Fire development from a point source in surface fuels of a mature Anatolian black pine stand (original) (raw)
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Modeling surface fire rate of spread within a thinned Anatolian black pine stand in Turkey
Forest Systems
Aim of the study: To develop regression models for estimating the rate of surface fire spread in a thinned even-aged black pine stand (Pinus nigra J.F. Arnold subsp. nigra var. caramanica (Loudon) Rehder).Area of the study: The study was carried out within a thinned black pine forest located in the Kastamonu Forest District, northwestern Turkey. The study area is located at 546819, 4577880 UTM.Material and methods: A total of 33 small scale surface fires were ignited under varying weather and fuel conditions. Line ignition was used during the burnings. Surface fuels consisted generally of thinned material (needle+branches).Main results: Within the stand, surface fuel loading ranged from 3.0 to 10.2 kg/m2. Wind speed ranged from 0.3 to 8.4 km/h. Needle moisture content ranged from 8 to 15%. The rate of fire spread ranged from 0.47 to 6.92 m/min. Relationships between the rate of fire spread and fuel and weather conditions were determined through regression analyses.Research highlight...
RATES OF SURFACE FIRE SPREAD IN A YOUNG CALABRIAN PINE (Pinus brutia Ten.) PLANTATION
Environmental Engineering and Management Journal, 2012
Fire behaviour data and models are essential in modern fire management. Thirty five experimental line-ignited fires were carried out in a young calabrian pine (Pinus brutia Ten.) stand with the objective of modelling the rate of surface fire spread. Relationships between rate of fire spread, and fuel, weather and topographical conditions were established by correlation and regression analyses. Dead fine fuel loading ranged from 0.19 to 0.68 kg m-2. Rate of fire spread varied from 0.3 to 3.75 m min-1 and flame length ranged from 5 cm to 55 cm. Rate of fire spread equations were generated that described the relationships of spread rate with fuel and weather conditions, using linear regression models. Wind speed had a dominant effect on rate of surface fire spread and explained 72% (P < 0.01) of the observed variation.
Fire risk in Austrian pine (Pinus nigra) plantations under various temperature and wind conditions
Acta Botanica Croatica, 2000
The Austrian pine (Pinus nigra), an introduced conifer in Hungary, forms a highly flammable vegetation type. The fire risk of such stands was examined using McArthur's empirical forest fire danger model. Our study focused on the effects of temperature and wind speed on fire behaviour. By keeping the input parameters of the model constant while changing temperature and wind speed within a specified interval the resulting fire danger index (FDI) and fire behaviour were examined. The applied fixed parameters were: 30°C temperature, 30% relative humidity, 30 km h -1 wind speed, 30 degree of slope and drought factor value 10. The annual trends of the Byram-Keetch drought index (BKDI) and the drought factor were also calculated. Our results show that increasing temperature and wind speed raises the FDI, flame height, rate of fire spread (ROS) and spotting distance. The amount of fuel does not influence the FDI, but increasing the amount promotes the ROS and raises the flame height. Wind speed was the most important factor in the ROS. A serious fire risk of these plantations was determined. The reliability of McArthur's model was proved by comparison of our results with experimental laboratory data based on literature.
Some Parameters Affecting Fire Behavior in Anatolian Black Pine Slash
Turkish Journal of Agriculture and Forestry, 2008
Each action taken in a forest stand has an effect on fuel properties (Bilgili, 2003). Silvicultural interventions, for example, dramatically alter not only the slash fuel properties but also stand structure parameters, which play an important role in fire behavior.
Empirical modelling of surface fire behaviour in maritime pine stands
International Journal of Wildland Fire, 2009
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.
In this study we establish quantitative relationships between important fire behaviour descriptors and its environment, that are applicable to low-to-moderately intense fires in maritime pine (Pinus pinaster) stands. Sustained fire propagation is presented as a function of fuel moisture content, wind speed, air temperature and fuel type. The thresholds for marginal fire spread depend on fuel moisture, time since rain and propagation mode (backfire or headfire). The available models to predict fire spread rate proved inadequate for operational use in prescribed fire, and an empirical model based on wind speed, dead fuel moisture content, slope, understory height and fuel type is developed, while backing spread rate is satisfactorily predicted by dead fuel moisture content and understory vegetation cover. Flame length is related to Byram's fireline intensity, and, in alternative, to spread rate, fine fuel load and fuel moisture content. Flame tilt angle is described in terms of wind speed and fine fuel load, or as a function of wind speed and flame height.
Annals of Forest Science, 2007
Canopy fuel characteristics that influence the initiation and spread of crown fires were measured in representative Aleppo pine (Pinus halepensis Mill.) stands in Greece. Vertical distribution profiles of canopy fuel load, canopy base height and canopy bulk density are presented. Aleppo pine canopy fuels are characterized by low canopy base height (3.0–6.5 m), while available canopy fuel load (0.96–1.80 kg/m2) and canopy bulk density (0.09–0.22 kg/m3) values are similar to other conifers worldwide. Crown fire behavior (probability of crown fire initiation, crown fire type, rate of spread, fireline intensity and flame length) in Aleppo pine stands with various understory fuel types was simulated with the most updated crown fire models. The probability of crown fire initiation was high even under moderate burning conditions, mainly due to the low canopy base height and the heavy surface fuel load. Passive crown fires resulted mostly in uneven aged stands, while even aged stands gave high intensity active crown fires. Assessment of canopy fuel characteristics and potential crown fire behavior can be useful in fuel management and fire suppression planning. Les caractéristiques des combustibles qui influencent le démarrage et la propagation des feux de couronnes ont été mesurées dans des peuplements représentatifs de Pinus halepensis Mill. en Grèce. Des profils verticaux de la charge en combustible de la canopée, la hauteur de la base de la canopée et la densité volumique de la canopée sont présentés. La charge combustible de la canopée est caractérisée par une faible hauteur de la base de la canopée (3,0–6,5 m), tandis que la charge en combustible disponible (0,96–1,80 kg/m2) et la densité volumique de la canopée (0,09–0,22 kg/m3) sont similaires à celles des autres conifères dans le monde. Le comportement du feu de couronne (probabilité de démarrage du feu dans les couronnes, type de feu de couronne, taux de propagation, intensité de la ligne de feu et longueur des flammes) dans les peuplements de Pinus halepensis avec différents types de combustibles de sous-bois a été simulé avec le maximum de modèles actuels de feux de couronnes. La probabilité de démarrage de feu de couronne était forte même en conditions de faible embrasement, principalement en relation avec la faible hauteur de la base des couronnes et la forte charge en combustible au sol. Des feux passifs de couronnes se produisent principalement dans les peuplements inéquiennes tandis que les peuplements équiennes ont présenté de fortes intensités de feux actifs de couronnes. L’évaluation des caractéristiques des combustibles de la canopée et le comportement du potentiel de feu peuvent être très utiles pour la gestion des combustibles et la planification de la lutte contre les feux.
Canadian Journal of Forest Research, 2008
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.
Ignition characteristics of forest species in relation to thermal analysis data
Thermochimica Acta, 2002
The ignitability of various forest species was measured with a specifically designed apparatus, under precisely controlled temperature and airflow conditions. The ignitability tests were based on ignition delay time versus temperature measurements using five different forest species: Pinus halepensis, Pistacia lentiscus, Cupressus sempervirens, Olea europaea, Cistus incanus. These species are common in the Mediterranean region and frequently devastated by forest fires. The ignition characteristics of the forest fuels examined were related to thermogravimetric analysis data. The DTG curves showed that the mass changes related to cellulose decomposition in the temperature range of 320-370 8C are greatly responsible for the ignition behavior of the species tested. In addition, the mass of volatiles evolving between 120-160 8C has a significant effect on the ignitability. On the contrary, the inorganic ash content of forest fuels, measured by atomic absorption spectroscopy, seems to play an insignificant role on the ignitability characteristics of the forest fuels examined.