Surface Fire Research Articles

Bark functional ecology and its influence on the distribution of Australian half‐butt eucalypts

AbstractHalf‐butt eucalypts (genera: Eucalyptus and Corymbia) have both thick outer bark at the stem base (half‐butt) conferring resistance to surface fire, and thin photosynthetic canopy bark that reduces moisture stress. Here we examine how the functional ecology of dual outer bark types influences the wide distribution of Australian half‐butt species. We evaluate the proposition that half‐butts should predominate in semi‐arid environments prone to surface fires. We measured the bark thickness, butt height relative to flame/fire char height and tree height, height of first branch, and the location and prevalence of epicormic resprouting of co‐occurring Eucalyptus miniata (half‐butt) and E. tetrodonta (fibrous bark only) individuals, across 15 sites with contrasting fire frequencies (2000–2015) in the Darwin region. Total tree height was compared with butt height for all E. miniata individuals. The survival of half‐butt and other eucalypt species, as well as non‐eucalypts, was investigated at three sites affected by intense gamba grass (Andropogon gayanus) fire. The proportion of half‐butt species in each of Australia’s 85 bioregions was calculated from geographic distribution records of 618 eucalypt species. Mean annual fire frequency (1997–2010), fire type (crown or surface fires) and climate in each bioregion was determined from satellite‐derived records.Butt height at a site, including gamba grass sites, was not induced by flame height or affected by fire frequency and was approximately half the canopy height of the tree, suggesting it is internally regulated. The half‐butt E. miniata and full‐bark eucalypts were similarly resilient (survival) under surface fire conditions. Half‐butt species predominated in arid and semi‐arid bioregions characterised by surface fire, consistent with our proposition that half‐butt bark is an adaptation to surface fire, and thin photosynthetic outer canopy bark reduces moisture stress, accounting for the wide distribution of half‐butt eucalypts in arid and seasonally dry regions of Australia.

Bioclimatic drivers of fire severity across the Australian geographical range of giant Eucalyptus forests

Abstract The relationships between productivity, fire frequency and fire severity shape the distribution of plant communities globally. Dry forests are expected to burn frequently and wet forests to burn infrequently. However, the effect of productivity on intensity and severity of wildfire is less consistent and poorly understood. One productive ecosystem where this is especially true is the Australian tall wet Eucalyptus‐dominated forest (TWEF), which spans wet areas across the continent. This study aims to characterise how climate shapes the likelihood of low‐ and high‐severity wildfire across Australian TWEF. We performed a continental‐scale analysis of fuels in 48 permanent plots in early‐mature stage TWEF across four climate regions in Australia. We estimated fuel loads and measured understorey microclimate. We then obtained historical fire‐weather observations from nearby meteorological stations and used fuel moisture and fire behaviour equations to predict the historical frequency with which TWEF could burn and what fire severities were expected. We investigated how this varies across the different TWEF climate regions. Lastly, we validated our approach by remeasuring eight plots that burned unexpectedly post‐measurement. We found that surface fuels in cooler, moister regions were available to burn 1–16 days per year historically, with only low‐severity, surface fire possible most of these days: high‐severity fire was only possible under rare, extreme fire‐weather conditions. However, in warmer, drier regions, fuels were available to burn 23–35 days annually, and high‐severity fire was more likely than low‐severity fire. Validation showed that we slightly overestimated flame heights, inflating high‐severity risk estimates. If we used elevated fuel loads to predict flame heights, however, high‐severity fire was more likely than low‐severity fire everywhere. Lastly, the likelihood of high‐severity fire increased with increasing temperature and worsening fire weather. Synthesis. Fire activity in early‐mature TWEF is limited by climatic constraints on fire weather and availability to burn, with high‐severity fire more likely in warmer, drier regions than in cooler, wetter ones. This indicates a particularly worrisome vulnerability to climate change, given TWEF's diminished ability to recover from disturbance in a warmer world. The occurrence of both low‐ and high‐severity fire means the fire regimes of TWEF are best described as mixed severity.

The Environment at Lake El’gygytgyn Area (Northeastern Russian Arctic) Prior to and After the Meteorite Impact at 3.58 Ma

Upper Pliocene sediments from a number of fluvial outcrops in central Chukotka, northeastern Russian Arctic, along the Enmyvaam, Mechekrynnetveem, and Chanuvenvaam Rivers, have been newly studied for pollen, non-pollen-palynomorphs and, for the first time for Pliocene sediments in Eurasia, charcoals. The sediments have survived the El’gygytgyn meteorite impact event at ∼3.58 Ma. The stratigraphy of the studied outcrops suggests that the lowermost sediments were accumulated shortly before the impact event, between ∼3.60 and 3.58 Ma. At that time, coniferous forests with spruces, pines, firs, birches, larches, and alders dominated in the area. Some relatively thermophilic broad-leaved taxa (Corylus, Carpinus, Ulmus, and Myrica) might also have grown in local forests. Summer temperatures were at least 10°C warmer than today. Charcoal concentrations and composition suggest the presence of high intensity fires. Periods of rather wet climate and soil conditions are marked by common shrubby and boggy habitats with ericaceous plants and Sphagnum, and are associated with less, and probably low-intensity surface fires with less charcoal. The impact event caused widespread fires reflected by up to 4 times higher charcoal concentrations in the sediments. The sediments found above the so-called “chaotic horizon” (sediments accumulated synchronously or very shortly after the impact event) contain late Pliocene pollen assemblages comparable to those in Lake El’gygytgyn, reflecting that pine-spruce forests with some firs, birches, larches, and alder dominated in the study area. Some thermophilic taxa might also still have grown in the area. However, the age control for the sediments above the so-called chaotic horizon is poor. The uppermost sediments from the studied sections can be attributed with certainty to the Late Pleistocene and Holocene according to their stratigraphic positions and pollen assemblages. The combined pollen and charcoal analysis allowed correlating hardly datable fluvial sediments and points to varying fire regimes in warmer-than-present climates, when forest extended further north compared to today.

Overstory Longleaf Pines and Hardwoods Create Diverse Patterns of Energy Release and Fire Effects During Prescribed Fire

Litter from pine trees in open woodlands is an important fuel for surface fires, but litter from hardwood species may quell fire behavior. Lower intensity fires favor hardwood over longleaf pine regeneration, and while overstory hardwoods are important sources of food and shelter for many wildlife species, too many could result in canopy closure and a loss of ground layer diversity. Although some researchers have found synergies in fire effects when leaves of different species are combined, field tests of effects of tree guild diversity on fire behavior are lacking from the literature. We used neighborhood modeling to understand how diverse overstory trees in longleaf pine forests affect fire radiative energy density (FRED), and to determine the effect on top-kill of shrub-form hardwood trees. We measured the effects of three guilds of overstory trees (longleaf pine, upland oaks, and mesic oaks) on FRED, and related FRED to post-fire damage in four guilds of understory hardwoods (sandhill oaks, upland oaks, mesic oaks, and fleshy-fruited hardwoods). We found that FRED increased 33–56% near overstory longleaf pine but decreased 23–37% near overstory mesic oaks. Additive models of FRED performed well and no synergies or antagonisms were present. Seventy percent of stems of understory hardwoods survived fire with energy release typical of dormant-season fires in canopy gaps and near overstory mesic oaks. We also found that among understory trees >2 m tall, upland and sandhill oaks were more likely than mesic oaks or fleshy-fruited hardwoods to avoid top-kill. We conclude that neighborhood models provide a method to predict longleaf pine forest structure and composition that allows for the ecological benefits of overstory hardwoods while maintaining ground-layer diversity. To maintain hardwood control, fire practitioners may need to select fire weather conditions to increase fire behavior especially during dormant-season burns.

Forest fire detection on LANDSAT images using support vector machine

SummaryIn recent days, the major threat in the world is forest fire that affects the biodiversity, climate change, and so forth. So detection process is more essential to monitor the forest region. To detect the forest fire, the paper proposes a novel detection technique of support vector machine (SVM)‐Krill herd that can effectively detect the fire region using different kinds of features. Land surface temperature, fire intensity, water vapor, and top of atmosphere temperature are being extracted as some of the features that can be exposed. These features are preferred to classify the LANDSAT image into two classes using SVM optimized by Krill herd. The Euclidean distance is chosen to find the similarity between the test and trained image and then predict the giving query image containing a fire or not based on its training samples. With the help of the feature extractor parameters, the performances have to be analyzed. When compared with existing fire detection algorithms like active fire detection, SFIDE, convolutional neural network (CNN), hybrid intelligent, and PSO‐SVM algorithm, the proposed SVM‐Krill herd‐based detection method increases the accuracy by 1.562%, 0.675%, 1.290%, 0.876%, and 1.038%. The proposed detection method of SVM‐Krill herd achieves 99.21% accuracy and high precision as 98.41%.

Fire Behavior Prediction in Larch Forests of the Kazakhstan Altai

This paper considers automated fire behavior prediction in larch forests of the Kazakhstan Altai based on large-scale vegetation fuel maps (VF maps). First-time pyrological description of the Kazakhstan Altai larch forests was performed, thus facilitating VF maps’ creation using forest inventory information in a geographical information system (GIS). Based on the methodological developments of the Sukachev Institute of Forest, types of primary fire carriers were identified for larch forests and other categories of sites. On the example of the Markakol Forestry area (Kazakhstan Altai), our fire growth simulation modeling system was adapted for predicting fire behavior in the mountain terrain. The developed fire simulation software helped not only identify inventory plots ready to burn, but also assess spread rate for fire parts dependent upon weather conditions, predict fire intensity and fire development, and calculate the required manpower and resources for fire suppression. The effects of each specific fire were predicted in terms of percentage of tree mortality dependent upon fire intensity, tree species, and average tree diameter. Examples of VF maps were made for different periods of a fire season and analysis was given to behavior of a simulated surface fire in the Markakol Forestry area.

Managing Wildlife Habitat: Complex Interactions With Biotic and Abiotic Disturbances

Sustainable forest management strategies include emulating historical disturbance regimes to achieve multiple objectives. Partial-harvesting strategies are used to overcome conflicts between timber production and wildlife habitat conservation; however, the potential impacts on complex disturbance interactions and ecological functions remain largely unknown. In 1984, a controlled experiment was initiated in the dry forests of central British Columbia, Canada, to test partial harvesting intended to enhance mule deer habitat while allowing timber extraction. To determine the short- and long-term impacts on complex disturbance regimes, we quantified changes in forest structure and susceptibility to western spruce budworm, Douglas-fir beetle, and wildfire. We compared structural attributes in 2014 (30 years after the first harvest) and 2015 (1 year after the second harvest) in treated forests, and contrasted them with control forests that were measured in 2015. In the short term (1 year post-harvest), partial harvesting altered forest structure by reducing total canopy cover, subcanopy tree density and basal area, and increasing the abundance of large woody surface fuels. In the long term (30 years post-harvest), the forest canopy attributes did not differ between the treatment and control areas, partly due to increased growth of subcanopy trees. Harvesting had little impact on forest susceptibility to western spruce budworm. Susceptibility to Douglas-fir beetle was lower in the short term due to fewer available mature host trees, but increased to levels similar to the control forest over the long term. Reduced canopy fuels and increased canopy base height decreased the likelihood of crown fire in favor of surface fire. In the long term, canopy fuels and likelihood of crown fire recovered, but woody fuel loads remained low after 30 years. Harvesting to enhance mule deer habitat interacts with biotic and abiotic disturbances in the short and long term. Potential cascading affects depended more on the decision to remove harvesting residuals to mitigate potential Douglas-fir beetle infestations and wildfire than on time since treatment. Provided partial harvesting occurs at intervals ≤ 30 years and residuals are immediately removed, timber extraction and mule deer habitat can be compatible with complex disturbance regimes and sustainable forest management.

Environmentally persistent free radicals are ubiquitous in wildfire charcoals and remain stable for years

Globally landscape fires produce about 256 Tg of pyrogenic carbon or charcoal each year. The role of charcoal as a source of environmentally persistent free radicals, which are precursors of potentially harmful reactive oxygen species, is poorly constrained. Here, we analyse 60 charcoal samples collected from 10 wildfires, that include crown as well as surface fires in forest, shrubland and grassland spanning different boreal, temperate, subtropical and tropical climate. Using electron spin resonance spectroscopy, we measure high concentrations of environmentally persistent free radicals in charcoal samples, much higher than those found in soils. Concentrations increased with degree of carbonization and woody fuels favoured higher concentrations. Moreover, environmentally persistent free radicals remained stable for an unexpectedly long time of at least 5 years. We suggest that wildfire charcoal is an important global source of environmentally persistent free radicals, and therefore potentially of harmful reactive oxygen species.

The Wildland Fire Heat Budget-Using Bi-Directional Probes to Measure Sensible Heat Flux and Energy in Surface Fires.

Sensible energy is the primary mode of heat dissipation from combustion in wildland surface fires. However, despite its importance to fire dynamics, smoke transport, and in determining ecological effects, it is not routinely measured. McCaffrey and Heskestad (A robust bidirectional low-velocity probe for flame and fire application. Combustion and Flame 26:125–127, 1976) describe measurements of flame velocity from a bi-directional probe which, when combined with gas temperature measurements, can be used to estimate sensible heat fluxes. In this first field application of bi-directional probes, we describe vertical and horizontal sensible heat fluxes during the RxCADRE experimental surface fires in longleaf pine savanna and open ranges at Eglin Air Force Base, Florida. Flame-front sensible energy is the time-integral of heat flux over a residence time, here defined by the rise in gas temperatures above ambient. Horizontal flow velocities and energies were larger than vertical velocities and energies. Sensible heat flux and energy measurements were coordinated with overhead radiometer measurements from which we estimated fire energy (total energy generated by combustion) under the assumption that 17% of fire energy is radiated. In approximation, horizontal, vertical, and resultant sensible energies averaged 75%, 54%, and 64%, respectively, of fire energy. While promising, measurement challenges remain, including obtaining accurate gas and velocity measurements and capturing three-dimensional flow in the field.

Intensive Wildfire Associated With Volcanism Promoted the Vegetation Changeover in Southwest China During the Permian−Triassic Transition

Palaeo-wildfire, which had an important impact on the end Permian terrestrial ecosystems, became more intense in the latest Permian globally, evidenced by extensive occurrence of fossil charcoals. In this study, we report abundant charcoals from the upper part of the Xuanwei Formation and the Permian–Triassic transitional Kayitou Formation in the Lengqinggou section, western Guizhou Province, Southwest China. These charcoals are well-preserved with anatomical structures and can be classified into seven distinctive types according to their characteristics. Organic carbon isotopic analyses of both bulk rocks and charcoals show that the δ13Corg values in the Kayitou Formation are notably more negative than those in the Xuanwei Formation, with a negative excursion of 4.08‰ immediately above the volcanic ash bed in the middle of the uppermost coal bed of the Xuanwei Formation. Charcoals with high reflectance values (Romean = 2.38%) are discovered below the ash bed. By contrast, the reflectance values (Romean = 1.51%) of the charcoals in the Kayitou Formation are much lower than those of the Xuanwei Formation, indicating the palaeo-wildfire types have changed from crown fires to surface fires, which was probably due to the retrogression of vegetation systems during the extinction. Based on the above evidence, we suppose that palaeo-wildfires became more frequent and more severe since the climate became drier during the latest Permian in Southwest China, and the eventual vegetation changeover of the terrestrial ecosystems in Southwest China could be caused by volcanism.

Petroleum Well Blowouts as a Threat to Drilling Operation and Wellbore Sustainability: Causes, Prevention, Safety and Emergency Response

Sustainability in petroleum wells drilling operation systems strongly depends on the use of sustainable materials and a set of technical and safety measures that lead to the survival and proper operation of drilling rig equipment's and personnel. Adherence to the highest levels of standards of tools, materials and methods, although always recommended as the most important option for advancing a safe drilling operation and completing the well efficiently, low risk and stable, but drilling operation is inherently a battle with underground challenges and unexpected dangers. Learning from past such well blowout events and the problems they pose to rapidly control is essential to reduce future impacts including injuries, damage and emissions. Such analysis offers guidance for adapting working practices to improve both prevention and emergency response to such incidents. The causes of blowout during drilling and the necessary technical and safety measures to adopt are reviewed, highlighting how best practices can prevent blowout incidents by improving responses to early warning signals. The particular risks associated with potential shallow gas blowouts are identified and described with the aid of a case study associated with a catastrophic blowout of an onshore well in Iran and the methods used to ultimately control it. The multiple causes of the incident relating to defects in safety systems, equipment and operating procedures are addressed. Lessons learned from the incident reveal the complexity of well control once a blowout incident has occurred and developed into a surface fire. from the stage of the incident to fire control. There is a need for further research into top-hole well kill techniques for wells in a blowout state, as drilling bottom-hole relief wells takes substantial time, during which much surface damage, resource loss and emission typically occurs.

Postfire tree mortality and fire resistance patterns in pine forests of Ukraine

Abstract The study was conducted in pure Scots pine (Pinus sylvestris L.) stands within the forest steppe physiographic region of Ukraine damaged by surface fires with different intensity. The aim of the research is to determine the effect of different fire intensity on pine stand and individual trees, considering tree morphometric parameters and type of damage. The intensity and duration of fire-related tree mortality was different in stands with different age. We found that tree fire resistance is driven by tree diameter, height of the rough bark, and natural degree of thickness. The proportion of dead trees one year after the spring fires in the middle-aged pine stands was 5 times lower and in mature pine stands even 10 times lower than after the summer fires. The critical damage to tree crowns in young pine trees causing their death is 80% of the needles burned. In the middle-aged pine trees, critical damage depended on the size of trees. The death of large, mature trees after smoldering summer fires was associated with the accumulation of a large stock of forest litter and duff near the tree-base, which contributed to the increased intensity of fire and its localization near the base part of the trees. Based on our findings, postfire tree mortality models have been developed for different age groups of pine stands.

Study on simulation and prediction of environmental risk material leakage in an Equipment Manufacturing Industrial Park

From the perspective of environmental risks, the groundwater pollution, surface water pollution, and fire and explosion scenarios were simulated and predicted with the analytical method in an equipment manufacturing industrial park in Shenyang. The results showed that: after the accident, the maximum migration distance of COD pollution factor leakage in groundwater in the next ten years could reach 1500m, and its peak concentration was 786.35mg/L; the leakage of WSCLC wastewater treatment system would affect Xihe river, and its hazard range mainly concentrated within 17m downstream of the discharge port; the vapor cloud explosion of the HCBM enterprise oil tank caused slight damage to the equipment, and the maximum radius of minor injuries was 15.3m.

Petroleum Well Blowouts as a Threat to Drilling Operation and Wellbore Sustainability: Causes, Prevention, Safety and Emergency Response

Sustainability in petroleum wells drilling operation systems strongly depends on the use of sustainable materials and a set of technical and safety measures that lead to the survival and proper operation of drilling rig equipment's and personnel. Adherence to the highest levels of standards of tools, materials and methods, although always recommended as the most important option for advancing a safe drilling operation and completing the well efficiently, low risk and stable, but drilling operation is inherently a battle with underground challenges and unexpected dangers. Learning from past such well blowout events and the problems they pose to rapidly control is essential to reduce future impacts including injuries, damage and emissions. Such analysis offers guidance for adapting working practices to improve both prevention and emergency response to such incidents. The causes of blowout during drilling and the necessary technical and safety measures to adopt are reviewed, highlighting how best practices can prevent blowout incidents by improving responses to early warning signals. The particular risks associated with potential shallow gas blowouts are identified and described with the aid of a case study associated with a catastrophic blowout of an onshore well in Iran and the methods used to ultimately control it. The multiple causes of the incident relating to defects in safety systems, equipment and operating procedures are addressed. Lessons learned from the incident reveal the complexity of well control once a blowout incident has occurred and developed into a surface fire. from the stage of the incident to fire control. There is a need for further research into top-hole well kill techniques for wells in a blowout state, as drilling bottom-hole relief wells takes substantial time, during which much surface damage, resource loss and emission typically occurs.

Three-dimensional distribution and oxidation degree analysis of coal gangue dump fire area: A case study

Spontaneous combustion of coal gangue dumps poses a significant threat to the health and safety of nearby residents and has adverse effects on the environment. The establishment of measures to extinguish these fires requires information on the three-dimensional characteristics and oxidation degree of the dumps. An acquisition method for the index data was proposed. The temperature and the radon concentration were used as the principal indicators, and the gas concentration was a secondary index for verifying the results. Kriging interpolation was applied to predict the value of the unsampled points. Additionally, the three-dimensional characteristics of the temperature and radon anomalies were determined, thresholds were set, and the changes in the temperature and radon migration were considered to estimate the extent and depth of the fire in the coal gangue dumps. The oxidation degree of the anomalous area was identified according to the critical value of the temperature and radon anomalies. The application of this method in the gangue dump of the Tashan coal mine showed the existence of 17 oxidation areas, covering an area of 31,433 m2, including 4 shallow oxidation areas, 4 deep oxidation areas in coal waste dumps, and 9 medium-deep oxidation areas. According to the decision criterion, 4 areas with relatively high oxidation degree were identified, whereas the remaining sites were low-oxidation areas. Additionally, surface fires and internal fires can be transformed into each other, posing a significant threat. The results obtained from the various data sources were consistent and in agreement with the ground survey results, indicating that the proposed method is effective for the detection of fires in coal gangue dumps.

Wildfires in the Siberian taiga.

The majority of area burned by wildfire are located in Siberia. Mainly low-intensity surface fires occur in larch forests, whereas in evergreen forests both surface and crown fires are observed. Warming has led to an increase in the frequency and area of wildfires that have reached the Arctic Ocean shore. However, wildfires are the most important factor in taiga dynamics; larch and Scots pine have evolved under conditions of periodic forest fires, thereby gaining a competitive advantage over non-fire adapted species; in the permafrost zone, periodic fires are a prerequisite for the dominance of larch. Wildfires support ecosystem health, biodiversity, and conservation; periodic wildfires decrease the danger of catastrophic wildfires. With an amplified rate of increase in fires, it is necessary to focus fire suppression on areas of high social, natural, and economic value, while allowing a greater number of wildfires to burn in the vast Siberian forest landscapes.

Mesophication of Oak Landscapes: Evidence, Knowledge Gaps, and Future Research

AbstractPyrophytic oak landscapes across the central and eastern United States are losing dominance as shade-tolerant, fire-sensitive, or opportunistic tree species encroach into these ecosystems in the absence of periodic, low-intensity surface fires. Mesophication, a hypothesized process initiated by intentional fire exclusion by which these encroaching species progressively create conditions favorable for their own persistence at the expense of pyrophytic species, is commonly cited as causing this structural and compositional transition. However, many questions remain regarding mesophication and its role in declining oak dominance. In the present article, we review support and key knowledge gaps for the mesophication hypothesis. We then pose avenues for future research that consider which tree species and tree traits create self-perpetuating conditions and under what conditions tree-level processes might affect forest flammability at broader scales. Our goal is to promote research that can better inform restoration and conservation of oak ecosystems experiencing structural and compositional shifts across the region.

Forest Fire Spreading Using Free and Open-Source GIS Technologies

Forest fires are one of the most dangerous events, causing serious land and environmental degradation. Indeed, besides the loss of a huge quantity of plant species, the effects of fires can go far beyond: desertification, increased risk of landslides, soil erosion, death of animals, etc. For these reasons, mathematical models able to predict fire spreading are needed in order to organize and optimize the extinguishing interventions during fire emergencies. This work presents a new system to simulate and predict the movement of the fire front based on free and open source Geographic Information System (GIS) technologies and the Rothermel surface fire spread model, with the adjustments made by Albini. We describe the mathematical models used, provide an overview of the GIS design and implementation, and present the results of some simulations at Etna volcano (Sicily, Italy), characterized by high geomorphological heterogeneity, and where the native flora and fauna may be preserved and perpetuated. The results consist of raster maps representing the progress times of the fire front starting from an ignition point and as a function of the topography and wind directions. The reliability of results is strictly affected by the correct positioning of the fire ignition point, by the accuracy of the topography that describes the morphology of the territory, and by the setting of the meteorological conditions at the moment of the ignition and propagation of the fire.

Native American fire management at an ancient wildland–urban interface in the Southwest United States

The intersection of expanding human development and wildland landscapes-the "wildland-urban interface" or WUI-is one of the most vexing contexts for fire management because it involves complex interacting systems of people and nature. Here, we document the dynamism and stability of an ancient WUI that was apparently sustainable for more than 500 y. We combine ethnography, archaeology, paleoecology, and ecological modeling to infer intensive wood and fire use by Native American ancestors of Jemez Pueblo and the consequences on fire size, fire-climate relationships, and fire intensity. Initial settlement of northern New Mexico by Jemez farmers increased fire activity within an already dynamic landscape that experienced frequent fires. Wood harvesting for domestic fuel and architectural uses and abundant, small, patchy fires created a landscape that burned often but only rarely burned extensively. Depopulation of the forested landscape due to Spanish colonial impacts resulted in a rebound of fuels accompanied by the return of widely spreading, frequent surface fires. The sequence of more than 500 y of perennial small fires and wood collecting followed by frequent "free-range" wildland surface fires made the landscape resistant to extreme fire behavior, even when climate was conducive and surface fires were large. The ancient Jemez WUI offers an alternative model for fire management in modern WUI in the western United States, and possibly other settings where local management of woody fuels through use (domestic wood collecting) coupled with small prescribed fires may make these communities both self-reliant and more resilient to wildfire hazards.

Wildland Fire Tree Mortality Mapping from Hyperspatial Imagery Using Machine Learning

The use of imagery from small unmanned aircraft systems (sUAS) has enabled the production of more accurate data about the effects of wildland fire, enabling land managers to make more informed decisions. The ability to detect trees in hyperspatial imagery enables the calculation of canopy cover. A comparison of hyperspatial post-fire canopy cover and pre-fire canopy cover from sources such as the LANDFIRE project enables the calculation of tree mortality, which is a major indicator of burn severity. A mask region-based convolutional neural network was trained to classify trees as groups of pixels from a hyperspatial orthomosaic acquired with a small unmanned aircraft system. The tree classification is summarized at 30 m, resulting in a canopy cover raster. A post-fire canopy cover is then compared to LANDFIRE canopy cover preceding the fire, calculating how much the canopy was reduced due to the fire. Canopy reduction allows the mapping of burn severity while also identifying where surface, passive crown, and active crown fire occurred within the burn perimeter. Canopy cover mapped through this effort was lower than the LANDFIRE Canopy Cover product, which literature indicated is typically over reported. Assessment of canopy reduction mapping on a wildland fire reflects observations made both from ground truthing efforts as well as observations made of the associated hyperspatial sUAS orthomosaic.