Research Database
Displaying 41 - 60 of 79
It takes a few to tango: changing climate and fire regimes can cause regeneration failure of two subalpine conifers
Year: 2018
Environmental change is accelerating in the 21st century, but how multiple drivers may interact to alter forest resilience remains uncertain. In forests affected by large high-severity disturbances, tree regeneration is a resilience linchpin that shapes successional trajectories for decades. We modeled stands of two widespread western U.S. conifers, Douglas-fir (Pseudotsuga menziesii var. glauca), and lodgepole pine (Pinus contorta var. latifolia), in Yellowstone National Park (Wyoming, USA) to ask (1) What combinations of distance to seed source, fire return interval, and warming-drying…
Publication Type: Journal Article
Towards an understanding of the evolutionary role of fire in animals
Year: 2018
Wildfires underpin the dynamics and diversity of many ecosystems worldwide, and plants show a plethora of adaptive traits for persisting recurrent fires. Many fire-prone ecosystems also harbor a rich fauna; however, knowledge about adaptive traits to fire in animals remains poorly explored. We review existing literature and suggest that fire is an important evolutionary driver for animal diversity because (1) many animals are present in fire-prone landscapes and may have structural and phenotypic characters that contribute to adaptation to these open landscapes; and (2) in some cases, animals…
Publication Type: Journal Article
Cover of tall trees best predicts California spotted owl habitat
Year: 2017
Restoration of western dry forests in the USA often focuses on reducing fuel loads. In the range of the spotted owl, these treatments may reduce canopy cover and tree density, which could reduce preferred habitat conditions for the owl and other sensitive species. In particular, high canopy cover (≥70%) has been widely reported to be an important feature of spotted owl habitat, but averages of stand-level forest cover do not provide important information on foliage height and gap structure. To provide better quantification of canopy structure, we used airborne LiDAR imagery to identify canopy…
Publication Type: Journal Article
Does prescribed fire promote resistance to drought in low elevation forests of the Sierra Nevada, California, USA?
Year: 2016
Prescribed fire is a primary tool used to restore western forests following more than a century of fire exclusion, reducing fire hazard by removing dead and live fuels (small trees and shrubs). It is commonly assumed that the reduced forest density following prescribed fire also reduces competition for resources among the remaining trees, so that the remaining trees are more resistant (more likely to survive) in the face of additional stressors, such as drought. Yet this proposition remains largely untested, so that managers do not have the basic information to evaluate whether prescribed…
Publication Type: Journal Article
Review of broad-scale drought monitoring of forests: Toward an integrated data mining approach
Year: 2016
Efforts to monitor the broad-scale impacts of drought on forests often come up short. Drought is a direct stressor of forests as well as a driver of secondary disturbance agents, making a full accounting of drought impacts challenging. General impacts can be inferred from moisture deficits quantified using precipitation and temperature measurements. However, derived meteorological indices may not meaningfully capture drought impacts because drought responses can differ substantially among species, sites and regions. Meteorology-based approaches also require the characterization of current…
Publication Type: Journal Article
Effects of Drought on Forests and Rangelands in the United States: A Comprehensive Science Synthesis
Year: 2016
This assessment provides input to the reauthorized National Integrated Drought Information System (NIDIS) and the National Climate Assessment (NCA), and it establishes the scientific foundation needed to manage for drought resilience and adaptation. Focal areas include drought characterization; drought impacts on forest processes and disturbances such as insect outbreaks and wildfire; and consequences for forest and rangeland values. Drought can be a severe natural disaster with substantial social and economic consequences. Drought becomes most obvious when large-scale changes are observed;…
Publication Type: Report
Wildfire, climate, and perceptions in Northeast Oregon
Year: 2016
Wildfire poses a rising threat in the western USA, fueled by synergies between historical fire suppression, changing land use, insects and disease, and shifts toward a drier, warmer climate. The rugged landscapes of northeast Oregon, with their historically forest- and resource-based economies, have been one of the areas affected. A 2011 survey found area residents highly concerned about fire and insect threats, but not about climate change. In 2014 we conducted a second survey that, to explore this apparent disconnect, included questions about past and future summertime (fire season)…
Publication Type: Journal Article
Models predict longer, deeper U.S. droughts
Year: 2015
Severe, decades-long "megadroughts" that hit the southwestern and midwestern United States over the past millennium may be just a preview of droughts to come in the next century as a result of climate change, new research suggests. According to a new analysis of 17 state-of-the-art climate models and reconstructions of historical drought based on 1000 years of tree-ring data, the regions are heading into a period of unprecedented dryness even if CO2 emissions are dramatically reduced. Under a "business-as-usual" emission scenario, there's an 80% likelihood that at least one decades-long…
Publication Type: Journal Article
Historical northern spotted owl habitat and old-growth dry forests maintained by mixed-severity wildfires
Year: 2015
Context: Reconstructing historical habitat could help reverse declining animal populations, but detailed, spatially comprehensive data are rare. For example, habitat for the federally threatened Northern spotted owl (NSO; Strix occidentalis caurina) was thought historically rare because low-severity fires kept forests open and habitat restricted to fire refugia, but spatial historical data are lacking. Objectives: Here I use public land-surveys to spatially reconstruct NSO habitat and old-growth forests in dry forests in Oregon's Eastern Cascades in the late-1800s. I used reconstructions of…
Publication Type: Journal Article
California Spotted Owl, Songbird, and Small Mammal Responses to Landscape Fuel Treatments
Year: 2014
A principal challenge of federal forest management has been maintaining and improving habitat for sensitive species in forests adapted to frequent, low- to moderate-intensity fire regimes that have become increasingly vulnerable to uncharacteristically severe wildfires. To enhance forest resilience, a coordinated landscape fuel network was installed in the northern Sierra Nevada, which reduced the potential for hazardous fire, despite constraints for wildlife protection that limited the extent and intensity of treatments. Small mammal and songbird communities were largely unaffected by this…
Publication Type: Journal Article
Assessing the Compatibility of Fuel Treatments, Wildfire Risk, and Conservation of Northern Spotted Owl Habitats and Populations in the Eastern Cascades: A Multi-Scale Analysis
Year: 2014
National Forests in the dry forest provinces on the east‐side of the Oregon and Washington Cascades have been managed under the guidelines of local Forest Plans and the Northwest Forest Plan (NWFP), both of which specify large areas of late‐successional reserves (LSRs). In contrast, the recently‐released USDI Fish and Wildlife Service Revised Recovery Plan (RRP) for the Northern Spotted Owl (NSO) calls for development of dynamic and shifting mosaics in the dry forests, and retention of LSRs in moist forests of eastern Cascades of Oregon and Washington, to address NSO habitat and wildfire…
Publication Type: Report
Resprouting Chaparral Dies from Postfire Drought
Year: 2014
California’s chaparral plant community composition can change when fire is followed by intense drought. By measuring postfire population demography coupled with physiological measurements during a severe drought, Pratt et al. were the first to directly link resprout mortality to mechanisms of drought stress and show how chaparral may be affected in the future by the increased frequency of fires combined with drought.
Publication Type: Report
Climate change vulnerability and adaptation in the North Cascades region, Washington
Year: 2014
The North Cascadia Adaptation Partnership (NCAP) is a science-management partnership consisting of the U.S. Department of Agriculture Forest Service Mount Baker-Snoqualmie and Okanogan-Wenatchee National Forests and Pacific Northwest Research Station; North Cascades National Park Complex; Mount Rainier National Park; and University of Washington Climate Impacts Group. These organizations worked with numerous stakeholders over 2 years to identify climate change issues relevant to resource management in the North Cascades and to find solutions that will facilitate the transition of the diverse…
Publication Type: Report
Correlations between components of the water balance and burned area reveal insights for predicting forest fire area in the southwest United States
Year: 2014
We related measurements of annual burned area in the southwest United States during 1984–2013 to records of climate variability. Within forests, annual burned area correlated at least as strongly with spring–summer vapour pressure deficit (VPD) as with 14 other drought-related metrics, including more complex metrics that explicitly represent fuel moisture. Particularly strong correlations with VPD arise partly because this term dictates the atmospheric moisture demand. Additionally, VPD responds to moisture supply, which is difficult to measure and model regionally due to complex…
Publication Type: Journal Article
Climate change tipping points: A point of no return?
Year: 2013
Summer 2012 saw records fall for intensity of drought and number, size, and cost of wildfires in the Central and Western United States, and the climate forecast calls for more of the same in the near and distant future. When wildfire breaks out, emergency responders decide their immediate strategy based on past experience and quick judgment calls. But in the long term, land managers need to plan for a warmer climate on a time scale of decades, or even a century or more, to better reflect the life span of trees and forests. Studies supported by the Joint Fire Science Program (JFSP) are…
Publication Type: Report
The relationship of large fire occurrence with drought and fire danger indices in the western USA, 1984-2008: the role of temporal scale
Year: 2013
The relationship between large fire occurrence and drought has important implications for fire prediction under current and future climates. This study’s primary objective was to evaluate correlations between drought and fire-danger-rating indices representing short- and long-term drought, to determine which had the strongest relationships with large fire occurrence at the scale of the western United States during the years 1984–2008. We combined 4–8-km gridded drought and fire-danger-rating indices with information on fires greater than 404.7 ha (1000 acres). To account for differences in…
Publication Type: Journal Article
Assessing the compatability of fuel treatments, wildfire risk, and conservation of Northern spotted owl habitats and populations in the eastern Cascades: A multi-scale analysis
Year: 2013
National Forests in the dry forest provinces on the east-side of the Oregon and Washington Cascades have been managed under the guidelines of local Forest Plans and the Northwest Forest Plan (NWFP), both of which specify large areas of late-successional reserves (LSRs). In contrast, the recently-released USDI Fish and Wildlife Service Revised Recovery Plan (RRP) for the Northern Spotted Owl (NSO) calls for development of dynamic and shifting mosaics in the dry forests, and retention of LSRs in moist forests of eastern Cascades of Oregon and Washington, to address NSO habitat and wildfire…
Publication Type: Report
Vegetation's importance in regulating surface elevation in a coastal salt marsh facing elevated rates of sea level rise
Year: 2012
Rising sea levels threaten the sustainability of coastal wetlands around the globe, thus understanding how increased inundation alters the elevation change mechanisms in these systems is increasingly important. Typically, the ability of coastal marshes to maintain their position in the intertidal zone depends on the accumulation of both organic and inorganic materials, so one, if not both, of these processes must increase to keep pace with rising seas, assuming all else constant. To determine the importance of vegetation in these processes, we measured elevation change and surface accretion…
Publication Type: Journal Article
Photo Series for Quantifying Natural Fuels Volume XI : Eastern Oregon Sagebrush - Steppe and Spotted Owl Nesting Habitat in the Pacific Northwest
Year: 2012
Three series of photographs display a range of natural conditions and fuel loadings for sagebrush-steppe types that are ecotonal with grasses, western juniper, and ponderosa pine in eastern Oregon, and one series of photographs displays a range of natural conditions and fuel loadings for northern spotted owl nesting habitat in forest types in Washington and Oregon. Each group of photos includes inventory information summarizing vegetation composition, structure, and loading; woody material loading and density by size class; forest floor depth and loading; and various site characteristics. The…
Publication Type: Report
USGS Fire Science - Fire danger monitoring and forecasting
Year: 2012
The United States Geological Survey (USGS) uses moderate resolution satellite data to assess live fuel condition for estimating fire danger. Using 23 years of vegetation condition measurements, we are able to determine the relative greenness of current live fuels. High relative greenness values indicate the vegetation is healthy and vigorous; low greenness values indicate the vegetation is under stress, dry (possibly from drought), behind in annual development, or dead. Forest, shrub, and grassland vegetation with low relative greenness are susceptible to fire ignition during the fire season…
Publication Type: Report