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Research Database

Displaying 41 - 60 of 214

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…
Fire Effects and Fire Ecology, Mixed-Conifer Management
regeneration, disturbance, post-fire, fire severity
Publication Type: Journal Article

Changing fire regimes and nuanced impacts on a critically imperiled species

Year: 2024
Wildfire activity throughout western North America is increasing which can have important consequences for species persistence. Native species have evolved disturbance-adapted traits that confer resilience to natural disturbance provided disturbances operate within their historical range of variability. This resilience can erode as disturbance regimes change and begin operating outside this range. We assessed wildfire impacts during 1987–2018 on the northern spotted owl, an imperiled species with complex relationships with late and early seral forest in the Pacific Northwest, USA. We analyzed…
Fire Effects and Fire Ecology, Fire History, Fish and Wildlife Habitat
wildlife, fire regimes
Publication Type: Journal Article

Climate limits vegetation green-up more than slope, soil erodibility, and immediate precipitation following high-severity wildfire

Year: 2024
BackgroundIn the southwestern United States, post-fire vegetation recovery is increasingly variable in forest burned at high severity. Many factors, including temperature, drought, and erosion, can reduce post-fire vegetation recovery rates. Here, we examined how year-of-fire precipitation variability, topography, and soils influenced post-fire vegetation recovery in the southwestern United States as measured by greenness to determine whether erosion-related factors would have persistent effects in the longer post-fire period. We modeled relationships between post-fire vegetation and these…
Climate Change and Fire, Fire Effects and Fire Ecology, Soils and Woody Debris
post-fire, fire severity
Publication Type: Journal Article

Parcel-Level Risk Affects Wildfire Outcomes: Insights from Pre-Fire Rapid Assessment Data for Homes Destroyed in 2020 East Troublesome Fire

Year: 2024
Parcel-level risk (PLR) describes how wildfire risk varies from home to home based on characteristics that relate to likely fire behavior, the susceptibility of homes to fire, and the ability of firefighters to safely access properties. Here, we describe the WiRē Rapid Assessment (RA), a parcel-level rapid wildfire risk assessment tool designed to evaluate PLR with a small set of measures for all homes in a community. We investigate the relationship between 2019 WiRē RA data collected in the Columbine Lake community in Grand County, Colorado, and whether assessed homes were destroyed in the…
Communicating about Fire, Risk Assessment and Analysis, Social and Community Impacts of Fire
post-fire, mitigation
Publication Type: Journal Article

Quantifying Aspect-Dependent Snowpack Response to High-Elevation Wildfire in the Southern Rocky Mountains

Year: 2024
Increasing wildfire frequency and severity in high-elevation seasonal snow zones presents a considerable water resource management challenge across the western United States (U.S.). Wildfires can affect snowpack accumulation and melt patterns, altering the quantity and timing of runoff. While prior research has shown that wildfire generally increases snow melt rates and advances snow disappearance dates, uncertainties remain regarding variations across complex terrain and the energy balance between burned and unburned areas. Utilizing paired in situ data sources within the 2020 Cameron Peak…
Climate Change and Fire, Fire Effects and Fire Ecology
post-fire, wildfire and water
Publication Type: Journal Article

Fire history in northern Sierra Nevada mixed conifer forests across a distinct gradient in productivity

Year: 2024
BackgroundUnderstanding the role of fire in forested landscapes is fundamental to fire reintroduction efforts, yet few studies have examined how fire dynamics vary in response to interactions between local conditions, such as soil productivity, and more broadscale changes in climate. In this study, we examined historical fire frequency, seasonality, and spatial patterning in mixed conifer forests across a distinct gradient of soil productivity in the northern Sierra Nevada. We cross-dated 46 different wood samples containing 377 fire scars from 6 paired sites, located on and off of…
Fire History, Mixed-Conifer Management, Soils and Woody Debris
fire regimes, drought
Publication Type: Journal Article

Western larch regeneration more sensitive to wildfire-related factors than seasonal climate variability

Year: 2024
To understand the impacts of changing climate and wildfire activity on conifer forests, we studied how wildfire and post-fire seasonal climate conditions influence western larch (Larix occidentalis) regeneration across its range in the northwestern US. We destructively sampled 1651 seedlings from 57 sites across 32 fires that burned at moderate or high severity between 2000 and 2015; sites were within 100 m of reproductively mature western larch. Using dendrochronological methods, we estimated germination years of seedlings to calculate annual recruitment rates. We used boosted…
Climate Change and Fire, Mixed-Conifer Management
post-fire, modeling
Publication Type: Journal Article

Characterizing post-fire delayed tree mortality with remote sensing: sizing up the elephant in the room

Year: 2024
BackgroundDespite recent advances in understanding the drivers of tree-level delayed mortality, we lack a method for mapping delayed mortality at landscape and regional scales. Consequently, the extent, magnitude, and effects of delayed mortality on post-fire landscape patterns of burn severity are unknown. We introduce a remote sensing approach for mapping delayed mortality based on post-fire decline in the normalized burn ratio (NBR). NBR decline is defined as the change in NBR between the first post-fire measurement and the minimum NBR value up to 5 years post-fire for each pixel…
Fire Effects and Fire Ecology
fire refugia, post-fire, tree mortality
Publication Type: Journal Article

Pre-contact Indigenous fire stewardship: a research framework and application to a Pacific Northwest temperate rainforest

Year: 2024
Fire is a key disturbance process that shapes the structure and function of montane temperate rainforest in the Pacific Northwest (PNW). Recent research is revealing more frequent historical fire activity in the western central Cascades than expected by conventional theory. Indigenous peoples have lived in the PNW for millennia. However, Indigenous people's roles in shaping vegetation mosaics in montane temperate forests of the PNW has been overlooked, despite archaeological evidence of long-term, continuous human use of these landscapes. In this paper, we present a generalizable research…
Fire History, Fuels and Fuel Treatments
indigenous fire stewardship, fire regimes
Publication Type: Journal Article

Centering socioecological connections to collaboratively manage post- fire vegetation shifts

Year: 2024
Climate  change  is  altering  fire  regimes  and  post-fire  conditions,  contributing  to  relatively  rapid  transformation  of  landscapes  across  the  western  US.  Studies  are  increasingly  documenting  post-fire  vegetation  transitions,  particularly  from  forest  to  non-  forest conditions or from sagebrush to invasive annual grasses. The prevalence of climate-driven, post-fire vegetation transitions is likely to increase…
Climate Change and Fire, Fire Effects and Fire Ecology
post-fire, management
Publication Type: Journal Article

Moderating effects of past wildfire on reburn severity depend on climate and initial severity in Western US forests

Year: 2024
Rising global fire activity is increasing the prevalence of repeated short-interval burning (reburning) in forests worldwide. In forests that historically experienced frequent-fire regimes, high-severity fire exacerbates the severity of subsequent fires by increasing prevalence of shrubs and/or by creating drier understory conditions. Low- to moderate-severity fire, in contrast, can moderate future fire behavior by reducing fuel loads. The extent to which previous fires moderate future fire severity will powerfully affect fire-prone forest ecosystem trajectories over the next century. Further…
Fire Effects and Fire Ecology, Fire History, Restoration and Hazardous Fuel Reduction
fire severity, post-fire, weather
Publication Type: Journal Article

When do contemporary wildfires restore forest structures in the Sierra Nevada?

Year: 2024
Background: Following a century of fire suppression in western North America, managers use forest restoration treatments to reduce fuel loads and reintroduce key processes like fire. However, annual area burned by wildfire frequently outpaces the application of restoration treatments. As this trend continues under climate change, it is essential that we understand the effects of contemporary wildfires on forest ecosystems and the extent to which post-fire structures are meeting common forest restoration objectives. In this study, we used airborne lidar to evaluate fire effects across yellow…
Fire Effects and Fire Ecology, Restoration and Hazardous Fuel Reduction
fire severity, post-fire
Publication Type: Journal Article

Historical pyrodiversity in Douglas-fir forests of the southern Cascades of Oregon, USA

Year: 2024
Our understanding of forest dynamics and successional pathways in coastal Douglas-fir (Pseudotsuga menziesii var menziesii) forests with relatively frequent mixed-severity fires is limited by a lack of annually precise dendroecological reconstructions that combine records of historical fires and tree establishment. The processes by which old-forest heterogeneity developed under historical fire regimes with recurrent low- and moderate-severity fires has not been well studied at fine temporal scales and across spatial scales. We developed crossdated multi-century records of fire and…
Fire Effects and Fire Ecology, Fire History, Prescribed Burning
indigenous fire stewardship, fire regimes
Publication Type: Journal Article

A fast spectral recovery does not necessarily indicate post-fire forest recovery

Year: 2024
BackgroundClimate change has increased wildfire activity in the western USA and limited the capacity for forests to recover post-fire, especially in areas burned at high severity. Land managers urgently need a better understanding of the spatiotemporal variability in natural post-fire forest recovery to plan and implement active recovery projects. In burned areas, post-fire “spectral recovery”, determined by examining the trajectory of multispectral indices (e.g., normalized burn ratio) over time, generally corresponds with recovery of multiple post-fire vegetation types, including trees and…
Fire Effects and Fire Ecology, Restoration and Hazardous Fuel Reduction
post-fire, modeling, remote sensing
Publication Type: Journal Article

Fuel constraints, not fire weather conditions, limit fire behavior in reburned boreal forests

Year: 2024
Fire frequency in boreal forests has increased via longer burning seasons, drier conditions, and higher temperatures. However, fires have historically self-regulated via fuel limitations, mediating the effects of changes in climate and fire weather. Early post-fire boreal forests (10–15 years postfire) are often dominated by mixed conifer-broadleaf or broadleaf regeneration, considered less flammable due to the higher foliar moisture of broadleaf trees and shrubs compared to their more intact conifer counterparts. However, the strength of self-regulation in the context of changing fire…
Fire Effects and Fire Ecology, Fire History, Fuels and Fuel Treatments
regeneration, post-fire, fire behavior
Publication Type: Journal Article

Indigenous pyrodiversity promotes plant diversity

Year: 2024
Pyrodiversity (temporally and spatially diverse fire histories) is thought to promote biodiversity by increasing environmental heterogeneity and replicating Indigenous fire regimes, yet studies of pyrodiversity-biodiversity relationships from areas under active Indigenous fire stewardship are rare. Here, we explored whether Indigenous pyrodiversity promoted plant richness and diversity in an arid ecosystem from north-western Australia. We selected landscapes that ranged from highly pyrodiverse and under active Indigenous burning to more coarse-scale and less diverse mosaics under lightning…
Fire Effects and Fire Ecology, Social and Community Impacts of Fire
indigenous fire stewardship, biodiversity, fire regimes
Publication Type: Journal Article

Patterns, drivers, and implications of postfire delayed tree mortality in temperate conifer forests of the western United States

Year: 2024
Conifer forest resilience may be threatened by increasing wildfire activity and compound disturbances in western North America. Fire refugia enhance forest resilience, yet may decline over time due to delayed mortality—a process that remains poorly understood at landscape and regional scales. To address this uncertainty, we used high-resolution satellite imagery (5-m pixel) to map and quantify delayed mortality of conifer tree cover between 1 and 5 years postfire, across 30 large wildfires that burned within three montane ecoregions in the western United States. We used statistical models to…
Fire Effects and Fire Ecology
post-fire, resilience, tree mortality, fire severity
Publication Type: Journal Article

Prefire Drought Intensity Drives Postfire Recovery and Mortality in Pinus monticola and Pseudotsuga menziesii Saplings

Year: 2024
Increasing frequency of droughts and wildfire are sparking concerns that these compounded disturbance events are pushing forested ecosystems beyond recovery. An improved understanding of how compounded events affect tree physiology and mortality is needed given the reliance of fire management planning on accurate estimates of postfire tree mortality. In this study, we use a toxicological dose-response approach to quantify the impact of variable-intensity drought and fire on the physiology and mortality of Pinus monticola and Pseudotsuga menziesii saplings. We show that the…
Fire Effects and Fire Ecology
drought, post-fire, disturbance
Publication Type: Journal Article

Climate influences on future fire severity: a synthesis of climate-fire interactions and impacts on fire regimes, high-severity fire, and forests in the western United States

Year: 2023
Background Increases in fire activity and changes in fire regimes have been documented in recent decades across the western United States. Climate change is expected to continue to exacerbate impacts to forested ecosystems by increasing the frequency, size, and severity of wildfires across the western United States (US). Warming temperatures and shifting precipitation patterns are altering western landscapes and making them more susceptible to high-severity fire. Increases in large patches of high-severity fire can result in significant impacts to landscape processes and ecosystem function…
Climate Change and Fire, Fire Effects and Fire Ecology, Fire History
synthesis, fire regimes, resilience
Publication Type: Journal Article

Modification of Soil Hydroscopic and Chemical Properties Caused by Four Recent California, USA Megafires

Year: 2023
While it is well known that wildfires can greatly contribute to soil water repellency by changing soil chemical composition, the mechanisms of these changes are still poorly understood. In the past decade, the number, size, and intensity of wildfires have greatly increased in the western USA. Recent megafires in California (i.e., the Dixie, Beckwourth Complex, Caldor, and Mosquito fires) provided us with an opportunity to characterize pre- and post-fire soils and to study the effects of fires on soil water repellency, soil organic constituents, and connections between the two. Water drop…
Soils and Woody Debris
post-fire, wildland fire
Publication Type: Journal Article