Research Database
Displaying 1 - 14 of 14
Simulated Future Shifts in Wildfire Regimes in Moist Forests of Pacific Northwest, USA
Year: 2024
Fire is an integral natural disturbance in the moist temperate forests of the Pacific Northwest of the United States, but future changes remain uncertain. Fire regimes in this climatically and biophysically diverse region are complex, but typically climate limited. One challenge for interpreting potential changes is conveying projection uncertainty. Using projections of Energy Release Component (ERC) derived from 12 global climate models (GCM) that vary in performance relative to the region's contemporary climate, we simulated thousands of plausible fire seasons with the stochastic spatial…
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…
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…
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…
Publication Type: Journal Article
Managing fire-prone forests in a time of decreasing carbon carrying capacity
Year: 2024
Changing climatic conditions are increasing overstory tree mortality in forests globally. This restructuring of the distribution of biomass is making already flammable forests more combustible, posing a major challenge for managing the transition to a lower biomass state. In western US dry conifer forests, tree density resulting from over a century of fire-exclusion practices has increased the risk of high-severity wildfire and susceptibility to climate-driven mortality. Reducing dead fuel loads will require new approaches to mitigate risk to the remaining live trees by preparing forests to…
Publication Type: Journal Article
Hydrometeorology-wildfire relationship analysis based on a wildfire bivariate probabilistic framework in different ecoregions of the continental United States
Year: 2024
Wildfires are a natural part of the ecosystem in the U.S.. It is vital to classify wildfires using a comprehensive approach that simultaneously considers wildfire activity (the number of wildfires) and burned area. On this basis, the influence of hydrometeorological variables on wildfires can be further analyzed. Therefore, this study first classified wildfire types using a wildfire bivariate probability framework. Then, by considering six hydrometeorological variables, the dominant hydrometeorological variables for different wildfire types in 17 ecoregions of the United States were…
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…
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…
Publication Type: Journal Article
Increasing prevalence of hot drought across western North America since the 16th century
Year: 2024
Across western North America (WNA), 20th-21st century anthropogenic warming has increased the prevalence and severity of concurrent drought and heat events, also termed hot droughts. However, the lack of independent spatial reconstructions of both soil moisture and temperature limits the potential to identify these events in the past and to place them in a long-term context. We develop the Western North American Temperature Atlas (WNATA), a data-independent 0.5° gridded reconstruction of summer maximum temperatures back to the 16th century. Our evaluation of the WNATA with existing…
Publication Type: Journal Article
The impacts of rising vapour pressure deficit in natural and managed ecosystems
Year: 2024
An exponential rise in the atmospheric vapour pressure deficit (VPD) is among the most consequential impacts of climate change in terrestrial ecosystems. Rising VPD has negative and cascading effects on nearly all aspects of plant function including photosynthesis, water status, growth and survival. These responses are exacerbated by land–atmosphere interactions that couple VPD to soil water and govern the evolution of drought, affecting a range of ecosystem services including carbon uptake, biodiversity, the provisioning of water resources and crop yields. However, despite the…
Publication Type: Journal Article
Drought triggers and sustains overnight fires in North America
Year: 2024
Overnight fires are emerging in North America with previously unknown drivers and implications. This notable phenomenon challenges the traditional understanding of the ‘active day, quiet night’ model of the diurnal fire cycle1,2,3 and current fire management practices4,…
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…
Publication Type: Journal Article
Anthropogenic climate change has reduced drought recovery probabilities across the western US
Year: 2024
During drought, resource managers want to know when the drought will end to make informed management decisions. However, as anthropogenic climate change has intensified drought conditions, we hypothesize it has affected drought recovery. Here, we leverage monthly self-calibrating Palmer Drought Severity Index data across the western US derived from observations and climate models, and quantify the probability of drought recovery following severe drought. We find that the probability of drought recovery is ~25–50% lower in recent decades (2000–2021) than in the historical record (1901–1980),…
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