Research Database
Displaying 61 - 80 of 95
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
Source of Sediment Hazards on Steep Slopes
Year: 2014
On steep slopes between 30-45 degrees, loose soil is stored behind plant “dams.” After a fire, > 75% of stored sediment is rapidly released to the channel system by dry ravel (the rolling, bouncing, and sliding of individual particles). The postfire hazard from stored sediment can be calculated at the catchment scale if the size and distribution of vegetation cover are known.
Publication Type: Report
Examining fire-prone forest landscapes as coupled human and natural systems
Year: 2014
Fire-prone landscapes are not well studied as coupled human and natural systems (CHANS) and present many challenges for understanding and promoting adaptive behaviors and institutions. Here, we explore how heterogeneity, feedbacks, and external drivers in this type of natural hazard system can lead to complexity and can limit the development of more adaptive approaches to policy and management. Institutions and social networks can counter these limitations and promote adaptation. We also develop a conceptual model that includes a robust characterization of social subsystems for a fire-prone…
Publication Type: Journal Article
Wildland firefighter safety zones: a review of past science and summary of future needs
Year: 2014
Current wildland firefighter safety zone guidelines are based on studies that assume flat terrain, radiant heating, finite flame width, constant flame temperature and high flame emissivity. Firefighter entrapments and injuries occur across a broad range of vegetation, terrain and atmospheric conditions generally when they are within two flame heights of the fire. Injury is not confined to radiant heating or flat terrain; consequently, convective heating should be considered as a potential heating mode. Current understanding of energy transport in wildland fires is briefly summarised, followed…
Publication Type: Journal Article
Beyond reducing fire hazard: fuel treatment impacts on overstory tree survival
Year: 2014
Fuel treatment implementation in dry forest types throughout the western United States is likely to increase in pace and scale in response to increasing incidence of large wildfires. While it is clear that properly implemented fuel treatments are effective at reducing hazardous fire potential, there are ancillary ecological effects that can impact forest resilience either positively or negatively depending on the specific elements examined, as well as treatment type, timing, and intensity. In this study, we use overstory tree growth responses, measured seven years after the most common fuel…
Publication Type: Journal Article
Managing burned landscapes: Evaluating future management strategies for resilient forests under a warming climate
Year: 2014
Climate change effects on forested ecosystems worldwide include increases in drought-related mortality, changes to disturbance regimes and shifts in species distributions. Such climate-induced changes will alter the outcomes of current management strategies, complicating the selection of appropriate strategies to promote forest resilience. We modelled forest growth in ponderosa pine forests that burned in Arizona’s 2002 Rodeo-Chediski Fire using the Forest Vegetation Simulator Climate Extension, where initial stand structures were defined by pre-fire treatment and fire severity. Under extreme…
Publication Type: Journal Article
Conifer regeneration following stand-replacing wildfires varies along an elevation gradient in a ponderosa pine forest, Oregon, USA
Year: 2013
Climate change is expected to increase disturbances such as stand-replacing wildfire in many ecosystems, which have the potential to drive rapid turnover in ecological communities. Ecosystem recovery, and therefore maintenance of critical structures and functions (resilience), is likely to vary across environmental gradients such as moisture availability, but has received little study. We examined conifer regeneration a decade following complete stand-replacing wildfire in dry coniferous forests spanning a 700 m elevation gradient where low elevation sites had relatively high moisture stress…
Publication Type: Journal Article
Restoration of dry forests in eastern Oregon: A field guide
Year: 2013
Dry Forest landscapes dominated by pine and mixed-conifer forests composed of ponderosa pine and associated coniferous species, such as Douglas-fir and white or grand fir, are extensive in western North America, including the Pacific Northwest (Franklin and Dyrness, 1988). These forests typically occupy landscapes that are moisture limited and historically experienced disturbance regimes that included frequent wildfire. On many sites fires were predominantly low severity but mixed-severity and, occasionally, even high-severity wildfire occurred, the latter primarily in areas at higher…
Publication Type: Report
Mapping multiple forest threats in the northwestern United States
Year: 2013
US forestlands are increasingly subject to disturbances including wildfire, insects and disease, and urban and exurban development. Devising strategies for addressing these “forest threats“ depends on anticipating where individual disturbances are most likely and where they might occur in combination. However, many spatial data sets describing forest threats are produced at fine scales but are intended only for coarse-scale planning and policy purposes. We demonstrate one way to combine and display forest threat data at their appropriate spatial scales, using spatial data characterizing…
Publication Type: Journal Article
Living in a tinderbox: wildfire risk perceptions and mitigating behaviors
Year: 2013
The loss of homes to wildfires is an important issue in the USA and other countries. Yet many homeowners living in fire-prone areas do not undertake mitigating actions, such as clearing vegetation, to decrease the risk of losing their home. To better understand the complexity of wildfire risk-mitigation decisions and the role of perceived risk, we conducted a survey of homeowners in a fire-prone area of the front range of the Rocky Mountains in Colorado. We examine the relationship between perceived wildfire risk ratings and risk-mitigating behaviours in two ways. First, we model wildfire…
Publication Type: Journal Article
Latent resilience in ponderosa pine forest: effects of resumed frequent fire
Year: 2013
Ecological systems often exhibit resilient states that are maintained through negative feedbacks. In ponderosa pine forests, fire historically represented the negative feedback mechanism that maintained ecosystem resilience; fire exclusion reduced that resilience, predisposing the transition to an alternative ecosystem state upon reintroduction of fire. We evaluated the effects of reintroduced frequent wildfire in unlogged, fire-excluded, ponderosa pine forest in the Bob Marshall Wilderness, Montana, USA. Initial reintroduction of fire in 2003 reduced tree density and consumed surface fuels,…
Publication Type: Journal Article
Assessing potential climate change effects on vegetation using a linked model approach
Year: 2013
We developed a process that links the mechanistic power of dynamic global vegetation models with the detailed vegetation dynamics of state-and-transition models to project local vegetation shifts driven by projected climate change. We applied our approach to central Oregon (USA) ecosystems using three climate change scenarios to assess potential future changes in species composition and community structure. Our results suggest that: (1) legacy effects incorporated in state-and-transition models realistically dampen climate change effects on vegetation; (2) species-specific response to fire…
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
Restoring and Managing Mixed Conifer Forests in the PNW
Year: 2013
Many collaborative groups working across the eastside of Oregon and Washington have developed good working agreements on treatments appropriate for ponderosa pine forest types. These groups are actively supporting and helping to develop projects that will meet ecological objectives for dry forests while generating jobs and economic activity in local communities. Currently, there is less agreement on how to approach restoration and management of mixed-conifer forests, in large part because there does not appear to be a comparable scientific consensus as that which exists for ponderosa pine…
Publication Type: Conference Proceedings
ArcFuels10 System Overview
Year: 2013
Fire behavior modeling and geospatial analyses can provide tremendous insight for land managers as they grapple with the complex problems frequently encountered in wildfire risk assessments and fire and fuels management planning. Fuel management often is a particularly complicated process in which the benefits and potential impacts of fuel treatments need to be demonstrated in the context of land management goals and public expectations. The fuel treatment planning process is complicated by the lack of data assimilation among fire behavior models and weak linkages to geographic information…
Publication Type: Report
Simulating effects of climate change and ecological restoration on fire behaviour in a south-western USA ponderosa pine forest
Year: 2012
Global climate change has the potential to affect future wildfire activity, particularly in south-western USA ponderosa pine forests that have been substantially altered by land-use practices and aggressive fire suppression. Using two regional general circulation models for the A1B greenhouse gas emission scenario, Australia's CSIRO:MK3 and Germany's MPIM:ECHAMS, we predicted fire behaviour under the 80th, 90th and 97th percentiles of future fire-weather conditions at a study site on the Kaibab National Forest, Arizona. We then altered the fuel structure by simulating alternative ecological…
Publication Type: Journal Article
Comparative Hazard Assessment for Protected Species in a Fire-Prone Landscape
Year: 2012
We conducted a comparative hazard assessment for 325,000 ha in a fire-prone area of southwest Oregon, USA. The landscape contains a variety of land ownerships, fire regimes, and management strategies. Our comparative hazard assessment evaluated the effects of two management strategies on crown fire potential and northern spotted owl (Strix occidentalis caurina) conservation: (1) no action, and (2) active manipulation of hazardous fuels. Model simulations indicated that active management of sites with high fire hazard was more favorable to spotted owl conservation over the long term (75 years…
Publication Type: Journal Article
Mastication and Prescribed Fire Influences on Tree Mortality and Predicted Fire Behavior in Ponderosa Pine
Year: 2012
The purpose of this study was to provide land managers with information on potential wildfire behavior and tree mortality associated with mastication and masticated/fire treatments in a plantation. Additionally, the effect of pulling fuels away from tree boles before applying fire treatment was studied in relation to tree mortality. Fuel characteristics and tree mortality data were gathered before and after treatments in a 25-year-old ponderosa pine (Pinus ponderosa C. Lawson) plantation. A random block design was used with three treatments plus a control at each of four blocks. Four plots…
Publication Type: Journal Article
Fuel treatment impacts on estimated wildfire carbon loss from forests in Montana, Oregon, California, and Arizona
Year: 2012
Using forests to sequester carbon in response to anthropogenically induced climate change is being considered across the globe. A recent U.S. executive order mandated that all federal agencies account for sequestration and emissions of greenhouse gases, highlighting the importance of understanding how forest carbon stocks are influenced by wildfire. This paper reports the effects of the most common forest fuel reduction treatments on carbon pools composed of live and dead biomass as well as potential wildfire emissions from six different sites in four western U.S. states. Additionally, we…
Publication Type: Journal Article
Temporal dynamics and decay of coarse wood in early seral habitats of dry-mixed conifer forests in Oregon’s Eastern Cascades
Year: 2012
Early seral forest habitats are increasingly valued for the unique structural resources they provide in many western US forests. Coarse woody detritus (CWD) are a significant feature of this developmental stage and are highly dynamic, suggesting these environments exhibit temporally diverse structural conditions prior to forest canopy closure. In dry-mixed conifer forests, snags are hypothesized to decay slower than logs making long-term dynamics in these forests dependent on snag fall, breakage and the decay rates of both standing and surface CWD. We estimated snag fall and breakage rates…
Publication Type: Journal Article