The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Anne Ganteaume - One of the best experts on this subject based on the ideXlab platform.
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How terpene content affects fuel Flammability of wildland–urban interface vegetation
International Journal of Wildland Fire, 2019Co-Authors: Bastien Romero, Catherine Fernandez, Caroline Lecareux, Elena Ormeño, Anne GanteaumeAbstract:Among plant characteristics promoting Flammability, terpenes have received far less attention, especially regarding the vegetation surrounding housing. Here, mono-, sesqui-, and diterpenes were screened in live and dead leaves of ornamental species found in Wildland-Urban Interfaces (WUI) of southeastern France. Terpene content and composition were compared among species and between fuel types. Their influence on Flammability was assessed through several variables and compared to that of leaf thickness and moisture content. Six of the 17 species examined contained terpenes. Terpene diversity and content differed among species but not between fuel types. Mono-, sesqui-, and diterpenes (especially the highly concentrated compounds) were involved to varying degrees in both leaf and litter Flammability. Their effects could be the opposite according to the Flammability variable and the fuel type considered. Leaf sesquiterpene content and litter total terpene content had the strongest influence on maximum temperature; the former also mainly drove leaf flaming duration. The other Flammability variables were more strongly associated with either moisture content or leaf thickness. Our findings underlined the idea that fire management in WUI must also acknowledge the potential for ornamental species containing terpenes, such as P. halepensis, in affecting fire behaviour.
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Does plant Flammability differ between leaf and litter bed scale? Role of fuel characteristics and consequences for Flammability assessment
International Journal of Wildland Fire, 2018Co-Authors: Anne GanteaumeAbstract:The increasing concern regarding fire in the wildland–urban interface (WUI) around the world highlights the need to better understand the Flammability of WUI fuels. Research on plant Flammability is rapidly increasing but commonly only considers a single fuel scale. In some cases, however, different fuel scales (e.g. leaf and litter bed) have greater influence on fire, for instance, when it spreads from the litter bed to the lower canopy. Examining fuel Flammability at these different scales is necessary to better know the overall Flammability but also provides insights into the drivers of Flammability. To investigate if leaf and litter bed Flammability differed, laboratory experiments were conducted on 15 species (native or exotic) commonly found in the WUI of south-eastern France. Species were ranked and the association of fuel characteristics with Flammability sought at both scales. For most species, leaf and litter bed Flammability differed because of strong fuel characteristics (e.g. leaf thickness or litter bulk density), entailing differences in rankings based on fuel scale and potentially leading to a misrepresentation of Flammability of the species studied. Favouring species with lower Flammability at both scales in the WUI, especially near housing, may help reduce undesired effects during wildfires.
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How ornamental vegetation burns: from particle Flammability to vertical flame propagation
2016Co-Authors: Anne Ganteaume, A. Bertin, M. Audouard, F. Guerra, J.m. Lopez, D. Morge, C. Travaglini, Marielle JappiotAbstract:In WUI, the ornamental vegetation can be an efficient vector of fire propagation towards the housing. Assessing this vegetation Flammability and ranking ornamental species accordingly can be a way to assess the fire risk in these areas. As both live and dead surface fuels are targeted in fire propagation (due to spot fire or radiant heat), the Flammability of both types of fuel was assessed for each species, as well as, at larger scale, the fire propagation from the litter to the first branch. The objectives of this work were to show if the ranking of species varied from one type of fuel to the other, but also according to the fuel scale, from the finest (particle=live leaf) to intermediate (litter samples), and to larger scale (fire propagation from litter to branch). The Flammability of the 15 main ornamental species used in WUI of SE France was assessed for these different fuel scales using a fire bench to burn the litter samples and to assess the fire propagation from litter to branch (tested on 4 species) while live leaves were burned on an epiradiator. In each case, the different species were ranked from the least flammable to the most flammable according to the Flammability variables recorded during the burning experiments. Then, the different rankings were compared with one another. The comparison of rankings of species for live leaf and litter showed that the ranking did not vary for only two species (regardless of fuel type, Pittosporum tobira: least flammable species and Cotoneaster franchetti: most flammable species). However, for most species, the ranking varied; some species having litters more flammable than live leaves and some presented the opposite pattern. The fire propagation from the litter to the branch significantly varied according to species (Elaeagnus being the most flammable species and Pyracantha the least flammable species), even if, on the whole, fire propagated very well vertically and horizontally, consuming the branch almost completely. In this case, the ranking of species was the same as that of live leaves for Prunus (intermediate Flammability), as that of litters for Pyracantha (low Flammability) and Elaeagnus (high Flammability) but was in between these rankings for Ligustrum (intermediate Flammability). Ranking the ornamental species according to their Flammability was not that simple especially because some species did not present the same Flammability at different fuel scales. For each species, the Flammability assessment should take into account the most severe ranking, along with the combustibility of the whole plant, in order to avoid an underestimation of fire risk.
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Flammability of litter sampled according to two different methods: comparison of results in laboratory experiments
International Journal of Wildland Fire, 2014Co-Authors: Anne Ganteaume, Marielle Jappiot, Thomas Curt, Corinne Lampin, Laurent BorgnietAbstract:In the laboratory, different types of litter samples (constructed v. intact) can be used in Flammability experiments but the sampling method of these litters could affect litter Flammability results. To assess this effect, samples of litters were collected in South-eastern France, according to two different methods previously used in other studies, one keeping intact the structure of the litter layers (non-constructed litter) and the other requiring the construction of the litter, using mainly the surface litter layer (constructed litter). The comparison of Flammability results showed that the sampling method had a significant effect on litter bulk-density, rate of spread and rate of consumption, intact litter being more flammable than reconstructed litter that was artificially compacted. The type of vegetation had a significant effect on litter depth, ignitability, sustainability, consumability and combustibility (except on rate of spread) and the litter composition could explain in part this fire behaviour. The effect of the construction of litters on Flammability parameters and its magnitude also differed according to vegetation types. Intact litter structure appeared to be an important driver of its Flammability, especially of combustibility and consumability. The assessment of these Flammability components will differ when using constructed litter samples instead of intact litter samples, especially according to vegetation types. Future research on litter Flammability should take into account the bias due to the litter sampling method when the litter is constructed.
A. Ganteaume - One of the best experts on this subject based on the ideXlab platform.
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Does plant Flammability vary according to terpene content throughout the year?
2019Co-Authors: A. Ganteaume, B. RomeroAbstract:The role of terpenes on Flammability is not clearly determined, especially for species used in wildland-urban interfaces (WUI) where the fire risk is high. This work aims at checking if the leaf Flammability of different WUI species (Pinus halepensis, Cupressus sempervirens, C. leylandii, and C. arizonica) varied across seasons possibly highlighting the role of leaf moisture content (FMC) and terpene content (investigated at three levels: total, family and compounds). All year round, P. halepensis presented the highest Flammability related to high content in sesquiterpenes, mostly caryophyllene and α-humulene, and low FMC in contrast to C. arizonica. Species presented different seasonal Flammability and terpene patterns. Diterpene totarol, sesquiterpene germacrene, and monoterpene myrcene increased Flammability (in C. sempervirens, C. arizonica, and P. halepensis, respectively) while monoterpene α-pinene (in P. halepensis) and several other diterpene compounds, especially manool oxyde-13-epi, decreased it (in C. leylandii). Terpene compounds linked to Flammability seasonally varied only in C. leylandii, the species showing the highest diversity of compounds. FMC did not affect Flammability, except time-to-ignition in C. sempervirens. Regardless of season, the highly flammable species should be avoided close to housing, especially when they form horizontal fuel continuity (as in ornamental hedge) that can easily propagate the fire.
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Does plant Flammability differ between leaf and litter bed scale? Role of fuel characteristics and consequences for Flammability assessment
International Journal of Wildland Fire, 2018Co-Authors: A. GanteaumeAbstract:The increasing concern regarding fire in the wildland-urban interface (WUI) around the world highlights the need to better understand the Flammability of WUI fuels. Research on plant Flammability is rapidly increasing but commonly only considers a single fuel scale. In some cases, however, different fuel scales (e.g. leaf and litter bed) have greater influence on fire, for instance, when it spreads from the litter bed to the lower canopy. Examining fuel Flammability at these different scales is necessary to better know the overall Flammability but also provides insights into the drivers of Flammability. To investigate if leaf and litter bed Flammability differed, laboratory experiments were conducted on fifteen species (native or exotic) commonly found in WUI of southeastern France. Species were ranked and the association of fuel characteristics with Flammability sought at both scales. For most species, leaf and litter bed Flammability differed due to strong fuel characteristics (e.g. leaf thickness or litter bulk density), entailing differences in rankings based on fuel scale and potentially leading to a misrepresentation of Flammability of the species studied. Favoring species with lower Flammability at both scales in WUI, especially near housing, may help reduce undesired impacts during wildfires.
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Can ranking the Flammability of ornamental species be used for the fire risk assessment in WUI ?
2015Co-Authors: A. Ganteaume, F. Guerra, J.m. Lopez, Romain Esteve, Marielle JappiotAbstract:In WUI, the ornamental vegetation is an efficient vector of fire propagation towards the housings. One way to assess the fire risk around housing is the ranking of the Flammability of the ornamental species. The objective of this work was to show if the ranking of the Flammability of the species varied between live and dead fuels of the main ornamental species in SE France. Flammability variables were recorded during burning experiments using a fire bench for litters and an epiradiator for live leaves. For both types of fuel, the different species were ranked from the least flammable to the most flammable according to these variables. The rankings were compared together as well as to the “total” ranking obtained using the variables of live and dead fuels. The main results showed that a few species presented the same ranking regardless of the type of fuel. However, for most species, the ranking of litter Flammability differed from that of live leaf Flammability; the litter of some species being ranked more flammable than their live leaves or the opposite. For the “total” ranking of these species, the most flammable species corresponded to the species presenting the most flammable litters and the moderately flammable ones to those of moderately flammable live leaves. However, the poorly flammable species corresponded to species either with highly flammable litters or moderately flammable live leaves. Among the least flammable species, Ligustrum japonicum presented litters ranked as highly flammable. The underestimation of the Flammability of some species in the “total” ranking can be an issue in the fire risk assessment.
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Comparison of Flammability of litters sampled according to two different methods
2012Co-Authors: A. Ganteaume, Marielle Jappiot, Corinne Lampin, T. Curt, Laurent BorgnietAbstract:In laboratory conditions, reconstructed or intact litter samples can be used to assess the Flammability of dead surface fuels but the sampling method could affect litter Flammability results. To assess this effect, samples of litters were collected in south-eastern France, according to two different methods previously used in other studies, one keeping intact the structure of litter layers (intact litter) and the other using mainly the surface litter layer to reconstruct the litter sample (reconstructed litter). The sampling occurred in representative ecosystems of the study area: pure Pinus halepensis stands, mixed pine-oak stands, pure cork oak stands and in two types of shrubland (maquis and garrigue). Flammability experiments were carried out on fire bench, using a glowing firebrand as ignition source and a 10 kmh-1 wind. The main variables recorded were: ignition frequency, time-to-ignition, flaming duration, flame rate of spread, flame propagation, mean flame temperature, maximum flame height and rate of consumption. The comparison of Flammability results showed that the sampling method had a significant effect on litter bulk-density, rate of spread and rate of consumption, intact litter being more flammable than reconstructed litter. The type of vegetation had a significant effect on litter depth, ignitability and combustibility (except on flame temperature and rate of spread) and the litter composition could explain in part this fire behaviour. The effect of the reconstruction of litters on Flammability parameters and its magnitude differed according to vegetation types. The intact structure of the litter appeared to be an important driver of its Flammability, especially for combustibility and consumability. The assessment of these parameters will differ when using reconstructed litter samples compared to intact litter samples. Future research on litter Flammability should take into account the bias due to the litter sampling method when the litter is reconstructed.
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Litter Flammability in oak woodlands and shrublands of southeastern France
Forest Ecology and Management, 2011Co-Authors: T. Curt, A. Schaffhauser, Marielle Jappiot, Laurent Borgniet, A. Ganteaume, C. Dumas, Romain Esteve, William Martin, A. N'diaye, B. PoilvetAbstract:Characterizing the Flammability of litter fuels is of major importance for assessing wildland fire ignition hazard. Here we compared the Flammability of litter within a mosaic of Quercus suber (cork oak) woodlands and shrublands in a Mediterranean fire-prone area (Maures massif, southeastern France) to test whether the characteristics and the Flammability of litter vary with the vegetation types. We tested experimentally the ignitability, the sustainability, the combustibility and the consumability of undisturbed (= non-reconstructed) litter samples with a point-source mode of ignition. Although the frequency of ignition was similar between all the vegetation types, we distinguished four groups having litter of specific composition and Flammability: low and sparse shrublands dominated by Cistus species, medium shrublands with cork oak, high Erica shrublands with sparse cork oak woodlands, and mixed mature oak woodlands with Q. suber, Q. ilex and Q. pubescens. As these vegetation types corresponded to a specific range of past fire recurrence, we also tested the effect of the number of fires and the time since the last fire on litter Flammability. Litters of plots recurrently burned had low ability to propagate flames and low flame sustainability. We discuss how the recent fire history can modify vegetation and litter Flammability, and thus the fire ignition hazard.
B. Poilvet - One of the best experts on this subject based on the ideXlab platform.
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Litter Flammability in oak woodlands and shrublands of southeastern France
Forest Ecology and Management, 2011Co-Authors: T. Curt, A. Schaffhauser, Marielle Jappiot, Laurent Borgniet, A. Ganteaume, C. Dumas, Romain Esteve, William Martin, A. N'diaye, B. PoilvetAbstract:Characterizing the Flammability of litter fuels is of major importance for assessing wildland fire ignition hazard. Here we compared the Flammability of litter within a mosaic of Quercus suber (cork oak) woodlands and shrublands in a Mediterranean fire-prone area (Maures massif, southeastern France) to test whether the characteristics and the Flammability of litter vary with the vegetation types. We tested experimentally the ignitability, the sustainability, the combustibility and the consumability of undisturbed (= non-reconstructed) litter samples with a point-source mode of ignition. Although the frequency of ignition was similar between all the vegetation types, we distinguished four groups having litter of specific composition and Flammability: low and sparse shrublands dominated by Cistus species, medium shrublands with cork oak, high Erica shrublands with sparse cork oak woodlands, and mixed mature oak woodlands with Q. suber, Q. ilex and Q. pubescens. As these vegetation types corresponded to a specific range of past fire recurrence, we also tested the effect of the number of fires and the time since the last fire on litter Flammability. Litters of plots recurrently burned had low ability to propagate flames and low flame sustainability. We discuss how the recent fire history can modify vegetation and litter Flammability, and thus the fire ignition hazard.
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Fire recurrence impacts litter Flammability in oak woodlands and shrublands on acidic soils of southeastern France
2009Co-Authors: T. Curt, A. Schaffhauser, Marielle Jappiot, Laurent Borgniet, A. Ganteaume, C. Dumas, Romain Esteve, William Martin, A. N'diaye, B. PoilvetAbstract:Characterizing the Flammability of litter fuels is of major importance to assess the wildland fire hazard. We present here a comparison of the Flammability of litter fuels for the main ecosystems of the Maures massif (southeastern France) forming a mosaic of oak woodlands (Quercus suber, Q. ilex and Q. pubescens) and shrublands dominated by Erica arborea, Calicotome spinosa and Cistus spp. This mosaic is partly driven by the historic fire regime, and each vegetation type corresponds to a specific range of fire recurrence. We thus tested the hypothesis that, as the fire regime impacts the composition and biomass of live fuels, it may subsequently affect the characteristics and the Flammability of dead fuels. We studied undisturbed litter samples (diameter 38 cm) with at least 30 replicates per vegetation type. Each sample was submitted to an experimental burning in laboratory conditions using a glowing firebrand, in order to assess the four main components of Flammability (i.e. ignitibility, sustainability, combustibility, and consumability).
Marielle Jappiot - One of the best experts on this subject based on the ideXlab platform.
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How ornamental vegetation burns: from particle Flammability to vertical flame propagation
2016Co-Authors: Anne Ganteaume, A. Bertin, M. Audouard, F. Guerra, J.m. Lopez, D. Morge, C. Travaglini, Marielle JappiotAbstract:In WUI, the ornamental vegetation can be an efficient vector of fire propagation towards the housing. Assessing this vegetation Flammability and ranking ornamental species accordingly can be a way to assess the fire risk in these areas. As both live and dead surface fuels are targeted in fire propagation (due to spot fire or radiant heat), the Flammability of both types of fuel was assessed for each species, as well as, at larger scale, the fire propagation from the litter to the first branch. The objectives of this work were to show if the ranking of species varied from one type of fuel to the other, but also according to the fuel scale, from the finest (particle=live leaf) to intermediate (litter samples), and to larger scale (fire propagation from litter to branch). The Flammability of the 15 main ornamental species used in WUI of SE France was assessed for these different fuel scales using a fire bench to burn the litter samples and to assess the fire propagation from litter to branch (tested on 4 species) while live leaves were burned on an epiradiator. In each case, the different species were ranked from the least flammable to the most flammable according to the Flammability variables recorded during the burning experiments. Then, the different rankings were compared with one another. The comparison of rankings of species for live leaf and litter showed that the ranking did not vary for only two species (regardless of fuel type, Pittosporum tobira: least flammable species and Cotoneaster franchetti: most flammable species). However, for most species, the ranking varied; some species having litters more flammable than live leaves and some presented the opposite pattern. The fire propagation from the litter to the branch significantly varied according to species (Elaeagnus being the most flammable species and Pyracantha the least flammable species), even if, on the whole, fire propagated very well vertically and horizontally, consuming the branch almost completely. In this case, the ranking of species was the same as that of live leaves for Prunus (intermediate Flammability), as that of litters for Pyracantha (low Flammability) and Elaeagnus (high Flammability) but was in between these rankings for Ligustrum (intermediate Flammability). Ranking the ornamental species according to their Flammability was not that simple especially because some species did not present the same Flammability at different fuel scales. For each species, the Flammability assessment should take into account the most severe ranking, along with the combustibility of the whole plant, in order to avoid an underestimation of fire risk.
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Can ranking the Flammability of ornamental species be used for the fire risk assessment in WUI ?
2015Co-Authors: A. Ganteaume, F. Guerra, J.m. Lopez, Romain Esteve, Marielle JappiotAbstract:In WUI, the ornamental vegetation is an efficient vector of fire propagation towards the housings. One way to assess the fire risk around housing is the ranking of the Flammability of the ornamental species. The objective of this work was to show if the ranking of the Flammability of the species varied between live and dead fuels of the main ornamental species in SE France. Flammability variables were recorded during burning experiments using a fire bench for litters and an epiradiator for live leaves. For both types of fuel, the different species were ranked from the least flammable to the most flammable according to these variables. The rankings were compared together as well as to the “total” ranking obtained using the variables of live and dead fuels. The main results showed that a few species presented the same ranking regardless of the type of fuel. However, for most species, the ranking of litter Flammability differed from that of live leaf Flammability; the litter of some species being ranked more flammable than their live leaves or the opposite. For the “total” ranking of these species, the most flammable species corresponded to the species presenting the most flammable litters and the moderately flammable ones to those of moderately flammable live leaves. However, the poorly flammable species corresponded to species either with highly flammable litters or moderately flammable live leaves. Among the least flammable species, Ligustrum japonicum presented litters ranked as highly flammable. The underestimation of the Flammability of some species in the “total” ranking can be an issue in the fire risk assessment.
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Flammability of litter sampled according to two different methods: comparison of results in laboratory experiments
International Journal of Wildland Fire, 2014Co-Authors: Anne Ganteaume, Marielle Jappiot, Thomas Curt, Corinne Lampin, Laurent BorgnietAbstract:In the laboratory, different types of litter samples (constructed v. intact) can be used in Flammability experiments but the sampling method of these litters could affect litter Flammability results. To assess this effect, samples of litters were collected in South-eastern France, according to two different methods previously used in other studies, one keeping intact the structure of the litter layers (non-constructed litter) and the other requiring the construction of the litter, using mainly the surface litter layer (constructed litter). The comparison of Flammability results showed that the sampling method had a significant effect on litter bulk-density, rate of spread and rate of consumption, intact litter being more flammable than reconstructed litter that was artificially compacted. The type of vegetation had a significant effect on litter depth, ignitability, sustainability, consumability and combustibility (except on rate of spread) and the litter composition could explain in part this fire behaviour. The effect of the construction of litters on Flammability parameters and its magnitude also differed according to vegetation types. Intact litter structure appeared to be an important driver of its Flammability, especially of combustibility and consumability. The assessment of these Flammability components will differ when using constructed litter samples instead of intact litter samples, especially according to vegetation types. Future research on litter Flammability should take into account the bias due to the litter sampling method when the litter is constructed.
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Comparison of Flammability of litters sampled according to two different methods
2012Co-Authors: A. Ganteaume, Marielle Jappiot, Corinne Lampin, T. Curt, Laurent BorgnietAbstract:In laboratory conditions, reconstructed or intact litter samples can be used to assess the Flammability of dead surface fuels but the sampling method could affect litter Flammability results. To assess this effect, samples of litters were collected in south-eastern France, according to two different methods previously used in other studies, one keeping intact the structure of litter layers (intact litter) and the other using mainly the surface litter layer to reconstruct the litter sample (reconstructed litter). The sampling occurred in representative ecosystems of the study area: pure Pinus halepensis stands, mixed pine-oak stands, pure cork oak stands and in two types of shrubland (maquis and garrigue). Flammability experiments were carried out on fire bench, using a glowing firebrand as ignition source and a 10 kmh-1 wind. The main variables recorded were: ignition frequency, time-to-ignition, flaming duration, flame rate of spread, flame propagation, mean flame temperature, maximum flame height and rate of consumption. The comparison of Flammability results showed that the sampling method had a significant effect on litter bulk-density, rate of spread and rate of consumption, intact litter being more flammable than reconstructed litter. The type of vegetation had a significant effect on litter depth, ignitability and combustibility (except on flame temperature and rate of spread) and the litter composition could explain in part this fire behaviour. The effect of the reconstruction of litters on Flammability parameters and its magnitude differed according to vegetation types. The intact structure of the litter appeared to be an important driver of its Flammability, especially for combustibility and consumability. The assessment of these parameters will differ when using reconstructed litter samples compared to intact litter samples. Future research on litter Flammability should take into account the bias due to the litter sampling method when the litter is reconstructed.
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Litter Flammability in oak woodlands and shrublands of southeastern France
Forest Ecology and Management, 2011Co-Authors: T. Curt, A. Schaffhauser, Marielle Jappiot, Laurent Borgniet, A. Ganteaume, C. Dumas, Romain Esteve, William Martin, A. N'diaye, B. PoilvetAbstract:Characterizing the Flammability of litter fuels is of major importance for assessing wildland fire ignition hazard. Here we compared the Flammability of litter within a mosaic of Quercus suber (cork oak) woodlands and shrublands in a Mediterranean fire-prone area (Maures massif, southeastern France) to test whether the characteristics and the Flammability of litter vary with the vegetation types. We tested experimentally the ignitability, the sustainability, the combustibility and the consumability of undisturbed (= non-reconstructed) litter samples with a point-source mode of ignition. Although the frequency of ignition was similar between all the vegetation types, we distinguished four groups having litter of specific composition and Flammability: low and sparse shrublands dominated by Cistus species, medium shrublands with cork oak, high Erica shrublands with sparse cork oak woodlands, and mixed mature oak woodlands with Q. suber, Q. ilex and Q. pubescens. As these vegetation types corresponded to a specific range of past fire recurrence, we also tested the effect of the number of fires and the time since the last fire on litter Flammability. Litters of plots recurrently burned had low ability to propagate flames and low flame sustainability. We discuss how the recent fire history can modify vegetation and litter Flammability, and thus the fire ignition hazard.
Laurent Borgniet - One of the best experts on this subject based on the ideXlab platform.
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Flammability of litter sampled according to two different methods: comparison of results in laboratory experiments
International Journal of Wildland Fire, 2014Co-Authors: Anne Ganteaume, Marielle Jappiot, Thomas Curt, Corinne Lampin, Laurent BorgnietAbstract:In the laboratory, different types of litter samples (constructed v. intact) can be used in Flammability experiments but the sampling method of these litters could affect litter Flammability results. To assess this effect, samples of litters were collected in South-eastern France, according to two different methods previously used in other studies, one keeping intact the structure of the litter layers (non-constructed litter) and the other requiring the construction of the litter, using mainly the surface litter layer (constructed litter). The comparison of Flammability results showed that the sampling method had a significant effect on litter bulk-density, rate of spread and rate of consumption, intact litter being more flammable than reconstructed litter that was artificially compacted. The type of vegetation had a significant effect on litter depth, ignitability, sustainability, consumability and combustibility (except on rate of spread) and the litter composition could explain in part this fire behaviour. The effect of the construction of litters on Flammability parameters and its magnitude also differed according to vegetation types. Intact litter structure appeared to be an important driver of its Flammability, especially of combustibility and consumability. The assessment of these Flammability components will differ when using constructed litter samples instead of intact litter samples, especially according to vegetation types. Future research on litter Flammability should take into account the bias due to the litter sampling method when the litter is constructed.
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Comparison of Flammability of litters sampled according to two different methods
2012Co-Authors: A. Ganteaume, Marielle Jappiot, Corinne Lampin, T. Curt, Laurent BorgnietAbstract:In laboratory conditions, reconstructed or intact litter samples can be used to assess the Flammability of dead surface fuels but the sampling method could affect litter Flammability results. To assess this effect, samples of litters were collected in south-eastern France, according to two different methods previously used in other studies, one keeping intact the structure of litter layers (intact litter) and the other using mainly the surface litter layer to reconstruct the litter sample (reconstructed litter). The sampling occurred in representative ecosystems of the study area: pure Pinus halepensis stands, mixed pine-oak stands, pure cork oak stands and in two types of shrubland (maquis and garrigue). Flammability experiments were carried out on fire bench, using a glowing firebrand as ignition source and a 10 kmh-1 wind. The main variables recorded were: ignition frequency, time-to-ignition, flaming duration, flame rate of spread, flame propagation, mean flame temperature, maximum flame height and rate of consumption. The comparison of Flammability results showed that the sampling method had a significant effect on litter bulk-density, rate of spread and rate of consumption, intact litter being more flammable than reconstructed litter. The type of vegetation had a significant effect on litter depth, ignitability and combustibility (except on flame temperature and rate of spread) and the litter composition could explain in part this fire behaviour. The effect of the reconstruction of litters on Flammability parameters and its magnitude differed according to vegetation types. The intact structure of the litter appeared to be an important driver of its Flammability, especially for combustibility and consumability. The assessment of these parameters will differ when using reconstructed litter samples compared to intact litter samples. Future research on litter Flammability should take into account the bias due to the litter sampling method when the litter is reconstructed.
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Litter Flammability in oak woodlands and shrublands of southeastern France
Forest Ecology and Management, 2011Co-Authors: T. Curt, A. Schaffhauser, Marielle Jappiot, Laurent Borgniet, A. Ganteaume, C. Dumas, Romain Esteve, William Martin, A. N'diaye, B. PoilvetAbstract:Characterizing the Flammability of litter fuels is of major importance for assessing wildland fire ignition hazard. Here we compared the Flammability of litter within a mosaic of Quercus suber (cork oak) woodlands and shrublands in a Mediterranean fire-prone area (Maures massif, southeastern France) to test whether the characteristics and the Flammability of litter vary with the vegetation types. We tested experimentally the ignitability, the sustainability, the combustibility and the consumability of undisturbed (= non-reconstructed) litter samples with a point-source mode of ignition. Although the frequency of ignition was similar between all the vegetation types, we distinguished four groups having litter of specific composition and Flammability: low and sparse shrublands dominated by Cistus species, medium shrublands with cork oak, high Erica shrublands with sparse cork oak woodlands, and mixed mature oak woodlands with Q. suber, Q. ilex and Q. pubescens. As these vegetation types corresponded to a specific range of past fire recurrence, we also tested the effect of the number of fires and the time since the last fire on litter Flammability. Litters of plots recurrently burned had low ability to propagate flames and low flame sustainability. We discuss how the recent fire history can modify vegetation and litter Flammability, and thus the fire ignition hazard.
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Litter Flammability of French Mediterranean vegetation types : a cross-substratum analysis
2010Co-Authors: T. Curt, A. Schaffhauser, Marielle Jappiot, Laurent Borgniet, A. Ganteaume, R. Esteve, C. Lampin-maillet, W. Martin, A. N'diayeAbstract:Assessing the Flammability of litters in fire-prone ecosystems of major importance to quantify the wildland fire hazard. We compared undisturbed litter samples typical of French ecosystems on the two main types of substratum, i.e. acidic versus limestone, to investigate to which extent their characteristics and Flammability may differ. We measured in the laboratory several Flammability parameters on oven-dried samples that mimic the high fire hazard level in summer. On average, litters on limestone were much denser and had higher biomass than those on acidic soils. They also ignited more slowly, but they burned much more completely. The different components of Flammability (i.e. ignitability, combustibility, sustainability, and consumability) have been correlated to the characteristics of the litters such as biomass and bulk density. We discuss to which extent the management of these ecosystems could limit the fire ignition hazard.
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Fire recurrence impacts litter Flammability in oak woodlands and shrublands on acidic soils of southeastern France
2009Co-Authors: T. Curt, A. Schaffhauser, Marielle Jappiot, Laurent Borgniet, A. Ganteaume, C. Dumas, Romain Esteve, William Martin, A. N'diaye, B. PoilvetAbstract:Characterizing the Flammability of litter fuels is of major importance to assess the wildland fire hazard. We present here a comparison of the Flammability of litter fuels for the main ecosystems of the Maures massif (southeastern France) forming a mosaic of oak woodlands (Quercus suber, Q. ilex and Q. pubescens) and shrublands dominated by Erica arborea, Calicotome spinosa and Cistus spp. This mosaic is partly driven by the historic fire regime, and each vegetation type corresponds to a specific range of fire recurrence. We thus tested the hypothesis that, as the fire regime impacts the composition and biomass of live fuels, it may subsequently affect the characteristics and the Flammability of dead fuels. We studied undisturbed litter samples (diameter 38 cm) with at least 30 replicates per vegetation type. Each sample was submitted to an experimental burning in laboratory conditions using a glowing firebrand, in order to assess the four main components of Flammability (i.e. ignitibility, sustainability, combustibility, and consumability).
