◽  
Author(s):  
Luciana Valle De Loro ◽  
Nelson Akira Hiramatsu
Keyword(s):  
Laboratory Test ◽  
Fire Behavior ◽  
Pinus Elliottii ◽  
Fire Spread ◽  
Flame Length ◽  
Flame Height ◽  
Fire Intensity ◽  
Forest Fuels ◽  
Rate Of Spread ◽  
Fire Laboratory

De um povoamento de Pinus elliottii localizado na Fazenda Canguiri-UFPR, foram coletadas seis amostras de material combustível superficial. Este material foi separado em classes, pesado e levado para o laboratório. Efetuou-se a queima da classe acículas num leito de areia no laboratorio, em seis queimas, sendo cada queima com acículas proveniente de cada uma das amostras coletadas. Foram medidas a altura, o comprimento e a velocidade de propagação do fogo. Aplicou-se para cada queima cerca de 746 g de acículas, equivalente a 0,678 Kg/m2, com uma espessura média de 3 cm. Foram obtidos como dados médios: velocidade de propagação de 0,00423 m/s, comprimento da chama de 35,22 cm e altura de 38,79 cm, resultando numa intensidade do fogo igual a 57,07 kW/m. O resíduo médio ficou na ordem de 40,3 %. FIRE BEHAVIOR, IN LABORATORY CONDITIONS, OF FOREST FUELS FROM A Pinus elliottii L. STAND Abstract Pinus elliottii needles from a stand located at Fazenda Canguiri-UFPR were collected to run a laboratory test on fire behavior. The fuel from six samples was separated in classes, weight, and taken to the Federal University of Paraná Forest Fire Laboratory. The pine needles were burned in a sand bed. About 746.0g of each one of the six samples, equivalent to 0.678kg.m-2 and 3cm depth, were used in each fire run. Flame height and length, and rate of spread were measured. The average values obtained were: fire spread, 0,00423 m.s-1, flame length, 35,22cm, and flame height, 38,79cm. Fire intensity was of 57,07 kW.m-1 and residual fuel content about 40,3%.

Behavior of experimental grass fires vs. predictions based on Rothermel's fire model

1977 ◽  
Vol 7 (2) ◽  
pp. 357-367 ◽  
Author(s):  
Richard J. Sneeuwjagt ◽  
William H. Frandsen
Keyword(s):  
Combustion Zone ◽  
Fire Behavior ◽  
Fire Spread ◽  
Flame Length ◽  
Fuel Load ◽  
Physical Parameters ◽  
Rate Of Spread ◽  
Least Squares Fit ◽  
Zone Depth ◽  
Positive Agreement

Fire behavior observations with rates of spread up to 20 m/min (66 ft/min) have been recorded on 40 prescribed grass fires in central Washington and northern California. Physical parameters were also recorded describing the grass fuel array (fuel load, moisture content (≤ 15%), etc.), along with the wind speed (up to 8 km/h) and slope (near zero). These data were sufficient to allow a prediction of the fire spread rate, combustion zone depth, and flame length using the Rothermel fire spread model.A least squares fit of the observed versus the predicted results shows that positive agreement (slope = 1, intercept = 0) is supported for rate of spread. Flame length shows positive agreement for the intercept but not for slope. Combustion zone depth does not show positive agreement for either intercept or slope. The authors attribute the lack of positive agreement to less accurate measurements (ocular estimates) of the flame length and combustion zone depth.

scholarly journals Observed versus predicted fire behavior in an Alaskan black spruce forest ecosystem: an experimental fire case study

Fire Ecology ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Stacy A. Drury
Keyword(s):  
Black Spruce ◽  
Fire Behavior ◽  
Flame Length ◽  
Behavior Modeling ◽  
Fire Intensity ◽  
Modeling Tools ◽  
Rate Of Spread ◽  
Fire Behavior Modeling ◽  
Modeling Systems ◽  
Hazard And Risk

Abstract Background Fire managers tasked with assessing the hazard and risk of wildfire in Alaska, USA, tend to have more confidence in fire behavior prediction modeling systems developed in Canada than similar systems developed in the US. In 1992, Canadian fire behavior systems were adopted for modeling fire hazard and risk in Alaska and are used by fire suppression specialists and fire planners working within the state. However, as new US-based fire behavior modeling tools are developed, Alaskan fire managers are encouraged to adopt the use of US-based systems. Few studies exist in the scientific literature that inform fire managers as to the efficacy of fire behavior modeling tools in Alaska. In this study, I provide information to aid fire managers when tasked with deciding which system for modeling fire behavior is most appropriate for their use. On the Magitchlie Creek Fire in Alaska, I systematically collected fire behavior characteristics within a black spruce (Picea mariana [Mill.] Britton, Sterns & Poggenb.) ecosystem under head fire conditions. I compared my fire behavior observations including flame length, rate of spread, and head fire intensity with fire behavior predictions from the US fire modeling system BehavePlus, and three Canadian systems: RedAPP, CanFIRE, and the Crown Fire Initiation and Spread system (CFIS). Results All four modeling systems produced reasonable rate of spread predictions although the Canadian systems provided predictions slightly closer to the observed fire behavior. The Canadian fire behavior prediction modeling systems RedAPP and CanFIRE provided more accurate predictions of head fire intensity and fire type than BehavePlus or CFIS. Conclusions The most appropriate fire behavior modeling system for use in Alaskan black spruce ecosystems depends on what type of questions are being asked. For determining the rate of fire movement across a landscape, REDapp, CanFIRE, CFIS, or BehavePlus can all be expected to provide reasonably accurate estimates of rate of spread. If fire managers are interested in using predicted flame length or energy produced for informing decisions such as which firefighting tactics will be successful, or for evaluating the ecological impacts due to burning, then the Canadian fire modeling systems outperformed BehavePlus in this case study.

scholarly journals COMPORTAMENTO DO FOGO EM QUEIMAS CONTROLADAS DE VEGETAÇÃO DE ESTEPE NO MUNICÍPIO DE PALMEIRA, PARANÁ, BRASIL

FLORESTA ◽  
2013 ◽  
Vol 43 (4) ◽  
pp. 557
Author(s):  
Celso Darci Seger ◽  
Antonio Carlos Batista ◽  
Alexandre França Tetto ◽  
Ronaldo Viana Soares
Keyword(s):  
Fire Behavior ◽  
Fire Risk ◽  
Fire Spread ◽  
Flame Height ◽  
Fire Intensity ◽  
Average Moisture Content ◽  
Fuel Loading ◽  
Prescribed Burns ◽  
Controlled Burning ◽  
Heat Released

As queimas controladas constituem práticas de manejo utilizadas em diferentes tipos de vegetação e difundidas em vários países. No entanto, para a realização de tais práticas com segurança e eficiência é fundamental o conhecimento do comportamento do fogo. O objetivo desse trabalho foi caracterizar o comportamento do fogo em queimas controladas de vegetação Estepe Gramíneo-Lenhosa no estado do Paraná. Para isso, foi instalado um experimento no município de Palmeira, onde 20 parcelas foram queimadas, sendo metade a favor e metade contra o vento. A carga de material combustível fino estimada foi de 2,26 kg.m-2, com teor médio de umidade de 50,45%. A quantidade de material consumido pela queima foi de 1,76 kg.m-2, com uma eficiência média de queima de 76,86%. As médias obtidas, a favor e contra o vento, foram respectivamente: velocidade de propagação do fogo de 0,049 e 0,012 m.s-1, altura das chamas de 1,34 e 0,843 m, intensidade do fogo de 210,53 e 50,68 kcal.m-1.s-1 e calor liberado de 4.067,19 e 4.508,92 kcal.m-2. Os resultados permitiram concluir que as queimas controladas em vegetação de campos naturais, realizadas dentro dos critérios estabelecidos de planos de queima, são viáveis e seguras sob o ponto de vista de perigo de incêndios.Palavras chave: Queima prescrita; material combustível; intensidade do fogo; perigo de incêndios. AbstractFire behavior of prescribed burns in grassland on Palmeira county, Paraná, Brazil. The prescribed burns are practices of management used in different types of vegetation and widespread in several countries. However, to carry out such practices safely and effectively is fundamental knowledge of fire behavior. The aim of this study was to characterize the fire behavior in controlled burning of grassland vegetation in Paraná state. For this, an experiment was conducted in Palmeira County, where 20 plots were burned, half in favor and half against the wind. The estimated fine fuel loading was 2.26 kg.m-2, with average moisture content of 50.45%. The fuel consumption by burning was 1.76 kg.m-2 with an average efficiency of burning of 76.86%. The averages, for and against the wind, were: speed of fire spread of 0.049 and 0.012 m.s-1, the flame height of 1.34 m and 0.843, fire intensity of 210.53 and 50.68 kcal.m-1.s-1 and heat released from 4,067.19 and 4,508.92 kcal.m-2. The results show that the controlled burnings of grasslands vegetation, carried out within the established criteria burning plans are feasible and safe from the aspect of fire danger.Keywords: Prescribed burns; fuel loading; fire intensity; fire risk.

scholarly journals Meteorological Conditions Conducive to the Rapid Spread of the Deadly Wildfire in Eastern Attica, Greece

2019 ◽  
Vol 100 (11) ◽  
pp. 2137-2145 ◽  
Author(s):  
K. Lagouvardos ◽  
V. Kotroni ◽  
T. M. Giannaros ◽  
S. Dafis
Keyword(s):  
Fire Behavior ◽  
Fire Spread ◽  
High Rate ◽  
Contributing Factors ◽  
Suburban Areas ◽  
Rate Of Spread ◽  
Rapid Spread ◽  
Westerly Flow ◽  
Downslope Flow ◽  
Extreme Fire

AbstractOn 23 July 2018, Attica, Greece, was impacted by a major wildfire that took place in a wildland–urban interface area and exhibited extreme fire behavior, characterized by a very high rate of spread. One-hundred civilian fatalities were registered, establishing this wildfire as the second-deadliest weather-related natural disaster in Greece, following the heat wave of July 1987. On the day of the deadly wildfire, a very strong westerly flow was blowing for more than 10 h over Attica. Wind gusts up to 30–34 m s−1 occurred over the mountainous areas of Attica, with 20–25 m s−1 in the city of Athens and surrounding suburban areas. This strong westerly flow interacted with the local topography and acted as downslope flow over the eastern part of Attica, with temperatures rising up to 39°C and relative humidity dropping to 19% prior to the onset of the wildfire. These weather elements are widely acknowledged as the major contributing factors to extreme fire behavior. WRF-SFIRE correctly predicted the spatiotemporal distribution of the fire spread and demonstrated its utility for fire spread warning purposes.

Flame characteristics of wind-driven surface fires

1986 ◽  
Vol 16 (6) ◽  
pp. 1293-1300 ◽  
Author(s):  
Ralph M. Nelson Jr. ◽  
Carl W. Adkins
Keyword(s):  
Boundary Layer ◽  
Tilt Angle ◽  
Fire Behavior ◽  
Flame Length ◽  
Fire Intensity ◽  
Square Root ◽  
Pine Needle ◽  
Weather Variables ◽  
Practical Applications ◽  
Surface Fires

Twenty-two fires in a laboratory wind tunnel and 8 field fires were studied with video techniques to determine relationships between their flame characteristics and fire behavior. The laboratory fires were in pine needle fuel beds with and without an overlying stratum of live vegetation. These fuels simulated 2-year roughs in southeastern fuel types. The field bums were in 1- and 2-year roughs in similar fuels. Byram's fire intensity ranged from 98 to 590 kW/m in the laboratory, and from 355 to 2755 kW/m in the field. Flame lengths were proportional to the square root of fire intensity when fuel consumption exceeded 0.5 kg/m2, in agreement with predictions from buoyant flame theory. However, for burns in the needle layer (consumption approximately 0.5 kg/m2), flame lengths were constant at about 0.5 m, regardless of intensity. Similar values were observed on two of the field fires. It is speculated that flame length is limited by a boundary layer pattern for the overall flow, even though the flames themselves did not exhibit boundary layer characteristics. Also, laboratory correlations of flame tilt angle and fire intensity with other fire and weather variables depart from buoyant flame theory. Further study under field conditions is needed before relationships involving flame tilt angle, fire intensity, and wind speed should be used in practical applications.

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.

Estimation of Byram’s Fire Intensity and Rate of Spread from Spaceborne Remote Sensing Data in a Savanna Landscape

Fire ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 65
Author(s):  
Gernot Ruecker ◽  
David Leimbach ◽  
Joachim Tiemann
Keyword(s):  
Remote Sensing ◽  
Fuel Consumption ◽  
Spatial Resolution ◽  
Fire Behavior ◽  
Remote Sensing Data ◽  
Fire Intensity ◽  
Rate Of Spread ◽  
Radiative Power ◽  
Sentinel 2 ◽  
Fire Radiative Power

Fire behavior is well described by a fire’s direction, rate of spread, and its energy release rate. Fire intensity as defined by Byram (1959) is the most commonly used term describing fire behavior in the wildfire community. It is, however, difficult to observe from space. Here, we assess fire spread and fire radiative power using infrared sensors with different spatial, spectral and temporal resolutions. The sensors used offer either high spatial resolution (Sentinel-2) for fire detection, but a low temporal resolution, moderate spatial resolution and daily observations (VIIRS), and high temporal resolution with low spatial resolution and fire radiative power retrievals (Meteosat SEVIRI). We extracted fire fronts from Sentinel-2 (using the shortwave infrared bands) and use the available fire products for S-NPP VIIRS and Meteosat SEVIRI. Rate of spread was analyzed by measuring the displacement of fire fronts between the mid-morning Sentinel-2 overpasses and the early afternoon VIIRS overpasses. We retrieved FRP from 15-min Meteosat SEVIRI observations and estimated total fire radiative energy release over the observed fire fronts. This was then converted to total fuel consumption, and, by making use of Sentinel-2-derived burned area, to fuel consumption per unit area. Using rate of spread and fuel consumption per unit area, Byram’s fire intensity could be derived. We tested this approach on a small number of fires in a frequently burning West African savanna landscape. Comparison to field experiments in the area showed similar numbers between field observations and remote-sensing-derived estimates. To the authors’ knowledge, this is the first direct estimate of Byram’s fire intensity from spaceborne remote sensing data. Shortcomings of the presented approach, foundations of an error budget, and potential further development, also considering upcoming sensor systems, are discussed.

Fire spread in chaparral – a comparison of laboratory data and model predictions in burning live fuels

2016 ◽  
Vol 25 (9) ◽  
pp. 980 ◽  
Author(s):  
David R. Weise ◽  
Eunmo Koo ◽  
Xiangyang Zhou ◽  
Shankar Mahalingam ◽  
Frédéric Morandini ◽  
...  
Keyword(s):  
Laboratory Data ◽  
Slope Angle ◽  
Fire Spread ◽  
Flame Length ◽  
Important Variable ◽  
Rate Of Spread ◽  
Model Predictions ◽  
Physically Based ◽  
Live Fuels ◽  
Physically Based Models

Fire behaviour data from 240 laboratory fires in high-density live chaparral fuel beds were compared with model predictions. Logistic regression was used to develop a model to predict fire spread success in the fuel beds and linear regression was used to predict rate of spread. Predictions from the Rothermel equation and three proposed changes as well as two physically based models were compared with observed spread rates of spread. Flame length–fireline intensity relationships were compared with flame length data. Wind was the most important variable related to spread success. Air temperature, live fuel moisture content, slope angle and fuel bed bulk density were significantly related to spread rate. A flame length–fireline intensity model for Galician shrub fuels was similar to the chaparral data. The Rothermel model failed to predict fire spread in nearly all of the fires that spread using default values. Increasing the moisture of extinction marginally improved its performance. Modifications proposed by Cohen, Wilson and Catchpole also improved predictions. The models successfully predicted fire spread 49 to 69% of the time. Only the physical model predictions fell within a factor of two of actual rates. Mean bias of most models was close to zero. Physically based models generally performed better than empirical models and are recommended for further study.

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

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