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The 2022 summer fire in the Bohemian Switzerland National Park (BSNP) is the largest in the 30-year recorded history of the Czech Republic, with an affected area of over 1000 ha. The FlamMap fire modeling system was used to investigate the fire behavior in the BSNP and to evaluate scenarios under a range of fuel types, fuel moistures, and weather conditions. The model was used to simulate fire conditions, propagation, and extent. We focused on matching the observed fire perimeter and fire behavior characteristics. The fire occurred in a region of the BSNP heavily affected by Spruce bark beetle ( Ips typographus L.) infestation; hence, most of the burned area encompassed dead spruce forest ( Picea abies Karst.). The best FlamMap simulations of the observed fire behavior and progression were compared with several created scenarios exhibiting various input conditions. These scenarios included a fire in a healthy spruce forest, clearcuts, or different meteorological conditions. We could calibrate and use FlamMap to recreate the 2022 summer wildfire in the BSNP under the observed conditions. It was found that the fire would have likely spread to the observed final perimeter even if standing dead trees had been removed, albeit at a lower fire intensity and with a considerably shorter duration. Alternatively, if healthy standing vegetation with a closed canopy had been present, the wildfire perimeter would have reached approximately half the observed value. Similar results were obtained for both the non-native spruce forest and deciduous forest, which is a native alternative.

Most wildfires are started by humans, however, geographic variation of potential ignition sources is not often explicitly accounted for in wildfire simulation modelling or risk assessments. In this study, we investigated how patterns of human and lightning ignitions can influence modelled fire simulations and demonstrate how these data can be used to assess post-fire flooding and sediment transport. We used historical ignition data (1992-2015) to characterize ignition patterns for thirteen mountain ranges in southern Arizona, United States, and developed FlamMap burn probability (BP) models for three scenarios: human ignition, lightning ignition, and random ignition. We then developed a watershed-scale case study assessing the impacts of ignition scenarios on post-fire hydrology using the KINEROS2 model that simulates runoff and erosion. BP models illustrated considerable differences in landscape fire risk between the three ignition scenarios. Results from the watershed model indicate the greatest impacts from the post-fire human ignition scenario, with a 10-fold increase in sediment discharge and four-fold increase in peak flow compared to pre-fire conditions. Our results show that consideration of ignition source and location is important for assessing fire risk, and our modelling approach provides a planning mechanism to identify locations most at risk to fire-induced flood hazards, where prevention and mitigation activities can be focused.

BackgroundWildfires are increasing in size and severity due to climate change combined with overstocked forests. Fire increases the likelihood of debris flows, posing significant threats to life, property, and water supplies.AimsWe conducted a debris-flow hazard assessment of the Santa Fe Municipal Watershed (SFMW) to answer two questions: (1) where are debris flows most likely to occur; and (2) how much debris might they produce? We also document the influence of fuel treatments on fire severity and debris flows.MethodsWe modelled post-fire debris-flow likelihood and volume in 103 sub-basins for 2-year, 5-year, and Probable Maximum Precipitation rainfalls following modelled low-, moderate-, and high-severity wildfires.Key resultsPost-fire debris-flow likelihoods were >90% in all but the lowest fire and rain scenarios. Sub-basins with fuel treatments had the lowest burn severities, debris-flow likelihoods, and sediment volumes, but treatment effects decreased with increased fire severity and rain intensity.ConclusionsPost-fire debris flows with varying debris volumes are likely to occur following wildfire in the SFMW, but fuel treatments can reduce likelihood and volume.ImplicationsFuture post-fire debris flows will continue to threaten water supplies, but fuel reduction treatments and debris-flow mitigation provide opportunities to minimise effects.

Hakea decurrens subsp. physocarpa is an invasive fire-adapted shrub of Australian origin that is quickly expanding in Portugal with potential impacts on fire behavior and fire regime. In this study we examined the effects of H. decurrens on fire hazard by assessing fire behavior indicators at the landscape scale, using a modeling and simulation approach. Six fuel models for H. decurrens were developed through fuel characterization and experimental fires. The fuel models correspond to combinations of developmental stages of H. decurrens populations (Early, Intermediate and Mature) and management (Standing and Slashed fuels). These combinations were used with three levels of H. decurrens invasion, corresponding to 25%, 50% and 75% of cover of the landscape, applied to five real landscapes in northern Portugal (replicates) under three fuel moisture conditions (Low, Medium and High), used as surrogates of weather severity. Fire behavior simulations were conducted with FlamMap software. The relationships between fire behavior indicators (flame length, rate of spread and burn probability) at the landscape level and the four factors tested were analyzed using Generalized Linear Mixed Models. Standing fuels were found to be more hazardous than slashed fuels. Fire-hazard increased with H. decurrens stand maturity and slash, regardless of moisture conditions. The results of this study indicate that H. decurrens expansion might negatively affect the fire regime in the north of Portugal. Our findings add to other known negative impacts of the species on native ecosystems, calling for the need to reinforce its control.

A solution to the growing problem of catastrophic wildfires in Greece will require a more holistic fuel management strategy that focuses more broadly on landscape fire behavior and risk in relation to suppression tactics and ignition prevention. Current fire protection planning is either non-existent or narrowly focused on reducing fuels in proximity to roads and communities where ignitions are most likely. A more effective strategy would expand the treatment footprint to landscape scales to reduce fire intensity and increase the likelihood of safe and efficient suppression activities. However, expanding fuels treatment programs on Greek landscapes that are highly fragmented in terms of land use and vegetation requires: (1) a better understanding of how diverse land cover types contribute to fire spread and intensity; and (2) case studies, both simulated and empirical, that demonstrate how landscape fuel management strategies can achieve desired outcomes in terms of fire behavior. In this study, we used Lesvos Island, Greece as a study area to characterize how different land cover types and land uses contribute to fire exposure and used wildfire simulation methods to understand how fire spreads among parcels of forests, developed areas, and other land cover types (shrublands, agricultural areas, and grasslands) as a way to identify fire source–sink relationships. We then simulated a spatially coordinated fuel management program that targeted the fire prone conifer forests that generally burn under the highest intensity. The treatment effects were measured in terms of post-treatment fire behavior and transmission. The results demonstrated an optimized method for fuel management planning that accounts for the connectivity of wildfire among different land types. The results also identified the scale of risk and the limitations of relying on small scattered fuel treatment units to manage long-term wildfire risk.

We use the simulation model Envision to analyze long-term wildfire dynamics and the effects of different fuel management scenarios in central Oregon, USA. We simulated a 50-year future where fuel management activities were increased by doubling and tripling the current area treated while retaining existing treatment strategies in terms of spatial distribution and treatment type. We modeled forest succession using a state-and-transition approach and simulated wildfires based on the contemporary fire regime of the region. We tested for the presence of temporal trends and overall differences in burned area among four fuel management scenarios. Results showed that when the forest was managed to reduce fuels it burned less: over the course of 50 years there was up to a 40% reduction in area burned. However, simulation outputs did not reveal the expected temporal trend, i.e., area burned did not decrease progressively with time, nor did the absence of management lead to its increase. These results can be explained as the consequence of an existing wildfire deficit and vegetation succession paths that led to closed canopy, and heavy fuels forest types that are unlikely to burn under average fire weather. Fire (and management) remained relatively rare disturbances and, given our assumptions, were unable to alter long-term vegetation patterns and consequently unable to alter long-term wildfire dynamics. Doubling and tripling current management targets were effective in the near term but not sustainable through time because of a scarcity of stands eligible to treat according to the modeled management constraints. These results provide new insights into the long-term dynamics between fuel management programs and wildfire and demonstrate that treatment prioritization strategies have limited effect on fire activity if they are too narrowly focused on particular forest conditions.

Expanding the footprint of natural fire has been proposed as one potential solution to increase the pace of forest restoration programs in fire‐adapted landscapes of the western USA. However, studies that examine the long‐term socio‐ecological trade‐offs of expanding natural fire to reduce wildfire risk and create fire resilient landscapes are lacking. We used the model Envision to examine the outcomes that might result from increased area burned by what we call “restoration” wildfire in a landscape where the ecological benefits of wildfire are known, but the need to suppress high‐risk fires that threaten human values is also evident. Our study area, in the eastern Cascades of Oregon, USA, includes the Deschutes National Forest where large tracts of mixed conifer forest structure are outside the historical range of variation and characterized by multi‐layer, closed‐canopy stands. We found that simulation of one restoration wildfire per year in addition to high‐risk wildfires in the regular fire season and over the course of 50 yr resulted in a 23% increase in total area burned, but the same probability of fire‐on‐fire interactions. This translated into 0.3% of the national forest burned by restoration wildfire per year and had a small impact in area burned by high‐risk fires albeit more likely in extreme fire years. Smoke production doubled in the restoration scenario relative to the scenario without restoration wildfire, but still resulted in minimal smoke production in most years. Restoration fires burned with low‐ to mixed‐severity and led to a steady reduction in canopy cover and increase in resilient forest structure in dry‐forest types. Habitat for the federally protected northern spotted owl declined with the inclusion of restoration fire, while habitat for species that use recently burned forest stands (e.g., black‐backed woodpecker) increased. Our results suggest that restoration wildfire can improve forest resilience and contribute to restoration efforts in fire‐adapted forests, but there are trade‐offs (wildlife habitat, smoke, area burned in fire‐sensitive forest types), and the level of restoration fire use we simulated is unlikely to have a significant impact on the occurrence of high‐severity wildfires.

This study presents a comprehensive approach to assessing wildfire behavior in a Mediterranean landscape using the FlamMap fire moelling software. We employed geospatial tools to map and categorize land cover types, followed by field visits to validate the remote data and collect detailed vegetation and fuel load information. Key physical parameters, including slope, elevation, and historical weather data, were integrated into the FlamMap model to simulate wildfire behavior under two wind scenarios: one with an average wind speed of 10 km/h and another with a maximum wind speed of 23 km/h. The simulations provided detailed insights into fire behavior parameters such as fireline intensity, flame length, and rate of spread (ROS), emphasizing the critical roles of wind speed, vegetation type, and topography. Results showed significant variations in fire behavior across different vegetation types, with the highest fireline intensities and rates of spread occurring in areas dominated by Aleppo pine and dense shrublands, particularly under high wind conditions. The overlay of historical fire data with simulation results revealed that regions with dense shrub stands and Aleppo pine wooded shrub are most prone to wildfires, underscoring the need for targeted fire management strategies. This study demonstrates the utility of FlamMap in predicting fire behavior and guiding wildfire management efforts in high-risk areas.

This study investigates the role of prescribed grazing as a sustainable fire prevention strategy in Mediterranean ecosystems, with a focus on Sardinia, an area highly susceptible to wildfires. Using FlamMap simulation software, we modeled fire behavior across various grazing and environmental conditions to assess the impact of grazing on fire severity indicators such as flame length, rate of spread, and fireline intensity. Results demonstrate that grazing can reduce fire severity by decreasing combustible biomass, achieving reductions of 25.9% in fire extent in wet years, 60.9% in median years, and 45.8% in dry years. Grazed areas exhibited significantly lower fire intensity, particularly under high canopy cover. These findings support the integration of grazing into fire management policies, highlighting its efficacy as a nature-based solution. However, the study’s scope is limited to small biomass fuels (1-h fuels); future research should extend to larger fuel classes to enhance the generalizability of prescribed grazing as a fire mitigation tool.

Wildfires represent a growing concern worldwide, and their frequency has increased due to climate change and human activities, posing risks to biodiversity and human safety. In the Metropolitan District of Quito (DMQ), the combination of flammable vegetation and steep slopes increases the wildfire susceptibility. Although there are no formally designated firebreaks in these areas, many natural and artificial elements, such as roads, water bodies, and rocky terrain, can effectively function as firebreaks if properly adapted. This study aimed to evaluate the wildfire behavior and assess the effectiveness of both adapted existing barriers and proposed firebreaks using FlamMap simulations. Geospatial and meteorological data were integrated to generate landscape and weather inputs for simulating wildfires in nine high-susceptibility areas within the DMQ. Fuel vegetation models were obtained by matching the national land-cover data with Scott and Burgan fuel models, and OpenStreetMap data were used to identify the firebreak locations. The simulation results show that adapting existing potential firebreaks could reduce the burned area by an average of 42.6%, and the addition of strategically placed firebreaks could further reduce it by up to 70.2%. The findings suggest that implementing a firebreak creation and maintenance program could be an effective tool for wildfire mitigation.