MODELING OF PROCESSES OF OCCURRENCE AND SPREAD OF FIRES IN GRASS ECOSYSTEMS

Formulation of the problem. Fires in natural ecosystems are emergency that leads to a violation of the balance of the environment and human life. Along with forest fires, the consequences of which are significant material damage and a detrimental effect on the atmosphere, grass fires occur, which entail the destruction of phytocenoses and representatives of the animal world. Prevention of grass fires is an urgent task that requires research in this direction. The purpose of the work is to assess the fire hazard in areas dominated by creeping pyrium (Elytrigia repens) as a representative of the widespread species of grass vegetation in meadows, pastures, agricultural areas that are not exploited, etc., under meteorological conditions favorable for the spread of fires, and the humidity of combustible material, as well as the geometric parameters of plants. Description of the material. A study of the fire hazard of areas covered by grassy vegetation from the average grass height and wind speed using computer simulation of a grass fire in the environment of the Wildland-Urban Fire Dynamics Simulator (WFDS) physical model was carried out. The fire hazard was estimated for creeping wheatgrass with an average plant height of 20, 40, 60, 80 and 100 cm from the propagation speed of the fire front, taking into account wind speeds of 0, 1, 2, 3, 4, 6, 8 m/s. Cases are noted in which, under the influence of weather conditions, ignition did not occur, but only ignition of combustible material was observed without further spread of fire, as well as cases of occurrence and spread of burning over the entire area of grass cover. Results. Based on the simulation results, the values of the propagation rates of the fire front in grassy areas were obtained. The fire speed is greatest at a height of grass cover of 40 cm and a wind speed of 3 m/s, and the lowest at a height of grass cover of 60 cm and a wind speed of 0 m/s. A relationship is established that describes the dynamics of a fire along the height of the grass cover as a combustible material. Scientific novelty. It has been established that in terms of the speed of propagation of the fire front, the greatest fire hazard of the grassland of creeping grass is observed at an average grass height of 40 cm and a wind speed of 3 m/s, which is more than 5 times this figure compared to a grass height of 60 cm in the absence of wind.

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FIRE BEHAVIOR VARIABLES AND HAZARD INDICES OF FOREST FIRES

Revista Árvore ◽

10.1590/1806-90882018000300006 ◽

2018 ◽

Vol 42 (3) ◽

Cited By ~ 1

Author(s):

Fillipe Tamiozzo Pereira Torres ◽

Gumercindo Souza Lima ◽

Bráulio Furtado Alvares

Keyword(s):

Forest Fires ◽

Fire Hazard ◽

Fire Behavior ◽

Meteorological Conditions ◽

Fire Weather ◽

Fuel Moisture ◽

Combustible Material ◽

Hazard Indices ◽

Weather Index ◽

Fire Weather Index

ABSTRACT The objective of this study was to evaluate the performance of different fire hazard indices (FWI, FMA, FMA+, Telicyn, Nesterov, P-EVAP and EVAP/P), taking into account the fire behavior variables and the susceptibility to fire expressed by the moisture of the combustible material. For this purpose, controlled burnings were performed at different times and information was recorded in relation to the meteorological conditions, characteristics of the combustible material and fire behavior variables. In general, all the indices presented significant correlations with both the moisture of the combustible material and the behavior of the fire. However, in general, a higher linear correlation of components of the Canadian Fire Weather Index (FWI) system was observed in predicting fire behavior and EVAP / P index in fuel moisture. The consistency of the correlations between the various indices and the analyzed variables makes the methodology possible to be used in any place, facilitating the decision making in regions where records of occurrences of forest fires are absent or unreliable.

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Empirical Research on Climate Warming Risks for Forest Fires: A Case Study of Grade I Forest Fire Danger Zone, Sichuan Province, China

Sustainability ◽

10.3390/su13147773 ◽

2021 ◽

Vol 13 (14) ◽

pp. 7773

Author(s):

San Wang ◽

Hongli Li ◽

Shukui Niu

Keyword(s):

Wind Speed ◽

Forest Fire ◽

Climate Warming ◽

Forest Fires ◽

Meteorological Factors ◽

Sichuan Province ◽

Danger Zone ◽

Climatic Regions ◽

Area Burned ◽

Forest Fire Danger

The Sichuan province is a key area for forest and grassland fire prevention in China. Forest resources contribute significantly not only to the biological gene pool in the mid latitudes but also in reducing the concentration of greenhouse gases and slowing down global warming. To study and forecast forest fire change trends in a grade I forest fire danger zone in the Sichuan province under climate change, the dynamic impacts of meteorological factors on forest fires in different climatic regions were explored and a model between them was established by using an integral regression in this study. The results showed that the dominant factor behind the area burned was wind speed in three climatic regions, particularly in Ganzi and A’ba with plateau climates. In Ganzi and A’ba, precipitation was mainly responsible for controlling the number of forest fires while it was mainly affected by temperature in Panzhihua and Liangshan with semi-humid subtropical mountain climates. Moreover, the synergistic effect of temperature, precipitation and wind speed was responsible in basin mid-subtropical humid climates with Chengdu as the center and the influence of temperature was slightly higher. The differential forest fire response to meteorological factors was observed in different climatic regions but there was some regularity. The influence of monthly precipitation in the autumn on the area burned in each climatic region was more significant than in other seasons, which verified the hypothesis of a precipitation lag effect. Climate warming and the combined impact of warming effects may lead to more frequent and severe fires.

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Fine-Scale Fire Spread in Pine Straw

Fire ◽

10.3390/fire4040069 ◽

2021 ◽

Vol 4 (4) ◽

pp. 69

Author(s):

Daryn Sagel ◽

Kevin Speer ◽

Scott Pokswinski ◽

Bryan Quaife

Keyword(s):

Fire Spread ◽

Small Scale ◽

Natural Setting ◽

Fine Scale ◽

Prescribed Burn ◽

Fire Dynamics ◽

Rate Of Spread ◽

Scale Models ◽

Fire Front ◽

Visible Images

Most wildland and prescribed fire spread occurs through ground fuels, and the rate of spread (RoS) in such environments is often summarized with empirical models that assume uniform environmental conditions and produce a unique RoS. On the other hand, representing the effects of local, small-scale variations of fuel and wind experienced in the field is challenging and, for landscape-scale models, impractical. Moreover, the level of uncertainty associated with characterizing RoS and flame dynamics in the presence of turbulent flow demonstrates the need for further understanding of fire dynamics at small scales in realistic settings. This work describes adapted computer vision techniques used to form fine-scale measurements of the spatially and temporally varying RoS in a natural setting. These algorithms are applied to infrared and visible images of a small-scale prescribed burn of a quasi-homogeneous pine needle bed under stationary wind conditions. A large number of distinct fire front displacements are then used statistically to analyze the fire spread. We find that the fine-scale forward RoS is characterized by an exponential distribution, suggesting a model for fire spread as a random process at this scale.

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ABWiSE v1.0: Toward and Agent-Based Approach to Simulating Wildfire Spread

10.5194/nhess-2021-179 ◽

2021 ◽

Author(s):

Jeffrey Katan ◽

Liliana Perez

Keyword(s):

Human Life ◽

Simulation Models ◽

Empirical Models ◽

Physical Models ◽

Fire Behaviour ◽

Agent Based ◽

Agent Based Modelling ◽

Fire Front ◽

Wildfire Simulation ◽

Behaviour Simulation

Abstract. Wildfires are a complex phenomenon emerging from interactions between air, heat, and vegetation, and while they are an important component of many ecosystems’ dynamics, they pose great danger to those ecosystems, and human life and property. Wildfire simulation models are an important research tool that help further our understanding of fire behaviour and can allow experimentation without recourse to live fires. Current fire simulation models fit into two general categories: empirical models and physical models. We present a new modelling approach that uses agent-based modelling to combine the complexity found in physical models with the ease of computation of empirical models. Our model represents the fire front as a set of moving agents that respond to, and interact with, vegetation, wind, and terrain. We calibrate the model using two simulated fires and one real fire, and validate the model against another real fire and the interim behaviour of the real calibration fire. Our model successfully replicates these fires, with a Figure of Merit on par with simulations by the Prometheus simulation model. Our model is a stepping-stone in using agent-based modelling for fire behaviour simulation, as we demonstrate the ability of agent-based modelling to replicate fire behaviour through emergence alone.

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Experimental assessment of the influence of radiant heat transfer on the transition of a crown fire to settlements

Pozharnaia bezopasnost` ◽

10.37657/vniipo.pb.2021.76.10.002 ◽

2021 ◽

pp. 19-26

Author(s):

Николай Петрович Копылов ◽

Елена Юрьевна Сушкина ◽

Александр Евгеньевич Кузнецов ◽

Виктория Ивановна Новикова

Keyword(s):

Heat Flow ◽

Forest Fire ◽

Fire Resistance ◽

Fire Protection ◽

Forest Fires ◽

Radiant Heat ◽

Radiant Heat Transfer ◽

Crown Fire ◽

Fire Front ◽

The Impact

Проведены экспериментальные исследования влияния лучистого теплообмена на переход верхового лесного пожара на постройки IV и V степеней огнестойкости. Лесной верховой пожар моделировался горением штабеля древесины с интенсивностью тепловыделения, близкой к интенсивности при реальных пожарах. Получена зависимость изменения плотности теплового потока от расстояния до кромки горения. Экспериментально определены температура воздуха с подветренной стороны пожара и плотность выпадения искр в зависимости от расстояния. Проверена эффективность защиты растворами ретардантов деревянных строений от возгорания при лучистом теплообмене между факелом пламени пожара и объектом защиты. Crown fires are the main threat of the combustion transfer from the forest to objects located in it. Fire services dealing with forest fires face the problem how to protect these objects from forest fires. It is proposed to treat the object with retardant solutions before a forest fire approaches. To assess the effectiveness of such tactics for fire protection of objects when exposed to a heat flow from the combustion front there were carried out experiments on large-scale crown fire models. A crown fire is simulated with a pile of wood with a heat release rate of ≈ 13 MW m. The wind is generated by fans, its speed is close to the speed at which a forest fire occurs. Measurements of the heat flux density, medium temperature, and the density of sparks falling downwind of the fire front at different distances and heights were carried out. Calculations were carried out to assess the impact of heat flow on buildings of IV-V degrees of fire resistance. The results obtained are compared with experimental data and they are in good agreement. There have been determined the distances from the fire front at which the fire protection with retardant solutions is effective for structures of IV-V fire resistance degrees at radiant heat exchange.

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Evaluation of critical atmospheric patterns for the occurrence of forest fires in a climate change context in the northwest of Argentine Patagonia.

10.5194/egusphere-egu21-610 ◽

2021 ◽

Author(s):

Verónica Dankiewicz ◽

Matilde M. Rusticucci ◽

Soledad M. Collazo

Keyword(s):

Climate Change ◽

Forest Fires ◽

Fire Hazard ◽

Fire Danger ◽

Fire Season ◽

Historical Period ◽

Fire Weather Index ◽

Mitigation And Adaptation ◽

Argentine Patagonia ◽

In Fire

<p>Forest fires are a global phenomenon and result from complex interactions between weather and climate conditions, ignition sources, and humans. Understanding these relationships will contribute to the development of management strategies for their mitigation and adaptation. In the context of climate change, fire hazard conditions are expected to increase in many regions of the world due to projected changes in climate, which include an increase in temperatures and the occurrence of more intense droughts. In Argentina, northwestern Patagonia is an area very sensitive to these changes because of its climate, vegetation, the urbanizations highly exposed to fires, and the proximity of two of the largest and oldest National Parks in the country. The main objective of this work is to analyze the possible influence of climate change on some atmospheric patterns related to fire danger in northwestern Argentine Patagonia. The data were obtained from two CMIP5 global climate models CSIRO-Mk3-6-0 and GFDL-ESM2G and the CMIP5 multimodel ensemble, in the historical experiment and two representative concentration pathways: RCP2.6 and RCP8.5. The data used in this study cover the region's fire season (FS), from September to April, and were divided into five periods of 20 years each, a historical period (1986-2005), which was compared with four future periods: near (2021-2040), medium (2041-2060), far (2061-2080) and very far (2081-2100). The statistical distribution of the monthly composite fields of the FS was studied for some of the main fire drivers: sea surface temperature in the region of the index EN3.4 (SST EN3.4), sea level pressure anomalies &#8203;&#8203;(SLP), surface air temperature anomalies (TAS), the Antarctic Oscillation Index (AOI) and monthly accumulated precipitation (PR). In addition, the partial correlation coefficient was calculated to determine the independent contribution of each atmospheric variable to the Fire Weather Index (FWI), used as a proxy for the mean FS danger. As a result, we observed that SST EN3.4 is the only one that could indicate a reduction in fire danger in the future, although no variable presented a significant contribution to the FWI with respect to the others. In the RCP8.5 scenario, greater fire danger is projected by the TAS, the PR, the SLP, and relative by the AOI, while in the RCP2.6 scenario, only the TAS shows influence leading to an increase, which would be offset by the opposite influence of SST EN3.4 for the same periods in this scenario. In conclusion, in RCP8.5 it could be assumed that there is a trend towards an increase in fire danger given the influence in this sense of most of the variables analyzed, but not in RCP2.6 where there would be no significant changes.</p>

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Simulation study of grass fire using a physics-based model: striving towards numerical rigour and the effect of grass height on the rate of spread

International Journal of Wildland Fire ◽

10.1071/wf17126 ◽

2018 ◽

Vol 27 (12) ◽

pp. 800 ◽

Cited By ~ 5

Author(s):

K. A. M. Moinuddin ◽

D. Sutherland ◽

W. Mell

Keyword(s):

Boundary Layer ◽

Wind Speed ◽

Heat Release ◽

Bulk Density ◽

Simulation Study ◽

Release Rate ◽

Rate Of Spread ◽

Fire Front ◽

Physics Based Simulation ◽

Mode A

Grid-independent rate of spread results from a physics-based simulation are presented. Previously, such a numerical benchmark has been elusive owing to computational restrictions. The grid-converged results are used to systematically construct correlations between the rate of spread (RoS) and both wind speed and grass height, separately. The RoS obtained from the physics-based model is found to be linear with wind speed in the parameter range considered. When wind speed is varied, the physics-based model predicts faster RoS than the Mk III and V (McArthur) models (Noble et al. 1980) but slower than the CSIRO model (Cheney et al. 1998). When the grass height is varied keeping the bulk density constant, the fire front changes from a boundary layer flame mode to plume flame mode as the grass height increases. Once the fires are in plume mode, a higher grass height results in a larger heat release rate of the fire but a slower RoS.

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Translating Fire Impacts in Southwestern Amazonia into Economic Costs

Remote Sensing ◽

10.3390/rs11070764 ◽

2019 ◽

Vol 11 (7) ◽

pp. 764 ◽

Cited By ~ 4

Author(s):

Wesley Campanharo ◽

Aline Lopes ◽

Liana Anderson ◽

Thiago da Silva ◽

Luiz Aragão

Keyword(s):

Land Tenure ◽

Forest Fires ◽

Sustainable Use ◽

Economic Loss ◽

Spatiotemporal Variability ◽

Economic Losses ◽

Conservation Areas ◽

Fire Dynamics ◽

Climate Conditions ◽

Burned Areas

Between 1998 and 2017, climate-related disasters represented 91% of all occurrences worldwide, causing approximately US$ 2.245 billion of direct economic losses. In the Amazon region, fire is used as a widely spread technique for land clearing, agricultural management, hunting, and religious rituals. However, over the past 20 years, severe droughts caused a major amplification of fire occurrences, leading to several socioeconomic and environmental impacts. Particularly in Acre state, located in the southwestern Brazilian Amazon, the occurrence of extensive fires, associated with extreme climatic events, has been reported since 2005. However, fire dynamics, land tenure relationships, and associated impacts are poorly quantified. In this study, we aim to investigate the following: (1) The spatiotemporal variability of fire dynamics during anomalously dry and regular climate conditions; (2) the attribution of fire occurrence and land tenure relationship, and (3) the environmental, social, and economic impacts caused by fires and its consequences for Acre’s economy. We analyzed information on the spatial patterns of fire, its direct impacts on land use and land cover, carbon stocks, CO2 emissions, the indirect impact on human illness, and finally the costs of these impacts from 2008 to 2012. During the studied period, burned areas were concentrated around the major cities and roads, forming polygons up to 0.6 km2. However, in 2010, an extremely dry year, fires spread to remote areas, impacting protected private areas and sustainable-use conservation areas. In 2010, the total area affected by forest fires was approximately 16 times greater than in meteorologically normal years. The total economic loss estimated in 2010 was around US$ 243.36 ± 85.05 million and for the entire period, US$ 307.46 ± 85.41 million. These values represent 7.03 ± 2.45% and 9.07 ± 2.46% of Acre’s gross domestic product (GDP), respectively.

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Fire-growth modelling using meteorological data with random and systematic perturbations

International Journal of Wildland Fire ◽

10.1071/wf06069 ◽

2007 ◽

Vol 16 (2) ◽

pp. 174 ◽

Cited By ~ 20

Author(s):

Kerry Anderson ◽

Gerhard Reuter ◽

Mike D. Flannigan

Keyword(s):

Wind Speed ◽

Growth Model ◽

Forest Fires ◽

Meteorological Data ◽

Random Perturbation ◽

Weather Forecast ◽

Fire Spread ◽

Fire Growth ◽

Hourly Data ◽

Systematic Perturbation

The focus of this investigation is to quantify the effects of perturbations in the meteorological data used in a fire-growth model. Observed variations of temperature, humidity, wind speed, and wind direction are applied as perturbations to hourly values within a simulated weather forecast to produce several forecasts. In turn, these are used by a deterministic eight-point fire-growth model to produce an ensemble of possible final fire perimeters. Two studies were conducted to assess the value of applying perturbations. In the first study, fire growth using detailed, one-minute data was compared to growth based on the more commonly used hourly data. Results showed that the detailed weather produced fire growth larger and wider than the hourly based data. By applying perturbations, variations in the flank and back-fire spread were captured by the random-perturbation model while the forward spread fell within the 20 to 30% probability prediction. A sensitivity analysis based on the observed variations showed that wind speed accounted for a 44% difference in area burned, while temperature accounted for only a 16% difference. In the second study, case studies were conducted on four observed forest fires in Wood Buffalo National Park. Results showed that daily fire-growth predictions using simulated weather forecasts over-predicted fire growth using actual hourly weather observations by 27%. Systematic-perturbation models best compensated for this with most fire growth falling within the predicted range of the models (52 out of 63 days).

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Preference by Donkeys and Goats among Five Mediterranean Forest Species: Implications for Reducing Fire Hazard

Animals ◽

10.3390/ani10081302 ◽

2020 ◽

Vol 10 (8) ◽

pp. 1302

Author(s):

Jordi Bartolomé ◽

Jordi Miró ◽

Xavier Panadès ◽

Maria José Broncano ◽

Josefina Plaixats ◽

...

Keyword(s):

Forest Fires ◽

Pinus Halepensis ◽

Fire Hazard ◽

Mediterranean Forest ◽

Mediterranean Forests ◽

Forest Species ◽

Rubus Ulmifolius ◽

Key Species ◽

The Mediterranean ◽

Cafeteria Test

During the second half of the 20th century, European countries experienced an increase in their forest area due to the global change. Consequently, there has been an increase in large forest fires, mainly in the Mediterranean basin, and this has forced the development of several types of prevention programs. One of them is the control of the understory by livestock. In this sense, browsing with a combination of donkeys and goats could be a good option, as both animals usually feed on forest species. However, little is known about their preferences for the key species of the Mediterranean forest. Using a cafeteria test, the preferences and consumption of both animals have been determined for five typical species of the Mediterranean forest, such as Quercus ilex, Pinus halepensis, Phillyrea latifolia, Rubus ulmifolius, and Brachypodium retusum. Results showed that donkeys and goats could act complementarily in the reduction of the fuel biomass of forests. Donkeys appear to act more on fine fuel, such as B. retusum, and goats on the more pyrophyte species, in this case P. halepensis. In addition, given that donkeys are at severe risk of extinction in Europe, this role of providing ecosystem services could contribute to their conservation. Despite this study only showing that goats and donkeys would consume all five presented plant species and that there are some differences in consumption during a short-term test, it constitutes a useful first step for conservation and fire prevention in the Mediterranean forests.

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