RATES OF SURFACE FIRE SPREAD IN A YOUNG CALABRIAN PINE (Pinus brutia Ten.) PLANTATION (original) (raw)
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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.
Modeling surface fire rate of spread within a thinned Anatolian black pine stand in Turkey
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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...
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.
Fire development from a point source in surface fuels of a mature Anatolian black pine stand
Turkish Journal of Agriculture and Forestry, 2007
A total of 28 line and 24 point-source fires were ignited under varying weather and fuel loading conditions in Anatolian black pine (Pinus nigra J.F.Arnold subsp. nigra var. caramanica (Loudon) Rehder) stands. Relationships between the rate of fire spread and fuel and weather conditions were determined with correlation and regression analyses. The rate of fire spread ranged from 0.12 to 1.20 m min-1 in line fires. In the ignition, transition, and steady state phases of point-source fires, the rate of fire spread ranged from 0.04 to 0.78 m min-1 , from 0.11 to 0.59 m min-1 , and from 0.08 to 0.99 m min-1 , respectively. Surface fuel loading ranged from 1.27 to 2.45 kg m-2 for line fire and from 1.56 to 2.67 kg m-2 for point-source fire. The results showed that the rate of fire spread was closely related to wind speed and fuel moisture content for line and point-source fires. The linear prediction for wind conditions estimates that equilibrium spread rates may be achieved within 25 min after the ignition of pointsource fires.
Fire behaviour and severity in a maritime pine stand under differing fuel conditions
Annals of Forest Science, 2004
An experimental fire was conducted in the summer in a 28-year old maritime pine (Pinus pinaster) plantation in northeastern Portugal. Fuel conditions within the stand were age-dependent and comprised four situations: treated with prescribed fire at differing times, respectively 2, 3, and 13 years before the study, and undisturbed, where fuel accumulation time equalled stand age. The rate of fire spread did not respond to factors other than wind speed, in spite of the fuel-complex diversity. A high-intensity fire involving partially or totally the tree canopy and killing all trees was experienced in the older treatment area and in the untreated part of the stand, but the benefits of fuel management were still detectable in the former. Surface fire intensity, crown fire potential and fire severity (including tree mortality) were drastically reduced where prescribed fire had been carried recently. Fuel and fire management implications are discussed. fire behaviour / fire severity / experimental fire / fuel management / Pinus pinaster Résumé-Comportement et sévérité d'un feu dans un peuplement de pin maritime pour des conditions de végétation variées. Un feu expérimental a été réalisé pendant l'été dans une plantation de pin maritime (Pinus pinaster) âgé de 28 ans, situé au Nord-Est du Portugal. Les conditions du combustible dans le peuplement étaient dépendantes de la période d'accumulation, avec quatre situations; trois traitées avec brûlage dirigé en différents moments, respectivement 2, 3, et 13 ans avant l'étude, et une jamais traitée, où le temps d'accumulation de combustible était égal à l'âge du peuplement. Malgré la diversité des caractéristiques du combustible, la vitesse de propagation du feu n'a été influencée que par la vitesse du vent. La partie du peuplement traitée 13 ans auparavant et celle non traitée ont connu un feu d'une intensité élevée, qui a touché partiellement ou totalement le couvert arboré et tué tous les arbres, mais les effets bénéfiques du traitement furent encore décelables dans la partie brûlée antérieurement. En revanche, l'intensité du feu de surface, le potentiel à engendrer un feu de cime et la sévérité du feu (y compris la mortalité des arbres) ont été fortement réduits dans les zones où un brûlage dirigé avait été conduit récemment. Les conséquences en terme de gestion du combustible et du feu sont discutées. comportement du feu / sévérité du feu / feu experimental / gestion du combustible / Pinus pinaster
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.
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.
Forest Fire Studies on Fire Behaviour: Key Topics and Their Importance
INCOS2018, 2018
Every year thousands of hectares of forest fires occur in Mediterranean countries and there are major damages. The effects of forest fires are quite extensive when considered from the organism to landscape level in the short term and long term. Forest fires show different behaviours depending on where they come from and the factors that affect it with the flammable materials. Forest fire triangles provide important framework to study the forest fires. Flammable materials can be changed and controlled by time and space. Therefore, they are separated from meteorological and topographic factors that cannot be controlled. The main types of forest fire are ground, surface and crown fire. These types of fire reveal differences in terms of the danger and its fighting. In this study, the main topics of forest fire behaviour and fuel model researches and their importance will be present. The research of forest fire requires the need to study in very different areas. The studies required for the development of fire propagation and fuel models in fire management systems is gradually increasing. Estimations of typical forest fire features such as fire propagation ratio, fuel consumption, fire intensity, and flame size utilize fuel loading values, as well as spatial heterogeneity, which affects these factors. A significant feature of forest fire risk analyses is the fact that cause-based ignition, fire behaviour, and fire management have multivariate uncertainty factors. All of these research needs are basic components of the fire decision support system, which is a essential prerequisite of an effective fire management system.
International Journal of Wildland Fire, 2008
A dataset of 42 experimental fires in maritime pine (Pinus pinaster Ait.) stands was used to develop fuel models to describe pine litter and understorey surface fuel complexes. A backtracking calibration procedure quantified the surface fuel bed characteristics that best explained the observed rate of fire spread. The study suggested the need for two distinct fuel models to adequately characterise the variability in fire behaviour in this fuel type. In these heterogeneous fuel beds the fuel models do not necessarily represent the inventoried ...