Research Database
Displaying 41 - 60 of 191
Disentangling drivers of annual grass invasion: Abiotic susceptibility vs. fire-induced conversion to cheatgrass dominance in the sagebrush biome
Year: 2024
Invasive annual grasses are often facilitated by fire, yet they can become ecologically dominant in susceptible locations even in the absence of fire. We used an extensive vegetation plot database to model susceptibility to the invasive annual grass cheatgrass (Bromus tectorum L.) in the sagebrush biome as a function of climate and soil water availability variables. We built random forest models predicting cheatgrass presence or dominance (>15 % relative cover) under unburned (37,219 plots) and burned conditions (6340 plots). We mapped predicted probability of cheatgrass…
Publication Type: Journal Article
Drought before fire increases tree mortality after fire
Year: 2024
Fire and drought are expected to increase in frequency and severity in temperate forests due to climate change. To evaluate whether drought increases the likelihood of post-fire tree mortality, we used a large database of tree survival and mortality from 32 years of wildland fires covering four dominant western North American conifers. We used Bayesian hierarchical modeling to predict the probability of individual tree mortality after fire based on species—Pinus contorta (lodgepole pine), Abies concolor (white fir), Pseudotsuga menziesii (Douglas-fir), and Pinus…
Publication Type: Journal Article
Nonstructural carbohydrates explain post-fire tree mortality and recovery patterns
Year: 2024
Trees use nonstructural carbohydrates (NSCs) to support many functions, including recovery from disturbances. However, NSC’s importance for recovery following fire and whether NSC depletion contributes to post-fire delayed mortality are largely unknown. We investigated how fire affects NSCs based on fire-caused injury from a prescribed fire in a young Pinus ponderosa (Lawson & C. Lawson) stand. We assessed crown injury (needle scorch and bud kill) and measured NSCs of needles and inner bark (i.e., secondary phloem) of branches and main stems of trees subject to fire and at an…
Publication Type: Journal Article
Rare and highly destructive wildfires drive human migration in the U.S.
Year: 2024
The scale of wildfire impacts to the built environment is growing and will likely continue under rising average global temperatures. We investigate whether and at what destruction threshold wildfires have influenced human mobility patterns by examining the migration effects of the most destructive wildfires in the contiguous U.S. between 1999 and 2020. We find that only the most extreme wildfires (258+ structures destroyed) influenced migration patterns. In contrast, the majority of wildfires examined were less destructive and did not cause significant changes to out- or in-migration. These…
Economic Impacts of Fire, Public Perceptions of Fire and Smoke, Social and Community Impacts of Fire
Publication Type: Journal Article
Pile burns as a proxy for high severity wildfire impacts on soil microbiomes
Year: 2024
Wildfires in the western US are increasing in frequency, size, and severity. These disturbances alter soil microbiome structure and function, with greater fire severity leading to more pronounced impacts to bacterial, archaeal, and fungal communities. These changes have implications for the provisioning of microbially-mediated ecosystem services (e.g., carbon sequestration, clean water supplies) typically associated with forested watersheds. Challenges in sampling wildfire-impacted areas immediately post-burn have limited our assessment of short-term (i.e., days to weeks) changes in the soil…
Publication Type: Journal Article
Landsat assessment of variable spectral recovery linked to post-fire forest structure in dry sub-boreal forests
Year: 2024
Forest disturbances such as wildfires can dramatically alter forest structure and composition, increasing the likelihood of ecosystem changes. Up-to-date and accurate measures of post-disturbance forest recovery in managed forests are critical, particularly for silvicultural planning. Measuring the live and dead vegetation post-fire is challenging because areas impacted by wildfire may be remote, difficult to access, and/or dangerous to survey. The difficulties of post-fire monitoring are compounded by the global increase in the frequency and severity of disturbances, as expansion of…
Publication Type: Journal Article
‘Mind the Gap’—reforestation needs vs. reforestation capacity in the western United States
Year: 2024
Tree establishment following severe or stand-replacing disturbance is critical for achieving U.S. climate change mitigation goals and for maintaining the co-benefits of intact forest ecosystems. In many contexts, natural post-fire tree regeneration is sufficient to maintain forest cover and associated ecosystem services, but increasingly the pattern and scale of disturbance exceeds ecological thresholds and active reforestation may be warranted. Our capacity to plant trees, however, is not keeping pace with reforestation needs. This shortfall is uniquely apparent in the western U.S., where…
Publication Type: Journal Article
The geography of social vulnerability and wildfire occurrence (1984–2018) in the conterminous USA
Year: 2024
Wildfire is increasing in frequency, extent, and severity in many parts of the USA. Considering the unequal burden of natural hazards on socially vulnerable populations, we ask here, how are characteristics of social vulnerability associated with wildfire occurrence nationwide, at different scales and across differing levels of wildland–urban interface development? To answer this question, we first identify all non-urban census tracts in the USA that have experienced a wildfire since 1984. Using 26 different measures of social vulnerability, we compare these tracts to non-urban census tracts…
Publication Type: Journal Article
Trees have similar growth responses to first-entry fires and reburns following long-term fire exclusion
Year: 2024
Managing fire ignitions for resource benefit decreases fuel loads and reduces the risk of high-severity fire in fire-suppressed dry conifer forests. However, the reintroduction of low-severity wildfire can injure trees, which may decrease their growth after fire. Post-fire growth responses could change from first-entry fires to reburns, as first-entry fires reduce fuel loads and the vulnerability among trees to fire effects, which may result in trees sustaining less damage during reburns. To determine whether trees had growth responses that varied from first-entry fires to reburns, we cored…
Publication Type: Journal Article
Before the fire: predicting burn severity and potential post-fire debris-flow hazards to conservation populations of the Colorado River Cutthroat Trout (Oncorhynchus clarkii pleuriticus)
Year: 2024
Background: Colorado River Cutthroat Trout (CRCT; Oncorhynchus clarkii pleuriticus) conservation populations may be at risk from wildfire and post-fire debris flows hazards. Aim: To predict burn severity and potential post-fire debris flow hazard classifications to CRCT conservation populations before wildfires occur. Methods: We used remote sensing, spatial analyses, and machine learning to model 28 wildfire incidents (2016–2020) and spatially predict burn severity from pre-wildfire environmental factors to evaluate the likelihood…
Publication Type: Journal Article
Fire severity drives understory community dynamics and the recovery of culturally significant plants
Year: 2024
Anthropogenic influences are altering fire regimes worldwide, resulting in an increase in the size and severity of wildfires. Simultaneously, throughout western North America, there is increasing recognition of the important role of Indigenous fire stewardship in shaping historical fire regimes and fire-adapted ecosystems. However, there is limited understanding of how ecosystems are affected by or recover from contemporary “megafires,” particularly in terms of understory plant communities that are critical to both biodiversity and Indigenous cultures. To address this gap, our collaborative…
Publication Type: Journal Article
Prescribed fire increases forage mineral content in grazed rangeland
Year: 2024
BackgroundSustainable rangeland management balances production and conservation. While a broad literature describes the conservation benefits of prescribed fire, benefits for livestock production have emerged more slowly. Mineral nutrition is important for livestock health and performance, but the impact of prescribed fire on mineral concentration of forages, especially in the northern US Great Plains, remains unknown.AimsWe investigated how burning affects the mineral concentration of forage early and late in the growing season.MethodsData…
Publication Type: Journal Article
Montane springs provide regeneration refugia after high-severity wildfire
Year: 2024
In the mountainous regions of the Western United States, increasing wildfire activity and climate change are putting forests at risk of regeneration failure and conversion to non-forests. During periods with unfavorable climatic conditions, locations that are suitable for post-fire tree regeneration (regeneration refugia) may be essential for forest recovery. These refugia could provide scattered islands of recovering forest from which broader forest recovery may be facilitated. Spring ecosystems provide cool and wet microsites relative to the surrounding landscape and may act as regeneration…
Publication Type: Journal Article
Wildland–Urban Interface: Definition and Physical Fire Risk Mitigation Measures, a Systematic Review
Year: 2023
Due to the associated fire risk, the wildland–urban interface (WUI) has drawn the attention of researchers and managers from a range of backgrounds. From a land management point of view, it is important to identify the WUI to determine areas to prioritise for fire risk prevention. It is also important to know the fire risk mitigation measures available to select the most appropriate for each specific context. In this systematic review, definitions of the WUI were investigated and physical mitigation measures for reducing the risk of fire were examined from a land management perspective. The…
Publication Type: Journal Article
Factors influencing flood risk mitigation after wildfire: Insights for individual and collective action after the 2010 Schultz Fire
Year: 2023
Post-fire flooding is of significant concern in the U.S. Southwest, where burned areas can drastically alter local hydrology to increase the risk of floods and debris flows, posing new and dynamic flood risk to communities downslope that necessitate coordinated response across jurisdictional boundaries. However, limited research explores how residents in affected communities respond to post-fire flood risk, both individually and collectively. We address this need by exploring factors that may influence the uptake of individual and collective actions for post-fire flood mitigation after an…
Publication Type: Journal Article
Non-native plant invasion after fire in western USA varies by functional type and with climate
Year: 2023
Invasions by non-native plant species after fire can negatively affect important ecosystem services and lead to invasion-fire cycles that further degrade ecosystems. The relationship between fire and plant invasion is complex, and the risk of invasion varies greatly between functional types and across geographic scales. Here, we examined patterns and predictors of non-native plant invasion following fire across the western United States. We specifically analyzed how the abundance of non-native plants after fire was related to fire characteristics and environmental conditions, such as climate…
Publication Type: Journal Article
Burnover events identified during the 2018 Camp Fire
Year: 2023
Background: The Camp Fire burned through communities in Butte County, California, on 8 November 2018. The fire destroyed over 18 000 structures and caused 85 fatalities, mostly within the first 12 h of the incident. Aims: A post-fire case study was conducted to learn from the devastating incident. Methods: The case study was supported by detailed first-hand accounts from 157 first responders, photos and videos, first responder radio logs, and other field data. Subsequent analysis and data integration yielded a timeline reconstruction of the first 24 h of the entire event, as well as…
Publication Type: Journal Article
The analysis of traffic data of wildfire evacuation: the case study of the 2020 Glass Fire
Year: 2023
Evacuation is a crucial policy to mitigate wildfire impacts. Understanding traffic dynamics during a wildfire evacuation can help authorities to improve in improving emergency management plans, thus improving life safety. In this study, we developed a methodology to extract historical traffic data from vehicle detector stations and automate the analysis of traffic dynamics for actual wildfire evacuations. This has been implemented in an open-access tool called Traffic Dynamic Analyser (TDA) which generates speed-density and flow-density relationships from data using both commonly used…
Publication Type: Journal Article
Higher burn severity stimulates postfire vegetation and carbon recovery in California
Year: 2023
As the climate continues to warm, the severity of wildfires is increasing. However, the potential impact of higher burn severity on ecosystem resilience and regional carbon balance is still not clear. There are ongoing debates regarding whether increased burn severity stimulates or delays postfire vegetation and carbon recovery. In this study, we utilized remote sensing data to analyze burn severity and vegetation observations, as well as model simulations to assess wildfire carbon emissions and ecosystem carbon fluxes. Our focus was on examining the dynamics of vegetation and carbon flux…
Publication Type: Journal Article
Unprotected lands: A case study of a wildland-urban interface community in “No-Man's land”
Year: 2023
There are areas of the United States that have no formalized fire protection. These lands are colloquially referred to as “no-man’s land” but are recognized by many land management agencies as unprotected lands. Unprotected lands are generally rural landscapes and exist in areas that are sparsely populated and lack formalized fire protection. In some cases, lands that are designated as wildland-urban interface are comprised of significant portions of unprotected lands. Currently, there has been little in the way of research completed that pertains to the overall amount of land that is…
Publication Type: Journal Article