Fire Footprints Research Articles

A novel framework for identifying causes of forest fire events using environmental and temporal characteristics of the ignition point in fire footprint

BackgroundForest fire is a very common natural or human-made disaster, which not only burns precious forest resources, but also further alters the forest ecosystem structure and functions as well as global climate. Accordingly, effective information extraction, data management, and modeling of historical fire events are imperative for forecasting and mitigating the onset and progression of forest fires. Traditional remote sensing-based forest fire detection and risk prediction operate at the pixel scale, overlooking the integrity of fire behaviour. Moreover, fire cause records typically stem from ground reports, not fully leveraging the advantages of high temporal resolution thermal infrared remote sensing products. MethodsWe proposed a framework to identify the causes of forest fire events, experimenting with fire incidents from 2001 to 2020 in the Daxing'anling region of Northeast China. Initially, the Jenk-DBSCAN model was employed to acquire fire footprints representative of forest fire events from MODIS MCD64A1 product, and footprint-based fire event attribute information such as ignition locations and timings. Fire footprints matching ground surveys were subsequently filtered, and corresponding environmental variable datasets (including meteorological, topographical, fuel, and human activity factors) were derived in consideration of the spatio-temporal differences of footprint origin and center points. Finally, the optimal variable combinations of the two datasets were fed to three binary classification models including Random Forest (RF), Logistic Regression (LR), and Support Vector Machine (SVM) respectively to identify natural fires or human-induced fires, followed by assessing the accuracy of the fire cause identification models. ResultsResults revealed that there was a high spatio-temporal consistency of those matched fire footprints between the model-extracted and the ground-recorded fire events, evidenced by an overall R2 of 0.87 derived from their area validation. The ignition dates extracted from fire footprints often preceded those reported by local agencies. Among all the selected variable combinations for fire cause identification, the meteorological variables dominated, with daily mean dew point (DEWP) and daily mean visibility (VISIB) being preferentially selected by most models. Across the six models, the model training AUC values were almost greater than 0.8, with the LR model demonstrating superior validation accuracy over RF and SVM. Notably, the accuracy of the LR model using the origin point based dataset surpassed that of the center point-based dataset. The best model achieved an overall accuracy of 90.48%, with the user’s accuracies for human-made fire and natural fire being at 92.86% and 85.71%, respectively. ConclusionsThe proposed framework offers a reliable method for enriching attribute information in forest fire management databases. The resulting fire footprints and origin points can assist in better characterizing the progression of forest fire events. Such endeavours help devise targeted forest fire prevention regulations, fostering sustainable forest management.

Precision of Visual Perception of Developing Fires

An aspect of human responses to fires is perceiving changes in intensity. The nature of fires can make this challenging, as flames and smoke are dynamic and change with time. For developing fires, this is in addition to growth occurring vertically and sometimes horizontally, with the footprint of the fire either remaining the same or increasing in size. The present study investigated how precisely humans could visually detect differences in the intensities and growth rates of simulated fires. Using a similar approach to research with non-symbolic visual quantities, a series of experiments compared the precision of judgments regarding which of two simulated fires was greater in intensity or growing faster in intensity when the footprint was fixed or varied. In addition, participants reported what characteristics they used to make their judgments. Precision was significantly worse when comparing the growth rates versus the intensities of fires, and it was better when the fire footprint varied. This provides initial estimates of the precision of mental representations of fire intensity and growth. In addition, participants reported using multiple characteristics, including the size of flames and smoke produced. The present study indicates that humans can precisely detect differences in the intensities of fires using visual cues, but have difficulty when comparing growth rates. We discuss how this suggests that the growth rate may not be a reliable visual cue used by occupants when responding to fires.

Arthropod Recolonization of Soil Surface Habitat in Post-Fire Mulch Treatments

Increasing size, severity, and human proximity to fires in the western US are driving a need for more effective ecosystem restoration in the immediate post-fire period. Surface treatments, such as mastication of logging slash, reduce erosion and improve soil nutrient and water retention on steep slopes. However, few studies have investigated the impact of these treatments on arthropod communities over time. Our objective was to determine which insect communities return to these treated areas and if the mulch changes the community structure over time. We surveyed arthropod abundance using pitfall traps in mulch treatments in a landscape-scale fire near Flagstaff, Arizona, and a controlled split-plot experiment outside of the larger fire footprint. Predatory beetles were more abundant in mulch in the large landscape treatment, with no differences in abundance in the split plots. Fungivores had no significant mulch preference, and several native bark beetles were more abundant in the untreated sites. We found that the size of the fire footprint and distance to the intact forest matrix likely impact arthropod community composition over time. We were unable to fully evaluate vegetation recovery, but further work will allow us to understand how surface treatments impact the interaction of arthropods and vegetation.

Fire frequency and vulnerability in California

Wildfires pose a large and growing threat to communities across California, and understanding fire vulnerability and impacts can enable more effective risk management. Government hazard maps are often used to identify at-risk areas, but hazard zones and fire experience may have different implications for communities. This analysis of three decades of fire footprints, hazard maps, and census and real estate data shows that communities with high fire experience differ substantially from communities with high fire hazard. High-hazard communities average higher incomes than low- and no-hazard communities; conversely, communities with high fire experience average lower incomes than those with little to no experience. Home values have grown more slowly in communities with high fire experience, translating to differences in total appreciation of $165M-$630M per year relative to communities with no fire experience. Warming over the remainder of the century could add tens of thousands of homes to high-experience zones. This relationship between income and fire experience may be a reflection of the impacts of repeated fires relative to mapped hazards or single fires, or it could point to a relationship between income and the success of fire prevention or suppression. The discrepancies between dimensions indicates that considering fire frequency can support efforts to equitably target risk management resources.

Wildfire damage and contamination to private drinking water wells

AbstractFollowing the 2021 Marshall Fire in Colorado, this study was conducted to better understand private well and plumbing damage and to develop public health guidance. More than 20 post‐fire drinking water well guidance documents with varied recommendations were found. Approximately 227 wells were located in the fire footprint. Seventeen properties were visited, and a subset of wells were sampled for organic and inorganic contaminants. Property debris was also collected. Benzene, toluene, and 19 semi‐volatile organic compounds (SVOCs) were detected in water extracts of property debris. No wells contained volatile organic compound contamination. Two shallow wells (12 and 15 ft) had debris contamination; one well contained notable SVOC contamination. One multi‐home unregulated well system was extensively damaged, lost pressure, and had not been repressurized 11 months after the fire due to financial and technical challenges. Study results highlight the need for follow‐up work to understand well system damage and household response.

An improved spatio-temporal clustering method for extracting fire footprints based on MCD64A1 in the Daxing’anling Area of north-eastern China

Background Understanding the spatio-temporal dynamics associated with a wildfire event is essential for projecting a clear profile of its potential ecological influences. Aims To develop a reliable framework to extract fire footprints from MODIS-based burn products to facilitate the understanding of fire event evolution. Methods This study integrated the Jenks natural breaks classification method and the density-based spatial clustering of applications with noise (DBSCAN) algorithm to extract the fire footprints in Daxing’anling region of China between 2001 and 2006 from MCD64A1 burned area data. Key results The results showed that the fire footprints extracted by the model gained an overall accuracy of 80% in spatial and temporal domains after an intensive validation by using the historical fire records provided by the local agency. The agreement of burned area between the extracted fire patches and the historical fire records for those matched fire points was characterised by an overall determination coefficient R2 at 0.91. Conclusions The proposed framework serves as an efficient and convenient wildfire management tool for areas requiring large-scale and long-term wildfire monitoring. Implications The current framework can be used to create a reliable large-scale fire event database by providing an important alternative for the improvement of field investigation.

Combining financial costs and statistical power to optimize monitoring to detect recoveries of species after megafire

AbstractAimMegafire plays a crucial role in driving the distribution of biodiversity around the world. Long‐term monitoring is vital for understanding how species are impacted immediately by megafire and subsequently respond over time. However, monitoring should be designed with sufficient statistical power to detect impact and recovery. In this study, we developed a simulation framework for optimizing the design of biodiversity monitoring programmes to detect population recoveries after megafire.LocationVictoria, Australia.Time period2019–2020.Major taxa studiedVertebrates.MethodsWe collated species distribution models for 45 priority vertebrates most likely to respond to management after the 2019–2020 megafires in Victoria, Australia. We combined these models with fire severity maps to optimize the location of monitoring sites in and around the fire footprint. We simulated the impact of the megafires on species distributions and modelled plausible recoveries over the next 10 years. Using estimates of detectability for a suite of preferred sampling methods, we simulated monitoring at pairs of burnt and unburnt sites to evaluate the statistical power to detect the modelled recoveries. We tested the sensitivity of power to alternative monitoring designs, rates of recovery and monitoring budgets.ResultsPriority regions to establish monitoring sites varied by taxonomic group. Power to detect population recoveries increased as the monitoring budget increased, as the recovery rate increased and when the proportion of sites in burnt compared with unburnt habitat increased. According to the optimal monitoring design, an AUD $9M budget could detect 90% of recoveries to pre‐fire levels in 40% of species with >80% power. Power was highest for mammals, followed by birds, reptiles and amphibians.Main conclusionsOur simulation approach allowed us to test the relative performance of alternative post‐fire monitoring designs ahead of time. Although we focused on megafire, our approach could easily be applied to detect population recoveries after any large‐scale catastrophic disturbance.

Using wildfire as a management strategy to restore resiliency to ponderosa pine forests in the southwestern United States

AbstractThe long‐term outcome from accelerated forest restoration using resource objective wildfire in combination with fuel management on fire‐excluded landscapes is not well studied. We used simulation modeling to examine long‐term trade‐offs and synergies of alternative land management strategies by combining two wildfire management alternatives with three levels of contemporary forest restoration treatments on a 778,000‐ha landscape over 56 years. We found that managing wildfires for resource objectives diminished the likelihood of irregular fire events over time by making wildfire activity more predictable. Overall, adding resource objective wildfire reduced the proportion of high‐severity fire in relation to total area burned, but increased total area burned and the area of high‐severity fire. We also found resource objective wildfire changed the distribution of high‐severity burn patches by increasing their total number and range, their likelihood of containing disjunct core areas, and their edge complexity. The results suggested that alongside the current pace of active forest management, expanding the fire footprint to achieve low‐cost restoration carries the potential for increased high‐severity fire and associated impacts to ecological values including old forest structure and wildlife habitat. Concurrently, adding resource objective wildfire expanded the footprint of conventional restoration treatments by fivefold, and restoration objectives were achieved in 25 years when managing resource objective wildfires alongside restoration treatments five times the current pace. This study demonstrates the first fire suppression model to replicate local decision making by fire managers during simulated fire events to manage risk by considering both fire proximity to values at risk, and daily weather conditions. The study paves the way for further investigations of the synergies between wildfires and conventional forest restoration to improve resiliency in fire‐excluded pine forests.

Fire ecology for the 21st century: Conserving biodiversity in the age of megafire

Fire ecology for the 21st century: Conserving biodiversity in the age of megafire

Pirra Jungku: Comparison of traditional and contemporary fire practices on Karajarri Country, Western Australia

SummaryTraditional fire practices in Australia’s deserts may have created mosaics of post‐fire seral stages that benefitted some plants and animals. Managing fire to emulate the patterns produced by traditional burning practices is a common objective in contemporary conservation planning in Australia’s deserts. However, the extent to which traditional burning in deserts affected fire regimes across space and time is contested. We aim to contribute to knowledge about the impacts of traditional burning on fire patterns in the Great Sandy Desert, northwest Australia. Our study covered the traditional lands of the Karajarri people, where some families were living a traditional lifestyle on Country until the 1960s. We analysed high‐quality aerial photographs taken over 18,000 km2 of Karajarri Country in the 1940s. Fire footprints up to several years old were mapped from these images, and their spatial characteristics were compared to those of contemporary fire regimes over the same area, visualised using high‐resolution Sentinel satellite imagery. Fires in the 1940s (considered traditional) were more numerous but much smaller than contemporary (2016–2020) fires. The areal extent of recently burnt areas was smaller and the fire frequency was lower in the 1940s. Contemporary fire patterns around cultural sites differed little from fire patterns elsewhere in the landscape, possibly because people were burning over large areas rather than only at localised sites. Our study suggests that Karajarri influenced fire patterns at a landscape scale in the Great Sandy Desert, at least during periods of average rainfall. The findings are helping Karajarri refine fire management goals, for example, by informing the size and dispersion of future burns, and supporting community discussion about fire and culture. Fire management outcomes for plants and animals are being tracked with a biodiversity monitoring program.

Imaging documentation in the on-site investigation of explosion/fire events

Explosion/fire investigation is a procedure that involves significant resources of time and activities. The most important of the basic activities performed by the investigator/investigation team is the on-site research, which, if properly performed, allows the elaboration, foundation, and verification of hypotheses, while playing a defining role in establishing the final conclusions regarding the place of initiation and cause of the event. For these types of phenomena, the on-site investigation is hampered by the damage caused by the event, making it difficult to identify footprints or traces, or by the disruptive effects of the extinguishing products used. The investigation is carried out in the area of the outbreak as well as in all the areas where the fire spread and aims to examine the fire footprint, the set of traces, objects, and materials present in the burnt area, seen in interaction, both with each other and with the surrounding space and environment. Traditional verbal or written methods of presenting evidence or traces collected at the crime scene are no longer sufficient today, as technological advances are also evident in these areas. Important benefits include the coverage of the entire crime scene, which allows for complete and efficient documentation, using spherical or panoramic photography, or the use of spatial, three-dimensional scans. This paper aims to present the important contribution made by on-site documentation activities using SceneCam Forensic imaging scanning equipment, based on a high-resolution (HDR) image capture device capable of capturing spherical, 360° x 180° images at a resolution of up to 50 Megapixels in a single scanning operation (Spheron Cam VR).

The fire regime response of a reintroduced endangered species

Reintroduction and translocation are widely employed actions in restoration ecology. The broad aim of these activities is to re‐establish populations in places where they formerly existed. However, the success of re‐establishment efforts in terms of responses to key ecosystem processes such as natural disturbances like fires has rarely been quantified. Using the iconic and endangered Australian Eastern Bristlebird (Dasyornis brachypterus) as a case study, we quantified associations with fire regime variables in an intact population (surveyed for 17 years) and a translocated population (surveyed for 10 years). Both populations occurred in a similar environment and were surveyed on an (almost) annual basis using the same field protocols. We found that both the intact population and the translocated population of the Eastern Bristlebird were associated with the same key fire regime variable, time since fire, in a broadly similar way. In addition, the probability of species persistence was found to lowest on recently burnt sites. We tentatively suggest that the translocation program has not only successfully re‐established a population of the Eastern Bristlebird but associations with (and resilience to) fire as a key ecological process are similar in both populations. On the basis of our findings, we recommend that in areas where the Eastern Bristlebird occurs prescribed fire management should focus on ensuring there are patches of unburnt vegetation within the fire footprint. This is especially important given the widespread wildfires that have recently occurred throughout south‐eastern Australia.

Low-density aspen seedling establishment is widespread following recent wildfires in the western United States.

Sexual regeneration is increasingly recognized as an important regeneration pathway for aspen in the western United States, a region previously thought to be too dry for seedling establishment except for during unusually wet periods. Because of this historical assumption, information on aspen seedling establishment and factors influencing its occurrence is limited and frequently anecdotal. We conducted a systematic field survey of 15 recent fire footprints that burned in 2018 in the western United States to quantify how common aspen seedling establishment is following fire and to identify factors associated with establishment. We found aspen seedling establishment in 12 of 15 (80%) of fire footprints surveyed, although densities were mostly low. Establishment probability was positively associated with mean annual precipitation and negatively associated with seed-source distance and the density of asexual aspen regeneration. Our results suggest that aspen seedling establishment may be a widespread, if often low-density, feature in postdisturbance areas. Even in low numbers, aspen seedlings may play a disproportionately large role in aspen regeneration ecology, providing adaptive capacity and facilitating local range expansion.

Optimizing landscape‐scale monitoring programmes to detect the effects of megafires

AbstractAimBy virtue of their spatial extent, landscape‐scale monitoring programmes may be well‐suited to support before‐after/control‐impact (BACI) studies of major disturbances such as megafires, but they may only have a few affected sites, reducing statistical power. I tested whether a variety of hypothetical but logistically plausible survey designs could provide statistically powerful assessments of hypothetical but empirically based population responses to megafire.LocationSimulation focused on fire‐prone forests.MethodsI varied the number of affected sites, detection probability, baseline occupancy and species’ responses to fire to create 72 monitoring scenarios. I then simulated 10 years of site occupancy data in which a megafire or other disturbance occurred between years 5 and 6 (n = 500 iterations).ResultsStatistical power to correctly reject the null hypothesis of no population response to megafire was high (mean across all scenarios = 0.78), but power to identify the correct population response (e.g. post‐fire occupancy declined and then recovered) was low (mean = 0.29). Statistical power to not underestimate the effect of a megafire on site occupancy was fairly high (mean = 0.66), but power to accurately estimate site occupancy was low (mean = 0.25). Statistical power increased with the number of affected sites (i.e., sample size) and with the intensity of the focal species’ response to megafire. Case study simulations based on an existing acoustic monitoring programme in the Sierra Nevada, USA, indicate that it is likely to identify Spotted Owl and Black‐backed Woodpecker population responses to megafires. Researchers can use the included simulation tutorial to implement their own power analyses.Main conclusionsLandscape‐scale monitoring programmes can identify population changes following megafires, but cannot reliably produce nuanced results, especially with only five years of post‐fire data. Smaller‐bodied species, which could be studied at more sites, are likely to be better focal species for megafire BACI studies. Aggregating landscape‐scale studies’ sampling coverage across many fire footprints to study the overall effects of megafires—rather than the effects of individual fires—may be a more informative approach.

Aspen seedling establishment, survival, and growth following a high-severity wildfire

Quaking aspen (Populus tremuloides) is an important component of western U.S. forests, however knowledge concerning processes of aspen seedling establishment, survival, and growth is limited and frequently anecdotal. Following a widespread post-fire establishment event in southern Utah, we explored spatial establishment patterns of >1000 aspen seedlings and tracked their survival and growth for two growing seasons. Specifically, we assessed the influence of landscape-level variables, microsite factors, and competition with suckers on aspen seedling establishment, survival, and growth. Aspen seedlings occurred across large areas of the 29,000 ha fire footprint, with an average plot density of 23,033 seedlings ha−1, and establishment more likely at higher elevations and closer to seed sources. Aspen seedlings preferentially established in concave microsites and were tightly associated with burned soil. A total of 33% of tagged seedlings remained alive after two growing seasons. Seedling persistence was strongly impacted by competition with co-occurring aspen suckers, with survival lower for aspen seedlings closer to nearby suckers and seedling growth reduced in plots with high sucker density. Given the long dispersal distances of aspen seeds and the ability of seeds to take advantage of initial post-disturbance conditions, sexual regeneration in aspen may represent an important pathway for maintaining forest resilience and associated ecosystem services, especially following fires with large patches of high burn severity.

Recent bark beetle outbreaks influence wildfire severity in mixed-conifer forests of the Sierra Nevada, California, USA.

In temperate forests, elevated frequency of drought related disturbances will likely increase the incidence of interactions between disturbances such as bark beetle epidemics and wildfires. Our understanding of the influence of recent drought and insect-induced tree mortality on wildfire severity has largely lacked information from forests adapted to frequent fire. A recent unprecedented tree mortality event in California's Sierra Nevada provides an opportunity to examine this disturbance interaction in historically frequent-fire forests. Using field data collected within areas of recent tree mortality that subsequently burned in wildfire, we examined whether and under what conditions wildfire severity relates to severity of prefire tree mortality in Sierra Nevada mixed-conifer forests. We collected data on 180 plots within the 2015 Rough Fire and 2016 Cedar Fire footprints (California, USA). Our analyses identified prefire tree mortality as influential on all measures of wildfire severity (basal area killed by fire, RdNBR, and canopy torch) on the Cedar Fire, although it was less influential than fire weather (relative humidity). Prefire tree mortality was influential on two of three fire-severity measures on the Rough Fire, and was the most important predictor of basal area killed by fire; topographic position was influential on two metrics. On the Cedar Fire, the influence of prefire mortality on basal area killed by fire was greater under milder weather conditions. All measures of fire severity increased as prefire mortality increased up to prefire mortality levels of approximately 30-40%; further increases did not result in greater fire severity. The interacting disturbances shifted a pine-dominated system (Rough Fire) to a cedar-pine-fir system, while the pre-disturbance fir-cedar system (Cedar Fire) saw its dominant species unchanged. Managers of historically frequent-fire forests will benefit from utilizing this information when prioritizing fuels reduction treatments in areas of recent tree mortality, as it is the first empirical study to document a relationship between prefire mortality and subsequent wildfire severity in these systems. This study contributes to a growing body of evidence that the influence of prefire tree mortality on wildfire severity in temperate coniferous forests may depend on other conditions capable of driving extreme wildfire behavior, such as weather.

Propensities of Old Growth, Mature and Regrowth Wet Eucalypt Forest, and Eucalyptus nitens Plantation, to Burn During Wildfire and Suffer Fire-Induced Crown Death

There are conflicting conclusions on how the flammability of wet eucalypt forests changes in the time after disturbances such as logging or wildfire. Some conclude that forests are most flammable in the decades following disturbance, while others conclude that disturbance has no effect on flammability. The comparative flammability of Eucalyptus nitens plantations in the same environment as wet eucalypt forest is not known. We determined fire incidence and fire severity in regrowth, mature and old growth wet eucalypt forest, and E. nitens plantation, in the Huon Valley, Tasmania after the January–February 2019 wildfire. To control for topographic variation and fire weather, we randomly selected sites within the fire footprint, then randomly located a paired site for each in different forest types in the same topographic environment within 3 km. Each pair of sites was burned on the same day. Old growth forest and plantations were the least likely to burn. Old growth and mature forest exhibited scorched eucalypt crowns to a much lesser degree than regrowth forests. In a comparison of paired sites, plantation forest was less likely to burn than combined mature and old growth forests, but in all cases of detected ignition the canopy of plantation was scorched. The lower flammability of older forests, and their importance as an increasing store of carbon, suggests that a cessation of logging outside plantations might have considerable benefits.

Rethinking fire‐adapted species in an altered fire regime

AbstractNovel combinations of fire regime and forest type are emerging in areas affected by climate change, fire exclusion, and other stressors. Species interactions following wildfire in these areas are not well understood. In Sierra Nevada mixed‐conifer forests, large patches of stand‐replacing fire were once rare but are becoming increasingly prevalent and are quickly revegetated by native shrubs. There is uncertainty as to which tree species are best adapted to recover in the resulting post‐fire environments. We introduce a conceptual framework for understanding how the altered fire regime in the Sierra Nevada may affect species composition. We investigate an understudied link in this framework: how juvenile ponderosa pine (Pinus ponderosa) and white fir (Abies lowiana) growth and mortality rates are affected by shrub competition following stand‐replacing fire. We measured juvenile conifer growth in relation to shrub competition in five fire footprints ranging from 8 to 35 yr old and >400 ha in size. To test whether reductions in conifer growth may lead to increased mortality, we also evaluated how recent tree growth predicts mortality of similarly aged juvenile trees in nearby managed stands. We found that juvenile ponderosa pine growth was negatively associated with nearby shrub competition, but white fir growth was not. Both species grew slower preceding mortality, with a steeper relationship found in ponderosa pine. Across the range of shrub competition in this study, expected pine annual relative growth rate varied from 0.27 to 0.10, which corresponded to an eleven‐fold difference in annual probability of mortality (0.1–1.1%, respectively). These results show that ponderosa pine is sensitive to shrub competition following wildfire in terms of both growth and survival while white fir is less sensitive, presumably due to its high shade tolerance. Though pines are generally considered fire‐adapted, this study argues that post‐fire species interactions in a novel fire regime may exacerbate the already shifting species composition toward shade‐tolerant species, which are less well adapted to survive through future fires and to persist in future drier, warmer climates.

Previous fires and roads limit wildfire growth in Arizona and New Mexico, U.S.A.

Fire shapes landscapes long after the flames are extinguished by leaving legacies of heterogeneous fuel mosaics, species composition patterns, and age classes. Fire perimeters have received little research attention, but their locations have implications for both landscape patterns and processes, including vegetation structure and subsequent disturbances. In this study, we focused on the role of previous wildfires and roads in limiting wildfire growth and influencing the pattern of fire at a regional scale. Using fire perimeter data from the U.S. Southwest, we asked (1) to what degree previous wildfires and roads limit the spread of subsequent fires, (2) what the temporal patterns are in fire perimeter limitations, in terms of time-since-fire and stability of patterns over time, and (3) whether limitations to fire spread differ across National Forests and topographic variables. We found strong evidence that previous fires and roads play a role in limiting subsequent fire progression. Of fires that spatially intersected previous wildfires, 8.7% of fire perimeters aligned only with previous wildfire perimeters. On average, 25.7% of fire perimeters aligned only with roads, compared to 11.6% when fires were randomly shifted, and road alignments tended to be on less steep slopes than wildfire alignments. More than 60% of fire perimeter alignments occurred when time since the previous fire was 5 years or less. Finally, results varied by National Forest; the Coconino and Kaibab National Forests, which have fairly flat terrain, had high percentages of fire-road alignments while the Gila National Forest, which contains a large amount of Wilderness, had the most fire-fire alignments. As more fires burn, fire interactions are likely to increase, and previous fire footprints may have more opportunity to act as fuel breaks or control points for subsequent fires.

Timber Losses from West Fork Complex Fire in Southwest Colorado

Abstract This article provides an assessment of fire effects on timber burned in the West Fork Complex fire area, located in the San Juan Mountains of Colorado. The West Fork Complex fire burned 109,615 acres in 2013, and suppression costs alone totaled $33.2 million. Much of the fire occurred in spruce–fir forests that were previously affected by spruce beetle (Dendroctonus rufipennis). Several timber sales were actively occurring within the fire footprint, and more were anticipated to begin in subsequent years. To provide a more accurate valuation estimate, base log stumpage data from 2003 through 2017 were included in this study to show high degrees of variation over time. With base log stumpage values determined, estimates of total hundred cubic feet of each significant species were calculated using geospatial and forest inventory analysis data. This study determined the timber value loss resulting from the coupled disturbance events of the spruce beetle epidemic and a wildland fire to be $19,083,102. This estimate will allow for a more accurate valuation of the actual damage resulting from the West Fork Complex fire. This study may also be useful in supporting the literary basis for salvage and fuels management after a beetle outbreak to prevent such timber value losses from occurring.