Pub Date : 2023-10-31DOI: 10.1186/s42408-023-00227-x
David A. Davim, Carlos G. Rossa, José M. C. Pereira, Nuno Guiomar, Paulo M. Fernandes
Abstract Background The study of wildfire interactions (i.e., spread limitation and reburns) is gaining traction as a means of describing the self-limiting process of fire spread in the landscape and has important management implications but has scarcely been attempted in Europe. We examined to what extent previously burned areas restricted the development of individual large wildfires (> 500 ha) in mainland Portugal. Results For the 1984–2021 period, we (1) modeled the proportion of large wildfire perimeters coinciding with transitions to shorter time since fire (TSF), i.e., locations where fire spread ceased upon encountering assumedly less flammable fuels, and (2) characterized the prevalence of different TSF in the composition of the area burned by large wildfires in relation to available TSF. Only 4% of the large wildfires did not comprise edges intersecting past wildfires. Low TSF (especially up to 8 years) resulted in large-wildfire perimeter limitation at TSF transitions. This effect was further enhanced by high historical burn probability and proximity to roadways and watercourses. Perimeter limitation did also increase under high (but not very high or extreme) fire danger, benefiting from maximum seasonal firefighting preparedness. TSF prevalence in the composition of large-wildfire area was extremely variable and thus an overall weak pattern emerged, with minimum and maximum prevalence respectively at TSF < 2 years and TSF ≥ 6 years. Conclusions Large wildfire limitation in Portugal is hampered by fast fuel build-up after fire, indicating a short-lived fire-hazard reduction effect under the prevailing Mediterranean humid climate of the study region. Nonetheless, such effect should be considered when planning fuel-reduction treatments and can be used opportunistically during large-wildfire suppression operations.
{"title":"The effectiveness of past wildfire at limiting reburning is short-lived in a Mediterranean humid climate","authors":"David A. Davim, Carlos G. Rossa, José M. C. Pereira, Nuno Guiomar, Paulo M. Fernandes","doi":"10.1186/s42408-023-00227-x","DOIUrl":"https://doi.org/10.1186/s42408-023-00227-x","url":null,"abstract":"Abstract Background The study of wildfire interactions (i.e., spread limitation and reburns) is gaining traction as a means of describing the self-limiting process of fire spread in the landscape and has important management implications but has scarcely been attempted in Europe. We examined to what extent previously burned areas restricted the development of individual large wildfires (> 500 ha) in mainland Portugal. Results For the 1984–2021 period, we (1) modeled the proportion of large wildfire perimeters coinciding with transitions to shorter time since fire (TSF), i.e., locations where fire spread ceased upon encountering assumedly less flammable fuels, and (2) characterized the prevalence of different TSF in the composition of the area burned by large wildfires in relation to available TSF. Only 4% of the large wildfires did not comprise edges intersecting past wildfires. Low TSF (especially up to 8 years) resulted in large-wildfire perimeter limitation at TSF transitions. This effect was further enhanced by high historical burn probability and proximity to roadways and watercourses. Perimeter limitation did also increase under high (but not very high or extreme) fire danger, benefiting from maximum seasonal firefighting preparedness. TSF prevalence in the composition of large-wildfire area was extremely variable and thus an overall weak pattern emerged, with minimum and maximum prevalence respectively at TSF < 2 years and TSF ≥ 6 years. Conclusions Large wildfire limitation in Portugal is hampered by fast fuel build-up after fire, indicating a short-lived fire-hazard reduction effect under the prevailing Mediterranean humid climate of the study region. Nonetheless, such effect should be considered when planning fuel-reduction treatments and can be used opportunistically during large-wildfire suppression operations.","PeriodicalId":12273,"journal":{"name":"Fire Ecology","volume":"38 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135809210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-27DOI: 10.1186/s42408-023-00224-0
Rodrigo Balaguer-Romano, Rubén Díaz-Sierra, Miquel De Cáceres, Jordi Voltas, Matthias M. Boer, Víctor Resco de Dios
Abstract Background Current assessments of the effects of climate change on future wildfire risk are based on either empirical approaches or fire weather indices. No study has yet used process-based models over national scales to understand how and where will increases in climate aridity affect the likelihood of fire activity through changes in the moisture content of live (LFMC) and of dead (DFMC) fuels. Here, we used process-based models to forecast changes in LFMC and DFMC under the 21st century climatic conditions projected from moderate and high greenhouse gas emission scenarios (RCP4.5 and RCP8.5). Predictions were performed across broad productivity gradients in peninsular Spain to understand how productivity mediates the effects of climate change on fuel moisture dynamics. Results LFMC and DFMC were predicted to decline under the climatic conditions projected for the coming decades. Increases in the annual frequency of days with fuel moisture content below wildfire occurrence thresholds were predicted to extend fire season lengths by 20 days under RCP4.5 and by 50 days under RCP8.5. The effects of climate change on LFMC and DFMC varied linearly and negatively with productivity (stronger fuel moisture decreases in least productive environments). Although we observed a significant mitigation effect from rising CO 2 (via increases in water-use efficiency), it was not enough to offset LFMC declining trends induced by increased temperature and aridity. Conclusions We predicted that the warmer and more arid climatic conditions projected for the 21st century will lead to generalized declines in fuel moisture, lengthening fire seasons, and increasing wildfire danger. The use of process-based models to forecast LFMC dynamics allowed the consideration of plant species capabilities to buffer climate change impacts. Significant increases in the fire season length predicted in the most productive environments, currently with large fire return intervals, would pose an increase of fire danger in major Spanish carbon sinks. Finally, the CO 2 mitigation effect would not be enough to offset climate change-driven declines in seasonal LFMC levels.
{"title":"Modeling fuel moisture dynamics under climate change in Spain’s forests","authors":"Rodrigo Balaguer-Romano, Rubén Díaz-Sierra, Miquel De Cáceres, Jordi Voltas, Matthias M. Boer, Víctor Resco de Dios","doi":"10.1186/s42408-023-00224-0","DOIUrl":"https://doi.org/10.1186/s42408-023-00224-0","url":null,"abstract":"Abstract Background Current assessments of the effects of climate change on future wildfire risk are based on either empirical approaches or fire weather indices. No study has yet used process-based models over national scales to understand how and where will increases in climate aridity affect the likelihood of fire activity through changes in the moisture content of live (LFMC) and of dead (DFMC) fuels. Here, we used process-based models to forecast changes in LFMC and DFMC under the 21st century climatic conditions projected from moderate and high greenhouse gas emission scenarios (RCP4.5 and RCP8.5). Predictions were performed across broad productivity gradients in peninsular Spain to understand how productivity mediates the effects of climate change on fuel moisture dynamics. Results LFMC and DFMC were predicted to decline under the climatic conditions projected for the coming decades. Increases in the annual frequency of days with fuel moisture content below wildfire occurrence thresholds were predicted to extend fire season lengths by 20 days under RCP4.5 and by 50 days under RCP8.5. The effects of climate change on LFMC and DFMC varied linearly and negatively with productivity (stronger fuel moisture decreases in least productive environments). Although we observed a significant mitigation effect from rising CO 2 (via increases in water-use efficiency), it was not enough to offset LFMC declining trends induced by increased temperature and aridity. Conclusions We predicted that the warmer and more arid climatic conditions projected for the 21st century will lead to generalized declines in fuel moisture, lengthening fire seasons, and increasing wildfire danger. The use of process-based models to forecast LFMC dynamics allowed the consideration of plant species capabilities to buffer climate change impacts. Significant increases in the fire season length predicted in the most productive environments, currently with large fire return intervals, would pose an increase of fire danger in major Spanish carbon sinks. Finally, the CO 2 mitigation effect would not be enough to offset climate change-driven declines in seasonal LFMC levels.","PeriodicalId":12273,"journal":{"name":"Fire Ecology","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136234371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-26DOI: 10.1186/s42408-023-00223-1
Matthew J. Reilly, Aaron Zuspan, Zhiqiang Yang
Abstract Background Despite recent advances in understanding the drivers of tree-level delayed mortality, we lack a method for mapping delayed mortality at landscape and regional scales. Consequently, the extent, magnitude, and effects of delayed mortality on post-fire landscape patterns of burn severity are unknown. We introduce a remote sensing approach for mapping delayed mortality based on post-fire decline in the normalized burn ratio (NBR). NBR decline is defined as the change in NBR between the first post-fire measurement and the minimum NBR value up to 5 years post-fire for each pixel. We validate the method with high-resolution aerial photography from six wildfires in California, Oregon, and Washington, USA, and then compare the extent, magnitude, and effects of delayed mortality on landscape patterns of burn severity among fires and forest types. Results NBR decline was significantly correlated with post-fire canopy mortality ( r 2 = 0.50) and predicted the presence of delayed mortality with 83% accuracy based on a threshold of 105 NBR decline. Plots with NBR decline greater than 105 were 23 times more likely to experience delayed mortality than those below the threshold ( p < 0.001). Delayed mortality occurred across 6–38% of fire perimeters not affected by stand-replacing fire, generally affecting more areas in cold (22–41%) and wet (30%) forest types than in dry (1.7–19%) types. The total area initially mapped as unburned/very low-severity declined an average of 38.1% and generally persisted in smaller, more fragmented patches when considering delayed mortality. The total area initially mapped as high-severity increased an average of 16.2% and shifted towards larger, more contiguous patches. Conclusions Differences between 1- and 5-year post-fire burn severity maps depict dynamic post-fire mosaics resulting from delayed mortality, with variability among fires reflecting a range of potential drivers. We demonstrate that tree-level delayed mortality scales up to alter higher-level landscape patterns of burn severity with important implications for forest resilience and a range of fire-driven ecological outcomes. Our method can complement existing tree-level studies on drivers of delayed mortality, refine mapping of fire refugia, inform estimates of habitat and carbon losses, and provide a more comprehensive assessment of landscape and regional scale fire effects and trends.
{"title":"Characterizing post-fire delayed tree mortality with remote sensing: sizing up the elephant in the room","authors":"Matthew J. Reilly, Aaron Zuspan, Zhiqiang Yang","doi":"10.1186/s42408-023-00223-1","DOIUrl":"https://doi.org/10.1186/s42408-023-00223-1","url":null,"abstract":"Abstract Background Despite recent advances in understanding the drivers of tree-level delayed mortality, we lack a method for mapping delayed mortality at landscape and regional scales. Consequently, the extent, magnitude, and effects of delayed mortality on post-fire landscape patterns of burn severity are unknown. We introduce a remote sensing approach for mapping delayed mortality based on post-fire decline in the normalized burn ratio (NBR). NBR decline is defined as the change in NBR between the first post-fire measurement and the minimum NBR value up to 5 years post-fire for each pixel. We validate the method with high-resolution aerial photography from six wildfires in California, Oregon, and Washington, USA, and then compare the extent, magnitude, and effects of delayed mortality on landscape patterns of burn severity among fires and forest types. Results NBR decline was significantly correlated with post-fire canopy mortality ( r 2 = 0.50) and predicted the presence of delayed mortality with 83% accuracy based on a threshold of 105 NBR decline. Plots with NBR decline greater than 105 were 23 times more likely to experience delayed mortality than those below the threshold ( p < 0.001). Delayed mortality occurred across 6–38% of fire perimeters not affected by stand-replacing fire, generally affecting more areas in cold (22–41%) and wet (30%) forest types than in dry (1.7–19%) types. The total area initially mapped as unburned/very low-severity declined an average of 38.1% and generally persisted in smaller, more fragmented patches when considering delayed mortality. The total area initially mapped as high-severity increased an average of 16.2% and shifted towards larger, more contiguous patches. Conclusions Differences between 1- and 5-year post-fire burn severity maps depict dynamic post-fire mosaics resulting from delayed mortality, with variability among fires reflecting a range of potential drivers. We demonstrate that tree-level delayed mortality scales up to alter higher-level landscape patterns of burn severity with important implications for forest resilience and a range of fire-driven ecological outcomes. Our method can complement existing tree-level studies on drivers of delayed mortality, refine mapping of fire refugia, inform estimates of habitat and carbon losses, and provide a more comprehensive assessment of landscape and regional scale fire effects and trends.","PeriodicalId":12273,"journal":{"name":"Fire Ecology","volume":"14 3-4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134908941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-23DOI: 10.1186/s42408-023-00215-1
Abigail R. Croker, Jeremy Woods, Yiannis Kountouris
Abstract Background Late dry-season wildfires in sub-Saharan Africa’s savanna-protected areas are intensifying, increasing carbon emissions, and threatening ecosystem functioning. Addressing these challenges requires active local community engagement and support for wildfire policy. Savanna burning emissions abatement schemes first implemented in Northern Australia have been proposed as a community-based fire management strategy for East and Southern Africa’s protected areas to deliver win–win-win climate, social, and biodiversity benefits. Here, we review and critically examine the literature exploring the design and application of savanna burning emissions abatement schemes in this region, characterizing their contextual and implementation challenges. Results We show that the application of Northern Australian savanna burning methodologies in East and Southern Africa tends to adopt centrally determined objectives and market-based approaches that prioritize carbon revenue generation at the national level. The exclusive prescription of early-dry season burns in African mesic savannas prone to woody thickening can compromise savanna burning objectives to mitigate late-dry season wildfires and their greenhouse gas emissions in the long-term, as well as present multiple biodiversity trade-offs in the absence of formal metrics monitoring species’ responses to changes in fire regime. These features restrict indigenous participation and leadership in fire management, creating uncertainties over the opportunities for local income generation through carbon trading. Findings suggest that future savanna burning applications will need to address asymmetries between formal institutions and local land governance systems, explicitly acknowledging colonial legacies in institutional arrangements across protected areas and hierarchies in agrarian politics that threaten processes of equitable decentralization in natural resource management. Conclusion We argue that the effective transfer of the Northern Australian fire management model is limited by a lack of long-term ecological and emissions data and political and institutional barriers, and is hindered by the region’s recent colonial history, population growth, and consequences of rapid climatic change. To provide a community-based strategy, savanna burning schemes need to establish context-specific legal frameworks and implement Free, Prior, and Informed Consent to safeguard the roles and responsibilities of indigenous and local people and their distribution of carbon benefits.
{"title":"Changing fire regimes in East and Southern Africa’s savanna-protected areas: opportunities and challenges for indigenous-led savanna burning emissions abatement schemes","authors":"Abigail R. Croker, Jeremy Woods, Yiannis Kountouris","doi":"10.1186/s42408-023-00215-1","DOIUrl":"https://doi.org/10.1186/s42408-023-00215-1","url":null,"abstract":"Abstract Background Late dry-season wildfires in sub-Saharan Africa’s savanna-protected areas are intensifying, increasing carbon emissions, and threatening ecosystem functioning. Addressing these challenges requires active local community engagement and support for wildfire policy. Savanna burning emissions abatement schemes first implemented in Northern Australia have been proposed as a community-based fire management strategy for East and Southern Africa’s protected areas to deliver win–win-win climate, social, and biodiversity benefits. Here, we review and critically examine the literature exploring the design and application of savanna burning emissions abatement schemes in this region, characterizing their contextual and implementation challenges. Results We show that the application of Northern Australian savanna burning methodologies in East and Southern Africa tends to adopt centrally determined objectives and market-based approaches that prioritize carbon revenue generation at the national level. The exclusive prescription of early-dry season burns in African mesic savannas prone to woody thickening can compromise savanna burning objectives to mitigate late-dry season wildfires and their greenhouse gas emissions in the long-term, as well as present multiple biodiversity trade-offs in the absence of formal metrics monitoring species’ responses to changes in fire regime. These features restrict indigenous participation and leadership in fire management, creating uncertainties over the opportunities for local income generation through carbon trading. Findings suggest that future savanna burning applications will need to address asymmetries between formal institutions and local land governance systems, explicitly acknowledging colonial legacies in institutional arrangements across protected areas and hierarchies in agrarian politics that threaten processes of equitable decentralization in natural resource management. Conclusion We argue that the effective transfer of the Northern Australian fire management model is limited by a lack of long-term ecological and emissions data and political and institutional barriers, and is hindered by the region’s recent colonial history, population growth, and consequences of rapid climatic change. To provide a community-based strategy, savanna burning schemes need to establish context-specific legal frameworks and implement Free, Prior, and Informed Consent to safeguard the roles and responsibilities of indigenous and local people and their distribution of carbon benefits.","PeriodicalId":12273,"journal":{"name":"Fire Ecology","volume":"33 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135413210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Background Mobile ad hoc networks have piqued researchers’ interest in various applications, including forest fire detection. Because of the massive losses caused by this disaster, forest fires necessitate regular monitoring, good communication, and technology. As a result, disaster response and rescue applications are mobile ad hoc network’s primary applications. However, quality of service becomes a significant and difficult issue, and the capabilities of the basic routing protocol limit mobile ad hoc network’s ability to deliver reasonable quality of service. Results The proposed research is for disaster-related scenarios, with nodes representing firefighters and vehicles (ambulances). Mobile nodes moving at 10 m/s are thought to be firefighters, while nodes moving at 20 m/s are thought to be vehicles (ambulances) delivering emergency healthcare. The NS-2 simulator is used in this research for the performance assessment of the two routing protocols, such as Optimized Link State Routing (OLSR) and Temporally Order Routing Algorithm (TORA), in terms of average latency, average throughput, and average packet drop. The simulation was run with varying node velocities and network densities to examine the impact of scalability on the two mobile ad hoc network routing protocols. Conclusions This work presents two main protocols: TORA (for reactive networks) and OLSR (for proactive networks). The proposed methods had no impact on the end-to-end bandwidth delay or the packet delivery delay. The performance is evaluated in terms of varying network density and node speed (firefighter speed), i.e., varying network density and mobility speed. The simulation revealed that in a highly mobile network with varying network densities, OLSR outperforms TORA in terms of overall performance. TORA’s speed may have been enhanced by adding more nodes to the 20 nodes that used a significant amount of transmission control protocol traffic.
{"title":"Analyzing the impacts of node density and speed on routing protocol performance in firefighting applications","authors":"Inam Ullah, Tariq Hussain, Aamir Khan, Iqtidar Ali, Farhad Ali, Chang Choi","doi":"10.1186/s42408-023-00220-4","DOIUrl":"https://doi.org/10.1186/s42408-023-00220-4","url":null,"abstract":"Abstract Background Mobile ad hoc networks have piqued researchers’ interest in various applications, including forest fire detection. Because of the massive losses caused by this disaster, forest fires necessitate regular monitoring, good communication, and technology. As a result, disaster response and rescue applications are mobile ad hoc network’s primary applications. However, quality of service becomes a significant and difficult issue, and the capabilities of the basic routing protocol limit mobile ad hoc network’s ability to deliver reasonable quality of service. Results The proposed research is for disaster-related scenarios, with nodes representing firefighters and vehicles (ambulances). Mobile nodes moving at 10 m/s are thought to be firefighters, while nodes moving at 20 m/s are thought to be vehicles (ambulances) delivering emergency healthcare. The NS-2 simulator is used in this research for the performance assessment of the two routing protocols, such as Optimized Link State Routing (OLSR) and Temporally Order Routing Algorithm (TORA), in terms of average latency, average throughput, and average packet drop. The simulation was run with varying node velocities and network densities to examine the impact of scalability on the two mobile ad hoc network routing protocols. Conclusions This work presents two main protocols: TORA (for reactive networks) and OLSR (for proactive networks). The proposed methods had no impact on the end-to-end bandwidth delay or the packet delivery delay. The performance is evaluated in terms of varying network density and node speed (firefighter speed), i.e., varying network density and mobility speed. The simulation revealed that in a highly mobile network with varying network densities, OLSR outperforms TORA in terms of overall performance. TORA’s speed may have been enhanced by adding more nodes to the 20 nodes that used a significant amount of transmission control protocol traffic.","PeriodicalId":12273,"journal":{"name":"Fire Ecology","volume":"45 26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135778554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-17DOI: 10.1186/s42408-023-00218-y
Ana Solares-Canal, Laura Alonso, Thais Rincón, Juan Picos, Domingo M. Molina-Terrén, Carmen Becerra, Julia Armesto
Abstract Background In the new era of large, high-intensity wildfire events, new fire prevention and extinction strategies are emerging. Software that simulates fire behavior can play a leading role. In order for these simulators to provide reliable results, updated fuel model maps are required. Previous studies have shown that remote sensing is a useful tool for obtaining information about vegetation structures and types. However, remote sensing technologies have not been evaluated for operational purposes in Atlantic environments. In this study, we describe a methodology based on remote sensing data (Sentinel-2 images and aerial point clouds) to obtain updated fuel model maps of an Atlantic area. These maps could be used directly in wildfire simulation software. Results An automated methodology has been developed that allows for the efficient identification and mapping of fuel models in an Atlantic environment. It mainly consists of processing remote sensing data using supervised classifications to obtain a map with the geographical distribution of the species in the study area and maps with the geographical distribution of the structural characteristics of the forest covers. The relationships between the vegetation species and structures in the study area and the Rothermel fuel models were identified. These relationships enabled the generation of the final fuel model map by combining the different previously obtained maps. The resulting map provides essential information about the geographical distribution of fuels; 32.92% of the study area corresponds to models 4 and 7, which are the two models that tend to develop more dangerous behaviors. The accuracy of the final map is evaluated through validation of the maps that are used to obtain it. The user and producer accuracy ranged between 70 and 100%. Conclusion This paper describes an automated methodology for obtaining updated fuel model maps in Atlantic landscapes using remote sensing data. These maps are crucial in wildfire simulation, which supports the modern wildfire suppression and prevention strategies. Sentinel-2 is a global open access source, and LiDAR is an extensively used technology, meaning that the approach proposed in this study represents a step forward in the efficient transformation of remote sensing data into operational tools for wildfire prevention.
{"title":"Operational fuel model map for Atlantic landscapes using ALS and Sentinel-2 images","authors":"Ana Solares-Canal, Laura Alonso, Thais Rincón, Juan Picos, Domingo M. Molina-Terrén, Carmen Becerra, Julia Armesto","doi":"10.1186/s42408-023-00218-y","DOIUrl":"https://doi.org/10.1186/s42408-023-00218-y","url":null,"abstract":"Abstract Background In the new era of large, high-intensity wildfire events, new fire prevention and extinction strategies are emerging. Software that simulates fire behavior can play a leading role. In order for these simulators to provide reliable results, updated fuel model maps are required. Previous studies have shown that remote sensing is a useful tool for obtaining information about vegetation structures and types. However, remote sensing technologies have not been evaluated for operational purposes in Atlantic environments. In this study, we describe a methodology based on remote sensing data (Sentinel-2 images and aerial point clouds) to obtain updated fuel model maps of an Atlantic area. These maps could be used directly in wildfire simulation software. Results An automated methodology has been developed that allows for the efficient identification and mapping of fuel models in an Atlantic environment. It mainly consists of processing remote sensing data using supervised classifications to obtain a map with the geographical distribution of the species in the study area and maps with the geographical distribution of the structural characteristics of the forest covers. The relationships between the vegetation species and structures in the study area and the Rothermel fuel models were identified. These relationships enabled the generation of the final fuel model map by combining the different previously obtained maps. The resulting map provides essential information about the geographical distribution of fuels; 32.92% of the study area corresponds to models 4 and 7, which are the two models that tend to develop more dangerous behaviors. The accuracy of the final map is evaluated through validation of the maps that are used to obtain it. The user and producer accuracy ranged between 70 and 100%. Conclusion This paper describes an automated methodology for obtaining updated fuel model maps in Atlantic landscapes using remote sensing data. These maps are crucial in wildfire simulation, which supports the modern wildfire suppression and prevention strategies. Sentinel-2 is a global open access source, and LiDAR is an extensively used technology, meaning that the approach proposed in this study represents a step forward in the efficient transformation of remote sensing data into operational tools for wildfire prevention.","PeriodicalId":12273,"journal":{"name":"Fire Ecology","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136033486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-17DOI: 10.1186/s42408-023-00222-2
Rebekah L. Stanton, Baylie C. Nusink, Kristina L. Cass, Tara B. B. Bishop, Brianna M. Woodbury, David N. Armond, Samuel B. St. Clair
Abstract Background Wildfire regimes are changing dramatically across North American deserts with the spread of invasive grasses. Invasive grass fire cycles in historically fire-resistant deserts are resulting in larger and more frequent wildfire. This study experimentally compared how single and repeat fires influence invasive grass-dominated plant fuels in the Great Basin, a semi-arid, cold desert, and the Mojave, a hyper-arid desert. Both study sites had identical study designs. In the summer of 2011, we experimentally burned half of each experimental block, the other half remaining as an unburned control. Half of the burned plots were reburned 5 years later to simulate increasing burn frequency. We estimated non-woody plant biomass, cover, and density in plots from 2017 to 2020. Results Biomass did not vary between sites, but there was higher plant cover and lower plant density at the Mojave site than at the Great Basin site. Plant biomass, density, and cover varied significantly across the years, with stronger annual fluctuations in the Great Basin. At both desert sites, fire increased plant density and biomass but had no effect on the cover. The effect of fire on plant cover varied significantly between years for both deserts but was greater in the Great Basin than in the Mojave site. Repeat fires did not amplify initial fire effects. Conclusions The results suggest that in general annual fluctuations in fine fuel production and fluctuations in response to fire were more apparent at the Great Basin site than at the Mojave site, with no immediate compounding effect of repeat fires at either site.
{"title":"Fire frequency effects on plant community characteristics in the Great Basin and Mojave deserts of North America","authors":"Rebekah L. Stanton, Baylie C. Nusink, Kristina L. Cass, Tara B. B. Bishop, Brianna M. Woodbury, David N. Armond, Samuel B. St. Clair","doi":"10.1186/s42408-023-00222-2","DOIUrl":"https://doi.org/10.1186/s42408-023-00222-2","url":null,"abstract":"Abstract Background Wildfire regimes are changing dramatically across North American deserts with the spread of invasive grasses. Invasive grass fire cycles in historically fire-resistant deserts are resulting in larger and more frequent wildfire. This study experimentally compared how single and repeat fires influence invasive grass-dominated plant fuels in the Great Basin, a semi-arid, cold desert, and the Mojave, a hyper-arid desert. Both study sites had identical study designs. In the summer of 2011, we experimentally burned half of each experimental block, the other half remaining as an unburned control. Half of the burned plots were reburned 5 years later to simulate increasing burn frequency. We estimated non-woody plant biomass, cover, and density in plots from 2017 to 2020. Results Biomass did not vary between sites, but there was higher plant cover and lower plant density at the Mojave site than at the Great Basin site. Plant biomass, density, and cover varied significantly across the years, with stronger annual fluctuations in the Great Basin. At both desert sites, fire increased plant density and biomass but had no effect on the cover. The effect of fire on plant cover varied significantly between years for both deserts but was greater in the Great Basin than in the Mojave site. Repeat fires did not amplify initial fire effects. Conclusions The results suggest that in general annual fluctuations in fine fuel production and fluctuations in response to fire were more apparent at the Great Basin site than at the Mojave site, with no immediate compounding effect of repeat fires at either site.","PeriodicalId":12273,"journal":{"name":"Fire Ecology","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135995982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-10DOI: 10.1186/s42408-023-00221-3
Frederick W. Rainsford, Katherine M. Giljohann, Andrew F. Bennett, Michael F. Clarke, Josephine MacHunter, Katharine Senior, Holly Sitters, Simon Watson, Luke T. Kelly
Abstract Background Understanding how temporal and spatial attributes of fire regimes, environmental conditions, and species’ traits interact to shape ecological communities will help improve biodiversity conservation in fire-affected areas. We compared the influence of time since the last fire at a site, and the area and diversity of post-fire successional vegetation surrounding a site (i.e., the “spatial context” of fire), on bird species and functional groups in two ecosystems in south-eastern Australia. These ecosystems, semi-arid “mallee” woodlands and temperate “foothill” forests, differ in stand-regeneration patterns, climate, and topography. For 22 bird species in mallee woodlands, 33 species in foothill forests and four functional groups of birds in both ecosystems, we fitted non-linear models that differed in fire regime predictor variables. Results In foothill forests, models that included both time since fire and a spatial context variable explained more variation in bird abundances than models that included only time since fire or a spatial variable. In mallee woodlands, the addition of spatial attributes of fire helped explain the occurrence of several species, but this finding was muted when measured across all species. There were key differences between ecosystems in functional group responses to fire regimes. Canopy/upper-midstorey foragers were positively associated with the amount of late -successional vegetation in mallee woodlands, but not in foothill forests. Lower-midstorey foragers showed a decline response to the amount of late -successional vegetation in mallee woodlands and a contrasting incline response in foothill forests. However, lower-midstorey foragers showed a similar response to the amount of surrounding early -successional vegetation in both ecosystems—decreasing in abundance when > 50% of the surrounding vegetation was early-successional. Conclusions The influence of fire regimes on birds varies among species within sites, across landscapes and between ecosystems. Species’ foraging traits influence bird associations with fire regimes, and help to make sense of a myriad of relationships, but are usefully understood in the context of ecosystem types and the regeneration patterns of their dominant flora. The spatial context of fire regimes is also important—the amount of successional vegetation surrounding a site influences bird abundance. Fire management strategies that incorporate the spatial contexts of fire regimes, as well as the temporal and ecological contexts of fire regimes, will have the greatest benefits for biodiversity.
{"title":"Ecosystem type and species’ traits help explain bird responses to spatial patterns of fire","authors":"Frederick W. Rainsford, Katherine M. Giljohann, Andrew F. Bennett, Michael F. Clarke, Josephine MacHunter, Katharine Senior, Holly Sitters, Simon Watson, Luke T. Kelly","doi":"10.1186/s42408-023-00221-3","DOIUrl":"https://doi.org/10.1186/s42408-023-00221-3","url":null,"abstract":"Abstract Background Understanding how temporal and spatial attributes of fire regimes, environmental conditions, and species’ traits interact to shape ecological communities will help improve biodiversity conservation in fire-affected areas. We compared the influence of time since the last fire at a site, and the area and diversity of post-fire successional vegetation surrounding a site (i.e., the “spatial context” of fire), on bird species and functional groups in two ecosystems in south-eastern Australia. These ecosystems, semi-arid “mallee” woodlands and temperate “foothill” forests, differ in stand-regeneration patterns, climate, and topography. For 22 bird species in mallee woodlands, 33 species in foothill forests and four functional groups of birds in both ecosystems, we fitted non-linear models that differed in fire regime predictor variables. Results In foothill forests, models that included both time since fire and a spatial context variable explained more variation in bird abundances than models that included only time since fire or a spatial variable. In mallee woodlands, the addition of spatial attributes of fire helped explain the occurrence of several species, but this finding was muted when measured across all species. There were key differences between ecosystems in functional group responses to fire regimes. Canopy/upper-midstorey foragers were positively associated with the amount of late -successional vegetation in mallee woodlands, but not in foothill forests. Lower-midstorey foragers showed a decline response to the amount of late -successional vegetation in mallee woodlands and a contrasting incline response in foothill forests. However, lower-midstorey foragers showed a similar response to the amount of surrounding early -successional vegetation in both ecosystems—decreasing in abundance when > 50% of the surrounding vegetation was early-successional. Conclusions The influence of fire regimes on birds varies among species within sites, across landscapes and between ecosystems. Species’ foraging traits influence bird associations with fire regimes, and help to make sense of a myriad of relationships, but are usefully understood in the context of ecosystem types and the regeneration patterns of their dominant flora. The spatial context of fire regimes is also important—the amount of successional vegetation surrounding a site influences bird abundance. Fire management strategies that incorporate the spatial contexts of fire regimes, as well as the temporal and ecological contexts of fire regimes, will have the greatest benefits for biodiversity.","PeriodicalId":12273,"journal":{"name":"Fire Ecology","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136295682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-10DOI: 10.1186/s42408-023-00219-x
Sebastian U. Busby, Angela M. Klock, Jeremy S. Fried
Abstract Background Six synchronous, wind-driven, high severity megafires burned over 300,000 hectares of mesic temperate forest in the western Cascades of NW Oregon and SW Washington states in early September 2020. While remote sensing data has been utilized to estimate fire severity across the fires, assessments of fire impacts informed by field observations are missing. We compiled field measurement data, pre- and post-fire, from a statistically representative sample of existing forest inventory analysis (FIA) plots, to estimate stand-level fire effects indices that describe (1) tree survival and its implications for carbon emissions, (2) effects on tree crowns, and (3) effects on soils. Field observations were analyzed in relation to fire weather when plots burned and to evaluate accuracy of remotely sensed burn severity classifications. Results Wind speed strongly interacted with tree size and stand age to influence tree survival. Under high fuel aridity but light winds, young stands composed of small trees, found primarily on private lands, exhibited a much lower survival rate than older stands composed of medium to large trees, found primarily on federal lands. Under moderate to high winds, poor tree survival was characteristic of all forest structures and ownerships. Fire impacts on tree crowns were strongly related to wind speed, while fire impacts on soils were not. These fires transferred nearly 70 MMT CO 2 e from wood in live and growing trees to a combination of immediate smoke and carbon emissions, plus delayed emissions from dead wood, that will release most of the embodied carbon over the next few decades. These emissions will exceed all 2020 anthropogenic emissions in Oregon (64 MMT CO 2 e). Substantial discrepancies were observed between two remotely sensed burn severity products, BAER-SBS and MTBS-TC, and field observed soil organic matter cover and tree mortality, respectively. Conclusions Post-fire FIA plot remeasurements are valuable for understanding fire’s impact on forest ecosystems and as an empirical basis for model validation and hypothesis testing. This continuous forest inventory system will compound the value of these post-fire remeasurements, enabling analysis of post-fire forest ecosystem trajectories in relation to both immediate fire impacts and pre-fire conditions.
{"title":"Inventory analysis of fire effects wrought by wind-driven megafires in relation to weather and pre-fire forest structure in the western Cascades","authors":"Sebastian U. Busby, Angela M. Klock, Jeremy S. Fried","doi":"10.1186/s42408-023-00219-x","DOIUrl":"https://doi.org/10.1186/s42408-023-00219-x","url":null,"abstract":"Abstract Background Six synchronous, wind-driven, high severity megafires burned over 300,000 hectares of mesic temperate forest in the western Cascades of NW Oregon and SW Washington states in early September 2020. While remote sensing data has been utilized to estimate fire severity across the fires, assessments of fire impacts informed by field observations are missing. We compiled field measurement data, pre- and post-fire, from a statistically representative sample of existing forest inventory analysis (FIA) plots, to estimate stand-level fire effects indices that describe (1) tree survival and its implications for carbon emissions, (2) effects on tree crowns, and (3) effects on soils. Field observations were analyzed in relation to fire weather when plots burned and to evaluate accuracy of remotely sensed burn severity classifications. Results Wind speed strongly interacted with tree size and stand age to influence tree survival. Under high fuel aridity but light winds, young stands composed of small trees, found primarily on private lands, exhibited a much lower survival rate than older stands composed of medium to large trees, found primarily on federal lands. Under moderate to high winds, poor tree survival was characteristic of all forest structures and ownerships. Fire impacts on tree crowns were strongly related to wind speed, while fire impacts on soils were not. These fires transferred nearly 70 MMT CO 2 e from wood in live and growing trees to a combination of immediate smoke and carbon emissions, plus delayed emissions from dead wood, that will release most of the embodied carbon over the next few decades. These emissions will exceed all 2020 anthropogenic emissions in Oregon (64 MMT CO 2 e). Substantial discrepancies were observed between two remotely sensed burn severity products, BAER-SBS and MTBS-TC, and field observed soil organic matter cover and tree mortality, respectively. Conclusions Post-fire FIA plot remeasurements are valuable for understanding fire’s impact on forest ecosystems and as an empirical basis for model validation and hypothesis testing. This continuous forest inventory system will compound the value of these post-fire remeasurements, enabling analysis of post-fire forest ecosystem trajectories in relation to both immediate fire impacts and pre-fire conditions.","PeriodicalId":12273,"journal":{"name":"Fire Ecology","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136295315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-02DOI: 10.1186/s42408-023-00212-4
Rodrigo San Martín, Catherine Ottlé, Anna Sörensson
Abstract Background Wildfires represent an important element in the bio-geophysical cycles of various ecosystems across the globe and are particularly related to land transformation in tropical and subtropical regions. In this study, we analyzed the links between fires, land use (LU), and meteorological variables in the South American Chaco (1.1 million km 2 ), a global deforestation hotspot and fire-exposed region that has recently attracted greater attention as the largest and one of the last tropical dry forests in the world. Results We found that the Dry Chaco (73% of the total area of Chaco) exhibits a unimodal fire seasonality (winter-spring), and the Wet Chaco (the remaining 23%) displays a bimodal seasonality (summer-autumn and winter-spring). While most of the burnt area (BA) was found in the Wet Chaco (113,859 km 2 ; 55% of the entire BA), the Dry Chaco showed the largest fraction of forest loss (93,261 km 2 ; 88% of the entire forest loss). Between 2001 and 2019, 26% of the entire Chaco’s forest loss occurred in areas with BA detections, and this percentage varies regionally and across countries, revealing potential connections to LU and policy. Argentina lost 51,409 km 2 of its Chaco tree cover, surpassing the forest losses of Paraguay and Bolivia, and 40% of this loss was related to fire detections. The effect of meteorological fluctuations on fuel production and flammability varies with land cover (LC), which emerged as the principal factor behind BA. While wet areas covered with herbaceous vegetation showed negative correlations between BA and precipitation, some dry regions below 800 mm/year, and mostly covered by shrublands, showed positive correlations. These results reveal the two different roles of precipitation in (a) moisture content and flammability and (b) production of biomass fuel. Conclusions As fires and deforestation keep expanding in the South American Chaco, our study represents a step forward to understanding their drivers and effects. BA is dependent on LC types, which explains the discrepancies in fire frequency and seasonality between the Wet and Dry Chaco subregions. The links between fires and deforestation also vary between regions and between countries, exposing the role of anthropic forcing, land management, and policy. To better understand the interactions between these drivers, further studies at regional scale combining environmental sciences with social sciences are needed. Such research should help policy makers take action to preserve and protect the remaining forests and wetlands of the Chaco.
野火是全球各种生态系统生物地球物理循环的重要组成部分，尤其与热带和亚热带地区的土地转化有关。在这项研究中，我们分析了南美洲查科(110万平方公里)的火灾、土地利用(LU)和气象变量之间的联系，查科是全球森林砍伐热点和火灾暴露地区，最近作为世界上最大和最后的热带干燥森林之一而引起了更大的关注。结果查科干区(占查科总面积的73%)表现为单峰性(冬春)，湿区(占查科总面积的23%)表现为双峰性(夏秋和冬春)。而大部分燃烧面积(BA)发现在湿查科(113,859 km 2;占整个BA的55%)，干查科的森林损失比例最大(93,261 km2;整个森林损失的88%)。2001年至2019年期间，查科整个森林损失的26%发生在发现BA的地区，这一比例因地区和国家而异，揭示了与LU和政策的潜在联系。阿根廷损失了51,409平方公里的查科树木覆盖面积，超过了巴拉圭和玻利维亚的森林损失，其中40%的损失与火灾探测有关。气象波动对燃料产量和可燃性的影响随土地覆盖(LC)的变化而变化，这是BA背后的主要因素。草本植被覆盖的湿润地区BA与降水呈负相关，而在800mm /年以下以灌丛为主的干旱地区BA与降水呈正相关。这些结果揭示了降水在(a)含水量和可燃性以及(b)生物质燃料生产中的两种不同作用。随着南美查科地区的火灾和森林砍伐不断扩大，我们的研究代表了了解其驱动因素和影响的一步。BA依赖于LC类型，这解释了干湿查科分区之间火灾频率和季节性的差异。火灾和森林砍伐之间的联系也因地区和国家而异，暴露了人为强迫、土地管理和政策的作用。为了更好地理解这些驱动因素之间的相互作用，需要进一步在区域尺度上进行环境科学与社会科学相结合的研究。这样的研究应该有助于决策者采取行动来保存和保护查科剩余的森林和湿地。
{"title":"Fires in the South American Chaco, from dry forests to wetlands: response to climate depends on land cover","authors":"Rodrigo San Martín, Catherine Ottlé, Anna Sörensson","doi":"10.1186/s42408-023-00212-4","DOIUrl":"https://doi.org/10.1186/s42408-023-00212-4","url":null,"abstract":"Abstract Background Wildfires represent an important element in the bio-geophysical cycles of various ecosystems across the globe and are particularly related to land transformation in tropical and subtropical regions. In this study, we analyzed the links between fires, land use (LU), and meteorological variables in the South American Chaco (1.1 million km 2 ), a global deforestation hotspot and fire-exposed region that has recently attracted greater attention as the largest and one of the last tropical dry forests in the world. Results We found that the Dry Chaco (73% of the total area of Chaco) exhibits a unimodal fire seasonality (winter-spring), and the Wet Chaco (the remaining 23%) displays a bimodal seasonality (summer-autumn and winter-spring). While most of the burnt area (BA) was found in the Wet Chaco (113,859 km 2 ; 55% of the entire BA), the Dry Chaco showed the largest fraction of forest loss (93,261 km 2 ; 88% of the entire forest loss). Between 2001 and 2019, 26% of the entire Chaco’s forest loss occurred in areas with BA detections, and this percentage varies regionally and across countries, revealing potential connections to LU and policy. Argentina lost 51,409 km 2 of its Chaco tree cover, surpassing the forest losses of Paraguay and Bolivia, and 40% of this loss was related to fire detections. The effect of meteorological fluctuations on fuel production and flammability varies with land cover (LC), which emerged as the principal factor behind BA. While wet areas covered with herbaceous vegetation showed negative correlations between BA and precipitation, some dry regions below 800 mm/year, and mostly covered by shrublands, showed positive correlations. These results reveal the two different roles of precipitation in (a) moisture content and flammability and (b) production of biomass fuel. Conclusions As fires and deforestation keep expanding in the South American Chaco, our study represents a step forward to understanding their drivers and effects. BA is dependent on LC types, which explains the discrepancies in fire frequency and seasonality between the Wet and Dry Chaco subregions. The links between fires and deforestation also vary between regions and between countries, exposing the role of anthropic forcing, land management, and policy. To better understand the interactions between these drivers, further studies at regional scale combining environmental sciences with social sciences are needed. Such research should help policy makers take action to preserve and protect the remaining forests and wetlands of the Chaco.","PeriodicalId":12273,"journal":{"name":"Fire Ecology","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135895116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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