Research Database
Displaying 121 - 140 of 157
Tamm Review: Management of mixed-severity fire regime forests in Oregon, Washington, and Northern California
Year: 2016
Increasingly, objectives for forests with moderate- or mixed-severity fire regimes are to restore successionally diverse landscapes that are resistant and resilient to current and future stressors. Maintaining native species and characteristic processes requires this successional diversity, but methods to achieve it are poorly explained in the literature. In the Inland Pacific US, large, old, early seral trees were a key historical feature of many young and old forest successional patches, especially where fires frequently occurred. Large, old trees are naturally fire-tolerant, but today are…
Publication Type: Journal Article
Evaluating crown fire rate of spread predictions from physics-based models
Year: 2015
Modeling the behavior of crown fires is challenging due to the complex set of coupled processes that drive the characteristics of a spreading wildfire and the large range of spatial and temporal scales over which these processes occur. Detailed physics-based modeling approaches such as FIRETEC and the Wildland Urban Interface Fire Dynamics Simulator (WFDS) simulate fire behavior using computational fluid dynamics based methods to numerically solve the three-dimensional, time dependent, model equations that govern, to some approximation, the component physical processes and their interactions…
Publication Type: Journal Article
Enhancing adaptive capacity for restoring fire-dependent ecosystems: the Fire Learning Network’s Prescribed Fire Training Exchanges
Year: 2015
Prescribed fire is a critical tool for promoting restoration and increasing resilience in fire-adapted ecosystems, but there are barriers to its use, including a shortage of personnel with adequate ecological knowledge and operational expertise to implement prescribed fire across multijurisdictional landscapes. In the United States, recognized needs for both professional development and increased use of fire are not being met, often because of institutional limitations. The Fire Learning Network has been characterized as a multiscalar, collaborative network that works to enhance the adaptive…
Publication Type: Journal Article
A Wildfire-relevant climatology of the convective environment of the United States
Year: 2015
Convective instability can influence the behaviour of large wildfires. Because wildfires modify the temperature and moisture of air in their plumes, instability calculations using ambient conditions may not accurately represent convective potential for some fire plumes. This study used the North American Regional Reanalysis to develop a climatology of the convective environment specifically tied to large fire events. The climatology is based on the period 1979–2009 and includes ambient convective available potential energy (CAPE) as well as values when surface air is warmed by 0.5, 1.0 or 2.0…
Publication Type: Journal Article
Fuel and vegetation trends after wildfire in treated versus untreated forests
Year: 2015
Increasing size and severity of wildfires have led to increased interest in managing forests for resiliency to future disturbances. Comparing and contrasting treated versus untreated stands through multiple growing seasons postfire provide an opportunity to understand processes driving responses and can guide management decisions regarding resiliency. In treated and untreated forests, we compared fire effects 2‐10 growing seasons following fire on 3 different fires in New Mexico and Arizona. We estimated understory cover, standing crop, fuel loading, and basal area in (1) lop, pile, burn; (2…
Publication Type: Journal Article
Local Ecological Knowledge and Fire Management: What Does the Public Understand?
Year: 2015
As fire management agencies seek to implement more flexible fire management strategies, local understanding and support for these strategies become increasingly important. One issue associated with implementing more flexible fire management strategies is educating local populations about fire management and identifying what local populations know or do not know related to fire management. This study used survey data from three 2010 wildland fires to understand how ecological knowledge and education level affected fire management perception and understanding. Results indicated that increased…
Publication Type: Journal Article
Wildland fire management: insights from a foresight panel
Year: 2015
Wildland fire management faces unprecedented challenges in the 21st century: the increasingly apparent effects of climate change, more people and structures in the wildland-urban interface, growing costs associated with wildfire management, and the rise of high-impact fires, to name a few. Given these significant and growing challenges, conventional fire management approaches are unlikely to be effective in the future. Innovative and forward-looking approaches are needed. This study explored wildland fire management futures by using methods and diverse perspectives from futures research. To…
Publication Type: Report
Winter grazing can reduce wildfire size, intensity and behaviour in a shrub-grassland
Year: 2015
An increase in mega-fires and wildfires is a global issue that is expected to become worse with climate change. Fuel treatments are often recommended to moderate behaviour and decrease severity of wildfires; however, the extensive nature of rangelands limits the use of many treatments. Dormant-season grazing has been suggested as a rangeland fuel treatment, but its effects on fire characteristics are generally unknown. We investigated the influence of dormant-season (winter) grazing by cattle (Bos taurus) on fuel characteristics, fire behaviour and area burned in Wyoming big sagebrush (…
Publication Type: Journal Article
Re-envisioning community-wildfire relations in the U.S. West as adaptive governance
Year: 2015
Prompted by a series of increasingly destructive, expensive, and highly visible wildfire crises in human communities across the globe, a robust body of scholarship has emerged to theorize, conceptualize, and measure community-level resilience to wildfires. To date, however, insufficient consideration has been given to wildfire resilience as a process of adaptive governance mediated by institutions at multiple scales. Here we explore the possibilities for addressing this gap through an analysis of wildfire resilience among wildland-urban interface communities in the western region of the…
Publication Type: Journal Article
Fire and non-native grass invasion interact to suppress tree regeneration in temperate deciduous forests
Year: 2015
While many ecosystems depend on fire to maintain biodiversity, non-native plant invasions can enhance fire intensity, suppressing native species and generating a fire–invasion feedback. These dynamics have been observed in arid and semi-arid ecosystems, but fire–invasion interactions in temperate deciduous forests, where prescribed fires are often used as management tools to enhance native diversity, have rarely been investigated. Here we evaluated the effects of a widespread invasive grass on fire behaviour in eastern deciduous forests in the USA and the potential effects of fire and…
Publication Type: Journal Article
Experimental analysis of fire spread across a two-dimensional ridge under wind conditions
Year: 2015
Results from a laboratory-scale investigation of a fire spreading on the windward face of a triangular-section hill of variable shape with wind perpendicular to the ridgeline are reported. They confirm previous observations that the fire enlarges its lateral spread after reaching the ridgeline, entering the leeward face with a much wider front. Reference fire spread velocities were measured and analysed, putting in evidence the importance of the dynamic effect due to flow velocity and its associated horizontal-axis separation vortex strength without dependence on hill geometry. Similar…
Publication Type: Journal Article
The Ecology and Management of Moist Mixed-Conifer Forests in Eastern Oregon and Washington: a Synthesis of the Relevant Biophysical Science and Implications for Future Land Management
Year: 2014
Land managers in the Pacific Northwest have reported a need for updated scientific information on the ecology and management of mixed-conifer forests east of the Cascade Range in Oregon and Washington. Of particular concern are the moist mixed-conifer forests, which have become drought-stressed and vulnerable to high-severity fire after decades of human disturbances and climate warming. This synthesis responds to this need. We present a compilation of existing research across multiple natural resource issues, including disturbance regimes, the legacy effects of past management actions,…
Publication Type: Report
Recent mountain pine beetle outbreaks, wildfire severity, and postfire tree regeneration in the US Northern Rockies
Year: 2014
Widespread tree mortality caused by outbreaks of native bark beetles (Circulionidae: Scolytinae) in recent decades has raised concern among scientists and forest managers about whether beetle outbreaks fuel more ecologically severe forest fires and impair postfire resilience. To investigate this question, we collected extensive field data following multiple fires that burned subalpine forests in 2011 throughout the Northern Rocky Mountains across a spectrum of prefire beetle outbreak severity, primarily from mountain pine beetle (Dendroctonus ponderosae). We found that recent (2001–2010)…
Publication Type: Journal Article
Fire behavior in masticated fuels: A review
Year: 2014
Mastication is an increasingly common fuels treatment that redistributes “ladder” fuels to the forest floor to reduce vertical fuel continuity, crown fire potential, and fireline intensity, but fuel models do not exist for predicting fire behavior in these fuel types. Recent fires burning in masticated fuels have behaved in unexpected and contradictory ways, likely because the shredded, compact fuel created when trees and shrubs are masticated contains irregularly shaped pieces in mixtures quite different from other woody fuels. We review fuels characteristics and fire behavior in masticated…
Publication Type: Journal Article
Fire and fuels
Year: 2014
Recent studies of historical fire regimes indicate that fires occurring prior to Euro-American settlement were characterized by a high degree of spatial complexity that was driven by heterogeneity in vegetation/fuels and topography and influenced by variability in climate, which mediated the timing, effects, and extents of fires over time. Although there are many important lessons to learn from the past, we may not be able to rely completely on past forest conditions to provide us with blueprints for current and future forest management. Rather than attempting to achieve a particular forest…
Publication Type: Report
Simulated western spruce budworm defoliation reduces torching and crowning potential: a sensitivity analysis using a physics-based fire model
Year: 2014
The widespread, native defoliator western spruce budworm (Choristoneura occidentalis Freeman) reduces canopy fuels, which might affect the potential for surface fires to torch (ignite the crowns of individual trees) or crown (spread between tree crowns). However, the effects of defoliation on fire behaviour are poorly understood. We used a physics-based fire model to examine the effects of defoliation and three aspects of how the phenomenon is represented in the model (the spatial distribution of defoliation within tree crowns, potential branchwood drying and model resolution). Our…
Publication Type: Journal Article
Wildland Fire management: Are actively managed forests more resilient than passively managed forests?
Year: 2013
Large areas of federal lands in the western states are currently at high risk of severe wildfire and have many insect and disease problems, indicating a significant decline in forest health and resilience. Although research studies have not been done that would measure whether actively managed forests are more resilient to wildfires than passively managed forests, results from studies of hazardous fuels treatment effectiveness and the economic benefits from avoided costs of future wildfire suppression due to fuels treatment can be used to support an affirmative reply to the question. If a…
Publication Type: Report
Restoring forest resilience: From reference spatial patterns to silvicultural prescriptions and monitoring
Year: 2013
Stand-level spatial pattern influences key aspects of resilience and ecosystem function such as disturbance behavior, regeneration, snow retention, and habitat quality in frequent-fire pine and mixed-conifer forests. Reference sites, from both pre-settlement era reconstructions and contemporary forests with active fire regimes, indicate that frequent-fire forests are complex mosaics of individual trees, tree clumps, and openings. There is a broad scientific consensus that restoration treatments should seek to restore this mosaic pattern in order to restore resilience and maintain ecosystem…
Publication Type: Journal Article
Pre-wildfire fuel reduction treatments result in more resilient forest structure a decade after wildfire
Year: 2013
Increasing size and severity of wildfires have led to an interest in the effectiveness of forest fuels treatments on reducing fire severity and post-wildfire fuels. Our objective was to contrast stand structure and surface fuel loadings on treated and untreated sites within the 2002 Rodeo–Chediski Fire area. Data from 140 plots on seven paired treated–untreated sites indicated that pre-wildfire treatments reduced fire severity compared with untreated sites. In 2011, coarse woody debris loading (woody material >7.62 cm in diameter) was 257% higher and fine woody debris (woody material <7…
Publication Type: Journal Article