Globally, in remaining wildlands, tree densities and forested cover have increased in grasslands and open forests since European settlement. In the southern Rocky Mountains of Colorado, United States, we determined tree composition and tree cover from historical (years 1875 to 1896) surveys and compared them to current (2002 to 2011) tree composition and current (year 2016) forested land cover for 500,000 ha of the Routt National Forest. Additionally, we examined whether changes in precipitation occurred. Regarding composition, pine (primarily lodgepole pine; Pinus contorta) decreased from 65% to 32% of all trees, with increased subalpine fir (Abies lasiocarpa) from 0.5% to 23% of all trees, and quaking aspen (Populus tremuloides) from 13% to 30% of all trees. According to 80% of 5175 survey points not in forests, the historical landscape was very open, comprised of grasslands, mountain meadows, and other open ecosystems. In contrast, 75% of the current landscape is covered by forests. Change points in the Palmer Modified Drought Index were within historical limits, indicating that forestation was not related to a change in water availability. Based on historical surveys and accounts, we envisioned a historical landscape that was open but embedded with dense lodgepole pine clusters and spruce stands at high elevations, which has now become a predominantly forested landscape of dense forests, similar to global forestation patterns.
{"title":"Envisioning Transition from Open Landscapes to Forested Landscapes in the Routt National Forest, Colorado, United States","authors":"B. Hanberry, Jacob M. Seidel","doi":"10.3390/fire7030082","DOIUrl":"https://doi.org/10.3390/fire7030082","url":null,"abstract":"Globally, in remaining wildlands, tree densities and forested cover have increased in grasslands and open forests since European settlement. In the southern Rocky Mountains of Colorado, United States, we determined tree composition and tree cover from historical (years 1875 to 1896) surveys and compared them to current (2002 to 2011) tree composition and current (year 2016) forested land cover for 500,000 ha of the Routt National Forest. Additionally, we examined whether changes in precipitation occurred. Regarding composition, pine (primarily lodgepole pine; Pinus contorta) decreased from 65% to 32% of all trees, with increased subalpine fir (Abies lasiocarpa) from 0.5% to 23% of all trees, and quaking aspen (Populus tremuloides) from 13% to 30% of all trees. According to 80% of 5175 survey points not in forests, the historical landscape was very open, comprised of grasslands, mountain meadows, and other open ecosystems. In contrast, 75% of the current landscape is covered by forests. Change points in the Palmer Modified Drought Index were within historical limits, indicating that forestation was not related to a change in water availability. Based on historical surveys and accounts, we envisioned a historical landscape that was open but embedded with dense lodgepole pine clusters and spruce stands at high elevations, which has now become a predominantly forested landscape of dense forests, similar to global forestation patterns.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"19 8S7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140262534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper numerically analyzes the influence of heat release rate (HRR) and longitudinal ventilation velocity on smoke distribution characteristics in a T-shaped roadway when the fire source was located upstream of the T-junction. The back-layering length, critical ventilation velocity, smoke temperature, and CO concentration in the main and branched roadway were investigated and analyzed. The results showed that the ventilation velocity is the key factor influencing back-layering length, while the effect of HRR on back-layering length is gradually weakened as HRR increases. The critical ventilation velocity in the T-shaped roadway is higher than in a single-tube roadway, and the predicted model of dimensional critical ventilation velocity in a T-shaped bifurcated roadway is proposed. The correlation between average temperature (Z = 1.6 m) (both in the main roadway I and the branched roadway) and ventilation velocity fits the power function, and the variation in average temperature (Z = 1.6 m) according to HRR fits the linear formula. The relation between average concentration of CO (Z = 1.6 m) (both inside the main roadway I and the branched roadway) and longitudinal ventilation velocity follows the power relation, and the variation in average concentration of CO (Z = 1.6 m) according to HRR follows the linear function.
本文通过数值方法分析了当火源位于 T 型交叉口上游时，热释放率（HRR）和纵向通风速度对 T 型巷道烟雾分布特征的影响。研究分析了主巷道和支巷道的后分层长度、临界通风速度、烟温和 CO 浓度。结果表明，通风速度是影响背层长度的关键因素，而随着 HRR 的增加，HRR 对背层长度的影响逐渐减弱。T 型巷道的临界通风速度高于单管巷道，并提出了 T 型分岔巷道临界通风速度的尺寸预测模型。平均温度（Z = 1.6 米）（包括主巷道 I 和分支巷道）与通风速度之间的相关性符合幂函数，平均温度（Z = 1.6 米）随 HRR 的变化符合线性公式。一氧化碳平均浓度（Z = 1.6 米）（包括主巷道 I 和支巷道内）与纵向通风速度之间的关系遵循幂函数，一氧化碳平均浓度（Z = 1.6 米）随 HRR 的变化遵循线性函数。
{"title":"Numerical Simulation of the Smoke Distribution Characteristics in a T-Shaped Roadway","authors":"Cui Ding, Dou Chang, Diange Sun, Songling Zou","doi":"10.3390/fire7030080","DOIUrl":"https://doi.org/10.3390/fire7030080","url":null,"abstract":"This paper numerically analyzes the influence of heat release rate (HRR) and longitudinal ventilation velocity on smoke distribution characteristics in a T-shaped roadway when the fire source was located upstream of the T-junction. The back-layering length, critical ventilation velocity, smoke temperature, and CO concentration in the main and branched roadway were investigated and analyzed. The results showed that the ventilation velocity is the key factor influencing back-layering length, while the effect of HRR on back-layering length is gradually weakened as HRR increases. The critical ventilation velocity in the T-shaped roadway is higher than in a single-tube roadway, and the predicted model of dimensional critical ventilation velocity in a T-shaped bifurcated roadway is proposed. The correlation between average temperature (Z = 1.6 m) (both in the main roadway I and the branched roadway) and ventilation velocity fits the power function, and the variation in average temperature (Z = 1.6 m) according to HRR fits the linear formula. The relation between average concentration of CO (Z = 1.6 m) (both inside the main roadway I and the branched roadway) and longitudinal ventilation velocity follows the power relation, and the variation in average concentration of CO (Z = 1.6 m) according to HRR follows the linear function.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"81 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140267141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wildfire causes environmental, economic, and human problems or losses. This study reviewed wildfires induced by lightning strikes. This review focuses on the investigations of lightning mechanisms in the laboratory. Also, the paper aims to discuss some of the modeling studies on lightning-induced wildfires at different geographical locations using satellite-recorded lightning data and different statistical analyses. This review established that irrespective of the different models used to predict lightning wildfires, there is still a lack of understanding of the lightning-strike ignition mechanism; few experiments have been modeled to establish the dynamics of lightning-strike ignition. Therefore, further research needs to be carried out in this area to understand lightning ignition. It was ascertained from the various statistical modeling that lightning-induced wildfires are exacerbated by the abundant availability of fuel with a lower moisture content and high lightning efficiency. Moreover, because of changes in the climate and weather conditions, i.e., harsh weather and climate conditions due to anthropogenic activities, lightning-induced ignition wildfires have increased over the years, and they are expected to increase in the future if the climate and weather conditions continue to aggravate. Although various modeling studies have identified that lightning-induced wildfires have increased recently, no preventive measures have been conclusively proposed to reduce lightning-caused wildfires. Hence, this aspect of research has to be given critical attention. This review presents information that gives a profound understanding of lightning-induced wildfires, especially factors that influence lightning wildfires, and the state-of-the-art research that has been completed to understand lightning-induced wildfires.
{"title":"Lightning-Induced Wildfires: An Overview","authors":"Yang Song, Cang-su Xu, Xiaolu Li, F. Oppong","doi":"10.3390/fire7030079","DOIUrl":"https://doi.org/10.3390/fire7030079","url":null,"abstract":"Wildfire causes environmental, economic, and human problems or losses. This study reviewed wildfires induced by lightning strikes. This review focuses on the investigations of lightning mechanisms in the laboratory. Also, the paper aims to discuss some of the modeling studies on lightning-induced wildfires at different geographical locations using satellite-recorded lightning data and different statistical analyses. This review established that irrespective of the different models used to predict lightning wildfires, there is still a lack of understanding of the lightning-strike ignition mechanism; few experiments have been modeled to establish the dynamics of lightning-strike ignition. Therefore, further research needs to be carried out in this area to understand lightning ignition. It was ascertained from the various statistical modeling that lightning-induced wildfires are exacerbated by the abundant availability of fuel with a lower moisture content and high lightning efficiency. Moreover, because of changes in the climate and weather conditions, i.e., harsh weather and climate conditions due to anthropogenic activities, lightning-induced ignition wildfires have increased over the years, and they are expected to increase in the future if the climate and weather conditions continue to aggravate. Although various modeling studies have identified that lightning-induced wildfires have increased recently, no preventive measures have been conclusively proposed to reduce lightning-caused wildfires. Hence, this aspect of research has to be given critical attention. This review presents information that gives a profound understanding of lightning-induced wildfires, especially factors that influence lightning wildfires, and the state-of-the-art research that has been completed to understand lightning-induced wildfires.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"47 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140267402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fires resulting from antecedent fires, known as exposure fires, can manifest across diverse environments, including suburban, urban, and rural areas. Notably, exposure fires represented by structure-destroying fires within the wildland–urban interface (WUI) can extend into non-WUI suburban and urban regions, presenting significant challenges. Leveraging data from the United States National Fire Incident Reporting System (NFIRS) spanning 2002 to 2020, this study investigates 131,739 exposure fire incidents impacting 348,089 features (incidents). We analyze reported economic costs, affected feature types, and property utilization patterns for these exposure fires. We also compare these exposure fires to information documented in other databases. Finally, we examine structure separation distance at residential dwellings and describe ignition pathways for selected fires. Reported property losses for some fire incidents amounted to USD 5,647,121,172, with content losses totaling USD 1,777,345,793. Prominent fire incident categories include buildings, vehicles, and natural vegetation fires, predominantly occurring in residential, outdoor, and storage areas. While the NFIRS lacked information on most major structure-destroying WUI fires, highlighting this analysis’s lack of statistical representation, it did provide insights into less extensive exposure fires, both WUI and non-WUI, unrecorded elsewhere. Our study reveals significant distinctions in the distribution of separation distances between damaged-to-damaged structures (average separation of 6.5 m) and damaged-to-not-damaged structures (average separation of 18.1 m). Notably, 84% of the incidents in exposure fires involved fire suppression defensive actions. These defensive actions contributed to the differences in structure separation distance distributions, highlighting the often-neglected role of these measures in assessing structure responses during WUI fires. We examined ignition pathways at select exposure fires, highlighting some common features involved in fire spread and challenges in documenting these pathways. Finally, we propose a set of idealized attributes for documenting exposure fires, accentuating the inherent difficulties in collecting such data across expansive geographical areas, particularly when striving for statistical representation. Our findings yield valuable insights into the multifaceted nature of exposure fires, informing future research and database development to aid in mitigating their impact on vulnerable communities.
{"title":"Examining Exposure Fires from the United States National Fire Incident Reporting System between 2002 and 2020","authors":"Derek J. McNamara, William E. Mell","doi":"10.3390/fire7030074","DOIUrl":"https://doi.org/10.3390/fire7030074","url":null,"abstract":"Fires resulting from antecedent fires, known as exposure fires, can manifest across diverse environments, including suburban, urban, and rural areas. Notably, exposure fires represented by structure-destroying fires within the wildland–urban interface (WUI) can extend into non-WUI suburban and urban regions, presenting significant challenges. Leveraging data from the United States National Fire Incident Reporting System (NFIRS) spanning 2002 to 2020, this study investigates 131,739 exposure fire incidents impacting 348,089 features (incidents). We analyze reported economic costs, affected feature types, and property utilization patterns for these exposure fires. We also compare these exposure fires to information documented in other databases. Finally, we examine structure separation distance at residential dwellings and describe ignition pathways for selected fires. Reported property losses for some fire incidents amounted to USD 5,647,121,172, with content losses totaling USD 1,777,345,793. Prominent fire incident categories include buildings, vehicles, and natural vegetation fires, predominantly occurring in residential, outdoor, and storage areas. While the NFIRS lacked information on most major structure-destroying WUI fires, highlighting this analysis’s lack of statistical representation, it did provide insights into less extensive exposure fires, both WUI and non-WUI, unrecorded elsewhere. Our study reveals significant distinctions in the distribution of separation distances between damaged-to-damaged structures (average separation of 6.5 m) and damaged-to-not-damaged structures (average separation of 18.1 m). Notably, 84% of the incidents in exposure fires involved fire suppression defensive actions. These defensive actions contributed to the differences in structure separation distance distributions, highlighting the often-neglected role of these measures in assessing structure responses during WUI fires. We examined ignition pathways at select exposure fires, highlighting some common features involved in fire spread and challenges in documenting these pathways. Finally, we propose a set of idealized attributes for documenting exposure fires, accentuating the inherent difficulties in collecting such data across expansive geographical areas, particularly when striving for statistical representation. Our findings yield valuable insights into the multifaceted nature of exposure fires, informing future research and database development to aid in mitigating their impact on vulnerable communities.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"2008 21","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140416597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Forest fires represent a natural element in the dynamics of forest ecosystems. This study investigated the impact of a large-scale forest fire in 2022 (ca. 1300 ha) on epigeic ground beetles (Coleoptera: Carabidae). The research was conducted in coniferous forests at six pairwise study sites: burnt and unburnt dead spruce from bark beetles, burnt and unburnt clear cut, and burnt and unburnt healthy sites. Each site was replicated in four plots, with two pitfall traps deployed within each plot. In total, 48 pitfall traps (6 × 4 × 2) were installed in April 2023. It was tested how individual sites affected the similarity of ground beetle communities, whether they contained similar life guilds, and how significantly large-scale fire affects the abundance of pyrophilous ground beetles. A total of 5952 individuals and 63 species were recorded. We observed a significant decline in abundance at clear-cut and dead spruce burnt sites (73% and 77.5%, respectively) compared to the unburnt sites. Conversely, abundance increased by 88% at the burnt healthy site compared to the unburnt healthy site. Additionally, significant differences in the number of species per trap and species richness diversity (q = 0, q = 1, q = 2) were found only between burnt and unburnt healthy sites. In general, the highest species richness in the comparison of all study sites was at unburnt clear-cut and burnt healthy sites. Communities of ground beetles responded considerably to the fire, differing significantly from unburnt sites, and demonstrating a high degree of similarity. The original healthy spruce stands had highly homogeneous communities. On the contrary, any disturbance (bark beetle calamity, clear-cut) resulted in an increase in the alpha, beta, and gamma diversities of the ground beetle communities. Burnt sites attracted pyrophilous species (Sericoda quadripunctata, Pterostichus quadrifoveolatus) at very low abundances, with the highest activity in the second half of the season. In conclusion, ground beetles demonstrated a strong short-term response to large-scale fire, forming specific communities. However, pyrophilous ground beetles were unable to occupy a large-scale fire area due to the initial low abundance. Understanding post-fire processes can provide important guidance for management in areas designated for biodiversity enhancement.
{"title":"Short-Term Response of Ground Beetles (Coleoptera: Carabidae) to Fire in Formerly Managed Coniferous Forest in Central Europe","authors":"V. Zumr, J. Remeš, O. Nakládal","doi":"10.3390/fire7030076","DOIUrl":"https://doi.org/10.3390/fire7030076","url":null,"abstract":"Forest fires represent a natural element in the dynamics of forest ecosystems. This study investigated the impact of a large-scale forest fire in 2022 (ca. 1300 ha) on epigeic ground beetles (Coleoptera: Carabidae). The research was conducted in coniferous forests at six pairwise study sites: burnt and unburnt dead spruce from bark beetles, burnt and unburnt clear cut, and burnt and unburnt healthy sites. Each site was replicated in four plots, with two pitfall traps deployed within each plot. In total, 48 pitfall traps (6 × 4 × 2) were installed in April 2023. It was tested how individual sites affected the similarity of ground beetle communities, whether they contained similar life guilds, and how significantly large-scale fire affects the abundance of pyrophilous ground beetles. A total of 5952 individuals and 63 species were recorded. We observed a significant decline in abundance at clear-cut and dead spruce burnt sites (73% and 77.5%, respectively) compared to the unburnt sites. Conversely, abundance increased by 88% at the burnt healthy site compared to the unburnt healthy site. Additionally, significant differences in the number of species per trap and species richness diversity (q = 0, q = 1, q = 2) were found only between burnt and unburnt healthy sites. In general, the highest species richness in the comparison of all study sites was at unburnt clear-cut and burnt healthy sites. Communities of ground beetles responded considerably to the fire, differing significantly from unburnt sites, and demonstrating a high degree of similarity. The original healthy spruce stands had highly homogeneous communities. On the contrary, any disturbance (bark beetle calamity, clear-cut) resulted in an increase in the alpha, beta, and gamma diversities of the ground beetle communities. Burnt sites attracted pyrophilous species (Sericoda quadripunctata, Pterostichus quadrifoveolatus) at very low abundances, with the highest activity in the second half of the season. In conclusion, ground beetles demonstrated a strong short-term response to large-scale fire, forming specific communities. However, pyrophilous ground beetles were unable to occupy a large-scale fire area due to the initial low abundance. Understanding post-fire processes can provide important guidance for management in areas designated for biodiversity enhancement.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"43 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140411547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The fractional change in the reaction progress variable gradient depends on the flow normal straining within the flame and also upon the corresponding normal gradients of the reaction rate and its molecular diffusion transport. The statistical behaviours of the normal strain rate and the contributions arising from the normal gradients of the reaction rate and molecular diffusion rate within the flame were analysed by means of a Direct Numerical Simulation (DNS) database of statistically planar turbulent premixed flames ranging from the wrinkled/corrugated flamelets regime to the thin reaction zones regime. The interaction of flame-normal straining with the flame-normal gradient of molecular diffusion rate was found to govern the reactive scalar gradient transport in the preheat zone, where comparable timescales for turbulent straining and molecular diffusion are obtained for small values of Karlovitz numbers. However, the molecular diffusion timescale turns out to be smaller than the turbulent straining timescale for high values of Karlovitz numbers. By contrast, the reaction and hot product zones of the flame remain mostly unaffected by turbulence, and the reactive scalar gradient transport in this zone is determined by the interaction between the flame-normal gradients of molecular diffusion and chemical reaction rates.
{"title":"Timescales Associated with the Evolution of Reactive Scalar Gradient in Premixed Turbulent Combustion: A Direct Numerical Simulation Analysis","authors":"N. Chakraborty, C. Dopazo","doi":"10.3390/fire7030073","DOIUrl":"https://doi.org/10.3390/fire7030073","url":null,"abstract":"The fractional change in the reaction progress variable gradient depends on the flow normal straining within the flame and also upon the corresponding normal gradients of the reaction rate and its molecular diffusion transport. The statistical behaviours of the normal strain rate and the contributions arising from the normal gradients of the reaction rate and molecular diffusion rate within the flame were analysed by means of a Direct Numerical Simulation (DNS) database of statistically planar turbulent premixed flames ranging from the wrinkled/corrugated flamelets regime to the thin reaction zones regime. The interaction of flame-normal straining with the flame-normal gradient of molecular diffusion rate was found to govern the reactive scalar gradient transport in the preheat zone, where comparable timescales for turbulent straining and molecular diffusion are obtained for small values of Karlovitz numbers. However, the molecular diffusion timescale turns out to be smaller than the turbulent straining timescale for high values of Karlovitz numbers. By contrast, the reaction and hot product zones of the flame remain mostly unaffected by turbulence, and the reactive scalar gradient transport in this zone is determined by the interaction between the flame-normal gradients of molecular diffusion and chemical reaction rates.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"12 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140413426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Murramarang Country, Jessica Davis, Jack Simmons, Shane Snelson, Victor Channell, Katharine Haynes, Nicholas Deutscher, Leanne Brook, Anthony Dosseto
Fire management techniques play a critical role in mitigating the impact of bushfires on communities and ecosystems. In Australia, government agencies implement hazard reduction burn programs, while Indigenous communities have used fire for ecosystem management for thousands of years. The positive effect of prescribed burning goes beyond bushfire risk mitigation, with impacts also on soil and ecosystem health. This study evaluates the effects of prescribed burning on soil properties, with implications for soil and ecosystem health. Two fire management techniques were evaluated: agency-led prescribed burning and cultural burning. Both fire treatments resulted in an increase in soil moisture, showing that they positively affect the soil water balance (the greater effect seen following the agency-led burn). Both fire treatments also resulted in a decrease in soil bulk density and an increase in organic matter content, with the greater effect seen for soils affected by the Indigenous-led burn. These results show that both fire management techniques positively affect soil health, with important consequences for aboveground ecosystem health. Cultural burning is the most efficient to promote reduced soil bulk density (important for nutrient availability and microbial activity) and increase carbon and nitrogen stores.
{"title":"Quantitative Assessment of the Effect of Agency-Led Prescribed Burns and Cultural Burns on Soil Properties in Southeastern Australia","authors":"Murramarang Country, Jessica Davis, Jack Simmons, Shane Snelson, Victor Channell, Katharine Haynes, Nicholas Deutscher, Leanne Brook, Anthony Dosseto","doi":"10.3390/fire7030075","DOIUrl":"https://doi.org/10.3390/fire7030075","url":null,"abstract":"Fire management techniques play a critical role in mitigating the impact of bushfires on communities and ecosystems. In Australia, government agencies implement hazard reduction burn programs, while Indigenous communities have used fire for ecosystem management for thousands of years. The positive effect of prescribed burning goes beyond bushfire risk mitigation, with impacts also on soil and ecosystem health. This study evaluates the effects of prescribed burning on soil properties, with implications for soil and ecosystem health. Two fire management techniques were evaluated: agency-led prescribed burning and cultural burning. Both fire treatments resulted in an increase in soil moisture, showing that they positively affect the soil water balance (the greater effect seen following the agency-led burn). Both fire treatments also resulted in a decrease in soil bulk density and an increase in organic matter content, with the greater effect seen for soils affected by the Indigenous-led burn. These results show that both fire management techniques positively affect soil health, with important consequences for aboveground ecosystem health. Cultural burning is the most efficient to promote reduced soil bulk density (important for nutrient availability and microbial activity) and increase carbon and nitrogen stores.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"78 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140408652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Haley K. Skinner, Susan J. Prichard, Alison C. Cullen
Background: Climate change is a strong contributing factor in the lengthening and intensification of wildfire seasons, with warmer and often drier conditions associated with increasingly severe impacts. Land managers are faced with challenging decisions about how to manage forests, minimize risk of extreme wildfire, and balance competing values at risk, including communities, habitat, air quality, surface drinking water, recreation, and infrastructure. Aims: We propose that land managers use decision analytic frameworks to complement existing decision support systems such as the Interagency Fuel Treatment Decision Support System. Methods: We apply this approach to a fire-prone landscape in eastern Washington State under two proposed landscape treatment alternatives. Through stakeholder engagement, a quantitative wildfire risk assessment, and translating results into probabilistic descriptions of wildfire occurrence (burn probability) and intensity (conditional flame length), we construct a decision tree to explicitly evaluate tradeoffs of treatment alternative outcomes. Key Results: We find that while there are slightly more effective localized benefits for treatments involving thinning and prescribed burning, neither of the UWPP’s proposed alternatives are more likely to meaningfully minimize the risk of wildfire impacts at the landscape level. Conclusions: This case study demonstrates that a quantitatively informed decision analytic framework can improve land managers’ ability to effectively and explicitly evaluate tradeoffs between treatment alternatives.
{"title":"Decision Support for Landscapes with High Fire Hazard and Competing Values at Risk: The Upper Wenatchee Pilot Project","authors":"Haley K. Skinner, Susan J. Prichard, Alison C. Cullen","doi":"10.3390/fire7030077","DOIUrl":"https://doi.org/10.3390/fire7030077","url":null,"abstract":"Background: Climate change is a strong contributing factor in the lengthening and intensification of wildfire seasons, with warmer and often drier conditions associated with increasingly severe impacts. Land managers are faced with challenging decisions about how to manage forests, minimize risk of extreme wildfire, and balance competing values at risk, including communities, habitat, air quality, surface drinking water, recreation, and infrastructure. Aims: We propose that land managers use decision analytic frameworks to complement existing decision support systems such as the Interagency Fuel Treatment Decision Support System. Methods: We apply this approach to a fire-prone landscape in eastern Washington State under two proposed landscape treatment alternatives. Through stakeholder engagement, a quantitative wildfire risk assessment, and translating results into probabilistic descriptions of wildfire occurrence (burn probability) and intensity (conditional flame length), we construct a decision tree to explicitly evaluate tradeoffs of treatment alternative outcomes. Key Results: We find that while there are slightly more effective localized benefits for treatments involving thinning and prescribed burning, neither of the UWPP’s proposed alternatives are more likely to meaningfully minimize the risk of wildfire impacts at the landscape level. Conclusions: This case study demonstrates that a quantitatively informed decision analytic framework can improve land managers’ ability to effectively and explicitly evaluate tradeoffs between treatment alternatives.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"58 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140415779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fire is a major disaster event that can have a significant effect on public safety and social development. In a college or university, fire can seriously threaten the safety, lives, and property of those there due to the compact layout of apartment buildings and high population density. The ecological safety and sustainable development of buildings are also affected. In this study, PyroSim and Pathfinder software (version 2019) were used to simulate and analyze fire-spreading characteristics based on a multi-story university student apartment building. Additionally, the most effective safe evacuation plan from four fire evacuation drill schemes was identified by analyzing and comparing their performance. Results show that the spreading of fire smoke on different floors is significantly affected by the roof structure and the vertical and horizontal diffusion characteristics of smoke. While the smoke layer at the evacuation stairways has little effect on a safe evacuation, poor visibility due to smoke and ceiling temperatures has a significant effect. Safe evacuation becomes progressively more difficult at different floor levels from the top to the bottom of the building. The optimal safety scheme involves orderly evacuation through two open emergency exits. The number of emergency exits has a significant impact on the evacuation effectiveness. Measures and suggestions have been proposed to deal with apartment fires that address pre-event prevention, emergency loss reduction during the event, and post-event report-back. These proposals form an important theoretical reference for emergency evacuation and student apartment fire safety, providing important guidance for ecological safety protection of buildings and sustainable development.
{"title":"Fire-Spread Characteristics and Evacuation Plan Optimization of Old Style Multi-Story Student Apartments","authors":"Pu Wang, Hongtai Dai, Xiuhui Yu, Qingbiao Wang, Shun Li, Chuanyang Jia","doi":"10.3390/fire7030072","DOIUrl":"https://doi.org/10.3390/fire7030072","url":null,"abstract":"Fire is a major disaster event that can have a significant effect on public safety and social development. In a college or university, fire can seriously threaten the safety, lives, and property of those there due to the compact layout of apartment buildings and high population density. The ecological safety and sustainable development of buildings are also affected. In this study, PyroSim and Pathfinder software (version 2019) were used to simulate and analyze fire-spreading characteristics based on a multi-story university student apartment building. Additionally, the most effective safe evacuation plan from four fire evacuation drill schemes was identified by analyzing and comparing their performance. Results show that the spreading of fire smoke on different floors is significantly affected by the roof structure and the vertical and horizontal diffusion characteristics of smoke. While the smoke layer at the evacuation stairways has little effect on a safe evacuation, poor visibility due to smoke and ceiling temperatures has a significant effect. Safe evacuation becomes progressively more difficult at different floor levels from the top to the bottom of the building. The optimal safety scheme involves orderly evacuation through two open emergency exits. The number of emergency exits has a significant impact on the evacuation effectiveness. Measures and suggestions have been proposed to deal with apartment fires that address pre-event prevention, emergency loss reduction during the event, and post-event report-back. These proposals form an important theoretical reference for emergency evacuation and student apartment fire safety, providing important guidance for ecological safety protection of buildings and sustainable development.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140422517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiuquan Li, Dugang Kang, Lei Zhang, Jie Chen, Song Huang, Qunfeng Zou, Ziqiang He
Microchannel burners suffer from low combustion efficiency and poor stability in applications. In order to explore the effect of wall reaction on methane/air premixed combustion performances in the microchannel, the effects of wall activity, inlet velocity, pressure, and equivalence ratio on the temperature and radical distribution characteristics were studied by CFD computational simulations. It is found that as the reaction pressure increases, there are more free-radical collisions, causing the reaction temperature to rise. The OH radicals participate in the reaction at the active near wall so that the mass fraction of the OH radical on the active wall is lower than that on the inert wall. As the equivalence ratio increases from 0.6 to 1.2, the high-temperature regions increase but the maximum temperature decreases. The mass fraction of OH radical increases with the increase of the equivalence ratio, and the increase of OH radical near the inert wall is larger than that of the active wall. As the flow rate increases, the disturbance increases, and the combustion reaction becomes more intense, resulting in an increase in the temperature and the mass fraction of OH radicals. The mass fraction of H, O, OH, and CH3 radicals in the inert wall was slightly higher than that in the active wall, in which the peak mass fraction of CH3 radical appeared at the axial position closest to the entrance, while the other three radicals reached the peak at about the same axial position. This study provides a reference for combustion stability in microcombustors.
{"title":"Effect of Surface Reaction on the Distribution Characteristics of Temperature and OH Radicals in Microchannel Combustion","authors":"Xiuquan Li, Dugang Kang, Lei Zhang, Jie Chen, Song Huang, Qunfeng Zou, Ziqiang He","doi":"10.3390/fire7030071","DOIUrl":"https://doi.org/10.3390/fire7030071","url":null,"abstract":"Microchannel burners suffer from low combustion efficiency and poor stability in applications. In order to explore the effect of wall reaction on methane/air premixed combustion performances in the microchannel, the effects of wall activity, inlet velocity, pressure, and equivalence ratio on the temperature and radical distribution characteristics were studied by CFD computational simulations. It is found that as the reaction pressure increases, there are more free-radical collisions, causing the reaction temperature to rise. The OH radicals participate in the reaction at the active near wall so that the mass fraction of the OH radical on the active wall is lower than that on the inert wall. As the equivalence ratio increases from 0.6 to 1.2, the high-temperature regions increase but the maximum temperature decreases. The mass fraction of OH radical increases with the increase of the equivalence ratio, and the increase of OH radical near the inert wall is larger than that of the active wall. As the flow rate increases, the disturbance increases, and the combustion reaction becomes more intense, resulting in an increase in the temperature and the mass fraction of OH radicals. The mass fraction of H, O, OH, and CH3 radicals in the inert wall was slightly higher than that in the active wall, in which the peak mass fraction of CH3 radical appeared at the axial position closest to the entrance, while the other three radicals reached the peak at about the same axial position. This study provides a reference for combustion stability in microcombustors.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"7 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140424538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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