Research Database
Displaying 81 - 100 of 100
An accuracy assessment of the MTBS burned area product for shrub-steppe fires in the northern Great Basin, United States
Year: 2014
Although fire is a common disturbance in shrub–steppe, few studies have specifically tested burned area mapping accuracy in these semiarid to arid environments. We conducted a preliminary assessment of the accuracy of the Monitoring Trends in Burn Severity (MTBS) burned area product on four shrub–steppe fires that exhibited varying degrees of within-fire patch heterogeneity. Independent burned area perimeters were derived through visual interpretation and were used to cross-compare the MTBS burned area perimeters with classifications produced using set thresholds on the Relativised…
Publication Type: Journal Article
Modifying the Canadian Fine Fuel Moisture Code for masticated surface fuels
Year: 2014
Mechanical mastication is a fuel management technique that disrupts the vertical continuity of forest fuels by shredding of trees and understory vegetation into a highly compacted surface fuel bed. Despite the increasing application of mastication to manage wildfire risk, there is little information to date on fuel moisture in masticated fuels and optimal ignition patterns for prescribed burning. We investigated the applicability of the Fine Fuel Moisture Code (FFMC), a component of the Canadian Fire Weather Index (FWI) System, in tracking the diurnal and day-to-day changes in masticated…
Publication Type: Journal Article
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
The role of defensible space for residential structure protection during wildfires
Year: 2014
With the potential for worsening fire conditions, discussion is escalating over how to best reduce effects on urban communities. A widely supported strategy is the creation of defensible space immediately surrounding homes and other structures. Although state and local governments publish specific guidelines and requirements, there is little empirical evidence to suggest how much vegetation modification is needed to provide significant benefits. We analysed the role of defensible space by mapping and measuring a suite of variables on modern pre-fire aerial photography for 1000 destroyed and…
Publication Type: Journal Article
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
Challenges of assessing fire and burn severity using field measures, remote sensing and modelling
Year: 2014
Comprehensive assessment of ecological change after fires have burned forests and rangelands is important if we are to understand, predict and measure fire effects. We highlight the challenges in effective assessment of fire and burn severity in the field and using both remote sensing and simulation models. We draw on diverse recent research for guidance on assessing fire effects on vegetation and soil using field methods, remote sensing and models. We suggest that instead of collapsing many diverse, complex and interacting fire effects into a single severity index, the effects of fire should…
Publication Type: Journal Article
Use of night vision goggles for aerial forest fire protection
Year: 2014
Night-time flight searches using night vision goggles have the potential to improve early aerial detection of forest fires, which could in turn improve suppression effectiveness and reduce costs. Two sets of flight trials explored this potential in an operational context. With a clear line of sight, fires could be seen from many kilometres away (on average 3584 m for controlled point sources and 6678 m for real fires). Observers needed to be nearer to identify a light as a potential source worthy of further investigation. The average discrimination distance, at which a source could be…
Publication Type: Journal Article
2014 National Smoke Forum
Year: 2014
The Forum was an opportunity to discuss the importance of wildfire smoke, review the current technology and tools that help inform decision making, discuss the policies and issues related to smoke impacts, and suggest plans for projects and organizations to address smoke issues in the future. Get the presentations and posters at FireSmoke.ca.
Publication Type: Presentation
Has Fire Suppression Increased the Amount of Carbon Stored in Western US Forests?
Year: 2008
Active 20th century fire suppression in western US forests, and a resultingincrease in stem density, is thought to account for a significant fraction of the NorthAmerican carbon sink. We compared California forest inventories from the 1930s withinventories from the 1990s to quantify changes in aboveground biomass. Stem density inmid-montane conifer forests increased by 34%, while live aboveground carbon stocksdecreased by 26%. Increased stem density reflected an increase in the number of smalltrees and a net loss of large trees. Large trees contain a disproportionate amount ofcarbon, and the…
Publication Type: Journal Article
Four centuries of soil carbon and nitrogen change after stand-replacing fire in a forest landscape in the western Cascade range of Oregon
Year: 2008
Episodic stand-replacing wildfire is a significant disturbance in mesic and moist Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests of the Pacific Northwest. We studied 24 forest stands with known fire histories in the western Cascade Range in Oregon to evaluate long-term impacts of stand-replacing wildfire on carbon (C) and nitrogen (N) pools and dynamics within the forest floor (FF, Oe and Oa horizons) and the mineral soil (0–10 cm). Twelve of our stands burned approximately 150 years ago (“young”), and the other 12 burned approximately 550 years ago (“old”). Forest floor mean C…
Publication Type: Journal Article
Postfire woodpecker foraging in salvage-logged and unlogged forests of the Sierra Nevada
Year: 2008
In forests, high-severity burn patches—whereinmost or all of the trees are killed by fire—often occur within amosaic of low- and moderate-severity effects. Although therehave been several studies of postfire salvage-logging effects onbird species, there have been few studies of effects on bird speciesassociated with high-severity patches in forests that haveotherwise burned at lower severities. From 2004 to 2006, we investigatedthe foraging presence or absence of three woodpeckerspecies, the Black-backed (Picoides arcticus), Hairy (P. villosus),and White-headed (P. albolarvatus) Woodpeckers,…
Publication Type: Journal Article
The Ecological Importance of Severe Wildfires: Some Like it Hot
Year: 2008
Many scientists and forest land managers concur that past fire suppression, grazing, and timber harvesting practices have created unnatural and unhealthy conditions in the dry, ponderosa pine forests of the western United States. Specifically, such forests are said to carry higher fuel loads and experience fires that are more severe than those that occurred historically. It remains unclear, however, how far these generalizations can be extrapolated in time and space, and how well they apply to the more mesic ponderosa pine systems and to other forest systems within the western United States.…
Publication Type: Journal Article
Burned landscapes of southwestern Oregon: what's in it for Northern Spotted Owls?
Year: 2008
Northern spotted owls are known to spend time in areas burned by wildfire, but there has been little scientific investigation of how and why they use these landscapes. A trio of wildfires in southwestern Oregon during the summers of 2001 and 2002 burned through dozens of documented spotted owl territories, providing a rare opportunity to study many important aspects of how these raptors respond to wildfire in dry forest ecosystems. For this project researchers used radio telemetry and demographic surveys to investigate habitat selection, home range size, occupancy, productivity and survival…
Publication Type: Report
Lessons of the Hayman fire: weeds, woodpeckers and fire severity
Year: 2008
This project took advantage of pre-fi re data gathered within the perimeter of Colorado’s 2002 Hayman Fire. Researchers studied the unique fi re regime of Front Range ponderosa pine forests, and fi re effects on understory-plant communities and American Three-toed Woodpeckers. Results confirmed that historically, the diverse structure of these forests was maintained by a mixed-severity fi re regime that included large areas of severe fi re. In addition, researchers found that much of the burn meets habitat requirements for American Three-toed Woodpeckers, and that understory plant species…
Publication Type: Report
In a Ponderosa Pine Forest, Prescribed Fires Reduce the Likelihood of Scorched Earth
Year: 2008
The Malheur National Forest is located in the Blue Mountains on Oregon’s eastern side, the portion of the state that lies east of the Cascade Crest. In the mid 1990s, researchers and land managers conceived a suite of experiments to explore the effects of prescribed fire on forest health. The studies were designed to coincide with prescribed burns conducted by the USDA Forest Service. The experiments took place in the Emigrant Creek Ranger District, a remote area dominated by ponderosa pine. One of the research projects aimed to assess soil health after different intervals of fire frequency…
Publication Type: Report
Behavior Modification: Tempering Fire at the Landscape Level
Year: 2008
With a history of management choices that have suppressed fire in the West, ecosystems in which fire would play a vital role have developed tremendous fuel loads. As a result, conditions are prime for fires to grow large, escape attack measures, and become catastrophic conflagrations that damage watersheds, forest resources, and homes. With a quiver of treatment options, land managers have successfully used prescribed burning and thinning to modify landscapes at the stand level. But planning treatments to modify fuel build up on a patch of forest is vastly different than planning treatments…
Publication Type: Report
Pruning
Year: 2008
Pruning is removing the lower branches of trees. Increasing the distance between the ground and the lowest tree branches reduces the likelihood that a fire on the ground will use the branches as a ladder to move into tree crowns. A crown fire is more difficult to control and can advance much more rapidly than a surface fire, under certain weather conditions.Pruning is a particularly effective fuels-reduction technique when combined with other forms of treatment such as thinning.
Publication Type: Report
Mechanical Treatments
Year: 2008
Many manual and mechanical methods are used to reduce hazardous fuels on woodland properties. This publication describes three of the most common methods: Slashbusting and grinding Mowing and mastication Crushing Mechanical methods use several types of equipment to chop, chip, crush, or otherwise break apart fuels—such as brush, small trees, and slash—into small pieces or chips. The processed fuels carpet the ground, forming a relatively dense, compact layer of woody material. The material may be integral to the prime mover or may be then is left to decompose or is burned.Mechanical…
Publication Type: Report
Disposing of Woody Material
Year: 2008
Thinning to reduce hazardous fuels often generates large amounts of woody residues, such as small-diameter logs, tree tops, and branches. This publication discusses several options for economically and effectively using and disposing of woody material.
Publication Type: Report
Thinning
Year: 2008
Thinning is one of the most powerful forest management tools available to landowners for achieving a wide range of goals and objectives. Thinning influences: Trees’ growth rates and potential economic value Which species of trees and other plants will be in the stand Trees’ resistance to insects and disease Quality of wildlife habitat Forage production The stand’s aesthetic appearance Another, very important effect is that thinning increases a forest’s ability to survive wildfire.Thinning is: Removing trees that, if left in the stand, could increase fire risk and could lessen stand vigor (for…
Publication Type: Report