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1
Lyon, Zachary D., Penelope Morgan, Camille S. Stevens-Rumann, Aaron M. Sparks, Robert F. Keefe, and Alistair M. S. Smith. "Fire behaviour in masticated forest fuels: lab and prescribed fire experiments." International Journal of Wildland Fire 27, no. 4 (2018): 280. http://dx.doi.org/10.1071/wf17145.
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Managers masticate fuels to reduce extreme fire hazards, but the effect on fire behaviour within the resulting compact fuelbeds is poorly understood. We burned 54 masticated fuelbeds in laboratory experiments one and two growing seasons after mastication and 75 masticated fuelbeds in prescribed fire experiments one growing season after treatment in three replicate Pinus ponderosa stands. Mastication treatments reduced density of trees >5 cm diameter by 30–72% resulting in total fuel depth of 6.9–13.7 cm and surface woody fuel loading of 1.0–16.0 kg m−2. Flame length and rate of spread were low and similar for coarse and fine mastication treatments and controls. Smouldering combustion lasted 6–22 h in prescribed fire experiments where fuelbeds included duff and were well mixed by machinery, compared with <2 h in the laboratory where fuelbeds did not include duff and had varying fuel moisture. Fuel consumption in the prescribed fires was highly variable, ranging from 0 to 20 cm in depth and was less from 2-year-old fuelbeds than 1-year-old fuelbeds in laboratory burns. Compared with fine mastication treatments, coarse treatments took less time to implement and were more cost-effective. Although laboratory experiments expand our understanding of burning masticated fuels under controlled conditions, they did not readily translate to prescribed burning conditions where fuels, weather and ignition patterns were more variable. This highlights the need for more laboratory experiments and in situ research that together can be used to develop much-needed, scalable predictive models of mastication combustion.
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Pappa, Athina A., Nikolaos E. Tzamtzis, and Sofia E. Koufopoulou. "Nitrogen leaching from a forest soil exposed to fire retardant with and without fire: A laboratory study." Annals of Forest Science 65, no. 2 (January 2008): 210. http://dx.doi.org/10.1051/forest:2007093.
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Paoletti, Elena, Andrzej Bytnerowicz, Chris Andersen, Algirdas Augustaitis, Marco Ferretti, Nancy Grulke, Madeleine S. Günthardt-Goerg, et al. "Impacts of Air Pollution and Climate Change on Forest Ecosystems — Emerging Research Needs." Scientific World JOURNAL 7 (2007): 1–8. http://dx.doi.org/10.1100/tsw.2007.52.
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Outcomes from the 22ndmeeting for Specialists in Air Pollution Effects on Forest Ecosystems “Forests under Anthropogenic Pressure Effects of Air Pollution, Climate Change and Urban Development”, September 1016, 2006, Riverside, CA, are summarized. Tropospheric or ground-level ozone (O3) is still the phytotoxic air pollutant of major interest. Challenging issues are how to make O3standards or critical levels more biologically based and at the same time practical for wide use; quantification of plant detoxification processes in flux modeling; inclusion of multiple environmental stresses in critical load determinations; new concept development for nitrogen saturation; interactions between air pollution, climate, and forest pests; effects of forest fire on air quality; the capacity of forests to sequester carbon under changing climatic conditions and coexposure to elevated levels of air pollutants; enhanced linkage between molecular biology, biochemistry, physiology, and morphological traits.
4
McAlpine, R. S. "Temporal variations in elliptical forest fire shapes." Canadian Journal of Forest Research 19, no. 11 (November 1, 1989): 1496–500. http://dx.doi.org/10.1139/x89-228.
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Elliptical fire growth models are dependant on a relationship between the length to width ratio of the ellipse and the prevailing wind speed. A laboratory study of point source fires growing in two fuel types (Ponderosa Pine (Pinusponderosa Laws.) needle litter and excelsior) showed that the length to width ratio changes from the time of inception until a stabilized "equilibrium" eccentricity is established. The size of fuel bed required to allow stabilization of the length to width ratio is dependant on wind speed. Results indicate that a fuel bed 0.93 m wide is insufficient to allow length to width ratio stabilization for wind speeds above 1.6 km/h.
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Yokelson, R. J., T. J. Christian, T. G. Karl, and A. Guenther. "The tropical forest and fire emissions experiment: laboratory fire measurements and synthesis of campaign data." Atmospheric Chemistry and Physics 8, no. 13 (July 4, 2008): 3509–27. http://dx.doi.org/10.5194/acp-8-3509-2008.
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Abstract. As part of the Tropical Forest and Fire Emissions Experiment (TROFFEE), tropical forest fuels were burned in a large, biomass-fire simulation facility and the smoke was characterized with open-path Fourier transform infrared spectroscopy (FTIR), proton-transfer reaction mass spectrometry (PTR-MS), gas chromatography (GC), GC/PTR-MS, and filter sampling of the particles. In most cases, about one-third of the fuel chlorine ended up in the particles and about one-half remained in the ash. About 50% of the mass of non-methane organic compounds (NMOC) emitted by these fires could be identified with the available instrumentation. The lab fire emission factors (EF, g compound emitted per kg dry fuel burned) were coupled with EF obtained during the TROFFEE airborne and ground-based field campaigns. This revealed several types of EF dependence on parameters such as the ratio of flaming to smoldering combustion and fuel characteristics. The synthesis of data from the different TROFFEE platforms was also used to derive EF for all the measured species for both primary deforestation fires and pasture maintenance fires – the two main types of biomass burning in the Amazon. Many of the EF are larger than those in widely-used earlier work. This is mostly due to the inclusion of newly-available, large EF for the initially-unlofted smoldering emissions from residual logs in pastures and the assumption that these emissions make a significant contribution (~40%) to the total emissions from pasture fires. The TROFFEE EF for particles with aerodynamic diameter <2.5 microns (EFPM2.5) is 14.8 g/kg for primary deforestation fires and 18.7 g/kg for pasture maintenance fires. These EFPM2.5 are significantly larger than a previous recommendation (9.1 g/kg) and lead to an estimated pyrogenic primary PM2.5 source for the Amazon that is 84% larger. New regional budgets for biogenic and pyrogenic emissions were roughly estimated. Coupled with an estimate of secondary aerosol formation in the Amazon and source apportionment studies, the regional budgets suggest that ~5% of the total mass of the regionally generated NMOC end up as secondary organic aerosol within the Amazonian boundary layer within 1–3 days. New global budgets confirm that biogenic emissions and biomass burning are the two largest global sources of NMOC with an estimated production of approximately 1000 (770–1400) and 500 (250–630) Tg/yr, respectively. It follows that plants and fires may also be the two main global sources of secondary organic aerosol. A limited set of emission ratios (ER) is given for sugar cane burning, which may help estimate the air quality impacts of burning this major crop, which is often grown in densely populated areas.
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Yokelson, R. J., T. J. Christian, T. G. Karl, and A. Guenther. "The tropical forest and fire emissions experiment: laboratory fire measurements and synthesis of campaign data." Atmospheric Chemistry and Physics Discussions 8, no. 2 (March 3, 2008): 4221–66. http://dx.doi.org/10.5194/acpd-8-4221-2008.
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Abstract. As part of the Tropical Forest and Fire Emissions Experiment (TROFFEE), tropical forest fuels were burned in a large, biomass-fire simulation facility and the smoke was characterized with open-path Fourier transform infrared spectroscopy (FTIR), proton-transfer reaction mass spectrometry (PTR-MS), gas chromatography (GC), GC/PTR-MS, and filter sampling of the particles. In most cases, about one-third of the fuel chlorine ended up in the particles and about one-half remained in the ash. About 50% of the mass of non-methane organic compounds (NMOC) emitted by these fires could be identified with the available instrumentation. The lab fire emission factors (EF, g compound emitted per kg fuel burned) were coupled with EF obtained during the TROFFEE airborne and ground-based field campaigns. This revealed several types of EF dependence on parameters such as the ratio of flaming to smoldering combustion and fuel characteristics. The synthesis of data from the different TROFFEE platforms was also used to derive EF for all the measured species for both primary deforestation fires and pasture maintenance fires – the two main types of biomass burning in the Amazon. Many of the EF are larger than those in widely-used earlier work. This is mostly due to the inclusion of newly-available, large EF for the initially-unlofted smoldering emissions and the assumption that these emissions make a significant contribution (~40%) to the total emissions from pasture fires. The TROFFEE EF for particles with aerodynamic diameter <2.5 microns (EFPM2.5) is 14.8 g/kg for primary deforestation fires and 18.7 g/kg for pasture maintenance fires. These EFPM2.5 are significantly larger than a previous recommendation (9.1 g/kg) and lead to an estimated pyrogenic primary PM2.5 source for the Amazon that is 84% larger. Regional through global budgets for biogenic and pyrogenic emissions were roughly estimated. Coupled with previous measurements of secondary aerosol growth in the Amazon and source apportionment studies, the regional budgets suggest that ~5% of the total mass of the regionally generated NMOC end up as secondary organic aerosol within the Amazonian boundary layer within 1–3 days. The global budgets confirm that biogenic emissions and biomass burning are the two largest global sources of NMOC with an estimated production of approximately 1000 and 500 Tg/yr, respectively. It follows that plants and fires may also be the two main global sources of secondary organic aerosol. A limited set of emission ratios (ER) is given for sugar cane burning, which may help estimate the air quality impacts of burning this major crop, which is often grown in densely populated areas.
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Pappa, A., N. Tzamtzis, and S. Koufopoulou. "Effect of fire retardant application on phosphorus leaching from Mediterranean forest soil: short-term laboratory-scale study." International Journal of Wildland Fire 15, no. 3 (2006): 287. http://dx.doi.org/10.1071/wf05002.
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The application of fire retardants for forest fire prevention purposes can result in chemicals leaching from soil to the drainage water during the annual rainfall period. In addition, wildland fires can have an impact on the leaching of various chemicals from treated forest soils. In leachates, large concentrations of phosphorus (P) – one of the major components of long-term retardants – could affect the groundwater quality. In this present study, the leaching of phosphorus (contained in FIRE-TROL 931 – a long-term fire retardant based on polyphosphates) from a typical Mediterranean forest soil, was studied at the laboratory scale. The concentrations of P from the application of retardant in the resulting leachates from pots, containing forest soil and pine trees (Pinus halepensis), alone and in combination with fire, were determined by an inductively coupled plasma analytical method. The leaching of P, under the conditions used, was found to be a small percentage of the initially applied P quantities. However, it was different among the treated samples affected by both plant and fire conditions.
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Tovarianskyi, V., and I. Pasnak. "EXPERIMENTAL STUDIES OF FIRE HAZARD OF PINE NEEDLES IN LABORATORY AND FIELD CONDITIONS." Fire Safety, no. 33 (December 31, 2018): 107–11. http://dx.doi.org/10.32447/20786662.33.2018.15.
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Introduction. The fire hazard analysis of young pine stands was carried out. There are listed the most common sources of ignition as factors of influence on the occurrence of a fire. There is described the examples of studies on solid combustible materials` ignition, particularly, forest litter. The device developed is proposed for studying the process of forest fuels combustion.
The aim of the work is determine the time to ignition of pine needles, as well as the forest litter in young pine stands by using a Device for the study of flammable material combustion using an electric heating element.
Material statement. Laboratory studies have been done to ignite three types of needles of young pine plantations: fresh, inherent in the composition of forest underlay and dried needles. There was conducted an experimental studies of the time interval to the ignition of pine stands forest litter in the field condition with the use of the proposed device.
Scientific novelty. It for the first time was established that the time interval before ignition of freshly cut needles exceeds by almost 4 times the meaning of this value in comparison with the dried needles. It was established that the value of the time to ignition of pine needles fallen in the forest litter, obtained from the results of field studies, with a slight deviation of its moisture, is almost the same with the values obtained in laboratory conditions.
The results indicate that the forest litter in pine stands is fire-hazardous and can deal with a frequency close to ½ of a source with a temperature of 450°C, on average 25,7 seconds. There has been substantiated the expediency of using the device for the study of flammable material combustion using an electric heating element for investigating indicators of forest combustible materials` fire hazard.
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Abakumov, Evgeny, Ekaterina Maksimova, Anna Tsibart, and George Shamilishviliy. "Laboratory Assessment of Forest Soil Respiration Affected by Wildfires under Various Environments of Russia." International Journal of Ecology 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/3985631.
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Pyrogenic carbon emission rates were estimated in the soils of three natural zones in Russia: forest-tundra, south-taiga, and forest-steppe. Postfire soils were found to be characterized by essential losses of soil C due to the combustion fire effect. Soils lost 3 or 5 parts of initial carbon content and showed an essential decrease in the C/N ratio during the fire effect. The pH values increased due to soil enrichment by ash during the fire events. CO2 emission rates were highest in natural soil samples, because the amount of organic matter affected by mineralization in those soils was higher than in natural ones. Simultaneously, the total values of mineralized carbon were higher in postfire soils because the SOM quality and composition were altered due to the fire effect. The only exception was in forest-tundra soils, where a high portion of dissolved organic compounds was released during the surface fire. The quality of initial SOM and intensity of the wildfire play the most important roles in the fate of SOM in postfire environments. Further study of CO2 emissions is needed to better characterize postfire SOM dynamics and develop an approach to model this process.
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Grishin, A. M., A. A. Dolgov, V. P. Zima, A. V. Isakov, V. V. Reino, and R. Sh Tsvyk. "Laboratory studies of the origin and spread of a surface forest fire." Combustion, Explosion, and Shock Waves 32, no. 6 (November 1996): 601–7. http://dx.doi.org/10.1007/bf02111560.
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Marcelli, Thierry, Paul A. Santoni, Albert Simeoni, Eric Leoni, and Bernard Porterie. "Fire spread across pine needle fuel beds: characterization of temperature and velocity distributions within the fire plume." International Journal of Wildland Fire 13, no. 1 (2004): 37. http://dx.doi.org/10.1071/wf02065.
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The aim of this article is twofold. First, it concerns the improvement of knowledge on the fundamental physical mechanisms that control the propagation of forest fires. To proceed, an experimental apparatus was designed to study, in laboratory conditions, the flame of a fire spreading across a pine needle fuel bed. Characterization of temperature was managed by using a reconstruction method based on a double thermocouple probe technique developed recently. The vertical gas velocity distribution was derived from the previous reconstructed signals by measuring the transit time of a thermal fluctuation between two points of the flow. Second, the experimental data were used for the testing of a physical two-phase model of forest fire behavior in which the decomposition of solid fuel constituting a forest fuel bed as well as the multiple interactions with the gas phase are represented.
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E. Alexander, Martin, and Miguel G. Cruz. "Graphical aids for visualizing Byram's fireline intensity in relation to flame length and crown scorch height." Forestry Chronicle 88, no. 02 (April 2012): 185–90. http://dx.doi.org/10.5558/tfc2012-035.
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Summary graphs depicting 20 individual flame length–fire intensity relationships grouped by four different fuel complex types or settings (forest, grassland, shrubland, and laboratory) and 12 individual fireline intensity–crown scorch height relationships for two broad forest stand types (conifer- and eucalypt-dominated) are presented. Users will find these quick reference visual aids of value in a wide variety of fire management applications.
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Seiwa, Kenji. "Variable regeneration behaviour of Ulmus davidiana var. Japonica in response to disturbance regime for risk spreading." Seed Science Research 7, no. 2 (June 1997): 195–207. http://dx.doi.org/10.1017/s0960258500003536.
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AbstractRecruitment-related traits (development and dispersal of seeds, emergence, leaf dynamics, growth and survival of seedlings) were studied in Japanese elm (Ulmus davidiana var. japonica) in relation to disturbance at the soil level (bare soil, litter and control) or the canopy level (forest edge (FE), small gaps (SG) and forest understorey (FU)), or both, in a riverside forest from 1990 to 1993. Seed germination was also tested in the laboratory. Litter accumulation severely inhibited seedling emergence. Seedling emergence from a single seed rain occurred in summer immediately after seed dissemination and in the following spring. In summer, seedling emergence was higher in FE than in FU. In the following spring more seedlings emerged in FU than in FE and SG, resulting in non-significant differences in the percentage emergence among the three sites in bare soil. Darkness or far-red light induced seed dormancy, but after chilling they started to germinate again under white or red light conditions. These results explained emergence phenology under changing light conditions in the field. In FU, the spring emerging cohort grew and survived better than the summer emerging one. In FE the reverse was true. Japanese elm avoids unfavourable periods by escaping either in time (dormancy) or in space (dispersal). Such traits compensate for late and compressed seed dissemination, and improve seedling growth and survival not only when disturbance occurs at both canopy and soil level (bare soil in FE) but also only at soil level (bare soil in FU), which may occur more frequently in riverside forests.
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Hatten, Jeff A., and Darlene Zabowski. "Fire severity effects on soil organic matter from a ponderosa pine forest: a laboratory study." International Journal of Wildland Fire 19, no. 5 (2010): 613. http://dx.doi.org/10.1071/wf08048.
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This study investigated the changes in soil organic matter composition by controlling fire severity of laboratory burns on reconstructed surface soil profiles (O, A1 (0–1 cm), and A2 (1–2 cm)). Laboratory burning simulated prescribed burns that would be typical in the understorey of a ponderosa pine forest at low, moderate, and high–moderate severity levels. Soils were analysed for C, N and soil organic matter composition. Soil organic matter was fractionated into humin, humic acid, fulvic acid, soluble non‐humic materials and other hydrophobic compounds. In the O horizon, low‐, moderate‐, and high‐severity treatments consumed an increasing proportion of C and N. Carbon content of the mineral soil was unaffected by burning; however, N content of the A2 horizon decreased after the moderate‐ and high‐severity treatments, likely as a result of N volatilisation. The proportion of non‐soluble material in the O horizon increased with fire severity, whereas the proportion of humin C as total C of the A horizon decreased with fire severity. The decrease in humin was followed by an increase in the other hydrophobic compounds. The higher fire intensity experienced by the burning O horizon created recalcitrant materials while an increase in labile soil organic matter was observed in mineral soil. An increase in labile soil organic matter may cause elevated C and N mineralisation rates often seen after fire.
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Simeoni, Albert, Pierre Salinesi, and Frédéric Morandini. "Physical modelling of forest fire spreading through heterogeneous fuel beds." International Journal of Wildland Fire 20, no. 5 (2011): 625. http://dx.doi.org/10.1071/wf09006.
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Vegetation cover is a heterogeneous medium composed of different kinds of fuels and non-combustible parts. Some properties of real fires arise from this heterogeneity. Creating heterogeneous fuel areas may be useful both in land management and in firefighting by reducing fire intensity and fire rate of spread. The spreading of a fire through a heterogeneous medium was studied with a two-dimensional reaction–diffusion physical model of fire spread. Randomly distributed combustible and non-combustible square elements constituted the heterogeneous fuel. Two main characteristics of the fire were directly computed by the model: the size of the zone influenced by the heat transferred from the fire front and the ignition condition of vegetation. The model was able to provide rate of fire spread, temperature distribution and energy transfers. The influence on the fire properties of the ratio between the amount of combustible elements and the total amount of elements was studied. The results provided the same critical fire behaviour as described in both percolation theory and laboratory experiments but the results were quantitatively different because the neighbourhood computed by the model varied in time and space with the geometry of the fire front. The simulations also qualitatively reproduced fire behaviour for heterogeneous fuel layers as observed in field experiments. This study shows that physical models can be used to study fire spreading through heterogeneous fuels, and some potential applications are proposed about the use of heterogeneity as a complementary tool for fuel management and firefighting.
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Malmström, Anna. "Temperature tolerance in soil microarthropods: Simulation of forest-fire heating in the laboratory." Pedobiologia 51, no. 5-6 (April 2008): 419–26. http://dx.doi.org/10.1016/j.pedobi.2008.01.001.
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Kreye, Jesse K., J. Kevin Hiers, J. Morgan Varner, Ben Hornsby, Saunders Drukker, and Joseph J. O’Brien. "Effects of solar heating on the moisture dynamics of forest floor litter in humid environments: composition, structure, and position matter." Canadian Journal of Forest Research 48, no. 11 (November 2018): 1331–42. http://dx.doi.org/10.1139/cjfr-2018-0147.
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Much of fire behavior is driven by fine-scale patterns of fuel moisture; however, moisture predictions typically occur over large scales. The source of fine-scale variation in moisture results from a combination of fuelbed properties and overstory forest structure that influences water movement and distribution of solar radiation. Fine-scale moisture variation is of particular relevance in humid forests managed with frequent prescribed fire where fire behavior variation is tightly linked to differential fire effects. Results of a three-tiered experiment combining laboratory and field methods demonstrated that solar radiation exerted a strong influence on fuel moisture patterns in a temperate humid pine forest. Infrared radiation more rapidly dried Quercus and Pinus litter in laboratory experiments compared with controls. Litter exposed to sunlight during small-scale outdoor experiments was significantly drier than shaded litter. Quercus litter was wetter than Pinus on mornings, but dried more rapidly, becoming drier than Pinus litter by mid-day when exposed to sunlight. Field observations validated small-scale outdoor and laboratory results but also revealed the influence of fuel position: elevated litter was wetter than ground-level litter at peak burning time. Results provide insight into how overstory structure and composition may influence fine-scale heterogeneity of surface moisture dynamics and fire behavior.
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Raposo, J. R., S. Cabiddu, D. X. Viegas, M. Salis, and J. Sharples. "Experimental analysis of fire spread across a two-dimensional ridge under wind conditions." International Journal of Wildland Fire 24, no. 7 (2015): 1008. http://dx.doi.org/10.1071/wf14150.
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Results from a laboratory-scale investigation of a fire spreading on the windward face of a triangular-section hill of variable shape with wind perpendicular to the ridgeline are reported. They confirm previous observations that the fire enlarges its lateral spread after reaching the ridgeline, entering the leeward face with a much wider front. Reference fire spread velocities were measured and analysed, putting in evidence the importance of the dynamic effect due to flow velocity and its associated horizontal-axis separation vortex strength without dependence on hill geometry. Similar parameters estimated from three forest fires compared favourably with the laboratory-scale measurements.
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Mathews, Bill J., Eva K. Strand, Alistair M. S. Smith, Andrew T. Hudak, B. Dickinson, and Robert L. Kremens. "Laboratory experiments to estimate interception of infrared radiation by tree canopies." International Journal of Wildland Fire 25, no. 9 (2016): 1009. http://dx.doi.org/10.1071/wf16007.
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Estimates of biomass-burning in wildfires or prescribed fires are needed to account for the production of trace gases and aerosols that enter the atmosphere during combustion. Research has demonstrated that the biomass consumption rate is linearly related to fire radiative power (FRP), and that total biomass consumed is linearly related to fire radiative energy (FRE). Measurement of these is biased by certain characteristics of a forest canopy, such as foliar moisture content and tree canopy cover. Laboratory experiments were conducted to assess the influence of canopy cover on the FRP observed from an overhead sensor (e.g. an aircraft or satellite). A range of canopy cover from 0 to 90% and two classes of canopy (non-transpiring living and desiccated branches) were used in the experiments. Experiments suggest that in cases of complete or nearly complete canopy closure, fires obscured by the canopy may be below the detection threshold of above-canopy FRP sensors. Results from this research will reduce uncertainties in estimates of biomass consumption in surface fires burning under forest canopies.
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Yokelson, R. J., T. Karl, P. Artaxo, D. R. Blake, T. J. Christian, D. W. T. Griffith, A. Guenther, and W. M. Hao. "The Tropical Forest and Fire Emissions Experiment: overview and airborne fire emission factor measurements." Atmospheric Chemistry and Physics 7, no. 19 (October 9, 2007): 5175–96. http://dx.doi.org/10.5194/acp-7-5175-2007.
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Abstract. The Tropical Forest and Fire Emissions Experiment (TROFFEE) used laboratory measurements followed by airborne and ground based field campaigns during the 2004 Amazon dry season to quantify the emissions from pristine tropical forest and several plantations as well as the emissions, fuel consumption, and fire ecology of tropical deforestation fires. The airborne campaign used an Embraer 110B aircraft outfitted with whole air sampling in canisters, mass-calibrated nephelometry, ozone by UV absorbance, Fourier transform infrared spectroscopy (FTIR), and proton-transfer mass spectrometry (PTR-MS) to measure PM10, O3, CO2, CO, NO, NO2, HONO, HCN, NH3, OCS, DMS, CH4, and up to 48 non-methane organic compounds (NMOC). The Brazilian smoke/haze layers extended to 2–3 km altitude, which is much lower than the 5–6 km observed at the same latitude, time of year, and local time in Africa in 2000. Emission factors (EF) were computed for the 19 tropical deforestation fires sampled and they largely compare well to previous work. However, the TROFFEE EF are mostly based on a much larger number of samples than previously available and they also include results for significant emissions not previously reported such as: nitrous acid, acrylonitrile, pyrrole, methylvinylketone, methacrolein, crotonaldehyde, methylethylketone, methylpropanal, "acetol plus methylacetate," furaldehydes, dimethylsulfide, and C1-C4 alkyl nitrates. Thus, we recommend these EF for all tropical deforestation fires. The NMOC emissions were ~80% reactive, oxygenated volatile organic compounds (OVOC). Our EF for PM10 (17.8±4 g/kg) is ~25% higher than previously reported for tropical forest fires and may reflect a trend towards, and sampling of, larger fires than in earlier studies. A large fraction of the total burning for 2004 likely occurred during a two-week period of very low humidity. The combined output of these fires created a massive "mega-plume" >500 km across that we sampled on 8 September. The mega-plume contained high PM10 and 10–50 ppbv of many reactive species such as O3, NH3, NO2, CH3OH, and organic acids. This is an intense and globally important chemical processing environment that is still poorly understood. The mega-plume or "white ocean" of smoke covered a large area in Brazil, Bolivia, and Paraguay for about one month. The smoke was transported >2000 km to the southeast while remaining concentrated enough to cause a 3–4-fold increase in aerosol loading in the São Paulo area for several days.
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Yokelson, R. J., T. Karl, P. Artaxo, D. R. Blake, T. J. Christian, D. W. T. Griffith, A. Guenther, and W. M. Hao. "The Tropical Forest and fire emissions experiment: overview and airborne fire emission factor measurements." Atmospheric Chemistry and Physics Discussions 7, no. 3 (May 23, 2007): 6903–58. http://dx.doi.org/10.5194/acpd-7-6903-2007.
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Abstract. The Tropical Forest and Fire Emissions Experiment (TROFFEE) used laboratory measurements followed by airborne and ground based field campaigns during the 2004 Amazon dry season to quantify the emissions from pristine tropical forest and several plantations as well as the emissions, fuel consumption, and fire ecology of tropical deforestation fires. The airborne campaign used an Embraer 110B aircraft outfitted with whole air sampling in canisters, mass-calibrated nephelometry, ozone by uv absorbance, Fourier transform infrared spectroscopy (FTIR), and proton-transfer mass spectrometry (PTR-MS) to measure PM10, O3, CO2, CO, NO, NO2, HONO, HCN, NH3, OCS, DMS, CH4, and up to 48 non-methane organic compounds (NMOC). The Brazilian smoke/haze layers extended to 2–3 km altitude, which is much lower than the 5–6 km observed at the same latitude, time of year, and local time in Africa in 2000. Emission factors (EF) were computed for the 19 tropical deforestation fires sampled and they largely compare well to previous work. However, the TROFFEE EF are mostly based on a much larger number of samples than previously available and they also include results for significant emissions not previously reported such as: nitrous acid, acrylonitrile, pyrrole, methylvinylketone, methacrolein, crotonaldehyde, methylethylketone, methylpropanal, "acetol plus methylacetate," furaldehydes, dimethylsulfide, and C1-C4 alkyl nitrates. Thus, we recommend these EF for all tropical deforestation fires. The NMOC emissions were ~80% reactive, oxygenated volatile organic compounds (OVOC). Our EF for PM10 (17.8±4 g/kg) is ~25% higher than previously reported for tropical forest fires and may reflect a trend towards, and sampling of, larger fires than in earlier studies. A large fraction of the total burning for 2004 likely occurred during a two-week period of very low humidity. The combined output of these fires created a massive "mega-plume" >500 km across that we sampled on September 8. The mega-plume contained high PM10 and 10–50 ppbv of many reactive species such as O3, NH3, NO2, CH3OH, and organic acids. This is an intense and globally important chemical processing environment that is still poorly understood. The mega-plume or "white ocean" of smoke covered a large area in Brazil, Bolivia, and Paraguay for about one month. The smoke was transported >2000 km to the southeast while remaining concentrated enough to cause a 3-4-fold increase in aerosol loading in the São Paulo area for several days.
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Dickinson, M. B., E. A. Johnson, and R. Artiaga. "Fire spread probabilities for experimental beds composed of mixedwood boreal forest fuels." Canadian Journal of Forest Research 43, no. 4 (April 2013): 321–30. http://dx.doi.org/10.1139/cjfr-2012-0291.
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Although fuel characteristics are assumed to have an important impact on fire regimes through their effects on extinction dynamics, limited capabilities exist for predicting whether a fire will spread in mixedwood boreal forest surface fuels. To improve predictive capabilities, we conducted 347 no-wind, laboratory test burns in surface fuels collected from the mixedwood boreal forest of Saskatchewan. The beds were composed of single fuel types of contrasting characteristics, including feather moss, aspen leaf litter, aspen and alder leaf litter, and twigs. Shredded wood (i.e., excelsior) was included for comparison. An extinction index and logistic model from the literature that balances heat sources and sinks performed well for excelsior, a fuel used to develop the model, but poorly for forest fuels. As a result, we used logistic regression to develop a model for forest fuels finding that fire spread was largely determined by the heat sink, heat of combustion, and fuel bed depth. We found close correspondence between our model and fire spread in an independent sample of beds composed of mixtures of mixedwood fuels (N = 59). Our model can serve as a means of analyzing the relative importance of fuels and weather on extinction dynamics during mixedwood boreal forest fires.
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Paré, David, and Yves Bergeron. "Effect of colonizing tree species on soil nutrient availability in a clay soil of the boreal mixedwood." Canadian Journal of Forest Research 26, no. 6 (June 1, 1996): 1022–31. http://dx.doi.org/10.1139/x26-113.
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Soil nutrient availability was assessed around stems of trembling aspen (Populustremuloides Michx.), white spruce (Piceaglauca (Moench) Voss), and paper birch (Betulapapyrifera Marsh.) that regenerated after fire 49, 77, and 123 years ago on a clayey soil of the southern boreal forest. For all stand ages, forest floor pH was greater by 0.5 unit under aspen than under other species, while the accumulation of organic matter and nutrients was generally greater in the forest floor of spruce. With time since fire, forest floor pH and mineral soil reserves of nitrogen (N) and exchangeable calcium declined significantly, while the C/N ratio increased, perhaps as a result of nutrient immobilization in the aggrading biomass. Net N mineralization and nitrification, measured by aerobic laboratory incubations, were higher under birch and aspen than under spruce in the forest floor and the mineral soil of the youngest stand (49 years old). However, in older stands, these parameters were significantly lower, and no significant differences were found between soils of deciduous and coniferous species. These results suggest that a decrease in N availability with time since fire was caused by factors other than the generally assumed succession to coniferous trees.
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Sparks, Aaron M., Alan F. Talhelm, Raquel Partelli Feltrin, Alistair M. S. Smith, Daniel M. Johnson, Crystal A. Kolden, and Luigi Boschetti. "An experimental assessment of the impact of drought and fire on western larch injury, mortality and recovery." International Journal of Wildland Fire 27, no. 7 (2018): 490. http://dx.doi.org/10.1071/wf18044.
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Climate change is increasing drought and fire activity in many fire-prone regions including the western USA and circumpolar boreal forest. These changes highlight the need for improved understanding of how multiple disturbances impact trees in these regions. Recent studies linking fire behaviour to plant ecophysiology have improved understanding of how fire affects tree function and mortality but have not investigated interactions between drought stress and fire. In this study, Larix occidentalis saplings were subjected to different levels of water stress followed by low-intensity surface fires in a controlled laboratory setting. Post-fire mortality, recovery and growth were monitored for up to 1 year post fire. Generally, increased pre-fire water stress resulted in decreased post-fire stem diameter (up to 5% lower) and height (up to 19% lower) growth. However, severely water-stressed saplings whose foliage had senesced before the fires had lower 1-year mortality (14%) and significantly greater post-fire bud densities than moderately stressed saplings that did not senesce (86% mortality). The mortality patterns suggest that water-stressed western larch saplings exposed to low-intensity wildfires, or prescribed fires conducted as part of forest management activities, may exhibit lower mortality rates if stress-induced foliar senescence has occurred.
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Gould, J. S., A. L. Sullivan, R. Hurley, and V. Koul. "Comparison of three methods to quantify the fire spread rate in laboratory experiments." International Journal of Wildland Fire 26, no. 10 (2017): 877. http://dx.doi.org/10.1071/wf17038.
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Different methods can be used to measure the time and distance of travel of a fire and thus its speed. The selection of a particular method will depend on the experimental objectives, design, scale, location (in the laboratory or field), required accuracy and resources available. In this study, measurements from ocular observation (directly by eye), visible spectrum video imagery and thermocouple instrumentation were used to compare their performance in quantifying the time of arrival and rate of spread of a fire burning across a eucalypt forest litter fuel bed in a combustion wind tunnel. All methods gave similar results, but there were some significant differences depending on the dryness of the fuel and speed of the wind.
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Viegas, Domingos Xavier, and Luis Paulo Pita. "Fire spread in canyons." International Journal of Wildland Fire 13, no. 3 (2004): 253. http://dx.doi.org/10.1071/wf03050.
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Canyons or ridges are associated with a large number of fatal accidents produced during forest fires all over the world. A contribution to the understanding of fire behaviour in these terrain conditions is given in this paper. The basic geometrical parameters of the canyon configuration are described. An analytical model assuming elliptical growth of point ignition fires and constant values of rate of spread is proposed. A non-dimensional formulation to transfer results from analytical, numerical, laboratory or field simulations to other situations is proposed. An experimental study at laboratory scale on a special test rig is described. A wide set of canyon configurations were covered in the experimental program. In spite of the relatively small scale of the experiments they were able to put in evidence some of the main features found in fires spreading in this type of terrain. They show that in practically all cases the rate of spread of the fire front is non-constant. On the contrary, the fire has a dynamic behaviour and its properties depend not only on the canyon geometry but on the history of fire development as well. The convection induced by the fire is enhanced by terrain curvature and the fire accelerates causing the well-known blow-up that is associated with canyon fires. The rate of spread of the head fire increases continuously even in the absence of wind or any other special feature or change of boundary conditions that are sometimes invoked to justify such fire behaviour. The results of the present study confirm the predictions of a previous numerical study of the flow and fire spread in canyons that showed the important feedback effect of the fire on the atmospheric flow and how this affects fire behaviour in canyons. Results from a field experiment carried out in a canyon-shaped plot covered by tall shrubs were used to validate the laboratory scale experiments. Case studies related to fatal accidents that occurred in canyon-shaped configurations are analysed and recommendations to deal with this problem are made. It is shown that these accidents may occur even in the absence of special fuel or atmospheric conditions as they are intrinsically related to terrain configuration.
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Schiks, T. J., and B. M. Wotton. "Assessing the probability of sustained flaming in masticated fuel beds." Canadian Journal of Forest Research 45, no. 1 (January 2015): 68–77. http://dx.doi.org/10.1139/cjfr-2014-0294.
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Mechanical mastication is increasingly used as a fuel management treatment to reduce fire risk at the wildland–urban interface, although ignition and fire behaviour in these novel fuel beds are poorly understood. We investigated the influence of observed fuel moisture content, wind speed, and firebrand size on the probability of sustained flaming of masticated fuel beds under both laboratory and field settings. Logistic regression techniques were applied to assess the probability of sustained flaming in both datasets. Models for the field were also developed using estimated moisture from three sets of weather-based models: (i) the hourly Fine Fuel Moisture Code (FFMC) from the Canadian Forest Fire Weather Index System, (ii) the National Fire Danger Rating System (NFDRS) moisture estimates for 1 h and 10 h fuels, and (iii) a masticated surface fuel moisture model (MAST). In both laboratory and field testing, the likelihood of a successful ignition increased with decreasing moisture content and increasing wind speed; the effect of firebrand size was only apparent in laboratory testing. The FFMC, NFDRS, and MAST predictions had somewhat reduced discriminative power relative to direct moisture in predicting the probability of sustained flaming based on our field observations. Our results speak to the disparity between the fire behaviour modeling that occurs in the laboratory and the fire behavior modeling that occurs in the field, as the methodology permitted comparison of predictions from sustained flaming models that were developed for one experimental setting and applied to the other.
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Wells, Jason B., Edward E. Little, and Robin D. Calfee. "BEHAVIORAL RESPONSE OF YOUNG RAINBOW TROUT (ONCORHYNCHUS MYKISS) TO FOREST FIRE–RETARDANT CHEMICALS IN THE LABORATORY." Environmental Toxicology and Chemistry 23, no. 3 (2004): 621. http://dx.doi.org/10.1897/02-635.
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Kemball, Kevin J., A. Richard Westwood, and G. Geoff Wang. "Laboratory assessment of the effect of forest floor ash on conifer germination." Canadian Journal of Forest Research 40, no. 4 (April 2010): 822–26. http://dx.doi.org/10.1139/x10-027.
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Mineral soils exposed by fire are often covered by a layer of ash due to complete consumption of the forest floor (litter and duff). To assess the possible effects of ash on seed germination and viability of jack pine ( Pinus banksiana Lamb.), black spruce ( Picea mariana (Mill.) Britton, Sterns, Poggenb.), white spruce ( Picea glauca (Moench) Voss), and balsam fir ( Abies balsamea (L.) Mill.), a laboratory experiment was conducted using ash derived from three types of forest floor samples. The samples represented areas of high conifer concentration, high aspen concentration, and mixed aspen and conifer and were collected from five mature aspen ( Populus tremuloides Michx.) – conifer mixedwood stands in southeastern Manitoba. Ash derived from each forest floor type neither prohibited nor delayed conifer germination, except that of balsam fir. Balsam fir had significantly less germination on ash derived from forest floor samples with high aspen concentration. When corrected for seed viability, balsam fir had significantly less germination on all three ash types compared with jack pine, black spruce, and white spruce. However, the impact of ash on balsam fir is unlikely to have meaningful ecological implications, as balsam fir is a climax species and will establish in undisturbed mature forests.
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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.
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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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Madrigal, Javier, Jennifer Souto-García, Rafael Calama, Mercedes Guijarro, Juan Picos, and Carmen Hernando. "Resistance of Pinus pinea L. bark to fire." International Journal of Wildland Fire 28, no. 5 (2019): 342. http://dx.doi.org/10.1071/wf18118.
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The stone pine (Pinus pinea L.) has thick bark as an adaptation to wildfire. In this study, laboratory tests were carried out to quantify the influence of bark thickness on flammability and fire resistance in this species. Heating rate in the cambium and the time to reach lethal temperatures in living tissues were determined using a mass loss calorimeter. In addition, data from permanent plots were used to generate linear mixed models to predict bark thickness along the trunk in stone pine stands. The combination of laboratory and field data provided information about the critical threshold of bark thickness (2cm) below which the heat transmission rate would increase, decreasing the time to reach lethal temperatures in the cambium and therefore the resistance to fire. A new model was developed to calculate critical thresholds of charring height that guarantee efficient protection from fire along the trunk. Predicting whether the bark is thick enough to help trees survive may have important applications in the field of forest fuel management and in the ecology of these pine forests, as well as in preventive silviculture to assess critical heights of trunks likely to be affected during wildfire and prescribed burning.
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Xifré-Salvadó, Miquel Àngel, Núria Prat-Guitart, Marcos Francos, Xavier Úbeda, and Marc Castellnou. "Smouldering Combustion Dynamics of a Soil from a Pinus halepensis Mill. Forest. A Case Study of the Rocallaura Fires in Northeastern Spain." Applied Sciences 10, no. 10 (May 16, 2020): 3449. http://dx.doi.org/10.3390/app10103449.
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This study analyses the smouldering combustion on soils that took place during the wildfires that occurred in Rocallaura (Northeastern Spain). The smouldering combustion after the first event, 23 June, was the potential source of flaming fire re-ignition of the second event, 19 July 2016. Re-ignitions are an important challenge for the firefighting system. Budget and efforts are spent on controlling these re-ignitions that can ultimately cause the collapse of the response system if the re-ignitions happen during periods of simultaneous fire events. Our objective is to contribute to better understand the dynamics of the smouldering combustion of organic soils associated with these wildfires and the impact on the Pinus halepensis Mill. forest ecosystem. Transects were established in adjacent control and post-fire zones. Laboratory analyses were conducted to determine some physical and chemical properties of both the duff and mineral soil. Using these variables, we estimate thresholds of duff ignition probability, percentage of duff consumption and smouldering combustion spread rates. Overall, we provide a set of tools for evaluating re-ignitions in forest ecosystems. We conclude that the concept of fire persistence should be a new variable for consideration in present and future analysis of fire regimes and demonstrates the significance of introducing smouldering combustion and re-ignition within the strategic framework of the wildfire hazard and integrating these phenomena into forest planning and management.
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Rodríguez y Silva, Francisco, Mercedes Guijarro, Javier Madrigal, Enrique Jiménez, Juan R. Molina, Carmen Hernando, Ricardo Vélez, and Jose A. Vega. "Assessment of crown fire initiation and spread models in Mediterranean conifer forests by using data from field and laboratory experiments." Forest Systems 26, no. 2 (July 24, 2017): e02S. http://dx.doi.org/10.5424/fs/2017262-10652.
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Aims of study: To conduct the first full-scale crown fire experiment carried out in a Mediterranean conifer stand in Spain; to use different data sources to assess crown fire initiation and spread models, and to evaluate the role of convection in crown fire initiation.Area of study: The Sierra Morena mountains (Coordinates ETRS89 30N: X: 284793-285038; Y: 4218650-4218766), southern Spain, and the outdoor facilities of the Lourizán Forest Research Centre, northwestern Spain.Material and methods: The full-scale crown fire experiment was conducted in a young Pinus pinea stand. Field data were compared with data predicted using the most used crown fire spread models. A small-scale experiment was developed with Pinus pinaster trees to evaluate the role of convection in crown fire initiation. Mass loss calorimeter tests were conducted with P. pinea needles to estimate residence time of the flame, which was used to validate the crown fire spread model.Main results: The commonly used crown fire models underestimated the crown fire spread rate observed in the full-scale experiment, but the proposed new integrated approach yielded better fits. Without wind-forced convection, tree crowns did not ignite until flames from an intense surface fire contacted tree foliage. Bench-scale tests based on radiation heat flux therefore offer a limited insight to full-scale phenomena.Research highlights: Existing crown fire behaviour models may underestimate the rate of spread of crown fires in many Mediterranean ecosystems. New bench-scale methods based on flame buoyancy and more crown field experiments allowing detailed measurements of fire behaviour are needed.
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Ne'eman, G. "Regeneration of Natural Pine Forest - Review of Work Done After the 1989 Fire in Mount Carmel, Israel." International Journal of Wildland Fire 7, no. 4 (1997): 295. http://dx.doi.org/10.1071/wf9970295.
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In September 1989 a fire burned a large natural Pinus halepensis Mill. forest on Mt. Carmel, Israel. This paper summarizes the main results of five years of research, in which the effects of natural factors and management on the development of the forest and the vegetation were studied. It was found that the burned pine tree skeletons were correlated with the spatial pattern of seed germination.. Fewer pine seedlings were found one year after the fire near the burned trunks, but the survival and growth rate of these young pine trees was higher in the following four years. Pine ash was found to inhibit post-fire seed germination, offering a possible explanation for the apparent effect of the old burned trees on the spatial pattern of the new pine seedlings. Both laboratory experiments and field measurements indicate that the high pH of the ash, is the main factor responsible for the inhibition of germination. We examined several management regimes designed to enhance the growth of the young post-fire pine trees and assess their influence on the recovery of the forest. The results revealed that four years after fire, and three years after treatments, forest regeneration was mainly affected by the natural process while management had only a marginal effect. Management such as cutting and leaving, or cutting and removing the burned trunks and twigs from the plots, had almost no effect on species composition and cover. However, thinning of Pinus and Cistus seedlings increased survival and growth of remaining seedlings.
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Ruiz-Gallardo, J. Reyes, Santiago Castaño, and Alfonso Calera. "Application of remote sensing and GIS to locate priority intervention areas after wildland fires in Mediterranean systems: a case study from south-eastern Spain." International Journal of Wildland Fire 13, no. 3 (2004): 241. http://dx.doi.org/10.1071/wf02057.
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Wildland fires are one of the major causes of ecosystem degradation, especially in semiarid climates, where the erosion hazard is high. The identification of potential erosion zones is typically difficult as it requires expensive field and laboratory work. This paper proposes a methodology based on remote sensing and GIS techniques, which permits speedy identification of erosional areas in a semi-automatic way, tested in a large burn scar in south-eastern Spain. Inputs were slope, aspect, and fire severity. In order to obtain the latter a new method has been proposed, based on the difference in NDVI between two images (acquired before and after the fire event). Combining these maps in a GIS, a Forest Intervention Priority map (FIP) is produced, which identifies areas of high erosion potential. Field work was conducted to assess the method. Results indicate that the applied methodology reliably predicted the extent of very severe fire and, further, was generally useful for identifying sites of significant erosion. Additional work is required to refine: (1) remotely sensed fire severity thresholds, particularly for other Mediterranean forest systems and substrate conditions; and (2) associated mapping tools for informing post-fire management applications.
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Spichtinger, N., R. Damoah, S. Eckhardt, C. Forster, P. James, S. Beirle, T. Marbach, T. Wagner, P. C. Novelli, and A. Stohl. "Boreal forest fires in 1997 and 1998: a seasonal comparison using transport model simulations and measurement data." Atmospheric Chemistry and Physics 4, no. 7 (September 14, 2004): 1857–68. http://dx.doi.org/10.5194/acp-4-1857-2004.
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Abstract. Forest fire emissions have a strong impact on the concentrations of trace gases and aerosols in the atmosphere. In order to quantify the influence of boreal forest fire emissions on the atmospheric composition, the fire seasons of 1997 and 1998 are compared in this paper. Fire activity in 1998 was very strong, especially over Canada and Eastern Siberia, whereas it was much weaker in 1997. According to burned area estimates the burning in 1998 was more than six times as intense as in 1997. Based on hot spot locations derived from ATSR (Along Track Scanning Radiometer) data and official burned area data, fire emissions were estimated and their transport was simulated with a Lagrangian tracer transport model. Siberian and Canadian forest fire tracers were distinguished to investigate the transport of both separately. The fire emissions were transported even over intercontinental distances. Due to the El Niño induced meteorological situation, transport from Siberia to Canada was enhanced in 1998. Siberian fire emissions were transported towards Canada and contributed concentrations more than twice as high as those due to Canada's own CO emissions by fires. In 1998 both tracers arrive at higher latitudes over Europe, which is due to a higher North Atlantic Oscillation (NAO) index in 1998. The simulated emission plumes are compared to CMDL (Climate Monitoring and Diagnostics Laboratory) CO2 and CO data, Total Ozone Mapping Spectrometer (TOMS) aerosol index (AI) data and Global Ozone Monitoring Experiment (GOME) tropospheric NO2 and HCHO columns. All the data show clearly enhanced signals during the burning season of 1998 compared to 1997. The results of the model simulation are in good agreement with ground-based as well as satellite-based measurements.
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Spichtinger, N., R. Damoah, S. Eckhardt, C. Forster, P. James, S. Beirle, T. Wagner, P. C. Novelli, and A. Stohl. "Boreal forest fires in 1997 and 1998: a seasonal comparison using transport model simulations and measurement data." Atmospheric Chemistry and Physics Discussions 4, no. 3 (May 18, 2004): 2747–79. http://dx.doi.org/10.5194/acpd-4-2747-2004.
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Abstract. Forest fire emissions have a strong impact on the concentrations of trace gases and aerosols in the atmosphere. In order to quantify the influence of boreal forest fire emissions on the atmospheric composition, the fire seasons of 1997 and 1998 are compared in this paper. Fire activity in 1998 was very strong, especially over Canada and Eastern Siberia, whereas it was much weaker in 1997. According to burned area estimates the burning in 1998 was more than six times as intense as in 1997. Based on hot spot locations derived from ATSR (Along Track Scanning Radiometer) data and official burned area data, fire emissions were estimated and their transport was simulated with a Lagrangian tracer transport model. Siberian and Canadian forest fire tracers were distinguished to investigate the transport of both separately. The fire emissions were transported even over intercontinental distances. Due to the El Niño induced meteorological situation, transport from Siberia to Canada was enhanced in 1998. Siberian fire emissions were transported towards Canada and contributed concentrations more than twice as high as those due to Canada's own CO emissions by fires. In 1998 both tracers arrive at higher latitudes over Europe, which is due to a higher North Atlantic Oscillation (NAO) index in 1998. The simulated emission plumes are compared to CMDL (Climate Monitoring and Diagnostics Laboratory) CO2 and CO data, Total Ozone Mapping Spectrometer (TOMS) aerosol index (AI) data and Global Ozone Monitoring Experiment (GOME) tropospheric NO2 columns. All the data show clearly enhanced signals during the burning season of 1998 compared to 1997. The results of the model simulation are in good agreement with ground-based as well as satellite-based measurements.
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Burrows, N. D. "Flame residence times and rates of weight loss of eucalypt forest fuel particles." International Journal of Wildland Fire 10, no. 2 (2001): 137. http://dx.doi.org/10.1071/wf01005.
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Shape, size, composition and arrangement of fuel particles within a fuel array significantly affect the way in which wildland fires behave. Australian eucalypt forest fire behaviour models characterise fine fuels according to the quantity burnt in the flaming zone, and the upper size limit for fine fuel particles is somewhat arbitrarily set at 6 mm for the McArthur Forest Fire Danger Meter and 10 mm for the Forest Fire Behaviour Tables for Western Australia. Flame residence time and rate of weight loss during combustion of dry eucalypt leaves and different dimensions of round wood were measured to provide a scientific basis for standardising litter fuel sampling in dry eucalypt forests. Eucalypt leaves burnt at a rate equivalent to a piece of 4 mm diameter round wood, with smaller diameter round wood being the most flammable component of the fuel array. Based on flame residence times of individual fuel particles measured in the laboratory, and eucalypt surface fuel arrays observed in the field, fine litter fuel sampling should be standardised to leaves and round wood less than 6 mm in diameter. This study also enables the determination of the contribution of larger fuel particles to flaming zone combustion and intensity.
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Mack, L. A., E. J. T. Levin, S. M. Kreidenweis, D. Obrist, H. Moosmüller, K. A. Lewis, W. P. Arnott, et al. "Optical closure experiments for biomass smoke aerosols." Atmospheric Chemistry and Physics 10, no. 18 (September 29, 2010): 9017–26. http://dx.doi.org/10.5194/acp-10-9017-2010.
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Abstract. A series of laboratory experiments at the Fire Laboratory at Missoula (FLAME) investigated chemical, physical, and optical properties of fresh smoke samples from combustion of wildland fuels that are burned annually in the western and southeastern US The burns were conducted in the combustion chamber of the US Forest Service Fire Sciences Laboratory in Missoula, Montana. Here we discuss retrieval of optical properties for a variety of fuels burned in FLAME 2, using nephelometer-measured scattering coefficients, photoacoustically-measured aerosol absorption coefficients, and size distribution measurements. Uncertainties are estimated from various instrument characteristics and instrument calibration studies. Our estimates of single scattering albedo for different dry smoke samples varied from 0.428 to 0.990, indicative of observed wide variations in smoke aerosol chemical composition. In selected case studies, we retrieved the complex refractive index from measurements but show that these are highly sensitive to uncertainties in measured size distributions.
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Dupuy, Jean-Luc, and Michel Larini. "Fire spread through a porous forest fuel bed: a radiative and convective model including fire-induced flow effects." International Journal of Wildland Fire 9, no. 3 (1999): 155. http://dx.doi.org/10.1071/wf00006.
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A simplified physical model for the steady-state propagation of an infinite fire front through a uniform forest fuel bed in still air is derived from a mechanistic approach that considers a forest fire as a compressible, reactive and radiative flow through a multiphase medium. This model, named the PIF97 model for shortness, includes the effects of the buoyancy induced gas flow on the preheating of the unburned fuel. Fuel is composed of one type of motionless particles uniformly distributed in a fuel bed of constant depth. The conservation equations used in the model are integrated over the fuel bed depth. The spatial domain is divided into the preheating zone ahead of the fire front and the flaming combustion zone. In the preheating zone (model A), pyrolysis and chemical reactions are neglected, and the gas flow is assumed to be one-dimensional. In the flaming combustion zone (model B), some average parameters over this zone are given in order to simplify the description of physical and chemical processes. Models A and B are coupled to form the PIF97 model. The predictions of this model are compared with experimental rates of spread measured during laboratory fire experiments in pine needle fuel beds. That shows the accomplished progress by comparison to the predictions of a purely radiative model and also the limits of the PIF97 model. Under the present experimental conditions, this model correctly predicts the effect of surface-to-volume ratio, and may predict the effect of fuel load, but the quantitative effect of slope is clearly underestimated. Possible reasons for the remaining discrepancies between predictions and experimental results are investigated through an analysis of separate predictions of model A and model B.
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Zimarin, Sergey, Maksim Gnusov, Viktor Popikov, and Nikita Sherstyukov. "RESULTS OF EXPERIMENTAL STUDIES OF OPERATING MODES OF A FORESTRY STRIP PLAYER WITH A HYDRAULIC DRIVE OF CUTTING DISC WORKING BODIES." Forestry Engineering Journal 11, no. 1 (March 30, 2021): 155–62. http://dx.doi.org/10.34220/issn.2222-7962/2021.1/14.
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The article is devoted to laboratory studies of the soil aggregates. To date, remain relevant tasks for preparing for a fire-hazardous season and conducting fire fighting events. Creation, replacing mineralized bands One of the methods for conducting preventive work on the preservation of a forest massif on the development of large forest fires. Foresting the forest soil from the burning elements to the open layer of the soil, namely the creation of mineralized bands is mainly in front of the fire-hazardous season, during which strips and breaks are replaced. For laboratory research, an experimental installation was developed and manufactured. According to the study method, we defined the factors that changed the angle (α) and angle (β) for a spherical disk with semicircular cuts during the experiment. During the experiments, to verify the normality of the distribution of the characteristics responsible for the energy readings of the unit, a series of 30 experiments was performed using 30 experiments when setting the angles of the spherical disk with semicircular cuts α = 100, β = 100. Detailing the hypothesis about the normality of the distribution of the response function by the Criterion X2 -Pirson was carried out. According to the criterion of Kohrene, the homogeneity of the dispersions of the experiments was carried out. Based on the obtained experimental data, the dependences of the rotation of the spherical disk with semicircular cuts from the angle of attack and tilt, the dependence of the power from the angle of attack were constructed.
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Varotsos, Costas A., Vladimir F. Krapivin, and Ferdenant A. Mkrtchyan. "A New Passive Microwave Tool for Operational Forest Fires Detection: A Case Study of Siberia in 2019." Remote Sensing 12, no. 5 (March 5, 2020): 835. http://dx.doi.org/10.3390/rs12050835.
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The purpose of this paper is to present a new method for early detection of forest fires, especially in forest zones prone to fires using microwave remote sensing and information-modeling tools. A decision-making system is developed as a tool for operational coupled analysis of modeling results and remote sensing data. The main operating structure of this system has blocks that calculate the moisture of forest canopy, the soil-litter layer, and the forest physical temperature using the observed brightness temperature provided by the flying platform IL-18 equipped with passive microwave radiometers of 1.43, 13.3 and 37.5 GHz frequencies. The hydrological parameters of the forest are assessed with both a developed regional hydrological model and remote sensing observations. The hydrological model allows for the detection of fire-prone zones that are subject to remote sensing when modeling results are corrected and thermal temperatures are evaluated. An approach for the real time forest fires classification via daytime remote sensing observations is proposed. The relative theoretical and experimental results presented here have allowed us to use a new approach to forests monitoring during periods of potential fire. A decision-making algorithm is presented that aims at analyzing data flows from radiometers located on the remote sensing platform to calculate the probability of forest fire occurring in geographical pixels. As case study, the state of forest fires that occurred in Siberia in 2019 using microwave remote sensing measurements conducted by a flying IL-18 laboratory is presented. This remote sensing platform is equipped with optical and microwave tools that allow the optical and microwave images of the observed forest areas. The main operating frequencies of microwave radiometers are 1.43, 13.3 and 37.5 GHz. Microwave radiometers provide data on water content in the forest canopy and on litter and physical temperatures. Based on the long-term measurements made in Siberia, the possible improvement of the proposed decision-making system for future relevant studies is discussed in detail. The basic idea of cost-effective monitoring of forested areas consists of a two-stage exploration of fire risk zones. The first monitoring stage is performed using the hydrological model of the study area to identify low moisture areas of the forest canopy and litter. The second stage of monitoring is conducted using the remote sensing platform only in the local fire-dangerous areas in order to more precisely identify the areas prone to fire and to detect and diagnose real burning zones. The developed algorithm allows the calculation of physical temperatures and the detection of temperature anomalies based on measured brightness temperatures. Finally, the spatial distribution of the probability of forest fire occurrence is given as an example of the decision-making system along with a comparison of this distribution with the satellite images provided by the EOSDIS Land data.
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Xifré-Salvadó, Miquel Àngel, Núria Prat-Guitart, Marcos Francos, Xavier Úbeda, and Marc Castellnou. "Effects of Fire on the Organic and Chemical Properties of Soil in a Pinus halepensis Mill. Forest in Rocallaura, NE Spain." Sustainability 13, no. 9 (May 6, 2021): 5178. http://dx.doi.org/10.3390/su13095178.
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The present study was conducted following a fire that took place in Rocallaura (NE Iberian Peninsula) in 23 June 2016 with the aim of analyzing the chemical properties of soil in burnt and unburnt areas in order to determine the short-term effects of fire on an ecosystem dominated by Pinus halepensis Mill. Transects were laid out in a control area and an adjacent burnt area. Laboratory analyses were performed to determine the chemical properties of the organic and mineral soil layers at 5 cm and 10 cm (total carbon, total nitrogen, organic and inorganic carbon, carbonates, pH, electrical conductivity, and major cations). The results show partial combustion of the organic substrate, with a significant increase in TC, OC, TN, EC and K+, and a slight decrease in pH in the post-fire area compared to the control area, demonstrating that the fire was of low intensity and did not generate significant short-term negative impacts on the soil. Soils of this type, with high organic matter content, tend to maintain their structure after a low-intensity fire and retain the nutrients necessary for ecosystem recovery and resilience.
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Nelson Jr., Ralph M., and Carl W. Adkins. "A dimensionless correlation for the spread of wind-driven fires." Canadian Journal of Forest Research 18, no. 4 (April 1, 1988): 391–97. http://dx.doi.org/10.1139/x88-058.
Full textAbstract:
Data for the behavior of 59 experimental wind-driven fires were extracted from the literature for use in determining a correlation among several variables known to influence the rate of forest fire spread. Also included in the correlation were unpublished data from six field fires. This information consisted of behavior measurements on small-scale burns of artificial fuels in the laboratory and measurements on field fires in diverse fuels such as grass and logging slash. Fire intensities ranged from about 40 to 4600 kW/m. Dimensional analysis was used to derive three variables governing the fire spread process. These variables, rearranged into a dimensionless rate of spread and a dimensionless wind speed, are strongly correlated and lead to a simple expression for fire spread rate in terms of fuel consumption, ambient wind speed, and flame residence time.
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Maksymenko, N. V., V. O. Voronin, N. I. Cherkashyna, and S. P. Sonko. "Geochemical aspect of landscape planning in forestry." Journal of Geology, Geography and Geoecology 27, no. 1 (July 10, 2018): 81–87. http://dx.doi.org/10.15421/111833.
Full textAbstract:
One of the modern methods of spatially estimating anthropogenic impact on a given territory is landscape planning, including the stage of assessment of the conditions of a natural complex . The results of such an evaluation are used in environmental management. The aim of the work is to assess the ecological conditions of the Vasyshchivsky forest area by means of landscape and environmental planning. The aim is achieved by performing the following stages of work: assessment of the distribution and intensity of contamination sources in the Vasyshchivsky forest area; drawing a scheme showing parts of the territory with probable conflicts; making a soil and geochemical survey of the forest area to assess acidity distribution and total content of carbonates in the soil as the consequences of pollution of the forest ecosystem ; specification of geochemical characteristics of soils on the forest sites in the established location of former fires; forecast of limits of afte-r fire areas based on the analysis of cartographic works developed by the authors. The geochemical characteristics of the soils in Vasyshchivsky forest have been studied to identify the areas affected by fire, and the results of this study are given in this paper. During the inventory phase of landscape and environmental planning, a complete survey of the forest territory was conducted and a landscape map was drawn. Based on the authors’ matrices filled with conflicts of natural use, the areas with low, medium and high levels of conflict have been marked within the study area. Landscape and environmental planning has been evaluated by soil sampling outside the test points on the network and their laboratory analysis. The results of the evaluation phase were maps illustrating the geochemical situation in the forest soil cover. The article presents cartographic models of the spatial distribution of carbonates in the forest soils, water and salt extraction pH. The results of the study are part of an environmental assessment of Vasyshchivsky forest area. In future they will be used in restoration of the forest ecosystems after fire.
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Doerr, Stefan H., William H. Blake, Richard A. Shakesby, Frank Stagnitti, Saskia H. Vuurens, Geoff S. Humphreys, and Peter Wallbrink. "Heating effects on water repellency in Australian eucalypt forest soils and their value in estimating wildfire soil temperatures." International Journal of Wildland Fire 13, no. 2 (2004): 157. http://dx.doi.org/10.1071/wf03051.
Full textAbstract:
Wildfires can induce or enhance soil water repellency under a range of vegetation communities. According to mainly USA-based laboratory studies, repellency is eliminated at a maximum soil temperature (T) of 280–400°C. Knowledge of T reached during a wildfire is important in evaluating post-fire soil physical properties, fertility and seedbed status. T is, however, notoriously difficult to ascertain retrospectively and often based on indicative observations with a large potential error. Soils under fire-prone Australian eucalypt forests tend to be water repellent when dry or moderately moist even if long unburnt. This study aims to quantify the temperature of water repellency destruction for Australian topsoil material sampled under three sites with contrasting eucalypt cover (Eucalyptus sieberi, E. ovata and E. baxteri). Soil water repellency was present prior to heating in all samples, increased during heating, but was abruptly eliminated at a specific T between 260 and 340°C. Elimination temperature varied somewhat between samples, but was found to be dependent on heating duration, with longest duration resulting in lowest elimination temperature. Results suggest that post-fire water repellency may be used as an aid in hindcasting soil temperature reached during the passage of a fire within repellency-prone environments.
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Ganatsas, Petros, Maria Giannakaki, Alexandros Gouvas, and Marianthi Tsakaldimi. "Is the Reproduction Capacity of Pinus brutia Stands 20 Years after Wildfire Efficient to Secure Forest Restoration in the Case of a Fire Re-Occurrence?" Forests 12, no. 8 (July 26, 2021): 991. http://dx.doi.org/10.3390/f12080991.
Full textAbstract:
A critical issue in effective post-fire regeneration and re-establishment of a burnt forest is the stage concerning the burned stands. When stands are mature and produce seeds, the regeneration can theoretically be achieved, while in the case of immature stands, they may not be able to produce enough quantities of germinable seeds that can secure stand re-establishment. It is estimated that a period of 15–16 years after fire is needed for enough seed production to achieve natural forest re-establishment. This study aimed at the estimation of the real reproduction capacity of Pinus brutia stands 20 years after a wildfire, in an area of northern Greece. The study focused on stand structure, cone production and their morphological characteristics, the morphological characteristics of the produced seed as well as quality of produced seeds. Results analyses showed that despite the young age of the stands, they are quite productive, producing a high number of cones per ha, with a high percentage of trees bearing cones, but with a low number of cones per tree (11.0 cones). An average number of 58.0 fully developed seeds per cone were found, which corresponds to a total number of 620,136 seeds per ha. Considering that the average rate of seed germination is 25.6% (at laboratory conditions), and the theoretical possibility for establishing viable seedling under ambient conditions, these data give an estimation of 1587.5 of one-year old seedlings to recruit the burnt area, in the case of a fire event, if all other parameters remain favorable. These data confirmed the hypothesis that a period of 15–16 years interval between two fires is enough for a burnt serotinous pine forest to reach in such a reproductive stage, able to secure its renewal if a fire occurs. This should be greatly considered in forest fire protection and management plans, which should aim to effectively protect young post-fire forests at least to the age of 15–16 years.
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Campbell, Monica L., Peter J. Clarke, and David A. Keith. "Seed traits and seed bank longevity of wet sclerophyll forest shrubs." Australian Journal of Botany 60, no. 2 (2012): 96. http://dx.doi.org/10.1071/bt11261.
Full textAbstract:
In wet sclerophyll forests seedling recruitment either occurs after intermittent fire events or continuously during intervals between fires in gaps created by small-scale disturbances. The dormancy and dispersal characteristics of seeds will influence how plant species exploit these contrasting recruitment opportunities. For example, long-lived seed banks may be crucial for persistence of species that are unable to recruit during intervals between fires if the length of fire intervals exceeds the life span of standing plants (senescence risk). To better understand mechanisms of population persistence during prolonged absence of fire in montane wet sclerophyll forests, we studied seed bank dynamics in four understorey species. We chose two species thought to have fire event-driven recruitment, Banksia integrifolia subsp. monticola (Proteaceae) and Goodia lotifolia (Fabaceae), and two species that are thought to have canopy gap-phase recruitment, Trochocarpa laurina (Ericaceae) and Tasmannia stipitata (Winteraceae). We measured seed rain, seed bank density and used seeds buried in nylon mesh bags to estimate rates of seed decay in the soil over time. All species produced a substantial seed crop on an annual basis. The annual seed crop in three species (G. lotifolia, T. stipitata and T. laurina) was released in a dormant state and developed a persistent seed bank, while one species (B. integrifolia) lacked dormancy and rapidly germinated under laboratory and field conditions. Seed bank characteristics of G. lotifolia appear to promote episodic recruitment after large landscape-scale fires, those of B. integrifolia appear to promote more continuous recruitment in response to smaller fires and other disturbances that avoid widespread mortality of established plants, while seed bank characteristics of T. stipitata and T. laurina may facilitate both episodic and continuous recruitment under respective types of disturbance. The four species appeared to have varied vulnerabilities and mechanisms for reducing immaturity risk and senescence risk to persistence of their populations under recurrent disturbance. Dormancy, seed bank longevity and seed rain are likely to be useful syndromes for predicting the response of wet sclerophyll forest understorey species to changed disturbance regimes.
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Popikov, P., Petr Popikov, Andrey Sharov, Aleksandr Petkov, and Anton Pozdnyakov. "INFLUENCE OF OPERATING MODES OF FOREST FIRE SOIL-THROWING MACHINE WITH HYDRAULIC DRIVE ON EFFICIENCY INDICATORS." Forestry Engineering Journal 10, no. 1 (April 6, 2020): 209–17. http://dx.doi.org/10.34220/issn.2222-7962/2020.1/25.
Full textAbstract:
Many areas of human activity, in particular, agriculture and the timber industry, use technological machines and
equipment having in their arsenal a hydraulic system for supplying pressure to the used units for soil cultivation,
sowing, cutting, rooting out and many others. The article discusses the use of an energy-saving hydraulic drive. It
provides experimental data on its use in a forest fire soil-throwing machine. The experiment was carried out using the
LHT-55 forestry tractor, on the rear hitch of which a laboratory sample of a fire-fighting soil-throwing machine with a
rotor-thrower drive from a hydraulic motor has been mounted. An adjustable hydraulic pump is installed on the rear
frame of LHT-55 tractor, on which there is a regulator of the volume of supplied fluid. In the course of experimental
studies we used the methods, specified in State Standard 20915–2011, Industrial Standard 70.2.16–73. During the
experiments, the main indicators of the efficiency of forest fire-fighting soil-throwing machine have been determined:
the maximum surge in the pressure of the working fluid in the hydraulic drive for the duty cycle Pm; the energy stored
by the pneumohydraulic accumulator in one working cycle Pm (operation of the safety valve); the maximum energy that
a pneumohydraulic accumulator with these parameters is able to accumulate per line kilometer or per shift Eav;, average
range of the soil throwing Lav and the thickness of the soil layer depending on the distance of throw T. A large number
of selected determining factors made it possible to depict graphically obtained data and conduct a visual analysis to
obtain the most effective operating modes of a forest fire soil-throwing machine with an energy-saving hydraulic drive.
The paper presents the rationale for the new design of a forest fire soil-throwing machine with an energy-saving
hydraulic drive. The dependences of the efficiency indicators of working flows on the design and technological
parameters of a forest fire soil-throwing machine have been obtained.
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Gould, Jim S., and Andrew L. Sullivan. "Two methods for calculating wildland fire rate of forward spread." International Journal of Wildland Fire 29, no. 3 (2020): 272. http://dx.doi.org/10.1071/wf19120.
Full textAbstract:
Accurate estimation of a wildland fire’s progression is critical for the development of robust fire spread prediction models and their validation. Two methods commonly used to determine spread rate are the cumulative spread rate, calculated as the total distance travelled by a fire divided by the total time of travel, and the interval spread rate, calculated using the minimum time and maximum distance between observations. This paper analyses the differences between these two methods using experimental fires conducted in dry eucalypt forest leaf litter in either a combustion wind tunnel or large (4ha) field sites. Fires were ignited from a point, 400-mm and 800-mm line ignitions in the wind tunnel, and point and 120-m line ignitions in the field experiments. A total of 312 and 397 observations of distance travelled and time taken were made during the laboratory and field experiments respectively, along with associated environmental variables. Mean spread rates and standard deviations were significantly greater for the interval method than those of the cumulative method for all the laboratory data and the field point ignition fires, and the difference between them varied with distance and time since ignition. These findings have important implications for fire spread and acceleration model development.