Research Database
Displaying 1 - 17 of 17
Prescribed Fire in Grassland Butterfly Habitat: Targeting Weather and Fuel Conditions to Reduce Soil Temperatures and Burn Severity
Year: 2017
Prescribed burning is a primary tool for habitat restoration and management in fire-adapted grasslands. Concerns about detrimental effects of burning on butterfly populations, however, can inhibit implementation of treatments. Burning in cool and humid conditions is likely to result in lowered soil temperatures and to produce patches of low burn severity, both of which would enhance survival of butterfly larvae at or near the soil surface. In this study, we burned 20 experimental plots in South Puget Sound, Washington, USA, prairies across a range of weather and fuel conditions to address the…
Publication Type: Journal Article
Fires following Bark Beetles: Factors Controlling Severity and Disturbance Interactions in Ponderosa Pine
Year: 2017
Previous studies have suggested that bark beetles and fires can be interacting disturbances, whereby bark beetle–caused tree mortality can alter the risk and severity of subsequent wildland fires. However, there remains considerable uncertainty around the type and magnitude of the interaction between fires following bark beetle attacks, especially in drier forest types such as those dominated by ponderosa pine (Pinus ponderosa Lawson & C. Lawson). We used a full factorial design across a range of factors thought to control bark beetle−fire interactions, including the temporal phase of the…
Publication Type: Journal Article
Accommodating mixed-severity fire to restore and maintain ecosystem integrity with a focus on the Sierra Nevada of California, USA
Year: 2017
Existing fire policy encourages the maintenance of ecosystem integrity in fire management, yet this is difficult to implement on lands managed for competing economic, human safety, and air quality concerns. We discuss a fire management approach in the mid-elevations of the Sierra Nevada, California, USA, that may exemplify similar challenges in other fire-adapted regions of the western USA. We also discuss how managing for pyrodiversity through mixed-severity fires can promote ecosystem integrity in Sierran mixed conifer and ponderosa pine (Pinus ponderosa Laws) forests.
Publication Type: Journal Article
Alternative characterization of forest fire regimes: incorporating spatial patterns
Year: 2017
The proportion of fire area that experienced stand-replacing fire effects is an important attribute of individual fires and fire regimes in forests, and this metric has been used to group forest types into characteristic fire regimes. However, relying on proportion alone ignores important spatial characteristics of stand-replacing patches, which can have a strong influence on post-fire vegetation dynamics. We propose a new more ecologically relevant approach for characterizing spatial patterns of stand-replacing patches to account for potential limitation of conifer seed dispersal. We applied…
Publication Type: Journal Article
Post-fire vegetation and fuel development influences fire severity patterns in reburns
Year: 2017
In areas where fire regimes and forest structure have been dramatically altered, there is increasing concern that contemporary fires have the potential to set forests on a positive feedback trajectory with successive reburns, one in which extensive stand-replacing fire could promote more stand-replacing fire. Our study utilized an extensive set of field plots established following four fires that occurred between 2000 and 2010 in the northern Sierra Nevada, California, USA that were subsequently reburned in 2012. The information obtained from these field plots allowed for a unique set of…
Publication Type: Journal Article
Landscape-scale quantification of fire-induced change in canopy cover following mountain pine beetle outbreak and timber harvest
Year: 2017
Across the western United States, the three primary drivers of tree mortality and carbon balance are bark beetles, timber harvest, and wildfire. While these agents of forest change frequently overlap, uncertainty remains regarding their interactions and influence on specific subsequent fire effects such as change in canopy cover. Acquisition of pre- and post-fire Light Detection and Ranging (LiDAR) data on the 2012 Pole Creek Fire in central Oregon provided an opportunity to isolate and quantify fire effects coincident with specific agents of change. This study characterizes the influence of…
Publication Type: Journal Article
Factors influencing fire severity under moderate burning conditions in the Klamath Mountains, northern California, USA
Year: 2017
Topography, weather, and fuels are known factors driving fire behavior, but the degree to which each contributes to the spatial pattern of fire severity under different conditions remains poorly understood. The variability in severity within the boundaries of the 2006 wildfires that burned in the Klamath Mountains, northern California, along with data on burn conditions and new analytical tools, presented an opportunity to evaluate factors influencing fire severity under burning conditions representative of those where management of wildfire for resource benefit is most likely. Fire severity…
Publication Type: Journal Article
Restoring and managing low-severity fire in dry-forest landscapes of the western USA
Year: 2017
Low-severity fires that killed few canopy trees played a significant historical role in dry forests of the western USA and warrant restoration and management, but historical rates of burning remain uncertain. Past reconstructions focused on on dating fire years, not measuring historical rates of burning. Past statistics, including mean composite fire interval (mean CFI) and individual-tree fire interval (mean ITFI) have biases and inaccuracies if used as estimators of rates. In this study, I used regression, with a calibration dataset of 96 cases, to test whether these statistics could…
Publication Type: Journal Article
Vegetation Response to Burn Severity, Native Grass Seeding, and Salvage Logging
Year: 2015
As the size and extent of wildfires has increased in recent decades, so has the cost and extent of post-fire management, including seeding and salvage logging. However, we know little about how burn severity, salvage logging, and post-fire seeding interact to influence vegetation recovery long-term. We sampled understory plant species richness, diversity, and canopy cover one to six years post fire (2006 to 2009, and 2011) on 72 permanent plots selected in a stratified random sample to define post-fire vegetation response to burn severity, post-fire seeding with native grasses, and salvage…
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
Are high-severity fires burning at much higher rates recently than historically in dry-forest landscapes of the Western USA.
Year: 2015
Dry forests at low elevations in temperate-zone mountains are commonly hypothesized to be at risk of exceptional rates of severe fire from climatic change and land-use effects. Their setting is fire-prone, they have been altered by land-uses, and fire severity may be increasing. However, where fires were excluded, increased fire could also be hypothesized as restorative of historical fire. These competing hypotheses are not well tested, as reference data prior to widespread land-use expansion were insufficient. Moreover, fire-climate projections were lacking for these forests. Here, I used…
Publication Type: Journal Article
Fire severity in southwestern Colorado unaffected by spruce beetle outbreak
Year: 2015
Recent large and severe outbreaks of native bark beetles have raised concern among the general public and land managers about potential for amplified fire activity in western North America. To date, the majority of studies examining bark beetle outbreaks and subsequent fire severity in the U.S. Rocky Mountains have focused on outbreaks of mountain pine beetle (MPB, Dendroctonus ponderosae) in lodgepole pine (Pinus contorta) forests, but few studies, particularly field studies, have addressed the effects of the severity of spruce beetle (Dendroctonus rufipennis Kirby) infestation on subsequent…
Publication Type: Journal Article
Recovery of small pile burn scars in conifer forests of the Colorado Front Range
Year: 2015
The ecological consequences of slash pile burning are a concern for land managers charged with maintaining forest soil productivity and native plant diversity. Fuel reduction and forest health management projects have created nearly 150,000 slash piles scheduled for burning on US Forest Service land in northern Colorado. The vast majority of these are small piles (<5 m diameter). Similar to larger piles, we found that burning small piles had significant immediate effects on soil nutrients and physical and chemical properties and native plant cover. To evaluate the need to rehabilitate…
Publication Type: Journal Article
Limitations and utilisation of Monitoring Trends in Burn Severity products for assessing wildfire severity in the USA
Year: 2015
The Monitoring Trends in Burn Severity project is a comprehensive fire atlas for the United States that includes perimeters and severity data for all fires greater than a particular size (~400 ha in the western US, and ~200 ha in the eastern US). Although the database was derived for management purposes, the scientific community has expressed interest in its research capacity. As with any derived data, it is critical to understand inherent limitations to maximise the utility of the dataset without compromising the inferences. The classified severity product in particular is of limited use to…
Publication Type: Journal Article
The Ecological Importance of Mixed-Severity Fires: Nature's Phoenix
Year: 2015
The Ecological Importance of High-Severity Fires, presents information on the current paradigm shift in the way people think about wildfire and ecosystems. While much of the current forest management in fire-adapted ecosystems, especially forests, is focused on fire prevention and suppression, little has been reported on the ecological role of fire, and nothing has been presented on the importance of high-severity fire with regards to the maintenance of native biodiversity and fire-dependent ecosystems and species.
Publication Type: Book
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
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