Статті в журналах з теми "High-intensity fires"
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1
Clark, Kenneth L., Warren E. Heilman, Nicholas S. Skowronski, Michael R. Gallagher, Eric Mueller, Rory M. Hadden, and Albert Simeoni. "Fire Behavior, Fuel Consumption, and Turbulence and Energy Exchange during Prescribed Fires in Pitch Pine Forests." Atmosphere 11, no. 3 (February 29, 2020): 242. http://dx.doi.org/10.3390/atmos11030242.
Повний текст джерелаАнотація:
Prescribed fires are conducted extensively in pine-dominated forests throughout the Eastern USA to reduce the risk of wildfires and maintain fire-adapted ecosystems. We asked how fire behavior and fuel consumption during prescribed fires are associated with turbulence and energy fluxes, which affect the dispersion of smoke and transport of firebrands, potentially impacting local communities and transportation corridors. We estimated fuel consumption and measured above-canopy turbulence and energy fluxes using eddy covariance during eight prescribed fires ranging in behavior from low-intensity backing fires to high-intensity head fires in pine-dominated forests of the New Jersey Pinelands, USA. Consumption was greatest for fine litter, intermediate for understory vegetation, and least for 1 + 10 hour wood, and was significantly correlated with pre-burn loading for all fuel types. Crown torching and canopy fuel consumption occurred only during high-intensity fires. Above-canopy air temperature, vertical wind velocity, and turbulent kinetic energy (TKE) in buoyant plumes above fires were enhanced up to 20.0, 3.9 and 4.1 times, respectively, compared to values measured simultaneously on control towers in unburned areas. When all prescribed fires were considered together, differences between above-canopy measurements in burn and control areas (Δ values) for maximum Δ air temperatures were significantly correlated with maximum Δ vertical wind velocities at all (10 Hz to 1 minute) integration times, and with Δ TKE. Maximum 10 minute averaged sensible heat fluxes measured above canopy were lower during low-intensity backing fires than for high-intensity head fires, averaging 1.8 MJ m−2 vs. 10.6 MJ m−2, respectively. Summed Δ sensible heat values averaged 70 ± 17%, and 112 ± 42% of convective heat flux estimated from fuel consumption for low-intensity and high-intensity fires, respectively. Surprisingly, there were only weak relationships between the consumption of surface and understory fuels and Δ air temperature, Δ wind velocities, or Δ TKE values in buoyant plumes. Overall, low-intensity fires were effective at reducing fuels on the forest floor, but less effective at consuming understory vegetation and ladder fuels, while high-intensity head fires resulted in greater consumption of ladder and canopy fuels but were also associated with large increases in turbulence and heat flux above the canopy. Our research quantifies some of the tradeoffs involved between fire behavior and turbulent transfer of smoke and firebrands during effective fuel reduction treatments and can assist wildland fire managers when planning and conducting prescribed fires.
2
Ivanova, Galina A., and Valery A. Ivanov. "ESTIMATING CARBON EMISSIONS FROM FIRES OF DIFFERENT INTENSITY IN THE PINE FORESTS OF SIBERIA." Interexpo GEO-Siberia 4, no. 2 (May 21, 2021): 63–67. http://dx.doi.org/10.33764/2618-981x-2021-4-2-63-67.
Повний текст джерелаАнотація:
In connection with global climate change, special attention is paid to the quantitative content of greenhouse gases in the atmosphere. Currently, forest fires are one of the main sources of gas and aerosol emissions into the atmosphere. Based on the conducted experimental studies, data on carbon emissions from fires of different intensity in the pine forests of Siberia were obtained. The most important factors affecting the amount of burned biomass and the amount of carbon emissions are the type and intensity of the fire. High-intensity fires have the greatest impact on the ecosystem and the amount of carbon emissions. With an increase in the number of large high-intensity fires, an increase in pyrogenic carbon emissions into the atmosphere can be expected.
3
Fayad, Jacky, Frédéric Morandini, Gilbert Accary, François-Joseph Chatelon, Clément Wandon, Antoine Burglin, Lucile Rossi, et al. "A Study of Two High Intensity Fires across Corsican Shrubland." Atmosphere 14, no. 3 (February 27, 2023): 473. http://dx.doi.org/10.3390/atmos14030473.
Повний текст джерелаАнотація:
This paper reports two experimental fires conducted at field-scale in Corsica, across a particular mountain shrubland. The orientation of the experimental plots was chosen in such a way that the wind was aligned along the main slope direction in order to obtain a high intensity fire. The first objective was to study the high intensity fire behavior by evaluating the propagation conditions related to its speed and intensity, as well as the geometry of the fire front and its impact on different targets. Therefore, an experimental protocol was designed to determine the properties of the fire spread using UAV cameras and its impact using heat flux gauges. Another objective was to study these experiments numerically using a fully physical fire model, namely FireStar3D. Numerical results concerning the fire dynamics, particularly the ROS, were also compared to other predictions of the FireStar2D model. The comparison with experimental measurements showed the robustness of the 3D approach with a maximum difference of 5.2% for the head fire ROS. The fire intensities obtained revealed that these experiments are representative of high intensity fires, which are very difficult to control in the case of real wildfires. Other parameters investigated numerically (flame geometry and heat fluxes) were also in fairly good agreement with the experimental measurements and confirm the capacity of FireStar3D to predict surface fires of high intensity.
4
Mupfiga, Upenyu Naume, Onisimo Mutanga, Timothy Dube, and Pedzisai Kowe. "Spatial Clustering of Vegetation Fire Intensity Using MODIS Satellite Data." Atmosphere 13, no. 12 (November 25, 2022): 1972. http://dx.doi.org/10.3390/atmos13121972.
Повний текст джерелаАнотація:
This work analyses the spatial clustering of fire intensity in Zimbabwe, using remotely sensed Moderate Resolution Imaging Spectroradiometer (MODIS) active fire occurrence data. In order to investigate the spatial pattern of fire intensity, MODIS-derived fire radiative power (FRP) was utilized. A local indicator of spatial autocorrelation method, the Getis-Ord (Gi*) spatial statistic, was applied to show the spatial distribution of high and low fire intensity clusters. Analysis of the relationship between topographic variables, vegetation type, agroecological zones and fire intensity was done. According to the study’s findings, the majority (44%) of active fires detected in the study area in 2019 were of low-intensity (cold spots), and the majority (49.3%) of them occurred in shrubland. High-intensity fires (22%) primarily occurred in the study area’s eastern and western regions. The study findings demonstrate the utility of spatial statistics methods in conjunction with satellite fire data in detecting clusters of high and low-intensity fires (hot spots and cold spots).
5
Reynard-Callanan, Jennifer R., Gregory A. Pope, Matthew L. Gorring, and Huan Feng. "Effects of High-Intensity Forest Fires on Soil Clay Mineralogy." Physical Geography 31, no. 5 (September 2010): 407–22. http://dx.doi.org/10.2747/0272-3646.31.5.407.
Повний текст джерела
6
Chernogor, L. F., A. N. Nekos, G. V. Titenko, and L. L. Chornohor. "Fire classification in natural ecosystems by physical and environmental characteristics." Visnyk of V. N. Karazin Kharkiv National University series "Ecology", no. 29 (December 9, 2023): 48–56. http://dx.doi.org/10.26565/1992-4259-2023-29-05.
Повний текст джерелаАнотація:
To qualitatively and quantitatively characterize and classify the intensity of forest fires and their environmental consequences, it is necessary to develop a special scale similar to the scale of wind strength, sea storms, earthquakes, geomagnetic storms, etc. Purpose. To describe the scales developed for the classification of forest fires according to various parameters characterizing physicochemical processes, environmental consequences and the level of danger from pyrogenic factors. Methods. System analysis, multifactorial analysis, mathematical modeling. Results. A seven-magnitude scale for classifying forest fires by intensity, energy characteristics, mass of emissions of the main combustion products and related chemical elements, as well as by environmental consequences and hazard level is proposed. It is substantiated that with moderate and weak winds, the intensity and energy of forest fires in Ukraine usually do not exceed 4-5 magnitudes, i.e., a moderate or high level. Fires of this level occurred, for example, in the spring, summer, and fall of 2020 in a number of regions of Ukraine. Conclusions. The developed special scales for classifying forest fires according to various parameters are an effective tool for qualitative and quantitative characterization of the intensity of forest fires and their environmental consequences. The obtained results can also be used to assess environmental impacts, material damage and social losses.
7
Josephson, Alexander J., Daniel Castaño, Marlin J. Holmes, and Rodman R. Linn. "Simulation Comparisons of Particulate Emissions from Fires under Marginal and Critical Conditions." Atmosphere 10, no. 11 (November 13, 2019): 704. http://dx.doi.org/10.3390/atmos10110704.
Повний текст джерелаАнотація:
Using a particulate emissions model developed for FIRETEC, we explore differences in particle emission profiles between high-intensity fires under critical conditions and low-intensity fires under marginal conditions. Simulations were performed in a chaparral shrubland and a coniferous pine forest representative of the southeast United States. In each case, simulations were carried out under marginal and critical fire conditions. Marginal fire conditions include high moisture levels and low winds, often desired for prescribed fires as these conditions produce a low-intensity burn with slower spread rates. Critical fire conditions include low moisture levels and high winds, which easily lead to uncontrollable wildfires which produce a high-intensity burn with faster spread rates. These simulations’ resultant particle emission profiles show critical fire conditions generate larger particle emission factors, higher total mass emissions, and a higher lofting potential of particles into the atmosphere when compared against marginal fire conditions but similar particle size distrubtions. In addition, a sensitivity analysis of the emissions model was performed to evaluate key parameters which govern particle emission factor and particle size.
8
Morrison, David A., and John A. Renwick. "Effects of variation in fire intensity on regeneration of co-occurring species of small trees in the Sydney region." Australian Journal of Botany 48, no. 1 (2000): 71. http://dx.doi.org/10.1071/bt98054.
Повний текст джерелаАнотація:
Fire is a common source of change for the plant species of Mediterranean-type ecosystems, but little is known about the comparative effects of different fire intensities. Accordingly, nine species of small tree (Acacia binervia, Acacia implexa, Acacia parramattensis, Casuarina littoralis, Casuarina torulosa, Hakea sericea, Jacksonia scoparia, Leptospermum trinervium, Persoonia linearis) were studied 1 year after each of two low-intensity prescribed fires and a high-intensity wildfire at a site in the outer western region of the Sydney metropolitan area, south-eastern Australia. All of the species except H. sericea proved to be at least partly tolerant of the low-intensity fires (40–80% of their stems surviving the fires), but only C. torulosa, L. trinervium and P. linearis were tolerant of the high-intensity fire (20–30% stem survival). All of the fire-tolerant species had more of their smaller stems killed by the fires, and the high-intensity fire killed larger stems than did the low-intensity-fires. The size of surviving stems was related to the fire-tolerance characteristics for these species, specifically the presence or absence of insulating bark and epicormic or lignotuberous buds, as well as stem height (preventing 100% leaf-scorch). Those species with post-fire shoots at the stem base produced them when the upper part of the stem had been killed, with variable response to the fire intensities in the number of shoots produced. Those species with post-fire epicormic shoots produced them if the stem was alive post-fire, usually with fewer shoots produced after the high-intensity than the low-intensity fire. The number of shoots produced was positively related to the size of the stem for both fire intensities. These different sets of responses to the fire intensities have important implications for the ability to predict community responses to fire based on the study of only a few species, as well for the long-term effects of prescribing a particular fire regime.
9
Hansen, Rickard. "Estimating the amount of water required to extinguish wildfires under different conditions and in various fuel types." International Journal of Wildland Fire 21, no. 5 (2012): 525. http://dx.doi.org/10.1071/wf11022.
Повний текст джерелаАнотація:
In wildland fires where water is used as the primary extinguishing agent, one of the issues of wildfire suppression is estimating how much water is required to extinguish a certain section of the fire. In order to use easily distinguished and available indicators, the flame length and the area of the active combustion zone were chosen as suitable for the modelling of extinguishing requirements. Using Byram’s and Thomas’ equations, the heat release rate per unit length of fire front was calculated for low-intensity surface fires, fires with higher wind conditions, fires in steep terrain and high-intensity crown fires. Based on the heat release rate per unit length of fire front, the critical water flow rate was calculated for the various cases. Further, the required amount of water for a specific active combustion zone area was calculated for various fuel models. Finally, the results for low-intensity surface fires were validated against fire experiments. The calculated volumes of water can be used both during the preparatory planning for incidents as well as during firefighting operations.
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Hansen, Rickard. "Corrigendum to: Estimating the amount of water required to extinguish wildfires under different conditions and in various fuel types." International Journal of Wildland Fire 21, no. 6 (2012): 778. http://dx.doi.org/10.1071/wf11022_co.
Повний текст джерелаАнотація:
In wildland fires where water is used as the primary extinguishing agent, one of the issues of wildfire suppression is estimating how much water is required to extinguish a certain section of the fire. In order to use easily distinguished and available indicators, the flame length and the area of the active combustion zone were chosen as suitable for the modelling of extinguishing requirements. Using Byram's and Thomas' equations, the heat release rate per unit length of fire front was calculated for low-intensity surface fires, fires with higher wind conditions, fires in steep terrain and high-intensity crown fires. Based on the heat release rate per unit length of fire front, the critical water flow rate was calculated for the various cases. Further, the required amount of water for a specific active combustion zone area was calculated for various fuel models. Finally, the results for low-intensity surface fires were validated against fire experiments. The calculated volumes of water can be used both during the preparatory planning for incidents as well as during firefighting operations.
11
Ponomarev, Evgenii I., Andrey N. Zabrodin, Eugene G. Shvetsov, and Tatiana V. Ponomareva. "Wildfire Intensity and Fire Emissions in Siberia." Fire 6, no. 7 (June 22, 2023): 246. http://dx.doi.org/10.3390/fire6070246.
Повний текст джерелаАнотація:
An analysis of fire characteristics in the boreal forests of Siberia (50–75° N, 60–140° E) was performed for the period 2002–2022. We found a positive trend in the proportion of high-intensity fires in dominant forest stands of Siberia based on long-term series of variations in the Fire Radiative Power (FRP) measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS). Our results showed that there was an increase in the proportion of areas of high-intensity fires over the past decade on about ~30% of the boreal forests of Siberia, including the Arctic zone. For the sample group of fires, the level of correlation (R2 = 0.80–0.94) between the fire impact, classified according to the NBR/dNBR technology, and the integral FRP values was revealed. The intensity of combustion in terms of FRP is associated with the volume of burned biomass and determines the dynamics of specific emissions values per unit area. The results suggest that further increase in fire emissions in Siberia will be determined not only by an increase of burned areas, but also by a redistribution of low- and high-intensity burning and an increase in specific emission values. Finally, we estimated that Siberian fires are responsible for about 5–20% of the total volume of greenhouse gas emissions in the Russian Federation, depending on the fire season scenario. The recurrence of extremely high emissions (296–350 Tg C/year) will make it possible to consider part of Siberian forests as a source of carbon in the nearest future.
12
Williams, RJ, AM Gill, and PHR Moore. "Seasonal Changes in Fire Behaviour in a Tropical Savanna in Northern Australia." International Journal of Wildland Fire 8, no. 4 (1998): 227. http://dx.doi.org/10.1071/wf9980227.
Повний текст джерелаАнотація:
In a landscape-scale experiment, fires were lit in replicate catchments 15-20 km2 in area, either early in the dry season (June) or late in the dry season (September) between 1990 and 1994. For each fire, Byram-intensity was determined in representative one ha areas of Eucalyptus miniata – E. tetrodonta open-forest, with a ground stratum dominated by annual grasses. Fuel weights were measured by harvest, fuel heat content was assumed to be constant, and the rate of spread was determined using electronic timers. Fuels consisted primarily of grass and leaf litter, and ranged from 1.5 to 13 t ha-1; in most years, average fuel loads were 2-4 t ha-1. Rates of spread were generally in the range of 0.2-0.8 ms-1. The mean intensity of early dry season fires (2100 kW m-1) was significantly less than that of the late dry season fires (7700 kW m-1), primarily because, in the late dry season, there was more leaf litter, fuels were drier, and fire weather was more extreme. Crown fires, a feature of forest fires of high intensity in southeastern Australia, were not observed in the Kapalga fires. Fire intensity was a very good predictor of both leaf-char height and leaf-scorch height for fires between 100 kW m-1 and 10,000 kW m-1, the range in which the majority of experimental fires fell.
13
Aryal, Biva, Bishnu Prasad Bhattarai, Mohan Pandey, and Anjana Giri. "Impact of forest floor fire on soil carbon sequestration of Pinus roxburghii forest in Langtang National Park, Nepal." Journal of Natural History Museum 30 (December 1, 2018): 148–63. http://dx.doi.org/10.3126/jnhm.v30i0.27550.
Повний текст джерелаАнотація:
Forest floor fires are known to be significantly important in carbon sequestration in soil. The present study investigated the total soil carbon stock (charcoal+soil organic carbon) andCO2 flux from four different depths (0-2, 2-10, 10-30 and >30cm) in fired and unfired forest of P. roxburghii from Langtang National Park, Nepal. The aim of this study was to test the impact of forest floor fire on soil carbon sequestration. We measured total carbon stock in soil of unfired and fired sites of different intensities namely: high frequency and high intensity, high frequency and moderate intensity and high frequency and low intensity. There was significant difference (P=0.00) of the soil organic carbon between the sites and different soil depths tested by one-way ANOVA. Similarly, one-way ANOVA test showed that soil charcoal stock was significantly different (P=0.00) at different soil depths. The value of CO2 flux was increased with increasing volumetric water content and decreasing soil temperature. One-way ANOVA showed significant difference (P=0.00) of volumetric water content, soil temperature and CO2 flux between the sites. In high frequency and medium intensity site, high amount of carbon sequestrated in soil suggested that fire of medium intensity mitigates high CO2 from the atmosphere.
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Twidwell, Dirac, William E. Rogers, Elizabeth A. McMahon, Bryce R. Thomas, Urs P. Kreuter, and Terry L. Blankenship. "Prescribed Extreme Fire Effects on Richness and Invasion in Coastal Prairie." Invasive Plant Science and Management 5, no. 3 (September 2012): 330–40. http://dx.doi.org/10.1614/ipsm-d-12-00017.1.
Повний текст джерелаАнотація:
AbstractWidely-held, untested assumptions in many prairies are that high-intensity fires conducted during droughts will decrease native herbaceous species richness and lead to rapid invasions by alien species. We compared native and exotic herbaceous species richness and aboveground herbaceous biomass one year following the application of high-intensity growing-season fires in Texas coastal prairie. Fires were conducted in June 2008, when precipitation was 96% below the long-term monthly average, at the end of a severe 5-mo drought, resulting in high fire intensities within treatment units. Native forb species richness was greater in burned than unburned areas. In contrast, species richness of native grasses, exotic forbs, and the frequency of King Ranch (KR) bluestem [Bothriochloa ischaemum (L.) Keng.] did not significantly differ between burned and unburned treatments. The potential to use prescribed extreme fire to maintain native herbaceous species richness while not increasing KR bluestem provides preliminary evidence that growing season fires conducted during droughts can be a viable management strategy in coastal prairies.
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Lee, Seoung Soo, George Kablick III, Zhanqing Li, Chang Hoon Jung, Yong-Sang Choi, Junshik Um, and Won Jun Choi. "Examination of effects of aerosols on a pyroCb and their dependence on fire intensity and aerosol perturbation." Atmospheric Chemistry and Physics 20, no. 6 (March 23, 2020): 3357–71. http://dx.doi.org/10.5194/acp-20-3357-2020.
Повний текст джерелаАнотація:
Abstract. Using a modeling framework, this study investigates how a pyrocumulonimbus (pyroCb) event influences water vapor concentrations and cirrus-cloud properties near the tropopause, specifically focusing on how fire-produced aerosols affect this role. Results from a case study show that when observed fire intensity is high, there is an insignificant impact of fire-produced aerosols on the development of the pyroCb and associated changes in water vapor and cirrus clouds near the tropopause. However, as fire intensity weakens, effects of those aerosols on microphysical variables and processes such as droplet size and autoconversion increase. Due to this, aerosol-induced invigoration of convection is significant for pyroCb with weak-intensity fires and associated weak surface heat fluxes. This leads to a situation where there is a greater aerosol effect on the transport of water vapor to the upper troposphere and the production of cirrus clouds with weak-intensity fires, whereas this effect is muted with strong-intensity fires.
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Sá, Ana C. L., Bruno Aparicio, Akli Benali, Chiara Bruni, Michele Salis, Fábio Silva, Martinho Marta-Almeida, Susana Pereira, Alfredo Rocha, and José Pereira. "Coupling wildfire spread simulations and connectivity analysis for hazard assessment: a case study in Serra da Cabreira, Portugal." Natural Hazards and Earth System Sciences 22, no. 12 (December 9, 2022): 3917–38. http://dx.doi.org/10.5194/nhess-22-3917-2022.
Повний текст джерелаАнотація:
Abstract. This study aims to assess wildfire hazard in northern Portugal by combining landscape-scale wildfire spread modeling and connectivity analysis to help fuel management planning. We used the Minimum Travel Time (MTT) algorithm to run simulations under extreme (95th percentile) fire weather conditions. We assessed wildfire hazard through burn probability, fire size, conditional flame length and fire potential index wildfire descriptors. Simulated fireline intensity (FLI) using historical fire weather conditions were used to build landscape networks and assess the impact of weather severity in landscape wildfire connectivity (Directional Index of Wildfire Connectivity, DIWC). Our results showed that 27 % of the study area is likely to experience high-intensity fires and 51 % of it is susceptible to spread fires larger than 1000 ha. Furthermore, the increase in weather severity led to the increase in the extent of high-intensity fires and highly connected fuel patches, covering about 13 % of the landscape in the most severe weather. Shrublands and pine forests are the main contributors for the spread of these fires, and highly connected patches were mapped. These are candidates for targeted fuel treatments. This study contributes to improving future fuel treatment planning by integrating wildfire connectivity in wildfire management planning of fire-prone Mediterranean landscapes.
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Braithwaite, Richard W. "Effects of fire regimes on lizards in the wet-dry tropics of Australia." Journal of Tropical Ecology 3, no. 3 (August 1987): 265–75. http://dx.doi.org/10.1017/s0266467400002145.
Повний текст джерелаАнотація:
ABSTRACTA quantitative analysis of the effect of fire regime on the abundance of common lizard species and genera and the species richness of two lizard groups in Kakadu National Park (12° S) is presented. A surprising range of relationships between species abundance and components of fire regimes was revealed. Carlia amax, Heteronotia binoei and Carlia gracilis appear to be fire-sensitive, Diporiphora bilineata and Carlia triacantha are favoured by early hot fires, Cryptoblepharus plagiocephalus seems relatively unaffected, Carlia foliorum seems very tolerant of fires, while Ctenotus and Sphenomorphus spp. are favoured by low intensity, patchy fires with high intensity spots.Lizard species experiencing the high-frequency fire regimes of the savannas and dry forests of the Australian wet-dry tropics are not able to select habitat at different stages of regeneration after fire but select habitat produced by fires of different types. The implication for management is that no one fire regime is optimal for the fauna as a whole. A range of fire regimes within a park should be maintained in order to retain the whole fauna.
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Han, Yongming, Zhisheng An, Jennifer R. Marlon, Raymond S. Bradley, Changlin Zhan, Richard Arimoto, Youbin Sun, et al. "Asian inland wildfires driven by glacial–interglacial climate change." Proceedings of the National Academy of Sciences 117, no. 10 (February 24, 2020): 5184–89. http://dx.doi.org/10.1073/pnas.1822035117.
Повний текст джерелаАнотація:
Wildfire can influence climate directly and indirectly, but little is known about the relationships between wildfire and climate during the Quaternary, especially how wildfire patterns varied over glacial–interglacial cycles. Here, we present a high-resolution soot record from the Chinese Loess Plateau; this is a record of large-scale, high-intensity fires over the past 2.6 My. We observed a unique and distinct glacial–interglacial cyclicity of soot over the entire Quaternary Period synchronous with marine δ18O and dust records, which suggests that ice-volume-modulated aridity controlled wildfire occurrences, soot production, and dust fluxes in central Asia. The high-intensity fires were also found to be anticorrelated with global atmospheric CO2 records over the past eight glacial–interglacial cycles, implying a possible connection between the fires, dust, and climate mediated through the iron cycle. The significance of this hypothetical connection remains to be determined, but the relationships revealed in this study hint at the potential importance of wildfire for the global climate system.
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Duchesne, Luc C., and Suzanne Wetzel. "Effect of Fire Intensity and Depth of Burn on Lowbush Blueberry, Vaccinium angustifolium, and Velvet Leaf Blueberry, Vaccinium myrtilloides, Production in Eastern Ontario." Canadian Field-Naturalist 118, no. 2 (April 1, 2004): 195. http://dx.doi.org/10.22621/cfn.v118i2.913.
Повний текст джерелаАнотація:
The effects of prescribed fire intensity and depth of burn were investigated on Lowbush Blueberry (Vaccinium angustifolium) and Velvet Leaf Blueberry (Vaccinium myrtilloides) stem density, blueberry production and the number of blueberries/stem in a clear-cut Jack Pine, Pinus banksiana, ecosystem of eastern Ontario. Blueberry production and stem density were significantly (P < 0.001) increased by low intensity prescribed fires of 597 and 1268 kW/m. In contrast, prescribed fires of medium and high intensities did not affect blueberry production and stem density. The number of blueberries/stem was not affected (P = 0.056) by prescribed burning, two years after treatment. Pearson's multiple correlation analysis showed that blueberry production (R: -0.683, P < 0.01), stem density (R: 0.733, P < 0.01) and the number of blueberries/stem (R: 0.803, P < 0.01) correlated with depth of burn. As well, blueberry production (R: 0.507, P < 0.05) and stem density (R: -0.504, P < 0.05) correlated with fire intensity. Depth of burn was a better predictor of berry production and stem density than fire intensity. These results suggest that only low intensity fires with little penetrating effect in the ground should be used to manage blueberry crops.
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Sari, Nurwita Mustika, Nurina Rachmita, and Masita Dwi Mandini Manessa. "Hotspot Distribution Analysis In East Kalimantan Province 2017-2019 to Support Forest and Land Fires Mitigation." Indonesian Journal of Environmental Management and Sustainability 4, no. 1 (March 29, 2020): 28–33. http://dx.doi.org/10.26554/ijems.2020.4.1.28-33.
Повний текст джерелаАнотація:
Forest and land fires that have occurred in the territory of East Kalimantan Province have caused immediate disaster to the area from year to year and become a global concern in recent years. Hotspots that potentially cause forest and land fires can be detected using satellites such as NOAA-20. The purposes of this study are to analyze the distribution pattern of hotspots in East Kalimantan Province during 2017-2019, identify areas with the highest risk of fires caused by the high intensity of hotspot. The method used in this study is the Nearest Neighbor Analysis and Kernel Density Estimation analysis. The results showed that the distribution pattern of hotspots in East Kalimantan Province during 2017-2019 was clustered with the highest intensity of hotspots were in Berau, East Kutai and Kutai Kartanegara Districts. And from the result of the analysis, the highest number of days has a peak hotspots on September each year.
Keywords: forest and land fires, hotspots, Nearest Neighbor, Kernel Density Estimation
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Bridges, Jack M., George P. Petropoulos, and Nicola Clerici. "Immediate Changes in Organic Matter and Plant Available Nutrients of Haplic Luvisol Soils Following Different Experimental Burning Intensities in Damak Forest, Hungary." Forests 10, no. 5 (May 24, 2019): 453. http://dx.doi.org/10.3390/f10050453.
Повний текст джерелаАнотація:
One of the major pedological changes produced by wildfires is the drastic modification of forest soil systems properties. To our knowledge, large research gaps are currently present concerning the effect of such fires on forest Haplic Luvisols soils in Central Europe. In this study, the effects of experimental fires on soil organic matter and chemical properties at different burning intensities in a Central European forest were examined. The study was conducted at Damak Forest, in Hungary, ecosystem dominated by deciduous broadleaf trees, including the rare Hungarian oak Quercus frainetto Ten. The experimental fires were carried out in nine different plots on Haplic Luvisol soils transferred from Damak Forest to the burning site. Three types of fuel load were collected from the forest: litter layer, understorey and overstorey. Groups of three plots were burned at low (litter layer), medium intensity (litter and understorey) and high intensity (litter, understorey and overstorey). Pre-fire and post-fire soil samples were taken from each plot, analysed in the laboratory and statistically compared. Key plant nutrients of organic matter, carbon, potassium, calcium, magnesium and phosphorus were analysed from each sample. No significant differences in soil organic matter and carbon between pre- and post-fire samples were observed, but high intensity fires did increase soil pH significantly. Calcium, magnesium and phosphorus availability increased significantly at all fire intensity levels. Soil potassium levels significantly decreased (ca. 50%) for all intensity treatments, in contrast to most literature. Potassium is a key nutrient for ion transport in plants, and any loss of this nutrient from the soil could have significant effects on local agricultural production. Overall, our findings provide evidence that support the maintaining of the current Hungarian fire prevention policy.
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Strydom, Tiaan, Tineke Kraaij, Mark Difford, and Richard M. Cowling. "Fire severity effects on resprouting of subtropical dune thicket of the Cape Floristic Region." PeerJ 8 (June 10, 2020): e9240. http://dx.doi.org/10.7717/peerj.9240.
Повний текст джерелаАнотація:
It has been hypothesised that high-intensity fires prevent fire-dependent fynbos from being replaced by fire-avoiding subtropical thicket on dune landscapes of the Cape Floristic Region (CFR). Recent extensive fires provided an opportunity to test this hypothesis. We posit that (1) fire-related thicket shrub mortality would be size dependent, with smaller individuals suffering higher mortality than larger ones; and (2) that survival and resprouting vigour of thicket shrubs would be negatively correlated with fire severity. We assessed survival and resprouting vigour post-fire in relation to fire severity and pre-fire shrub size at two dune landscapes in the CFR. Fire severity was scored at the base of the shrub and categorised into four levels. Pre-fire size was quantified as an index of lignotuber diameter and stem count of each shrub. Resprouting vigour consisted of two variables; resprouting shoot count and resprouting canopy volume. A total of 29 species were surveyed. Post-fire survival of thicket was high (83–85%). We found that smaller shrubs did have a lower probability of post-fire survival than larger individuals but could detect no consistent relationship between shrub mortality and fire severity. Fire severity had a positive effect on resprouting shoot count but a variable effect on resprouting volume. Pre-fire size was positively related to survival and both measures of resprouting vigour. We conclude that thicket is resilient to high-severity fires but may be vulnerable to frequent fires. Prescribed high-intensity fires in dune landscapes are unlikely to reduce the extent of thicket and promote fynbos expansion.
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Thompson, D. K., B. M. Wotton, and J. M. Waddington. "Estimating the heat transfer to an organic soil surface during crown fire." International Journal of Wildland Fire 24, no. 1 (2015): 120. http://dx.doi.org/10.1071/wf12121.
Повний текст джерелаАнотація:
The Peatland Smouldering and Ignition (PSI) model was developed to quantify the heat transfer from a wildfire to an organic soil or moss surface in a Sphagnum–black spruce peatland. The Canadian Fire Behaviour Prediction system was used as a basis for the relationship between wind speed and rate of spread. Convection, conduction, and radiation processes were modelled before and during the arrival of the flaming front. The net heat flux to the soil from fire varied between 1.1 and 8.6 MJ m–2, with moderate-intensity fires transferring more energy to the surface compared with higher-intensity fires under higher winds. Radiative heat transfer to the soil surface both before the fire’s arrival and within the flaming front were the primary mechanisms of energy gain to the peatland surface. The role of convective and conductive cooling was no greater than 30% of gross energy gain. Peatland surface ignition in hummock and hollow microforms was modelled under normal and drought conditions. Hollow microforms dried out significantly during the course of a summer and increased their ignition vulnerability. Small-scale changes in slope and aspect of the peatland surface increased the amount of heat transferred by radiation by up to 30%, allowing some areas of higher soil moisture content to ignite. While no direct model validation is available, model outputs showing the preferential combustion of lichen and feathermoss, and the lack of ignition in Sphagnum in all but the most severe drought generally mimic observed ignitions patterns. The modelled peak of net energy input to the surface occurred at moderate wind speeds, suggesting that high-intensity fires do not necessarily lead to greater energy transfer and risk of smouldering combustion.
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Oliveira, Sofia L. J., Stefan W. Maier, José M. C. Pereira, and Jeremy Russell-Smith. "Seasonal differences in fire activity and intensity in tropical savannas of northern Australia using satellite measurements of fire radiative power." International Journal of Wildland Fire 24, no. 2 (2015): 249. http://dx.doi.org/10.1071/wf13201.
Повний текст джерелаАнотація:
Earth observation sensors play an important role in quantifying the energy released by fires and capturing their spatial and temporal dynamics. Using estimates of MODIS-derived fire radiative power (FRP) we characterised bushfire activity and intensity in tropical savannas of northern Australia, by season and vegetation type, over the period 2004–2012. Our results indicate that fire activity was highest in the Northern Territory and lowest in Queensland. Mean daily number of fire detections was almost twice as high in the late dry season (August–November) compared to the early dry season (May–July). Fire season was bimodal with fire activity peaks in May and October. Median fire intensity was lower for early dry season fires (29 MW) than late dry season fires (56 MW), and was positively correlated with the number of fire detections. Vegetation types with sparse canopy structure showed lower fire activity and higher intensity. Remote sensing of FRP provides frequent estimates of fire intensity over broad areas, allowing the comparison of this key fire behaviour metric across ecosystems and throughout the fire season. FRP estimates may also be used to draw inferences regarding fire effects, once the complexity and ecosystem-specificity of the relationships between fire intensity and fire severity is acknowledged.
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Leahy, Lily, Sarah M. Legge, Katherine Tuft, Hugh W. McGregor, Leon A. Barmuta, Menna E. Jones, and Christopher N. Johnson. "Amplified predation after fire suppresses rodent populations in Australia’s tropical savannas." Wildlife Research 42, no. 8 (2015): 705. http://dx.doi.org/10.1071/wr15011.
Повний текст джерелаАнотація:
Context Changes in abundance following fire are commonly reported for vertebrate species, but the mechanisms causing these changes are rarely tested. Currently, many species of small mammals are declining in the savannas of northern Australia. These declines have been linked to intense and frequent fires in the late dry season; however, why such fires cause declines of small mammals is unknown. Aims We aimed to discover the mechanisms causing decline in abundance of two species of small mammals, the pale field rat, Rattus tunneyi, and the western chestnut mouse, Pseudomys nanus, in response to fire. Candidate mechanisms were (1) direct mortality because of fire itself, (2) mortality after fire because of removal of food by fire, (3) reduced reproductive success, (4) emigration, and (5) increased mortality because of predation following fire. Methods We used live trapping to monitor populations of these two species under the following three experimental fire treatments: high-intensity fire that removed all ground vegetation, low-intensity fire that produced a patchy burn, and an unburnt control. We also radio-tracked 38 R. tunneyi individuals to discover the fates of individual animals. Key results Abundance of both species declined after fire, and especially following the high-intensity burn. There was no support for any of the first four mechanisms of population decline, but mortality owing to predation increased after fire. This was related to loss of ground cover (which was greater in the high-intensity fire treatment), which evidently left animals exposed to predators. Also, local activity of two predators, feral cats and dingoes, increased after the burns, and we found direct evidence of predation by feral cats and snakes. Conclusions Fire in the northern savannas has little direct effect on populations of these small mammals, but it causes declines by amplifying the impacts of predators. These effects are most severe for high-intensity burns that remove a high proportion of vegetation cover. Implications To prevent further declines in northern Australia, fire should be managed in ways that limit the effects of increased predation. This could be achieved by setting cool fires that produce patchy burns, avoiding hot fires, and minimising the total area burnt.
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Feig, G., X. Ncipha, S. Naidoo, D. Mabaso, N. Ngcukana, C. Tshehla, and N. Masuku. "Analysis of a period of elevated ozone concentration reported over the Vaal Triangle on 2 June 2013." Clean Air Journal 24, no. 1 (June 3, 2014): 10–16. http://dx.doi.org/10.17159/caj/2014/24/1.7051.
Повний текст джерелаАнотація:
A peak in the ambient ozone concentration was observed at three of the six ambient air quality monitoring stations in the Vaal Triangle Airshed Priority Area on the second of June 2013. The ozone peak was associated with elevated concentrations of particulate matter, including PM10, PM2.5 and black carbon, but not sulphur dioxide, oxides of nitrogen, carbon monoxide nor benzene. Back trajectory analysis using Hysplit showed that the air masses containing the high levels of ozone passed over areas influenced by coal fired power stations in the Waterberg, metal processing in the Bojanala region and high intensity fires 30km to 50km upwind of the stations.
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Wu, Zechuan, Mingze Li, Bin Wang, Ying Quan, and Jianyang Liu. "Using Artificial Intelligence to Estimate the Probability of Forest Fires in Heilongjiang, Northeast China." Remote Sensing 13, no. 9 (May 6, 2021): 1813. http://dx.doi.org/10.3390/rs13091813.
Повний текст джерелаАнотація:
Although low-intensity forest fires are a necessary part of healthy echo system, high-intensity forest fires continue to affect the diversity of forest ecosystems and species. Therefore, it is necessary to study the driving factors of forest fires and explore their possible locations and probabilities in complex forest terrain. In this article, we determined the relative influences of different types of factors on the occurrence of forest fires in Heilongjiang forest areas and compared the performance of artificial neural networks and logistic regression for wildfire prediction. By analyzing Heilongjiang forest fire data from 2002 to 2015 and constructing a model, we found that climate factors, topographical factors, and vegetation type factors play a crucial role in Heilongjiang’s wildfires. During the fire prevention period, temperature and wind speed have a more significant influence than other factors. According to the variable screening that we conducted, the model built by the variables that we used can predict 84% of forest fires in Heilongjiang Province. For recent wildfires (2019–2020) in most areas, we can use artificial neural networks for relatively accurate verification (85.2%). Therefore, artificial neural networks are very suitable for the prediction of forest fires in Heilongjiang Province. Through the prediction results, we also created a probability distribution map of fire occurrence in the study area. On this basis, we also analyzed the changes in the probability of natural fires under the weather changing trend, which can effectively aid in fire prevention and extinguishment.
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Burrows, Neil D. "Fire dependency of a rock-outcrop plant Calothamnus rupestris (Myrtaceae) and implications for managing fire in south-western Australian forests." Australian Journal of Botany 61, no. 2 (2013): 81. http://dx.doi.org/10.1071/bt12240.
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Granite outcrops embedded in south-western Australian forests provide habitat for unique biotic assemblages and refugia for fire-sensitive taxa. Discontinuous vegetation and natural barriers to fire spread enable outcrops to function as fire refugia, provided fires in the surrounding forest are not of high intensity. In Summer 2003, lightning started a fire in jarrah forest that had not been burnt for almost 20 years. The high-intensity fire burned the vegetation on Mount Cooke, a large granite outcrop, providing an opportunity to study the response of Calothamnus rupestris Schauer, a fire-sensitive serotinous plant. The population was killed by the fire, but readily regenerated from seed stored in woody capsules. The post-fire population reached maturity after ~7.5 years, whereas the seed bank is unlikely to recover to the pre-fire level until ~14 years. The likelihood of intense forest wildfires affecting outcrop communities can be reduced by frequent low-intensity prescribed burning in the surrounding forests to reduce fuel hazard and quantity. Low-intensity forest fires are unlikely to be lethal to sensitive granite-outcrop communities.
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Doumas, Sandra L., and John L. Koprowski. "Effect of heterogeneity in burn severity on Mexican fox squirrels following the return of fire." International Journal of Wildland Fire 22, no. 3 (2013): 405. http://dx.doi.org/10.1071/wf12046.
Повний текст джерелаАнотація:
After decades of suppression, fire has returned to many forested areas of the western United States. Understanding responses of wildlife species to fire is essential to native species conservation because contemporary fires may not have the same effects as historical fires. Recent fires in the Chiricahua Mountains of Arizona provided an opportunity to investigate effects of fire heterogeneity on habitat selection of a native wildlife species. We used radiotelemetry to determine home ranges of Mexican fox squirrels (Sciurus nayaritensis chiricahuae) within fire-influenced forests. We then applied resource-utilisation functions to evaluate associations of use intensity within home ranges to heterogeneity of burn severity at two spatial scales. Squirrels used areas with moderate levels of burn heterogeneity at large scale more than areas of low or high heterogeneity. Squirrels used small (<0.5 ha) or narrow (<120 m) severely burnt patches, but incorporated only edges of large patches into home ranges. Use of burnt forests by Mexican fox squirrels demonstrates the complexities of fire’s effects on wildlife. Our results contribute to an understanding of the role and effect of fire in forest ecosystems and implications for wildlife conservation.
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Nurcholis, Omar, and Syahrul Kurniawan. "SIFAT KIMIA TANAH PASCA KEBAKARAN LAHAN DI KEBUN KELAPA SAWIT DI KABUPATEN TULANG BAWANG PROVINSI LAMPUNG." Jurnal Tanah dan Sumberdaya Lahan 8, no. 1 (December 31, 2020): 19–25. http://dx.doi.org/10.21776/ub.jtsl.2021.008.1.3.
Повний текст джерелаАнотація:
Fire is a serious problem that must be faced in the management of forest or plantation areas. Land fires have caused huge losses of soil nutrient. Lampung is one of the provinces in Indonesia having a problem related to land fires. The purpose of this study was to analyze the impact of land fires on the soil base cations (K, Mg, Ca, Na) and cation exchange capacity (CEC) in three different planting zones (i.e. fertilization, harvesting path, and frond stack areas) within oil palm plantations between land with low fire intensity and land with high fire intensity. Observations were made using a survey method in three zones of oil palm plantations, including fertilization area, harvesting path, and frond stack area. Soil samples were collected by using a soil drill at two depths, namely 0-10 cm and 10-30 cm from the soil surface. The study showed that at depth 0-10 cm, land A (land with low fire intensity) had higher K, Na, and Ca contents, as well as higher CEC as compared to land B (land with high fire intensity). At depth 10-30 cm, field A had higher K and CEC content, and lower Mg content than land B. comparing among different zones of oil palm plantations also showed that soil exchangeable K and Mg were significantly different, especially at depths of 10-30 cm. This was due to differences in land management (i.e. fertilization and liming).
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Maynard, Trevor, Marko Princevac, and David R. Weise. "A Study of the Flow Field Surrounding Interacting Line Fires." Journal of Combustion 2016 (2016): 1–12. http://dx.doi.org/10.1155/2016/6927482.
Повний текст джерелаАнотація:
The interaction of converging fires often leads to significant changes in fire behavior, including increased flame length, angle, and intensity. In this paper, the fluid mechanics of two adjacent line fires are studied both theoretically and experimentally. A simple potential flow model is used to explain the tilting of interacting flames towards each other, which results from a momentum imbalance triggered by fire geometry. The model was validated by measuring the velocity field surrounding stationary alcohol pool fires. The flow field was seeded with high-contrast colored smoke, and the motion of smoke structures was analyzed using a cross-correlation optical flow technique. The measured velocities and flame angles are found to compare reasonably with the predicted values, and an analogy between merging fires and wind-blown flames is proposed.
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Dietze, Elisabeth, Kai Mangelsdorf, Andrei Andreev, Cornelia Karger, Laura T. Schreuder, Ellen C. Hopmans, Oliver Rach, Dirk Sachse, Volker Wennrich, and Ulrike Herzschuh. "Relationships between low-temperature fires, climate and vegetation during three late glacials and interglacials of the last 430 kyr in northeastern Siberia reconstructed from monosaccharide anhydrides in Lake El'gygytgyn sediments." Climate of the Past 16, no. 2 (April 30, 2020): 799–818. http://dx.doi.org/10.5194/cp-16-799-2020.
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Abstract. Landscapes in high northern latitudes are assumed to be highly sensitive to future global change, but the rates and long-term trajectories of changes are rather uncertain. In the boreal zone, fires are an important factor in climate–vegetation interactions and biogeochemical cycles. Fire regimes are characterized by small, frequent, low-intensity fires within summergreen boreal forests dominated by larch, whereas evergreen boreal forests dominated by spruce and pine burn large areas less frequently but at higher intensities. Here, we explore the potential of the monosaccharide anhydrides (MA) levoglucosan, mannosan and galactosan to serve as proxies of low-intensity biomass burning in glacial-to-interglacial lake sediments from the high northern latitudes. We use sediments from Lake El'gygytgyn (cores PG 1351 and ICDP 5011-1), located in the far north-east of Russia, and study glacial and interglacial samples of the last 430 kyr (marine isotope stages 5e, 6, 7e, 8, 11c and 12) that had different climate and biome configurations. Combined with pollen and non-pollen palynomorph records from the same samples, we assess how far the modern relationships between fire, climate and vegetation persisted during the past, on orbital to centennial timescales. We find that MAs attached to particulates were well-preserved in up to 430 kyr old sediments with higher influxes from low-intensity biomass burning in interglacials compared to glacials. MA influxes significantly increase when summergreen boreal forest spreads closer to the lake, whereas they decrease when tundra-steppe environments and, especially, Sphagnum peatlands spread. This suggests that low-temperature fires are a typical characteristic of Siberian larch forests also on long timescales. The results also suggest that low-intensity fires would be reduced by vegetation shifts towards very dry environments due to reduced biomass availability, as well as by shifts towards peatlands, which limits fuel dryness. In addition, we observed very low MA ratios, which we interpret as high contributions of galactosan and mannosan from biomass sources other than those currently monitored, such as the moss–lichen mats in the understorey of the summergreen boreal forest. Overall, sedimentary MAs can provide a powerful proxy for fire regime reconstructions and extend our knowledge of long-term natural fire–climate–vegetation feedbacks in the high northern latitudes.
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Woodward, Craig, and Heather Ann Haines. "Unprecedented long-distance transport of macroscopic charcoal from a large, intense forest fire in eastern Australia: Implications for fire history reconstruction." Holocene 30, no. 7 (March 4, 2020): 947–52. http://dx.doi.org/10.1177/0959683620908664.
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Macroscopic charcoal records from wetland sediment cores are used to reconstruct long-term records of fire frequency. A central premise for the use of this tool is that macroscopic charcoal (>125 μm) represents local fires involving local vegetation. Several records reveal that there may often be exceptions to these guidelines. Previous studies have shown that particles larger than 1 cm long can travel at least 20 km from the location of a fire. We present observations of unprecedented long-distance transport of large (⩽5 cm long) charcoal particles at least 50 km from a fire west of Sydney, Australia. Factors that contribute to long-distance transport of large charcoal particles are fire intensity, upper level wind speed and landscape topography. The fires west of Sydney were large and intense, upper level (~10 km) winds exceeded 90 km h-1, and the topography east of the fire was flat or undulating. Smoke plumes from intense fires like this can reach an altitude of at least 15 km. Charcoal morphology also contributed to long-distance transport in this case. Eucalyptus trees can produce large quantities of aerodynamically efficient particles; from paper thin, smooth, decorticating bark and large sclerophyllous leaves. The presence of large macroscopic charcoal particles in wetland sediments does not automatically indicate local fires and could result from distant, large, intense fires. Large, intense fires can occur in Australia, the grasslands of Kazakhstan, Namibia, the Sahel and Patagonia. High intensity fires also occur in the forested areas of the western United States and Boreal North America. Fires in these regions could result in long-distance transport of large macroscopic charcoal particles under the right circumstances. Local charcoal flux studies are therefore critical for the interpretation of macroscopic charcoal records. We cannot rely on information from areas with different fire regimes, fire intensities or vegetation types.
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Laris, Paul, Moussa Koné, Fadiala Dembélé, Christine M. Rodrigue, Lilian Yang, Rebecca Jacobs, and Quincy Laris. "Methane gas emissions from savanna fires: what analysis of local burning regimes in a working West African landscape tell us." Biogeosciences 18, no. 23 (December 1, 2021): 6229–44. http://dx.doi.org/10.5194/bg-18-6229-2021.
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Abstract. Savanna fires contribute significantly to greenhouse gas emissions. While it is recognized that these fires play a critical role in the global methane cycle, there are too few accurate estimates of emissions from West Africa, the continent's most active fire region. Most estimates of methane emissions contain high levels of uncertainty as they are based on generalizations of diverse landscapes that are burned by complex fire regimes. To improve estimates we used an approach grounded in the burning practices of people who set fires to working landscapes. We collected and analyzed smoke samples for 36 experimental fires using a canister method for the early dry season (EDS) and mid-dry season (MDS). We also collected data for savanna type, grass type, biomass composition and amount consumed, scorch height, speed of fire front, fire type, and ambient air conditions for two sites in Mali. We report values for fire intensity, combustion completeness, patchiness, modified combustion efficiency (MCE), emission factor (EF) and methane emission density. Our study found that mean methane EFs ranged from 3.83 g kg−1 in the EDS to 3.18 g kg−1 in the MDS, but the small sample did not provide enough power for this effect to be significant. We found head fires had nearly double the CH4 EF of backfires (5.12 g kg−1 to 2.74), a significant difference. Byram's fire intensity was a significant driver of CH4 EF but with weak effect. Methane emission density increased marginally from 0.839 g m−2 in the EDS to 0.875 g m−2 in the MDS, a difference that was not significant. Head fires, however, had much higher emission densities than backfires – 1.203 vs. 0.708 g m−2 – respectively, a significant difference. We suggest the reason for the higher methane emissions from head fires, which have higher intensity, is the longer flame lengths that burn green leaves on trees, releasing methane. We conclude that policies aimed at shifting the burning regime earlier to reduce methane emissions will not have the desired effects, especially if fire type is not considered. Future research should consider the state and amount of leafy biomass combusted in savanna fires.
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Hafni, D. A. F., E. I. Putra, A. A. N. Harahap, B. H. Saharjo, L. Graham, A. D. Nurhayati, and M. A. Cochrane. "Peat fire risk assessment in Central Kalimantan, Indonesia using the Standardized Precipitation Index (SPI)." IOP Conference Series: Earth and Environmental Science 959, no. 1 (January 1, 2022): 012058. http://dx.doi.org/10.1088/1755-1315/959/1/012058.
Повний текст джерелаАнотація:
Abstract Decreased rainfall and drought due to the long dry season affecting peat fires in Indonesia. This condition causes a decrease in the groundwater level and peat drought, bringing a dry conditions of peat that are suitable for fires. Our prolonged studies revealed a close relationship between precipitation, groundwater levels, and peat fires. This paper aims to assess the risk of peat fires by applying the Standardized Precipitation Index (SPI). We used 18-year daily rainfall data (2000–2017), 16-year hotspot data (2002–2017), and 8-year groundwater level data (2010–2017). Our results showed the strong correlation (r = -0.61) between SPI-1 (short term) and the number of fires. The combination of low rainfall. the peat fire occurrences will increase significantly following less SPI-1 value and decreased groundwater levels during the peak of the dry season. A prolonged dry season followed by less rainfall in the normal rainy season will encourage high-intensity peat fires, bring the important of the using of drought patterns for a better risk assessment of future peat fire occurrences.
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Копылов, Н. П., Е. Ю. Сушкина, Д. В. Федоткин, and В. И. Новикова. "Protection of firefighters from exposure to the hazards of crown forest fires." Pozharnaia bezopasnost`, no. 3(112) (September 15, 2023): 16–23. http://dx.doi.org/10.37657/vniipo.pb.2023.112.3.001.
Повний текст джерелаАнотація:
В статье рассмотрены вопросы защиты людей, занятых на тушении лесных пожаров, от воздействия опасных факторов лесного пожара. Сделаны оценки по числовым значениям этих опасных факторов. Приведены статистические данные по США и России о гибели пожарных, попавших в ловушки при верховых лесных пожарах. Рассмотрены варианты защиты людей в виде укрытий легкого и тяжелого класса. Проанализированы нормативные документы, в частности стандарты, на предмет их применимости для сертификации укрытий. Предложены способы оценки эффективности защитных сооружений (укрытий), попавших в зону действия верхового лесного пожара. Fighting forest fires is often accompanied by the deaths of forest firefighters. The most frequent loss of life occurs when caught in the traps of crown forest fires. Standardized firefighter uniform does not provide protection against crown fires. Therte are proposed various options for solving this problem such as the development of individual means of protection – tents and collective protective constructions for several people. The estimation of efficiency of these means of protection at influence of fire hazards (powerful heat radiation, high temperature, products of burning (CO, CO2, smoke aerosol)) can be carried out in several stages - calculations and full-scale tests. The heating of the packages of protective materials used to make the shelters can be evaluated computationally. Full-scale experiments should be performed either in the forest area or to simulate a crown forest fire, for example, by the intensity of heat emission. The calculations made it possible to determine the range of possible heat release and to simulate both low-intensity and high-intensity crown forest fires. This approach makes it possible to achieve the necessary reproducibility of the experimental results. In the future in order to avoid uncertainties in evaluating the effectiveness of shelters for forest firefighters, it is necessary to develop a normative document (GOST) defining the requirements for shelters and methods of their testing.
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Gómez-González, Susana, and Lohengrin A. Cavieres. "Litter burning does not equally affect seedling emergence of native and alien species of the Mediterranean-type Chilean matorral." International Journal of Wildland Fire 18, no. 2 (2009): 213. http://dx.doi.org/10.1071/wf07074.
Повний текст джерелаАнотація:
Central Chile differs from other areas with Mediterranean-type climate by the scarcity of natural wildfires. The Chilean matorral is highly invaded by alien plant species from other Mediterranean zones of the world, where natural, recurrent wildfires have been one of their ecological features at least since the Pliocene. This suggests that anthropogenic fires in Chile might favour alien plant recruitment, increasing the invasive process. We assessed the effect of litter burning on the emergence of alien and native species from the soil seedbank of a matorral of central Chile. Soil samples were taken from three types of microhabitats: (i) closed matorral; (ii) beneath the canopy of shrubs and trees from an open matorral; (iii) grassland. Each sample was split in two subsamples. One subsample was exposed to fire by burning the litter taken from its corresponding microhabitat, and the other subsample was left unburned and used as a control. Fire intensity, determined by the fuel type, affected more markedly the native seedbank survival than the alien one. The low-intensity fire produced by grassland litter did not significantly affect the emergence of native herbs but increased alien species richness. The high-intensity and the very high-intensity fires produced by litter burning from beneath the canopy of the closed and the open matorral, respectively, negatively affected the seedling emergence of both native and alien species, but did so in a more pronounced manner to native species. Therefore, anthropogenic fires in central Chile may promote the invasion of alien plants with favourable traits (i.e. heat-shock resistance of seeds) that are not present in the native flora.
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Drewa, Paul B. "Effects of fire season and intensity on Prosopis glandulosa Torr. var. glandulosa." International Journal of Wildland Fire 12, no. 2 (2003): 147. http://dx.doi.org/10.1071/wf02021.
Повний текст джерелаАнотація:
In pyrogenic ecosystems, responses of resprouting woody vegetation may depend more on fire season than on intensity. I explored this hypothesis by examining fire season and intensity effects on response of Prosopis glandulosa, a resprouting shrub in Chihuahuan desert grasslands of the south-western United States. Clipping as well as low and high intensity fires (natural and added fuels, respectively) were applied during the 1999 growing season and the 2000 dormant season. Both fire season and intensity affected shrub responses. Numbers of resprouts increased 16%, and heights increased 8% after dormant season versus growing season treatments of fire and clipping combined. Height and resprout number decreased with increased fire intensity. Fire season and intensity effects on canopy area and stem growth were generally not detected. My results do not support the above hypothesis. Instead, fire season and intensity influence shrub responses in different ways via different mechanisms. Prosopis glandulosa has the potential to respond more after dormant season than growing season fires, perhaps as determined by carbohydrate availability in underground organs at the time of fire. However, realization of this potential is contingent on fire intensity as influenced primarily by fuel amount. In turn, fire intensity will determine the amount and duration of heat penetration into soils and thus the amount of damage to growing points of under-ground organs.
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Levchenko, Valeriy, Igor Shulga, Ihor Ivanyuk, Igor Budnik, Alena Korkulenko, and Taisa Ganzhalyuk. "RESTORATION OF FORESTS IN THE TERRITORIES PASSED BY LARGE-FOREST FOREST FIRE IN THE CONDITIONS OF THE STATE ENTERPRISE «OVRUTSKE FORESTRY»." Innovative Solution in Modern Science 6, no. 50 (October 18, 2021): 13. http://dx.doi.org/10.26886/2414-634x.6(50)2021.2.
Повний текст джерелаАнотація:
Topical issues of forest regeneration in the territories of the State Forest Fund of the Zhytomyr Regional Department of Forestry and Hunting, which were passed by large-scale forest fires, are substantiated. The processes of forest regeneration in the conditions of tracts of the State Enterprise «Ovruch Forestry» are analyzed, as well as organizational and ecological-forestry aspects are considered.The subject of the work is reforestation on fires, which were formed as a result of large-scale forest fires in 2018, 2020 in the forests of the State Enterprise «Ovruch Forestry». Particular attention in the research process was paid to the condition of areas after large-scale forest fires, as well as technological features of reforestation in areas that were passed by large-scale forest fires, including in terms of radioactively contaminated soils. Today, these aspects are becoming extremely important for the restoration of forests in the post-fire period on fires not only in the forest edatopes of the State Enterprise «Ovruch Forestry», but also in the forest ecosystems of the Zhytomyr Regional Department of Forestry and Hunting. All the above elements of reforestation have significant practical economic value for forestry enterprises, as the issue of reforestation of fires is quite relevant in their production activities. A significant degree of forest burnout as a result of large-scale forest fires in 2018, 2020 in the forest edatops of the State Enterprise «Ovruch Forestry» significantly affected not only the state of economic development, but also the strategic sustainable development and infrastructure of settlements located in areas of large-scale forest fires, as well as, unfortunately, human casualties from the local population. All this emphasizes the extreme relevance and prospects of research on reforestation and the impossibility of recurrence and spread to large areas of forest fires in the region of Ovruch-Slovenian ridge.The aim of the work is to study in detail the possibility of conducting operational reforestation measures in areas affected by the fire of large-scale forest fires in 2020 and to predict the possibility of preventing the recurrence and spread of forest fires in large forested areas and settlements located in the «Ovruch Forestry».The main methods of reforestation after large-scale forest fires in forest tracts of the State Enterprise «Ovruch Forestry» are calculation and analytical collection and processing of the results of the laid trial areas on forest fires in 2018, 2020 monitoring of the impact of various forest fires in the forest. period on fires of different degrees of burning of wood, shrub, grass vegetation and litter for the effectiveness of afforestation of large-scale fires in the forest edata of the State Enterprise «Ovruch Forestry», as well as route surveys of areas adjacent to the centers of large-scale forest fires determining the degree of thermal damage to stands from exposure to high temperatures, infrared irradiation of arriving and mature stands, analysis of the effectiveness of measures to localize and extinguish large-scale forest fires, including the use of aircraft of the SES of Ukraine. Determining the nature of the population of forest stands, which were weakened due to the direct impact of forest fires, but were not destroyed by fire, forest and coniferous rodent pests. This will make it possible in the next 10 years to predict possible outbreaks and spread of forest pests from weakened stands as a result of large-scale forest fires in 2020 in arriving and mature stands to determine the nature of drying and damage to various species of conifers and leaf-eating rodents.According to the results of the work it was established that forest fires of the State Forest Fund of Zhytomyr Regional Department of Forestry and Hunting and forest tracts of the State Enterprise «Ovruch Forestry» in particular should be restored by creating forest crops by planting after soil preparation taking into account the conditions of radioactive contamination -15 Ki/km2. It was found that most of the studied forest fires by the degree of burnout from the influence of combustion factors during the development of large-scale forest fires are suitable for reforestation without prior soil reclamation and reclamation measures, which will further effectively conduct forest reforestation after forest fires. in the conditions not only of the State Enterprise «Ovruch Forestry», but also in the area of Zhytomyr Polissya in particular.The scope of research is the forestry enterprises of the Zhytomyr Regional Department of Forestry and Hunting, forest tracts of the State Enterprise «Ovruch Forestry» in which appropriate measures were taken to preserve and protect forests from large-scale forest fires, as well as further prevent victims among pine, oak, aspen, birch, alder forest plantations from forest pests in the Polissya zone of Ukraine.The conclusions of the research are that the application of the proposed measures for reforestation after large-scale forest fires allows at the initial stage of forest formation after reforestation in edatopes C2-C3 of the State Enterprise «Ovruch Forestry» to create viable pine, pine, oak which is resistant to pests and diseases. The proposed methods of reforestation after large-scale forest fires make it possible to plant forests under different mixing schemes without additional reclamation and reclamation measures, including in conditions of radioactive contamination with a density of 10-15 Ki/km2, to implement measures for fire prevention in conditions of the Polissya zone of Zhytomyr region. Practical recommendations on the use of forest regeneration methods in the territories of the Zhytomyr Regional Department of Forestry and Hunting to prevent cases of rapid occurrence and rapid spread of large-scale forest fires. As a result of our research, we found that the most effective reforestation occurs after high-intensity forest fires, after which the combustion of a layer of above-ground forest combustible materials and subsequent loss of burnt trees creates favorable conditions for emergence and growth of seedlings. We have established a close link between reforestation in areas affected by large-scale forest fires with 45% burning of forest combustible materials and the duration of the period of post-pyrological impact, which is particularly clear after high-intensity forest fires, which were observed in 2018, 2020 territories of forest tracts of the State Enterprise «Ovruch Forestry». It is established that after low-intensity forest fires the process of formation of viable undergrowth in pines of types C2-C3 is stretched for a longer period. It is determined that reforestation in pine plantations of types C2-C3 after large-scale forest fires of high intensity is satisfactory. It is analyzed that reforestation after medium and low intensity fires in 55% of cases the amount of undergrowth is not enough for successful reforestation. It is proved that after fire restoration in the conditions of forest types C2-C3 of the State enterprise «Ovruch forestry» occurs without change of breeds. As a result of the conducted researches we proved that after fire reforestation in the territories affected by large-scale forest fires with application of the offered schemes of mixing of wood breeds will give the chance to carry out afforestation with survival of seedlings by 85-90% more effectively. The results of the research confirm the effectiveness of the proposed methods of reforestation of forest fires after large-scale forest fires and may be useful in addressing the urgency of reforestation measures in the affected forest tracts of the State Enterprise «Ovruch Forestry» and in the Zhytomyr Regional Department. hunting economy in particular.
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Podur, Justin, and B. Mike Wotton. "Defining fire spread event days for fire-growth modelling." International Journal of Wildland Fire 20, no. 4 (2011): 497. http://dx.doi.org/10.1071/wf09001.
Повний текст джерелаАнотація:
Forest fire managers have long understood that most of a fire’s growth typically occurs on a small number of days when burning conditions are conducive for spread. Fires either grow very slowly at low intensity or burn considerable area in a ‘run’. A simple classification of days into ‘spread events’ and ‘non-spread events’ can greatly improve estimates of area burned. Studies with fire-growth models suggest that the Canadian Forest Fire Behaviour Prediction System (FBP System) seems to predict growth well during high-intensity ‘spread events’ but tends to overpredict rate of spread for non-spread events. In this study, we provide an objective weather-based definition of ‘spread events’, making it possible to assess the probability of having a spread event on any particular day. We demonstrate the benefit of incorporating this ‘spread event’ day concept into a fire-growth model based on the Canadian FBP System.
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Amiridis, V., E. Giannakaki, D. S. Balis, E. Gerasopoulos, I. Pytharoulis, P. Zanis, S. Kazadzis, D. Melas, and C. Zerefos. "Smoke injection heights from agricultural burning in Eastern Europe as seen by CALIPSO." Atmospheric Chemistry and Physics Discussions 10, no. 8 (August 16, 2010): 19247–76. http://dx.doi.org/10.5194/acpd-10-19247-2010.
Повний текст джерелаАнотація:
Abstract. High frequency of agricultural fires is observed every year during the summer months over SW Russia and Eastern Europe. This study investigates the initial injection height of aerosol generated by the fires over these regions during the biomass burning season, which determines the potential for long-range transport of the smoke. This information is critical for aerosol transport modeling, as it determines the smoke plume evolution. The study focuses on the period 2006–2008, and is based on observations made by the CALIOP instrument on board the NASA CALIPSO satellite. MODIS data are synergistically used for the detection of the fires and the characterization of their intensity. CALIPSO aerosol vertical distributions generated by the active fires are analyzed to investigate the aerosol top height which is considered dependent on the heat generated by the fires and can be associated with the initial injection height. Aerosol top heights of the vertically homogenous smoke layers are found to range between 1.6 and 5.9 km. Smoke injection heights from CALIPSO are compared with mixing layer heights taken by the European Centre for Medium-range Weather Forecast (ECMWF), to investigate the direct injection of smoke particles to the free troposphere. Our results indicate that the aerosol plumes are observed within the boundary layer for the 50% of the cases examined. For the rest of the cases, the strong updrafts generated by the fires resulted to smoke injection heights greater than the ECMWF estimated mixing layer by 0.5 to 3.0 km, indicating a direct smoke injection into the free troposphere. The smoke injection height showed a dependence on the MODIS-Land Fire Radiative Power product which is indicative of the fire intensity.
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Higgins, Steven I., William J. Bond, Winston S. W. Trollope, and Richard J. Williams. "Physically motivated empirical models for the spread and intensity of grass fires." International Journal of Wildland Fire 17, no. 5 (2008): 595. http://dx.doi.org/10.1071/wf06037.
Повний текст джерелаАнотація:
We develop empirical models for the rate of spread and intensity of fires in grass fuels. The models are based on a well-known physical analogy for the rate of spread of a fire through a continuous fuelbed. Unlike other models based on this analogy, we do not attempt to directly estimate the model parameters. Rather, we use data on the rate of spread to indirectly estimate parameters that describe aggregate properties of the fire behaviour. The resulting models require information on the moisture content of the fuel and wind speed to predict the rate of spread of fires. To predict fire intensity, the models additionally use information on the heat yield of the fuel and the amount of fuel consumed. We evaluate the models by using them to predict the intensity of independent fires and by comparing them with linear and additive regression models. The additive model provides the best description of the training data but predicts independent data poorly and with high bias. Overall, the empirical models describe the data better than the linear model, and predict independent data with lower bias. Hence our physically motivated empirical models perform better than statistical models and are easier to parameterise than parameter-rich physical models. We conclude that our physically motivated empirical models provide an alternative to statistical models and parameter-rich physical models of fire behaviour.
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Li, Wenjun, Peng Li, and Zhiming Feng. "Delineating Fire-Hazardous Areas and Fire-Induced Patterns Based on Visible Infrared Imaging Radiometer Suite (VIIRS) Active Fires in Northeast China." Remote Sensing 14, no. 20 (October 13, 2022): 5115. http://dx.doi.org/10.3390/rs14205115.
Повний текст джерелаАнотація:
(1) Background: Fire affects global agricultural and/or forest ecosystems with high biomass accumulation. However, the delineation of fire-hazardous areas based on satellite-derived active fire intensity is not well-studied. Therefore, examining the characteristics of fire occurrence and development plays an important role in zoning fire-hazardous areas and promoting fire management. (2) Methods: A fire intensity (FI) index was developed with Visible Infrared Imaging Radiometer Suite (VIIRS) active fires and then applied to identify fire-hazardous areas in Northeast China. Combined with terrain, land cover and net primary productivity (NPP), the spatial and temporal characteristics of active fire occurrence were consistently analyzed. Next, a conceptual decision tree model was constructed for delineating fire-induced patterns impacted by varied factors in Northeast China. (3) Results: The accidental, frequent, prone and high-incidence areas of active fires defined by the FI index accounted for 31.62%, 30.97%, 26.23% and 11.18%, respectively. More than 90% of active fires occurred in areas with altitude <350 m above sea level (asl), slope <3° and NPP between 2500–5000 kg·C/m2. Similarly, about 75% occurred in cropland and forest. Then, four fire-induced conceptual patterns driven by different factors were classified, including the agricultural and forest active fire-induced patterns (i.e., the Agri-pattern and FRST pattern) with NPP ranging 2500–5000 kg·C/m2, and two others related to settlements and unused land with an altitude <350 m asl. The Agri-pattern dominates in Northeast China because of agricultural straw burning. (4) Conclusions: Despite the national bans of open burning of straws, active fires due to agricultural production have occurred frequently in Northeast China in the last decade, followed by small and sporadic forest fires. The approach for defining fire-hazardous areas and varied fire occurrence patterns is of significance for fire management and risk prediction at continental to global scales.
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Martínez-Abarca, Rodrigo, Socorro Lozano-García, Beatriz Ortega-Guerrero, and Margarita Caballero-Miranda. "Fires and volcanic activity: History of fire in the Mexico basin during late Pleistocene based on carbonized material records in the Chalco lake." Revista Mexicana de Ciencias Geológicas 36, no. 2 (July 28, 2019): 259–69. http://dx.doi.org/10.22201/cgeo.20072902e.2019.2.1090.
Повний текст джерелаАнотація:
Forest fires, considered as free and not programmed fire propagation, are perturbations that greatly alter ecosystems. During fires, variable quantities of charcoal particles are produced by the burning vegetation, which can be later deposited in lacustrine basins. The traditional charcoal size particle model associates the > 100 µm primary particles to local fire events, within the watershed, and the < 100 µm particles are linked to regional fire events, outside the watershed. Fires can be related with favorable climatic conditions, but in tectonically active areas like the basin of Mexico, volcanism can also be a factor producing fires and charcoal particles. We document the history, intensity and frequency of fires recorded in the lacustrine sediments of lake Chalco (core CHAVII-11), by performing a high-resolution charcoal particle analysis in sediments deposited before and after three main volcanic events. The sources of these events had different distances to lake Chalco: Tláhuac tephra (TTH; 28690 years cal BP), probably produced by the Teuhtli volcano, was a local event; the Tutti Frutti Pumice (PTF; 17000 years cal BP) produced by the Popocatépetl volcano, was an extra-local event and the Upper Toluca Pumice (PTS; 12300 years cal BP) produced by the Nevado de Toluca volcano, was a regional event. Charcoal accumulation rates (CHAR) and distribution of size particles indicate that paleoclimate was a direct factor defining the intensity and recurrence of fires before and after volcanic activity, as climate defines vegetation type and density, and therefore fuel availability. Fires before and after the TTH were frequent, local and intense in comparison with fires reconstructed before or after the PTF and PTS events. CHAR values were lower during the more widespread PTF event, than for the local TTH event, although the highest CHAR values were recorded for the most distant, regional, and intense PTS event. These results show that charcoal accumulation rates during the volcanic events in central Mexico cannot be interpreted following traditional model of charcoal particle dispersion. This model have important restrictions in active volcanic regions such as central Mexico.
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Nishino, Tomoaki, Takeyoshi Tanaka, and Shin-ichi Tsuburaya. "Development and Validation of a Potential-Based Model for City Evacuation in Post-Earthquake Fires." Earthquake Spectra 29, no. 3 (August 2013): 911–36. http://dx.doi.org/10.1193/1.4000155.
Повний текст джерелаАнотація:
A computational model for the city evacuation of residents in post-earthquake fires has been developed. When a major earthquake affects a city in Japan, a tremendous number of evacuees are likely to escape in an urban area from hazards due to urban fires following the earthquake. The proposed model is based on the concept of potential. In this concept, an evacuee travels toward a descending direction of potential in the same manner that water runs from a high point to a low point. The potential is calculated from such hazard levels as the intensity of thermal radiation and the temperature rise caused by wind-blown fire plumes. In this paper, we simulate the evacuation behavior of residents in the 1923 Kanto earthquake fires to validate the proposed model. The number of fatalities estimated by the model is in reasonable agreement with the number of fatalities reported from the survey after the fires.
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Li, Shuting, Zihan Zhang, Jiangkun Zheng, Guirong Hou, Han Liu, and Xinglei Cui. "Evaluation of Litter Flammability from Dominated Artificial Forests in Southwestern China." Forests 14, no. 6 (June 14, 2023): 1229. http://dx.doi.org/10.3390/f14061229.
Повний текст джерелаАнотація:
Southwestern China has a large area of artificial forests and has experienced massive environmental and social losses due to forest fires. Evaluating the flammability of fuels from dominated forests in this region can help assess the fire risk and predict potential fire behaviors in these forests, thus guiding forest fire management. However, such studies have been scarcely reported in this region. In this study, the flammability of litter from nine forest types, which are common in southwestern China, was evaluated by measuring organic matter content, ignition point, and calorific value. All these flammability characteristics of fuels varied significantly across forest types. By using principal component analysis and K-means clustering, litters were classified into three groups: highly susceptible to ignition with low fire intensity (Pinus densata, Pinus densata-Populus simonii, Pinus yunnanensis, Larix gmelini, Pinus armandii), less susceptible to ignition with high fire intensity (Abies fabri-Populus simonii), and median ignitibility and fire intensity (Abies fabri, Abies fabri-Picea asperata, Platycladus orientalis). Our study can help predict the risk and intensity of fires in the studied forests and serve as a source of information for fire management in southwestern China.
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Belcher, Claire M., Stacey L. New, Michael R. Gallagher, Mark J. Grosvenor, Kenneth Clark, and Nicholas S. Skowronski. "Bark charcoal reflectance may have the potential to estimate the heat delivered to tree boles by wildland fires." International Journal of Wildland Fire 30, no. 5 (2021): 391. http://dx.doi.org/10.1071/wf20071.
Повний текст джерелаАнотація:
Currently, our ability to link wildland fire behaviour to fire effects is through the lens of fire severity assessments, because there are no ground-based post-fire metrics that are able to quantitively capture aspects of heat transfer to plants. This presents a particular challenge when considering tree mortality linked to cambial damage, which can occur in both low-intensity surface fires through to high-intensity crown fires. Recent research suggests that measuring the amount of light reflected from charcoals produced by wildland fires will provide information about the energy flux that created the char. We created an experimental forest fire in which we had instrumented individual trees to record the energy delivered to the bark close to the base of the trees. We then assessed the bark charcoal reflectance of the same trees. We found that bark charcoal reflectance showed a strong positive correlation (r2>0.86, P=0.0031) with increasing duration of heating and the total energy delivered to the bark. We suggest that this may provide useful quantitative data that can be included in models or post-fire surveys to estimate tree mortality due to cambial kill.
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Perera, Ajith H., Benjamin D. Dalziel, Lisa J. Buse, and Robert G. Routledge. "Spatial variability of stand-scale residuals in Ontario’s boreal forest fires." Canadian Journal of Forest Research 39, no. 5 (May 2009): 945–61. http://dx.doi.org/10.1139/x09-024.
Повний текст джерелаАнотація:
Knowledge of postfire residuals in boreal forest landscapes is increasingly important for ecological applications and forest management. While many studies provide useful insight, knowledge of stand-scale postfire residual occurrence and variability remains fragmented and untested as formal hypotheses. We examined the spatial variability of stand-scale postfire residuals in boreal forests and tested hypotheses of their spatial associations. Based on the literature, we hypothesized that preburn forest cover characteristics, site conditions, proximity to water and fire edge, and local fire intensity influence the spatial variability of postfire residuals. To test these hypotheses, we studied live-tree and snag residuals in 11 boreal Ontario forest fires, using 660 sample points based on high resolution photography (1:408) captured immediately after the fires. The abundance of residuals varied considerably within and among these fires, precluding attempts to generalize estimates. Based on a linear mixed-effects model, our data did not support the hypotheses that preburn forest cover characteristics, site conditions, and proximity to water significantly affect the spatial variability of stand-scale residuals. The results do indicate, however, that stand-scale residual variability is associated with local fire intensity (strongly) and distance to fire edge (weakly).
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Ling, Han, Guangyu Wang, Wanli Wu, Anil Shrestha, and John L. Innes. "Grassland Resilience to Woody Encroachment in North America and the Effectiveness of Using Fire in National Parks." Climate 11, no. 11 (November 2, 2023): 219. http://dx.doi.org/10.3390/cli11110219.
Повний текст джерелаАнотація:
The grasslands of North America are threatened by woody encroachment. Restoring historical fire regimes has been used to manage brush encroachment. However, fire management may be insufficient due to the nonlinear and hysteretic responses of vegetation recovery following encroachment and the social–political constraints affecting fire management. We synthesized the fire thresholds required to control woody encroachment by typical encroaching species in North America, especially the Great Plains region, and identified the social–political constraints facing fire management in selected grassland national parks. Our synthesis revealed the resistance, hysteresis, and irreversibility of encroached grasslands using fire and emphasized the need for a combination of brush management methods if the impacts of climate change are to be addressed. Frequent fires alone may maintain grassland states, reflecting resistance. However, high-intensity fires exceeding fire-mortality thresholds are required to exclude non-resprouting shrubs and trees, indicating hysteresis. Fire alone may be insufficient to reverse encroachment by resprouting species, exhibiting reversibility. In practice, appropriate fire management may restore resistant grassland states. However, social–political constraints have restricted the use of frequent and high-intensity fires, thereby reducing the effectiveness of management actions to control woody encroachment of grasslands in national parks. This research proposes a resilience-based framework to manage woody encroachment in grassland national parks and similar protected areas.
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Amiridis, V., E. Giannakaki, D. S. Balis, E. Gerasopoulos, I. Pytharoulis, P. Zanis, S. Kazadzis, D. Melas, and C. Zerefos. "Smoke injection heights from agricultural burning in Eastern Europe as seen by CALIPSO." Atmospheric Chemistry and Physics 10, no. 23 (December 7, 2010): 11567–76. http://dx.doi.org/10.5194/acp-10-11567-2010.
Повний текст джерелаАнотація:
Abstract. High frequency of agricultural fires is observed every year during the summer months over SW Russia and Eastern Europe. This study investigates the initial injection height of aerosol generated by the fires over these regions during the biomass burning season, which determines the potential for long-range transport of the smoke. This information is critical for aerosol transport modeling, as it determines the smoke plume evolution. The study focuses on the period 2006–2008, and is based on observations made by the CALIOP instrument on board the NASA CALIPSO satellite. MODIS data are synergistically used for the detection of the fires and the characterization of their intensity. CALIPSO aerosol vertical distributions generated by the active fires are analyzed to investigate the aerosol top height which is considered dependent on the heat generated by the fires and can be associated with the initial injection height. Aerosol top heights of the vertically homogenous smoke layers are found to range between 1.6 and 5.9 km. Smoke injection heights from CALIPSO are compared with mixing layer heights taken by the European Centre for Medium-range Weather Forecast (ECMWF), to investigate the direct injection of smoke particles into the free troposphere. Our results indicate that the aerosol plumes are observed within the boundary layer for the 50% of the cases examined. For the rest of the cases, the strong updrafts generated by the fires resulted to smoke injection heights greater than the ECMWF estimated mixing layer by 0.5 to 3.0 km, indicating a direct smoke injection into the free troposphere. The smoke injection height showed a dependence on the MODIS-Land Fire Radiative Power product which is indicative of the fire intensity, especially in the cases of lower static stability in the upper part of the boundary layer and the free troposphere.