Research Database
Displaying 41 - 60 of 128
Forecasting natural regeneration of sagebrush after wildfires using population models and spatial matching
Year: 2023
Context Addressing ecosystem degradation in the Anthropocene will require ecological restoration across large spatial extents. Identifying areas where natural regeneration will occur without direct resource investment will improve scalability of restoration actions. Objectives An ecoregion in need of large scale restoration is the Great Basin of the Western US, where increasingly large and frequent wildfires threaten ecosystem integrity and its foundational shrub species. We develop a framework to forecast where post-wildfire regeneration of sagebrush cover (Artemisia spp.) is likely to occur…
Publication Type: Journal Article
The century-long shadow of fire exclusion: Historical data reveal early and lasting effects of fire regime change on contemporary forest composition
Year: 2023
Historical logging practices and fire exclusion have reduced the proportion of pine in mixed-conifer forests of the western United States. To better understand pine’s decline, we investigate the impact of historical logging on the tree regeneration layer and subsequent stand development over almost a century of fire exclusion. We use a unique dataset derived from contemporary (∼2016) remeasurement of 440 historical quadrats (∼4m2) in the central Sierra Nevada, California, in which overstory trees, tree regeneration, and microsite conditions were measured and mapped both before and after…
Publication Type: Journal Article
Patterns and drivers of early conifer regeneration following stand-replacing wildfire in Pacific Northwest (USA) temperate maritime forests
Year: 2023
Tree regeneration is a critical mechanism of forest resilience to stand-replacing wildfire (i.e., where fire results in >90 % tree mortality), and post-fire regeneration is a concern worldwide as the climate becomes warmer. Although post-fire tree regeneration has been relatively well-studied in fire-prone forests across western North America, it is less understood in fire regimes characterized by large patches of stand-replacing fire at long intervals, such as the nominally infrequent, high-severity fire regimes of the western Cascades of Washington and northern Oregon,…
Publication Type: Journal Article
The eco-evolutionary role of fire in shaping terrestrial ecosystems
Year: 2023
1. Fire is an inherently evolutionary process, even though much more emphasis has been given to ecological responses of plants and their associated communities to fire. 2. Here, we synthesize contributions to a Special Feature entitled ‘Fire as a dynamic ecological and evolutionary force’ and place them in a broader context of fire research. Topics covered in this Special Feature include a perspective on the im-pacts of novel fire regimes on differential forest mortality, discussions on new ap-proaches to investigate vegetation-fire feedbacks and resulting plant syndromes,…
Publication Type: Journal Article
Consistent spatial scaling of high-severity wildfire can inform expected future patterns of burn severity
Year: 2023
Increasing wildfire activity in forests worldwide has driven urgency in understanding current and future fire regimes. Spatial patterns of area burned at high severity strongly shape forest resilience and constitute a key dimension of fire regimes, yet remain difficult to predict. To characterize the range of burn severity patterns expected within contemporary fire regimes, we quantified scaling relationships relating fire size to patterns of burn severity. Using 1615 fires occurring across the Northwest United States between 1985 and 2020, we evaluated scaling relationships within fire…
Publication Type: Journal Article
Exceptional variability in historical fire regimes across a western Cascades landscape, Oregon, USA
Year: 2023
Detailed information about the historical range of variability in wildfire activity informs adaptation to future climate and disturbance regimes. Here, we describe one of the first annually resolved reconstructions of historical (1500–1900 ce) fire occurrence in coast Douglas-fir dominated forests of the west slope of the Cascade Range in western Oregon. Mean fire return intervals (MFRIs) across 16 sites within our study area ranged from 6 to 165 years. Variability in MFRIs was strongly associated with average maximum summer vapor pressure deficit. Fire occurred infrequently in Douglas-fir…
Fire Effects and Fire Ecology, Fire History, Mixed-Conifer Management, Restoration and Hazardous Fuel Reduction
Publication Type: Journal Article
Human Fire Use and Management: A Global Database of Anthropogenic Fire Impacts for Modelling
Year: 2022
Human use and management of fire in landscapes have a long history and vary globally in purpose and impact. Existing local research on how people use and manage fire is fragmented across multiple disciplines and is diverse in methods of data collection and analysis. If progress is to be made on systematic understanding of human fire use and management globally, so that it might be better represented in dynamic global vegetation models, for example, we need improved synthesis of existing local research and literature. The database of anthropogenic fire impacts (DAFI) presented here is a…
Publication Type: Journal Article
Contemporary (1984–2020) fire history metrics for the conterminous United States and ecoregional differences by land ownership
Year: 2022
Background: Remotely sensed burned area products are critical to support fire modelling, policy, and management but often require further processing before use. Aim: We calculated fire history metrics from the Landsat Burned Area Product (1984–2020) across the conterminous U.S. (CONUS) including (1) fire frequency, (2) time since last burn (TSLB), (3) year of last burn, (4) longest fire-free interval, (5) average fire interval length, and (6) contemporary fire return interval (cFRI). Methods: Metrics were summarised by ecoregion and land ownership, and related to historical and cheatgrass…
Publication Type: Journal Article
The contribution of Indigenous stewardship to an historical mixed-severity fire regime in British Columbia, Canada
Year: 2022
Indigenous land stewardship and mixed-severity fire regimes both promote landscape heterogeneity, and the relationship between them is an emerging area of research. In our study, we reconstructed the historical fire regime of Ne Sextsine, a 5900-ha dry, Douglas-fir-dominated forest in the traditional territory of the T’exelc (Williams Lake First Nation) in British Columbia, Canada. Between 1550 and 1982 CE, we found median fire intervals of 18 years at the plot-level and 4 years at the study site-level. Ne Sextsine was characterized by an historical mixed-severity fire regime, dominated by…
Publication Type: Journal Article
Extreme Winds Alter Influence of Fuels and Topography on Megafire Burn Severity in Seasonal Temperate Rainforests under Record Fuel Aridity
Year: 2022
Nearly 0.8 million hectares of land were burned in the North American Pacific Northwest (PNW) over two weeks under record-breaking fuel aridity and winds during the extraordinary 2020 fire season, representing a rare example of megafires in forests west of the Cascade Mountains. We quantified the relative influence of weather, vegetation, and topography on patterns of high burn severity (>75% tree mortality) among five synchronous megafires in the western Cascade Mountains. Despite the conventional wisdom in climate-limited fire regimes that regional drivers (e.g., extreme aridity, and…
Publication Type: Journal Article
Hazards of Risk: Identifying Plausible Community Wildfire Disasters in Low-Frequency Fire Regimes
Year: 2021
Optimized wildfire risk reduction strategies are generally not resilient in the event of unanticipated, or very rare events, presenting a hazard in risk assessments which otherwise rely on actuarial, mean-based statistics to characterize risk. This hazard of actuarial approaches to wildfire risk is perhaps particularly evident for infrequent fire regimes such as those in the temperate forests west of the Cascade Range crest in Oregon and Washington, USA (“Westside”), where fire return intervals often exceed 200 years but where fires can be extremely intense and devastating. In this study, we…
Publication Type: Journal Article
Fire and Forests in the 21st Century: Managing Resilience Under Changing Climates and Fire Regimes in USA Forests
Year: 2021
Higher temperatures, lower snowpacks, drought, and extended dry periods have contributed to increased wildfire activity in recent decades. Climate change is expected to increase the frequency of large fires, the cumulative area burned, andfire suppression costs and risks in many areas of the USA. Fire regimes are likely to change due to interactions among climate, fire, and other stressors and disturbances; resulting in persistent changes in forest structure and function. The remainder of the twenty-first century will present substantial challenges, as natural resource managers are faced with…
Publication Type: Book Chapter
Contrasting the role of human- and lightning-caused wildfires on future fire regimes on a Central Oregon landscape
Year: 2021
Climate change is expected to increase fire activity in many regions of the globe, but the relative role of human vs. lightning-caused ignitions on future fire regimes is unclear. We developed statistical models that account for the spatiotemporal ignition patterns by cause in the eastern slopes of the Cascades in Oregon, USA. Projected changes in energy release component from a suite of climate models were used with our model to quantify changes in frequency and extent of human and lightning-caused fires and record-breaking events based on sizes of individual fires between contemporary (2006…
Publication Type: Journal Article
Evidence for widespread changes in the structure, composition, and fire regimes of western North American forests
Year: 2021
Implementation of wildfire- and climate-adaptation strategies in seasonally dry forests of western North America is impeded by numerous constraints and uncertainties. After more than a century of resource and land use change, some question the need for proactive management, particularly given novel social, ecological, and climatic conditions. To address this question, we first provide a framework for assessing changes in landscape conditions and fire regimes. Using this framework, we then evaluate evidence of change and lack of change in contemporary conditions relative to those maintained by…
Publication Type: Journal Article
Wildfire severity and postfire salvage harvest effects on long-term forest regeneration
Year: 2020
Following a wildfire, regeneration to forest can take decades to centuries and is no longerassured in many western U.S. environments given escalating wildfire severity and warming trends. Afterlarge fire years, managers prioritize where to allocate scarce planting resources, often with limited informationon the factors that drive successful forest establishment. Where occurring, long-term effects of postfiresalvage operations can increase uncertainty of establishment. Here, we collected field data on postfireregeneration patterns within 13- to 28-yr-old burned patches in eastern Washington…
Publication Type: Journal Article
Changing wildfire, changing forests: the effects of climate change on fire regimes and vegetation in the Pacific Northwest, USA
Year: 2020
Wildfires in the Pacific Northwest (Washington, Oregon, Idaho, and western Montana, USA) have been immense in recent years, capturing the attention of resource managers, fire scientists, and the general public. This paper synthesizes understanding of the potential effects of changing climate and fire regimes on Pacific Northwest forests, including effects on disturbance and stress interactions, forest structure and composition, and post-fire ecological processes. We frame this information in a risk assessment context, and conclude with management implications and future research needs.
Publication Type: Journal Article
High‐severity wildfire leads to multi‐decadal impacts on soil biogeochemistry in mixed‐conifer forests
Year: 2020
During the past century, systematic wildfire suppression has decreased fire frequency and increased fire severity in the western United States of America. While this has resulted in large ecological changes aboveground such as altered tree species composition and increased forest density, little is known about the long‐term, belowground implications of altered, ecologically novel, fire regimes, especially on soil biological processes. To better understand the long‐term implications of ecologically novel, high‐severity fire, we used a 44‐yr high‐severity fire chronosequence in the Sierra…
Publication Type: Journal Article
Tamm review: The effects of prescribed fire on wildfire regimes and impacts: A framework for comparison
Year: 2020
Prescribed fire can result in significant benefits to ecosystems and society. Examples include improved wildlifehabitat, enhanced biodiversity, reduced threat of destructive wildfire, and enhanced ecosystem resilience.Prescribed fire can also come with costs, such as reduced air quality and impacts to fire sensitive species. To planfor appropriate use of prescribed fire, managers need information on the tradeoffs between prescribed fire andwildfire regimes. In this study, we argue that information on tradeoffs should be presented at spatial andtemporal scales commensurate with the scales at…
Publication Type: Journal Article
Long-term effects of fuel treatments, overstory structure, and wildfire on tree regeneration in dry forests of Central Washington
Year: 2020
The long-term effectiveness of dry-forest fuels treatments (restoration thinning and prescribed burning) depends, in part, on the pace at which trees regenerate and recruit into the overstory. Knowledge of the factors that shape post-treatment regeneration and growth is limited by the short timeframes and simple disturbance histories of past research. Here, we present results of a 15-year fuels-reduction experiment in central Washington, including responses to planned and unplanned disturbances.We explore the changing patterns of Douglas-fir regeneration in72 permanent plots (0.1 ha) varying…
Publication Type: Journal Article
How does tree regeneration respond to mixed‐severity fire in the western Oregon Cascades, USA?
Year: 2020
Dendroecological studies of historical tree recruitment patterns suggest mixed‐severity fire effects are common in Douglas‐fir/western hemlock forests of the Pacific Northwest (PNW), USA, but empirical studies linking observed fire severity to tree regeneration response are needed to expand our understanding into the functional role of fire in this forest type. Recent increases in mixed‐severity fires offered this opportunity, so we quantified the abundance, spatial distribution, species richness, and community composition of regenerating trees across a mixed‐severity fire gradient (unburned–…
Publication Type: Journal Article