Research Database
Displaying 881 - 900 of 1211
Restoring forest structure and process stabilizes forest carbon in wildfire-prone southwestern ponderosa pine forests
Year: 2016
Changing climate and a legacy of fire-exclusion have increased the probability of high-severity wildfire, leading to an increased risk of forest carbon loss in ponderosa pine forests in the southwestern USA. Efforts to reduce high-severity fire risk through forest thinning and prescribed burning require both the removal and emission of carbon from these forests, and any potential carbon benefits from treatment may depend on the occurrence of wildfire. We sought to determine how forest treatments alter the effects of stochastic wildfire events on the forest carbon balance. We modeled three…
Publication Type: Journal Article
Spatial variability in tree regeneration after wildfire delays and dampens future bark beetle outbreaks
Year: 2016
Climate change is altering the frequency and severity of forest disturbances such as wildfires and bark beetle outbreaks, thereby increasing the potential for sequential disturbances to interact. Interactions can amplify or dampen disturbances, yet the direction and magnitude of future disturbance interactions are difficult to anticipate because underlying mechanisms remain poorly understood. We tested how variability in postfire forest development affects future susceptibility to bark beetle outbreaks, focusing on mountain pine beetle (Dendroctonus ponderosae) and Douglas-fir beetle (…
Publication Type: Journal Article
Assessment of wildland fire impacts on watershed annual water yield: Analytical framework and case studies in the United States
Year: 2016
More than 50% of water supplies in the conterminous United States originate on forestland or rangeland, and are potentially under increasing stress as a result of larger and more severe wildfires. Little is known however about the long-term impacts of fire on annual water yield, and the role of climate variability within this context. We here propose a framework for evaluating wildland fire impacts on streamflow that combines double-mass analysis with new methods (change point analysis, climate elasticity modeling, and process-based modeling) to distinguish between multi-year fire and climate…
Publication Type: Journal Article
The Passing of the Lolo Trail, with an Introduction by Andrew J. Larson
Year: 2016
In 1935, Elers Koch argued in a Journal of Forestry article that a minimum fire protection model should be implemented in the backcountry areas of national forests in Idaho, USA. As a USDA Forest Service Supervisor and Assistant Regional Forester, Koch had led many major fire-fighting campaigns in the region, beginning with the great 1910 fires of Idaho and Montana. He argued in his classic article for wilderness values, and against throwing millions of dollars into unsuccessful attempts to suppress backcountry fires. His article was accompanied by a response from Earl Loveridge, a proponent…
Publication Type: Journal Article
The interagency fuels treatment decision support system: Functionality for fuels treatment planning
Year: 2016
The Interagency Fuels Treatment Decision Support System (IFTDSS) is a web-based software and data integration framework that organizes fire and fuels software applications into a single online application. IFTDSS is designed to make fuels treatment planning and analysis more efficient and effective. In IFTDSS, users can simulate fire behavior and fire effects using the scientific algorithms and processes found in desktop applications including FlamMap, Behave, FOFEM, and Consume. Strategic-level goals of IFTDSS are to• simplify the fuels treatment planning decision-support process;• improve…
Publication Type: Journal Article
Ignition patterns influence fire severity and plant communities in Pacific Northwest, USA, prairies
Year: 2016
In the prairies of the Pacific Northwest, USA, fire has been reintroduced as a tool for reducing non-native, invasive plant cover and promoting the growth and establishment of native plant communities. Head fires and backing fires are the two primary ignition patterns used to complete most prescribed burns, but the relative effectiveness of these two methods on invasive plant control and native enhancement is unknown. A clear understanding of the relationship between fire behavior, fire severity, and fire effects on vegetation and how these metrics are affected by fire ignition patterns could…
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
Topography, fuels, and fire exclusion drive fire severity of the Rim Fire in an old-growth mixed-conifer forest, Yosemite National Park, USA
Year: 2015
The number of large, high-severity fires has increased in the western United States over the past 30 years due to climate change and increasing tree density from fire suppression. Fuel quantity, topography, and weather during a burn control fire severity, and the relative contributions of these controls in mixed-severity fires in mountainous terrain are poorly understood. In 2013, the Rim Fire burned a previously studied 2125 ha area of mixed-conifer forest in Yosemite National Park. Data from 84 plots sampled in 2002 revealed increases in tree density, basal area, and fuel buildup since 1899…
Publication Type: Journal Article
Restoring fire-prone Inland Pacific landscapes: seven core principles
Year: 2015
More than a century of forest and fire management of Inland Pacific landscapes has transformed their successional and disturbance dynamics. Regional connectivity of many terrestrial and aquatic habitats is fragmented, flows of some ecological and physical processes have been altered in space and time, and the frequency, size and intensity of many disturbances that configure these habitats have been altered. Current efforts to address these impacts yield a small footprint in comparison to wildfires and insect outbreaks. Moreover, many current projects emphasize thinning and fuels reduction…
Publication Type: Journal Article
Effect of repeated burning on plant and soil carbon and nitrogen in cheatgrass (Bromus tectorum) dominated ecosystems
Year: 2015
Fire has profound effects on ecosystem properties, but few studies have addressed the effect of repeated burns on soil nutrients, and none have been conducted in cold desert ecosystems where invasion by exotic annual grasses is resulting in greater fire frequency.
Publication Type: Journal Article
Recent burning of boreal forests exceeds fire regime limits of the past 10,000 years
Year: 2015
Wildfire activity in boreal forests is anticipated to increase dramatically, with far-reaching ecological and socioeconomic consequences. Paleorecords are indispensible for elucidating boreal fire regime dynamics under changing climate, because fire return intervals and successional cycles in these ecosystems occur over decadal to centennial timescales. We present charcoal records from 14 lakes in the Yukon Flats of interior Alaska, one of the most flammable ecoregions of the boreal forest biome, to infer causes and consequences of fire regime change over the past 10,000 y. Strong…
Publication Type: Journal Article
A review of the challenges and opportunities in estimating above ground forest biomass using tree-level models
Year: 2015
Accurate biomass measurements and analyses are critical components in quantifying carbon stocks and sequestration rates, assessing potential impacts due to climate change, locating bio-energy processing plants, and mapping and planning fuel treatments. To this end, biomass equations will remain a key component of future carbon measurements and estimation. As researchers in biomass and carbon estimation, we review the present scenario of aboveground biomass estimation, focusing particularly on estimation using tree-level models and identify some cautionary points that we believe will improve…
Publication Type: Journal Article
Catching Fire? Social Interactions, Beliefs, and Wildfire Risk Mitigation Behaviors
Year: 2015
Social interactions are widely recognized as a potential influence on risk-related behaviors. We present a mediation model in which social interactions (classified as formal/informal and generic/fire-specific) are associated with beliefs about wildfire risk and mitigation options, which in turn shape wildfire mitigation behaviors. We test this model using survey data from fire-prone areas of Colorado. In several cases, our results are consistent with the mediation hypotheses for mitigation actions specifically targeting vegetative fuel reduction. Perceived wildfire probability partially…
Publication Type: Journal Article
Communication under Fire: The Role of Embeddedness in the Emergence and Efficacy of Disaster Response Communication Networks
Year: 2015
Communication networks among responders are critical to effective coordination and information transfer across agencies active in a disaster response. Using the theory of embeddedness, we investigate how aspects of relational and institutional embeddedness influence the emergence and efficacy of interactions among responding agencies using network data from three significant wildfire events in the wildland/urban interface. For this study, relational embeddedness is investigated as the degree of familiarity between two responders before the incident. Institutional embeddedness is explored in…
Publication Type: Journal Article
The climate space of fire regimes in north-western North America
Year: 2015
Aim Studies of fire activity along environmental gradients have been undertaken, but the results of such studies have yet to be integrated with fire-regime analysis. We characterize fire-regime components along climate gradients and a gradient of human influence. Location We focus on a climatically diverse region of north-western North America extending from northern British Columbia, Canada, to northern Utah and Colorado, USA. Methods We used a multivariate framework to collapse 12 climatic variables into two major climate gradients and binned them into 73 discrete climate domains. We…
Publication Type: Journal Article
Tree mortality from drought, insects, and their interactions in a changing climate
Year: 2015
Climate change is expected to drive increased tree mortality through drought, heat stress, and insect attacks, with manifold impacts on forest ecosystems. Yet, climate-induced tree mortality and biotic disturbance agents are largely absent from process-based ecosystem models. Using data sets from the western USA and associated studies, we present a framework for determining the relative contribution of drought stress, insect attack, and their interactions, which is critical for modeling mortality in future climates. We outline a simple approach that identifies the mechanisms associated with…
Publication Type: Journal Article
Understanding Gaps Between the Risk Perceptions of Wildland–Urban Interface (WUI) Residents and Wildfire Professionals
Year: 2015
Research across a variety of risk domains finds that the risk perceptions of professionals and the public differ. Such risk perception gaps occur if professionals and the public understand individual risk factors differently or if they aggregate risk factors into overall risk differently. The nature of such divergences, whether based on objective inaccuracies or on differing perspectives, is important to understand. However, evidence of risk perception gaps typically pertains to general, overall risk levels; evidence of and details about mismatches between the specific level of risk faced by…
Publication Type: Journal Article
Temperate forest health in an era of emerging megadisturbance
Year: 2015
Although disturbances such as fire and native insects can contribute to natural dynamics of forest health, exceptional droughts, directly and in combination with other disturbance factors, are pushing some temperate forests beyond thresholds of sustainability. Interactions from increasing temperatures, drought, native insects and pathogens, and uncharacteristically severe wildfire are resulting in forest mortality beyond the levels of 20th-century experience. Additional anthropogenic stressors, such as atmospheric pollution and invasive species, further weaken trees in some regions. Although…
Publication Type: Journal Article
Climate change and vulnerability of bull trout (Salvelinus confluentus) in a fire-prone landscape
Year: 2015
Linked atmospheric and wildfire changes will complicate future management of native coldwater fishes in fire-pronelandscapes, and new approaches to management that incorporate uncertainty are needed to address this challenge. We used aBayesian network (BN) approach to evaluate population vulnerability of bull trout (Salvelinus confluentus) in the Wenatchee Riverbasin, Washington, USA, under current and future climate and fire scenarios. The BN was based on modeled estimates ofwildfire, water temperature, and physical habitat prior to, and following, simulated fires throughout the basin. We…
Publication Type: Journal Article
The fire frequency-severity relationship and the legacy of fire suppression in California forests
Year: 2015
Fire is one of the most important natural disturbance processes in the western United States and ecosystems differ markedly with respect to their ecological and evolutionary relationships with fire. Reference fire regimes in forested ecosystems can be categorized along a gradient ranging from “fuel-limited” to “climate-limited” where the former types are often characterized by frequent, lower-severity wildfires and the latter by infrequent, more severe wildfires. Using spatial data on fire severity from 1984–2011 and metrics related to fire frequency, we tested how divergence from historic (…
Publication Type: Journal Article