Fire Severity

Quercus suber L (QS) resprouts as a key response to fire disturbance. It is well known that the development of a thick bark, that performs a thermal insulation, is a remarkable adaptation of QS to wildland fires. We studied fire effects in QS in NE Spain. We search for what is the diameter size that ensures individuals survive and recover crown size in less than two years. Sampling was performed in 2012 in an area that offered different levels of fire behavior (i.e., low intensity and high intensity as reported by forest firefighters). Trees with old (older than 2006), major fire scars were rejected since they did not allow us to infer the fire effect from the 2006 fire properly. 240 individuals were classified into three groups: “Dead”, “BB” (lost the crown foliage but resprouting from basal buds); and “KC” (those keeping crown foliage because either not very much damaged by fire or able to sprout from most branches; i.e., stem buds). Results show that, under low intensity fires (s...

Th is presentation will describe the current status of the Fire Eff ects Information System (FEIS) and explore lessons learned from this 23-yearold project about the application of science to fire management issues. FEIS contains literature reviews covering biology and fire ecology for approximately 1,100 species in North America: plants and animals, native and nonnative. Established in 1985 and continually updated, the system has served managers, researchers, students, and the general public for >20 years. Species reviews in FEIS provide information that can help managers plan a prescribed fire, write a fire or fuel management plan, determine the need for post-fire rehabilitation, or assess the potential for increase of invasive species aft er fire. FEIS is cited in nearly half of EISs written by federal wildland fire managers. Research Project Summaries, a recent addition to FEIS, supplement species reviews and provide information on fire eff ects for an additional 250 species....

The boreal forest contains large reserves of carbon. Across this region, wildfires influence the temporal and spatial dynamics of carbon storage. In this study, we estimate fire emissions and changes in carbon storage for boreal North America over the 21st century. We use a gridded data set developed with a multivariate adaptive regression spline approach to determine how area burned varies each year with changing climatic and fuel moisture conditions. We apply the process-based Terrestrial Ecosystem Model to evaluate the role of future fire on the carbon dynamics of boreal North America in the context of changing atmospheric carbon dioxide (CO 2 ) concentration and climate in the A2 and B2 emissions scenarios of the CGCM2 global climate model. Relative to the last decade of the 20th century, decadal total carbon emissions from fire increase by 2.5-4.4 times by 2091-2100, depending on the climate scenario and assumptions about CO 2 fertilization. Larger fire emissions occur with warmer climates or if CO 2 fertilization is assumed to occur. Despite the increases in fire emissions, our simulations indicate that boreal North America will be a carbon sink over the 21st century if CO 2 fertilization is assumed to occur in the future. In contrast, simulations excluding CO 2 fertilization over the same period indicate that the region will change to a carbon source to the atmosphere, with the source being 2.1 times greater under the warmer A2 scenario than the B2 scenario. To improve estimates of wildfire on terrestrial carbon dynamics in boreal North America, future studies should incorporate the role of dynamic vegetation to represent more accurately post-fire successional processes, incorporate fire severity parameters that change in time and space, account for human influences through increased fire suppression, and integrate the role of other disturbances and their interactions with future fire regime.

Climatic variability is a dominant factor affecting large wildfires in the western United States, an observation supported by palaeoecological data on charcoal in lake sediments and reconstructions from fire-scarred trees. Although current fire management focuses on fuel reductions to bring fuel loadings back to their historical ranges, at the regional scale extreme fire weather is still the dominant influence on area burned and fire severity. Current forecasting tools are limited to short-term predictions of fire weather, but increased understanding of large-scale oceanic and atmospheric patterns in the Pacific Ocean (e.g., El Niño Southern Oscillation, Pacific Decadal Oscillation) may improve our ability to predict climatic variability at seasonal to annual leads. Associations between these quasi-periodic patterns and fire occurrence, though evident in some regions, have been difficult to establish in others. Increased temperature in the future will likely extend fire seasons throughout the western United States, with more fires occurring earlier and later than is currently typical, and will increase the total area burned in some regions. If climatic change increases the amplitude and duration of extreme fire weather, we can expect significant changes in the distribution and abundance of dominant plant species in some ecosystems, which would thus affect habitat of some sensitive plant and animal species. Some species that are sensitive to fire may decline, whereas the distribution and abundance of species favored by fire may be enhanced. The effects of climatic change will partially depend on the extent to which resource management modifies vegetation structure and fuels.

Landscape-scale disturbance events, including ecological restoration and fuel reduction activities, can modify habitat and affect relationships between species and their environment. To reduce the risk of uncharacteristic stand-replacing fires in the southwestern United States, land managers are implementing restoration and fuels treatments (e.g., mechanical thinning, prescribed fire) in progressively larger stands of dry, lower elevation ponderosa pine (Pinus ponderosa) forest. We used a Before-After/Control-Impact experimental design to quantify the multi-scale response of avifauna to large (;250-400 ha) prescribed fire treatments on four sites in Arizona and New Mexico dominated by ponderosa pine. Using distance sampling and an information-theoretic approach, we estimated changes in density for 14 bird species detected before (May-June 2002 and after (May-June 2004-2005) prescribed fire treatments. We observed few site-level differences in pre-and posttreatment density, and no species responded strongly to treatment on all four sites. Pointlevel spatial models of individual species response to treatment, habitat variables, and fire severity revealed ecological relationships that were more easily interpreted. At this scale, pretreatment forest structure and patch characteristics were important predictors of posttreatment differences in bird species density. Five species (Pygmy Nuthatch [Sitta pygmaea], Western Bluebird [Sialia mexicana], Steller's Jay [Cyanocitta stelleri ], American Robin [Turdus migratorius], and Hairy Woodpecker [Picoides villosus]) exhibited a strong treatment response, and two of these species (American Robin and Hairy Woodpecker) could be associated with meaningful fire severity response functions. The avifaunal response patterns that we observed were not always consistent with those reported by more common studies of wildland fire events. Our results suggest that, in the short term, the distribution and abundance of common members of the breeding bird community in Southwestern ponderosa pine forests appear to be tolerant of low-to moderate-intensity prescribed fire treatments at multiple spatial scales and across multiple geographic locations.

Tree and plant structures remaining after fires reflect well their degree of consumption, and are therefore good indicators of fire severity. Satellite optical images are commonly used to estimate fire severity. However, depending on the severity of a fire, these sensors have a limited ability to penetrate the canopy down to the ground. Airborne light detection and ranging (LiDAR) can overcome this limitation. Assessing the differences between areas that have been burned in different fire severities based on satellite images of plant and tree structures remaining after fires is important, given its widespread use to characterize fires and fire impacts (e.g., carbon emissions). Here, we measured the remaining tree structures after a fire in a forest stand burned in SE Spain in the summer of 2017. We used high-resolution LiDAR data, acquired from an unmanned aerial vehicle (UAV) six months after the fire. This information was crossed with fire severity levels based on the relativized ...

Question: Do variations in fire intensity within a stand determine changes in fire intensity and plant demographics in a subsequent fire? Location: San Diego (CA, USA); chaparral dominated by Adenostoma fasciculatum (resprouter) and Ceanothus greggii (seeder). In 2003, a wildfire burned a young (16-yr-old) stand containing a set of experimental plots burned in 1987 with various levels of fire intensity. In 2004, all the 1987 plots were sampled for Adenostoma survival and the recruitment of both species. Similar measures were carried out in the adjacent old (75yr) stand. Fire intensity in 2003 was estimated by a surrogate fire severity measure [minimum diameter of burned branches (branch diameter)]. Results: In the young stand, branch diameter in 2003 was similar to the control plots in 1987, but lower than in the old stand. Fire intensity in 1987 did not significantly affect branch diameter in 2003. Survival of Adenostoma in the young stand was very low, much lower than after the 1987 burn and that in the old stand. Fire intensity in 1987 did not affect Adenostoma survival. Recruitment in Adenostoma increased, and in Ceanothus decreased, with increased fire intensity in 1987. We demonstrate that there is a carry-over effect of fire intensity across a whole fire cycle on plant recruitment of the two dominant species. The 2003 fire partially reversed the relative effects on recruitment caused by elevated fire intensity in 1987. Arguably, this effect was driven by the contrasted relationships of the two species to fire intensity. Adenostoma survival in the young stand was much lower in 2003 than in 1987, despite similar branch diameter, and was also lower than in the old stand, despite higher branch diameter in this case. The causes of such mortality are unknown. 2000) and across fires . In general, as heating at the soil surface increases, plant mortality, including seeds, increases, and changes in species composition, dominance and spatial distribution may follow, as shown by numerous studies across many world ecosystems (

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Fire has effects on diverse aspects of plant functioning and development, many of them linked to survival. However, the response of native vegetation to this disturbance possibly reveals a plant strategy to tolerate fire linked to the biosynthesis of compounds such as chlorophylls and secondary metabolites. The aim of this study was to evaluate whether fire severity could promote biochemical tolerance to fire by influencing the biosynthesis of chemical compounds. To test this, six woody species from the Chaco region were exposed to an experimental burn of medium severity at the end of fire season in the study area. In this burn, individual plots for each plant were established. Fire severity was estimated visually as the burnt biomass of each plant, which was considered as the percentage of the loss of aboveground biomass. Then, the biochemical plant response to fire was studied, through the changes in the concentration of photosynthetic pigments (chlorophyll and carotenoids), and s...

The present work aims to study the spatial variability of ash Total Carbon (TC%) and Total Nitrogen (TN%) after a wildfire occurred in Portugal. Ash TC% a mean of 26.72 % (±8.76 %) and ash TN% of 1.20 % (±0.32 %). We observed that the area recover very fast to wildfire and two years the great part of soil was cover by vegetation. The fire severity (assessed with ash color and CaCO 3 content) was more related with ash TC%, than ash TN% due the different vulnerability and response of these two elements to fire temperature and as consequence severity. Previous to model data we tested their normality that only was achieved in the case of TC% after a neperian logarithmic transformation (ln). TN% respected gaussian distribution, however showed a high skewness, thus this variable was also ln transformed. Ash TC%(ln) presented an excellent spatial structure and the experimental model fits better with the rational quadratic model and ash TN%(ln) with the lineal model. Among all interpolation methods tested, the most accurate to interpolate ash TC%(ln) was IDW2 and the less suitable LP3. In relation to ash TN%(ln) the best interpolation technique was SPT and the less precise LP3. This allow us to observe differences that the spatial distribution of both variables is different, that is due the small scale variability observed in ash TC%(ln). In general the models were well performed because the residuals mean were closed to 0 and no differences between average of predicted and estimated values were identified. Ash TC%(ln) spatial distribution was in higher amounts in western, northern part and southeast and northeast corner of the plot and lower in the centre and south of the interested area and ash TN%(ln) was observed in higher amounts in the southwest and southeast part of the plot and lesser in the central part.

In eastern deciduous forests, fire-disturbance and its ecological implications haven't been heavily studied. In Tennessee, an intensely burned plot of forest (2016) presented a unique opportunity to analyze successional habitat regrowth 2-3 years after a wildfire occurred. To examine post-fire recovery, we observed the diversity of avian species in 1 burned (1-km transect) and 1 unburned site (690-m transect) site during 2018-2019. We used line-transects to examine avian diversity and performed a vegetation analysis to compare the sites. Our results showed that though the unburned site was higher in avian diversity (mean Shannon diversity: 2.844 in unburned vs. 2.521 in burned), the burned site appeared to be suitable habitat for multiple disturbance-dependent avian species. Bird species associated with low to medium vegetation heights and overstory heights and low residual basal areas in early successional forests, such as Setophaga discolor (Prairie Warbler), Passerina cyanea (Indigo Bunting), and Icteria virens (Yellow-breasted Chat), were found only in the burned site, suggesting the fire created suitable habitat for these species, with its average canopy height of 3.55 m and canopy coverage of 18.75%.This study supports the need for greater fire research in Eastern deciduous forests. The results suggest regular fires could create patches of habitats that benefit struggling species of disturbance-dependent birds in this region.

Valuation of natural resources requires a multifunctional vision incorporating market and nonmarket values like environmental services and landscape goods. Though widely used in forest firest analysis, teledetection has never been used in the economic valuation of forest fires damages. Application of this tool in the valuation of forest fires damages provides a versatile tool with many benefits. For example, it allows identification and valuation of large forest fires inexpensively compare to on the ground monitoring by providing periodic information of vegetation post-fire behavior. Using Landsat 8 satellite images and the economic procedure in Visual SEVEIF we provide an economic valuation of the damages caused by the Alhama de Almeria fire (3,260 ha). The satellite images are an important source of georeferenced information and can be used to determine the resource net-value-change based on fire intensity by classifying the vegetation indexes as resource depreciation rates. For the Alhama de Almeria fire the dNBR index provides a more robust representation of fire severity than RdNBR because of the boosting effect caused by the pre-fire NBR due to the areas scant vegetation, low precipitation and intense sun light. The economic valuation of the damages caused by this fire was estimated at 656,981 € or 201.53 €/ha. The most important resources in the valuation were landscape goods because of their closedness to the province capital. Over 57% of the total losses correspond to landscape goods and environmental services.

This study evaluated if present-day wildfire potential (i.e. potential fireline intensity and percentage crown fire) differs for residential parcels developed at different time periods in the north-central Colorado Front Range. To answer this question, a model of wildfire potential was built based on 2001 fuels and vegetation and compared the output to actual fire severity of the 2002 Hayman and 2004 Picnic Rock fires (measured by satellite imagery). Except for low-load fuel types such as grass, the modeled wildfire potential corresponded well to observed fire severity. Wildfire potential was then evaluated within 7 classes:

The term “landscape structure” refers to the configuration of vegetation and other land features over a large land area (usually an extent of many square kilometers). A landscape can be regarded as a mosaic composed of patches of different kinds—for example, different forest types, landforms, or human-built structures such as roads. The scientific discipline of landscape ecology is concerned with quantitatively describing the features of landscape mosaics, including, for example, the variety of patch types, the sizes and shapes of ...

Description: The term landscape structure refers to the configuration of vegetation and other land features over a large land area (usually an extent of many square kilometers). A landscape can be regarded as a mosaic composed of patches of different kinds--for example, different forest types, landforms, or human-built structures such as roads. The scientific discipline of landscape ecology is concerned with quantitatively describing the features of landscape mosaics, including, for example, the variety of patch types, the sizes ...

In the Western High Atlas, forest landscapes are at risk due to drought, desertification, irregular recurrence of fires and human pressure. The forest massif of Mesguina presents a considerable number of species of different origins, dominated by the argan tree (Argania spinosa (L) Skeels) and (Tetraclinis articulata). This region constitutes a fragile and vulnerable environment due to severe anthropic intervention and high recurrence of forest fires. This requires urgent interventions and an adequate control system to fight against these pressures and reverse the tendency to degradation. In 2013, about 1600 ha of Mesguina forest was burned by fire, and many floristic species were destroyed, which strongly disrupted the regular functioning of these landscapes. To study these landscape dynamics, we called upon prior knowledge of analyzing the physical conditions of the study area and the use of geographic information systems (GIS) and remote sensing data. Thus, we generated normalized vegetation indices (NBRI, NDVI, NRI, AVI) from Landsat 8 OLI-TIRS satellite images, which allowed both spatialization and comparison of post-fire forest landscape dynamics at the 9-year scale. Furthermore, we were able to verify the results obtained by field investigations in 2018 and 2019. Today, we can certainly confirm a positive dynamic of the burned species of woody plants such as Tetraclinis articulata, Olea europea, and Argania spinosa, as well as the shrub and herbaceous cover. This significant recovery of the forest landscape has been recorded mainly on the north and west slopes, in areas of high humidity with favorable conditions for plant development and away from anthropized areas. The calculated indices and fieldwork results show significant regeneration of the plant cover, with much faster recovery in areas of medium and high severity. This was compared with other regions in Mediterranean environments.

The objective of this study was to assess between actual and modelled burned area accuracy, differences in fire spread and behaviour through the simulation of recent forest fires that affected the Mt Kenya Forest Reserve. The research analyzed differences between the actual and modelled fire predictions for two separate fires that occurred within the Mt Kenya Forest Reserve in March, 2015 at Irangi and March, 2012 at Chogoria forest stations. FlamMap minimum travel time (MTT) fire modelling software was used to compare spatial characteristics (fireline intensity and spread rate) of fires between the actual and the modelled fires. Comparative analysis between the actual and simulated fire area showed a relatively good agreement. The fire model provided a better understanding of the differences in fire growth and behaviour predictions over heterogeneous fuel landscapes, complex topography and changing weather conditions.

Resumo Las metodologías unitemporales habitualmente utilizadas para cartografiar el área afectada por un incendio forestal se basan en la clasificación de una imagen NDVI post-incendio; sin embargo, presentan algunas limitaciones. Este trabajo propone una ...

Russia and Its Forest Fires Russia's vast forests, spanning over 11 million square kilometers, are facing increasing threats from wildfires. These fires, often ignited by human activity or lightning strikes, have become a major concern, posing ecological, economic, and climate change risks.

Serotiny degree may hypothetically depend on mother plant age and fire severity, and fire severity can strongly affect the regeneration of Pinus pinaster Aiton, which is an obligate seeder species with aerial seed banks stocked in cones showing a certain degree of serotiny. The main objective of this study was to evaluate the effect of serotiny and mother plant age on seed germination of P. pinaster in relation to fire severity. For this purpose, cones were collected in two stands from mother trees of different ages. Serotinous cones were opened in oven at increasing temperatures to determine the number of seeds released. The length of cones and the number and weight of seeds were measured. Seeds from both classes of mother plant age were subjected to 34 different treatments simulating different fire severity levels, and their germination was recorded. The results showed that serotiny was significantly higher in cones from young mother trees. Seed germination in the control groups from serotinous cones was always higher than that from non-serotinous cones without thermal shock. Fire severity decreased seed germination as fire severity increases in both mother age classes. Mother plant age was related to the serotiny level, which was higher in young than in old trees, suggesting a strong selection in the population due to a recent fire.

Planted and invading non-native plant species can alter fire regimes through changes in fuel loads and in the structure and continuity of fuels, potentially modifying the flammability of native plant communities. Such changes are not easily predicted and deserve system-specific studies. In several regions of the southern hemisphere, exotic pines have been extensively planted in native treeless areas for forestry purposes and have subsequently invaded the native environments. However, studies evaluating alterations in flammability caused by pines in Patagonia are scarce. In the forest-steppe ecotone of northwestern Patagonia, we evaluated fine fuels structure and simulated fire behavior in the native shrubby steppe, pine plantations, pine invasions, and mechanically removed invasions to establish the relative ecological vulnerability of these forestry and invasion scenarios to fire. We found that pine plantations and their subsequent invasion in the Patagonian shrubby steppe produced sharp changes in fine fuel amount and its vertical and horizontal continuity. These changes in fuel properties have the potential to affect fire behavior, increasing fire intensity by almost 30 times. Pruning of basal branches in plantations may substantially reduce fire hazard by lowering the probability of fire crowning, and mechanical removal of invasion seems effective in restoring original fuel structure in the native community. The current expansion of pine plantations and subsequent invasions acting synergistically with climate warming and increased human ignitions warrant a highly vulnerable landscape in the near future for northwestern Patagonia if no management actions are undertaken.

Traffic accidents are becoming a global issue, causing enormous losses in both human and financial resources. According to a World Health Organization assessment, the severity of road accidents affects between 20 and 50 million people each year. This study intends to examine significant factors that contribute to road traffic accident severity. Seven machine learning models namely, Naive Bayes, KNN, Logistic model tree, Decision Tree, Random Tree, and Logistic Regression machine learning models were compared to the J48 pruned tree model to analyze and predict accident severity in the road traffic accident. To compare the effectiveness of the machine learning models, ten well-known performance evaluation metrics were employed. According to the experimental results, the J48 pruned tree model performed more accurately than the other seven machine learning models. According to the analysis, the number of casualties, the number of vehicles involved in the accident, the weather conditions, and the lighting conditions of the road, is the main determinant of road traffic accident severity.

In 2020, wildfires scarred over 4,000,000 hectares in the western United States, devastating urban populations and ecosystems alike. The significant impact that wildfires have on plants, animals, and human environments makes wildfire adaptation, management, and mitigation strategies a critical task. This study uses satellite imagery from Landsat to calculate burn severity and map the fire progression for the Dolan Fire of central Coastal California which occurred in August 2020. Several environmental factors, such as temperature, humidity, fuel type, topography, surface conditions, and wind velocity, are known to affect wildfire spread and burn severity. The aim of this study is the investigation of the relationship between these environmental factors, estimates of burn severity, and fire spread patterns. Burn severity is calculated and classified using the Difference in Normalized Burn Ratio (dNBR) before being displayed as a time series of maps. The Dolan Fire had a moderate severity burn with an average dNBR of 0.292. The ignition site location, when paired with the patterns of fire spread, is consistent with wind speed and direction data, suggesting fire movement to the southeast of the fire ignition site. Patterns of increased burn severity are compared with both topography (slope and aspect) and fuel type. Locations that were found to be more susceptible to high burn severity featured Long Needle Timber Litter and Mature Timber fuels, intermediate slope angles between 15 and 35°, and north- and east-facing slopes. This study has implications for the future predictive modeling of wildfires that may serve to develop wildfire mitigation strategies, manage climate change impacts, and protect human lives.

Fire is a widespread Earth system process with important carbon and climate feedbacks. Multispectral remote sensing has enabled mapping of global spatiotemporal patterns of fire and fire effects, which has significantly improved our understanding of interactions between ecosystems, climate, humans and fire. With several upcoming spaceborne hyperspectral missions like the Environmental Mapping And Analysis Program (EnMAP), the Hyperspectral Infrared Imager (HyspIRI) and the Precursore Iperspettrale Della Missione Applicativa (PRISMA), we provide a review of the state-of-the-art and perspectives of hyperspectral remote sensing of fire. Hyperspectral remote sensing leverages information in many (often more than 100) narrow (smaller than 20 nm) spectrally contiguous bands, in contrast to multispectral remote sensing of few (up to 15) non-contiguous wider (greater than 20 nm) bands. To date, hyperspectral fire applications have primarily used airborne data in the visible to short-wave infrared region (VSWIR, 0.4 to 2.5 μm). This has resulted in detailed and accurate discrimination and quantification of fuel types and condition, fire temperatures and emissions, fire severity and vegetation recovery. Many of these applications use processing techniques that take advantage of the high spectral resolution and dimensionality such as advanced spectral mixture analysis. So far, hyperspectral VSWIR fire applications are based on a limited number of airborne acquisitions, yet techniques will approach maturity for larger scale application when spaceborne imagery becomes available. Recent innovations in airborne hyperspectral thermal (8 to 12 μm) remote sensing show potential to improve retrievals of temperature and emissions from active fires, yet these applications need more investigation over more fires to verify consistency over space and time, and overcome sensor saturation issues. Furthermore, hyperspectral information and structural data from, for example, light detection and ranging (LiDAR) sensors are highly complementary. Their combined use has demonstrated advantages for fuel mapping, yet its potential for post-fire severity and combustion retrievals remains largely unexplored.

Fire impacts many vegetated ecosystems across the world. The severity of a fire is major component in determining post-fire effects, including soil erosion, trace gas emissions, and the trajectory of recovery. In this study, we used imaging spectroscopy data combined with Multiple Endmember Spectral Mixture Analysis (MESMA), a form of spectral mixture analysis that accounts for endmember variability, to map fire severity of the 2013 Rim Fire. We evaluated four endmember selection approaches: Iterative Endmember Selection (IES), count-based within endmember class (In-CoB), Endmember Average Root Mean Squared Error (EAR), and Minimum Average Spectral Angle (MASA). To reduce the dimensionality of the imaging spectroscopy data we used uncorrelated Stable Zone Unmixing (uSZU). Fractional cover maps derived from MESMA were validated using two approaches: (1) manual interpretation of fine spatial resolution WorldView-2 imagery; and (2) ground plots measuring the Geo Composite Burn Index (GeoCBI) and the percentage of co-dominant and dominant trees with green, brown, and black needles. Comparison to reference data demonstrated fairly high correlation for green vegetation and char fractions (r 2 values as high as 0.741 for the MESMA ash fractions compared to classified WorldView-2 imagery and as high as 0.841 for green vegetation fractions). The combination of uSZU band selection and In-CoB endmember selection had the best trade-off between accuracy and computational efficiency. This study demonstrated that detailed fire severity retrievals based on imaging spectroscopy can be optimized using techniques that would be viable also in a satellite-based imaging spectrometer.

Understanding the development of fire-generated thunderstorms in mega fire events is important given their high impact on the evolution of the fire fronts, where the fire spread becomes highly unpredictable and difficult to suppress. This study aims to investigate numerically the influence of strong pyro-convective activity on the local atmospheric conditions by means of a numerical simulation based on the coupled Meso-NH/ForeFire code. To our knowledge, it is the first time that the effect of wildfire spread on the local atmospheric conditions is accounted explicitly in a high-resolution NWP model to investigate pyro-convection activity. More specifically, we study numerically the Portuguese Pedrógão Grande mega fire, which was one of the most destructive and deadliest wildfire hazards affecting the Mediterranean region in the recent years. The spatio-temporal propagation of the wildfire was assigned a priori on the basis of the official investigation's reports, while the impact of the forced fire evolution and of the ensuing heat and water vapour emissions on the local atmospheric conditions is accounted explicitly. The simulation, configured with very-high spatial and temporal resolutions, was capable of resolving the intense convective column reaching the upper troposphere and the fast development of the associated cloud system. The numerical fire produced intense updraughts with vertical velocities above 15 m/s, whereas the associated pyroCb cloud was composed by five different hydrometeor species along the main convective column and reached an altitude of 10 km. It is remarkable that the numerical experiment reproduced phenomena occurring at a fine scale related to cloud microphysics, such as very-localized outflows. This study, based on a coupled numerical simulation, was capable of illustrating in detail the development of a pyroCb cloud from strong pyro-convective activity.

Recently, the Wildland Fire Leadership Council (WFLC) adopted a strategy to monitor the effectiveness of the National Fire Plan and the Healthy Forests Restoration Act. One component was to assess the environmental impacts of large wildland fires and identify trends in burn severity across the United States. The USGS, NPS and USFS provided the leadership to develop Monitoring Trends in Burn Severity (MTBS) in support of the WFLC monitoring strategy. This JFSP project formed a scientific basis for MTBS, which will rely on Landsat satellite imagery and the dNBR algorithm to assess burn severity in the United States, covering fires greater than 500 acres in the east and greater than 1000 acres in the west that have occurred since 1982. The MTBS project is designed for two primary applications: 1) local-to-regional planning, management and research using dNBR-based fire assessment products imported into land-unitbased GIS, and 2) national policies such as the National Fire Plan to analyze effects and effectiveness of fire management practices across large geographic regions. The MTBS project represents perhaps the most significant technology transfer of this JFSP sponsored study. Aside from those direct operational applications, a considerable amount of interest, discussion, and research has followed that centered on the approaches originally proposed in this project. Some have been based on relatively few observations and/or on only one to a few burns (Cocke

Space and airborne sensors have been used to map area burned, assess characteristics of active fires, and characterize post-fire ecological effects. Confusion about fire intensity, fire severity, burn severity, and related terms can result in the potential misuse of the inferred information by land managers and remote sensing practitioners who require unambiguous remote sensing products for fire management. The objective of the present paper is to provide a comprehensive review of current and potential remote sensing methods used to assess fire behavior and effects and ecological responses to fire. We clarify the terminology to facilitate development and interpretation of comprehensible and defensible remote sensing products, present the potential and limitations of a variety of approaches for remotely measuring active fires and their post-fire ecological effects, and discuss challenges and future directions of fire-related remote sensing research.

As part of the Russian FIRE BEAR (Fire Effects in the Boreal Eurasia Region) Project, replicated 4-ha experimental fires were conducted on a dry Scotch pine (Pinus sylvestris)/lichen (Cladonia sp.)/feathermoss (Pleurozeum schreberi) forest site in central Siberia. Observations from the initial seven surface fires (2000)(2001) ignited under a range of burning conditions quantified the different fuel consumption and fire behavior characteristics (e.g., rate of spread, fireline intensity, etc.) possible in this particular forest fuel type. Experimental results and dendrochronological study of local fire history both support the dominance of local fire regimes by low to moderate-intensity surface fires. Carbon released by the experimental fires ranged from 4.8 to 15.4 t C ha -1 depending on fuel conditions and fire severity. Preliminary emission data show a strong correlation between carbon dioxide (CO 2 ) and carbon monoxide (CO) emissions, which should facilitate accurate estimates of fire impacts on atmospheric chemistry. Carbon concentration in smoke samples was related to fire severity. The short landscape-scale fire-return interval (50 years), combined with typically low fire severity, in pine ecosystems of central Siberia is often associated with low tree mortality and relatively rapid buildup of litter and understory fuels after a fire.

The present study investigates the impact of fire (low and high severity) on soil fungal abundance and microbial efficiency in C assimilation and mineralisation in a Mediterranean maquis area of Southern Italy over 2 years after fire. In burned and control soils total and active fungal mycelium, microbial biomass C, percentage of microbial biomass C present as fungal C, metabolic quotient (qCO 2) and coefficient of endogenous mineralisation (CEM) were assayed together with several chemical properties of soil (i.e. pH and contents of organic C, total and mineral N, available K, Mg, Mn and water). Fire significantly decreased the fungal mycelium, whereas it stimulated microbial growth probably through the enhancement of bacterial growth because of the increase in organic C and nutrient contents in burned plots. This shift in microbial community composition might explain the observed reduction in soil microbial efficiency of C assimilation (high qCO 2) and the increase in C mineralisation rate (CEM) in the first 84 days after fire. Therefore, fire might increase CO 2 input to the atmosphere not only during combustion phase but also in the post-fire period.

Infrequent stand-replacing wildfires are characteristic of mesic and/or cool conifer forests in western North America, where forest recovery within high-severity burn patch interiors can be slow, yet successful over long temporal periods (decades to centuries). Increasing fire frequency and high-severity burn patch size, under a warming climate, however, may challenge post-fire forest recovery, promoting landscape-level shifts in forest structure, composition, and distribution of non-forest patches. Crucial to a delay and/or impediment to this shift, fire refugia (i.e., remnant seed sources) may determine forest recovery trajectories and potential forest state-transitions. To examine how fire refugia attributes (i.e. extent, composition, and structure) interact with local climate and environmental conditions to determine post-fire forest recovery responses, we developed fine-grain maps of fire refugia via remote sensing and conducted field-based assessment of post-fire conifer tree establishment largely originating (i.e., dispersed) from fire refugium in the Central Cascade Range of the Pacific Northwest United States. We found that limitations on seed availability, represented by the distance 2-weighted density (D 2 WD) of fine-grain refugia extent, largely explained post-fire tree establishment responses within our relatively mesic and cool subalpine study sites. Interactions between seed availability, climate, and environmental conditions indicated that the structural attributes of refugia (e.g., tree height) and site abiotic/biotic environmental controls (e.g., climate water deficit, canopy cover, and coarse woody debris cover) interplayed to constrain or enhance species-specific tree establishment responses. Importantly, these interactions illustrate that when seed availability is critically low for a given area, climate-environment conditions may strongly determine whether forests recover following fire(s). Toward modelling and predicting tree establishment responses and potential forest state-transitions after large stand-replacing fires(s), our study demonstrates the importance of accurately quantifying seed availability via the fine-grain extent, configuration, and attributes of remnant seed source legacies.

Increasing forest fuel aridity with climate change may be expanding mid-to-high-elevation forests' vulnerability to large, severe, and frequent wildfire. Long-lasting changes in forests' structure and composition may occur if dominant tree species are poorly adapted to shifting wildfire patterns. We hypothesized that altered fire activity may lower existing forest resilience and disrupt the recovery of upper-montane and subalpine conifer forest types. We empirically tested this hypothesis by quantifying post-fire forest structure and conifer tree regeneration after spatially large, severe, and rapidly repeated wildfires (<12-yr interval) in the Central Cascade Range in the U.S. Pacific Northwest. Post-fire conifer regeneration was generally very poor among plots that experienced either a single high-severity fire or rapid reburn, driven primarily by lack of proximate seed source. Pre-fire dominant, shade-tolerant species' abundance was highly negatively correlated with increasing seed source distances and dry, exposed postfire environmental conditions. In rapidly reburned plots, the order of burn severity was critical and promoted establishment of all conifer species, if low-then-high severity, or primarily fire-adapted pines, if high-then-low severity. Our findings suggest that these forests, affected by expansive high-severity and/or short-interval wildfire, may transition into a patchy, low-density, pine-dominated forest state under future warming trends. These emerging, early seral ecosystems will incorporate more fire-adapted tree species, lower tree densities, and more non-forest patches than prior forests, likely expanding their resilience to anticipated increases in fire frequency. If future larger, more severe, and more frequent wildfire patterns manifest as expected in the Cascade Range, previously denser, moist mid-to-high-elevation forests may begin resembling their drier, lower-elevation mixed-conifer counterparts in structure and composition.

Untangling the nuanced relationships between landscape, fire disturbance, human agency, and climate is key to understanding rapid population declines of firesensitive plant species. Using multiple lines of evidence across temporal and spatial scales (vegetation survey, stand structure analysis, dendrochronology, and fire history reconstruction), we document landscape-scale population collapse of the

Athrotaxis cupressoides is a slow-growing and long-lived conifer that occurs in the subalpine temperate forests of Tasmania, a continental island to the south of Australia. In 1960-1961, human-ignited wildfires occurred during an extremely dry summer that killed many A. cupressoides stands on the high plateau in the center of Tasmania. That fire year, coupled with subsequent regeneration failure, caused a loss of ca. 10% of the geographic extent of this endemic Tasmanian forest type. To provide historical context for these large-scale fire events, we (i) collected dendroecological, floristic, and structural data, (ii) documented the postfire survival and regeneration of A. cupressoides and co-occurring understory species, and (iii) assessed postfire understory plant community composition and flammability. We found that fire frequency did not vary following the arrival of European settlers, and that A. cupressoides populations were able to persist under a regime of low-to-mid severity fires prior to the 1960 fires. Our data indicate that the 1960 fires were (i) of greater severity than previous fires, (ii) herbivory by native marsupials may limit seedling survival in both burned and unburned A. cupressoides stands, and (iii) the loss of A. cupressoides populations is largely irreversible given the relatively high fuel loads of postfire vegetation communities that are dominated by resprouting shrubs. We suggest that the feedback between regeneration failure and increased flammability will be further exacerbated by a warmer and drier climate causing A. cupressoides to contract to the most fireproof landscape settings.

We evaluated spatial patterns of soil N and C mineralization, microbial community composition (phospholipid fatty acids), and local site characteristics (plant/forest floor cover, soil pH, soil %C and %N) in a 0.25-ha burned black spruce forest stand in interior Alaska. Results indicated that factors governing soil N and C mineralization varied at two different scales. In situ net N mineralization was autocorrelated with microbial community composition at relatively broad scales ($8 m) and with local site characteristics ('site' axis 1 of non-metric scaling ordination) at relatively fine scales (2-4 m). At the scale of the individual core, soil moisture was the best predictor of in situ net N mineralization and laboratory C mineralization, explaining between 47 and 67% of the variation (p < 0.001). Ordination of microbial lipid data showed that bacteria were more common in severely burned microsites, whereas fungi were more common in low fire severity microsites. We conclude that C and N mineralization rates in this burned black spruce stand were related to different variables depending on the scale of analysis, suggesting the importance of considering multiple scales of variability among key drivers of C and N transformations.

Dehydrogenase activity Microbial biomass Resprouter species Seeder species Soil basal respiration Water soluble carbon The strong relationships between plant and soil microbial communities suggest that post-fire vegetation may be a critical driver of the post-fire recovery of the structure and functioning of the soil microbial community. In this study, we conducted an experimental burning and evaluated the effect of the post-fire persistence traits of the vegetation (resprouter and seeder) on the medium-term (3 years after fire) post-fire response of the soil microbial activity in Mediterranean shrublands. The experiment was carried out in a Mediterranean shrubland (Eastern Spain), where four main types of microsites were selected: Bare-soil inter-patch (BS); Resprouter patch (R), Seeder patch (S), and Mixed patch (R+S). For each microsite, we analyzed soil basal respiration, water-soluble carbon, microbial biomass carbon, total organic carbon, and dehydrogenase activity at 0-5 cm soil depth. We also assessed plant cover dynamics. Our results suggest that, in general, fire impacts on soil microbial activity are not long-lasting, with most assessed soil variables being similar between burned and unburned areas three years after the fire. However, while the unburned microsites showed a trend in microbial biomass and activity from lower values in bare soils to higher values in R+S patches, these differences disappeared in the burned area, due to both a slight increase in microbial activity and biomass in bare soils, and the opposite response for soils under R+S patches. Our results highlight the role of the plant persistence trait in the microbial post-fire response of Mediterranean soils.

Fire severity influences the recovery and biodiversity of plant communities. We compared the early post-fire recovery of plant functional groups in two sites (one burnt with high severity and one with low severity) in the north-western Patagonian steppe. We sampled the post-fire soil seed banks, as well as the composition and cover of aboveground plant species, and calculated richness, diversity and the percentage of exotic species. Low fire severity increased the diversity of aboveground vegetation and seed banks, whereas high fire severity reduced the cover of all functional groups, with the exception of fugitive species. Tiller production of perennial grasses decreased due to bud bank mortality. In the seed bank, high severity fire reduced fugitive species and increased exotic species. Fugitive species need fire to recruit, and the combination of fire cues and post-fire environmental conditions can explain the high abundance of these species after fire. In Patagonia, the use of f...

Wildfire statistics report an increasing number of deaths, damages, and force society to face exceptional repair costs also due to secondary effects such as landslides, soils erosion and water quality problems. Literature agrees that the extent of the thermal disturbance of the soil due to wildfire is strongly dependent on fire intensity, on its duration and recurrence, as well as on fuel load, and soil properties. The unpredictability of these phenomena is one of the main challenges for scientists trying to study their characteristics. Degradation of the biological, chemical, and physical properties of forest soils due to the wildfires can reduce their capacity to function fully, with such effects either temporary or permanent. Direct measurements of the effects of these phenomena are difficult to be collected in the field, especially when the area affected by fires is a wilderness. In this study, controlled fires reproducing real conditions of wildfire affecting the Susa Valley (NW Italy) in 2017, which induced intense erosion and debris flows, have been monitored both above and below the ground surface. Moreover, numerical simulations based on real data increased the know-how to reproduce real changes on the underground. The small-scale fire simulations have allowed to verify how the depth affected by significant increases in temperatures is truly pellicular. Field tests show that at −2 cm depth temperature never exceed 70°C, meaning that it usually does not affect soil components or properties. The results of the study suggest that temperature variations in the subsoil are very localized and limited. If confirmed by further studies, the processes inferred to produce large ground effects on slopes after wildfires should be reconsidered .