Research Database
Displaying 101 - 120 of 125
The relationship of post-fire white ash cover to surface fuel consumption
Year: 2013
White ash results from the complete combustion of surface fuels, making it a logically simple retrospective indicator of surface fuel consumption. However, the strength of this relationship has been neither tested nor adequately demonstrated with field measurements. We measured surface fuel loads and cover fractions of white ash and four other surface materials (green vegetation, brown non-photosynthetic vegetation, black char and mineral soil) immediately before and after eight prescribed fires in four disparate fuelbed types: boreal forest floor, mixed conifer woody slash, mixed conifer…
Publication Type: Journal Article
Regional constraints to biological nitrogen fixation in post-fire forest communities
Year: 2013
Biological nitrogen fixation (BNF) is a key ecological process that can restore nitrogen (N) lost in wildfire and shape the pace and pattern of post-fire forest recovery. To date, there is limited information on how climate and soil fertility interact to influence different pathways of BNF in early forest succession. We studied asymbiotic (forest floor and soil) and symbiotic (the shrub Ceanothus integerrimus) BNF rates across six sites in the Klamath National Forest, California, USA. We used combined gradient and experimental phosphorus (P) fertilization studies to explore cross-site…
Publication Type: Journal Article
Using native annual plants to restore post-fire habitats in western North America
Year: 2013
Increasing fire frequencies and uncharacteristic severe fires have created a need for improved restoration methods across rangelands in western North America. Traditional restoration seed mixtures of native perennial mid- to late-seral plant species may not be suitable for intensely burned sites that have been returned to an early-seral condition. Under such conditions, native annual plant species are likely to be more successful at becoming established and competing with exotic annual plant species, such as Bromus tectorum L., for resources. We used a field study in Colorado and Idaho, USA,…
Publication Type: Journal Article
Fuels and Fire Behavior Dynamics in Bark Beetle-Attacked Forests in Western North America and Implications for Fire Management
Year: 2012
Declining forest health attributed to associations between extensive bark beetle-caused tree mortality, accumulations of hazardous fuels, wildfire, and climate change have catalyzed changes in forest health and wildfire protection policies of land management agencies. These changes subsequently prompted research to investigate the extent to which bark beetle-altered fuel complexes affect fire behavior. Although not yet rigorously quantified, the results of the investigations, in addition to a growing body of operational experience and research, indicates that predictable changes in surface,…
Publication Type: Journal Article
Surface fuel treatments in young, regenerating stands affect wildfire severity in a mixed conifer forest, eastside Cascade Range, Washington, USA
Year: 2012
Previous studies have debated the flammability of young regenerating stands, especially those in a matrix of mature forest, and no consensus has emerged as to whether young stands are inherently prone to high severity wildfire. This topic has recently been addressed using spatial imagery, and weak inferences were made given the scale mismatch between the coarse resolution of spatial imagery and the fine resolution of mechanisms driving fire severity. We collected empirical stand and fire-severity data from 44 regenerating stands that are interspersed in mature, mid-elevation forests in the…
Publication Type: Journal Article
Surface Fire Intensity Influences Simulated Crown Fire Behavior in Lodgepole Pine Forests with Recent Mountain Pine Beetle-Caused Tree Mortality
Year: 2012
Recent bark beetle outbreaks have had a significant impact on forests throughout western North America and have generated concerns about interactions and feedbacks between beetle attacks and fire. However, research has been hindered by a lack of experimental studies and the use of fire behavior models incapable of accounting for the heterogeneous fuel complexes. We populated the Wildland-Urban Interface Fire Dynamics Simulator with data from 11 field sites to investigate the effect of mountain pine beetle (MPB)-caused tree mortality on simulated crown fire behavior across a range of surface…
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
Impact of postfire logging on soil bacterial and fungal communities on biogeochemistry in a mixed-conifer forest in central Oregon
Year: 2012
Aims Postfire logging recoups the economic value of timber killed by wildfire, but whether such forest management activity supports or impedes forest recovery in stands differing in structure from historic conditions remains unclear. The aim of this study was to determine the impact of mechanical logging after wildfire on soil bacterial and fungal communities and other measures influencing soil productivity. Methods We compared soil bacterial and fungal communities and biogeochemical responses of 1) soils compacted, and 2) soils compacted and then subsoiled, to 3) soils receiving no…
Publication Type: Journal Article
Alteration and Recovery of Slash Pile Burn Sites in the Restoration of a Fire-Maintained Ecosystem
Year: 2012
Restoration practices incorporating timber harvest (e.g. to remove undesirable species or reduce tree densities) may generate unmerchantable wood debris that is piled and burned for fuel reduction. Slash pile burns are common in longleaf pine ecosystem restoration that involves hardwood removal before reintroduction of frequent prescribed fire. In this context, long-lasting effects of slash pile burns may complicate restoration outcomes due to unintended alterations to vegetation, soils, and the soil seed bank. In this study, our objectives were to (1) examine alterations to the soil seed…
Publication Type: Journal Article
Wildfire severity mediates fluxes of plant material and terrestrial invertebrates to mountain streams
Year: 2012
Wildfire effects upon riparian plant community structure, composition, and distribution may strongly influence the dynamic relationships between riparian vegetation and stream ecosystems. However, few studies have examined the influence of fire on these processes. To that end, we compared the quantity and composition of allochthonous inputs of plant material and terrestrial invertebrates among stream tributaries characterized by various degrees of burn severity 5 years post-fire in the Frank Church Wilderness of central Idaho, USA. The magnitude of inputs of coniferous leaf litter to unburned…
Publication Type: Journal Article
The Long-Term Effects of Wildfire and Post-Fire Vegetation on Sierra Nevada Forest Soils
Year: 2012
This paper compares carbon (C) and nutrient contents in soils (Alfisols derived from andesite), forest floor and vegetation in a former fire (1960) and an adjacent forest in the Sagehen Watershed in the Sierra Nevada Mountains of California. Soils from the former fire (now occupied predominantly by Ceanothus velutinus, a nitrogen-fixing shrub) had significantly lower contents of extractable SO42− and P (both Bray and bicarbonate) but significantly greater contents of exchangeable Ca2+ than the adjacent forested site (dominated by Pinus jeffreyii). N data suggested that N fixation had occurred…
Publication Type: Journal Article
Effectiveness of post-fire seeding at the Fitzner-Eberhardt Arid Land Ecology Reserve, Washington
Year: 2011
In August 2007, the Milepost 17 and Wautoma fires burned a combined total of 77,349 acres (31,302 hectares) of the Fitzner-Eberhardt Arid Land Ecology Reserve (ALE), part of the Hanford Reach National Monument administered by the U.S. Fish and Wildlife Service (USFWS) Mid-Columbia National Wildlife Refuge. In 2008, the USFWS implemented a series of seeding and herbicide treatments to mitigate potential negative consequences of these fires, including mortality of native vegetation, invasion of Bromus tectorum (cheatgrass), and soil erosion. Treatments included combinations of seeding (drill…
Publication Type: Report
After the Fire is Out
Year: 2011
Even before firefighters have left a burn site, a second wave of specialists is deployed. Their task: to assess the burn site; determine the level of risk to life, property, and ecological resources; and determine quickly the most effective postfire treatments for emergency stabilization and initial rehabilitation of the site. For the past 13 years, the Joint Fire Science Program (JFSP) has funded research on this critical phase of work, which often goes unnoticed after the fire is out. With support from the JFSP, scientists have made great strides in improving the tools available to assess…
Publication Type: Report
Assessing Fuel Treatment Effectiveness After the Tripod Complex Fires
Year: 2011
Over the past 50 years, wildfire frequency and area burned have increased in the dry forests of western North America. To help reduce high surface fuel loads and potential wildfire severity, a variety of fuel treatments are applied. In spite of the common use of these management practices, there have been relatively few opportunities to quantitatively measure their efficacy in wildfires. That changed with the 2006 Tripod Complex fires in the Okanogan-Wenatchee National Forest in Washington—one of the largest fire events in Washington state over the past five decades. A serendipitous…
Publication Type: Report
Nontribal community recovery from wildfire five years later: The case of the Rodeo-Chediski fire
Year: 2011
Recent literature suggests that natural disasters such as wildfires often have the short-term effect of ‘‘bringing people together’’ while also under some circumstances generating social conflict at the local level. Conflict has been documented particularly when social relations are disembedded by nonlocal entities and there is a perceived loss of local agency. There is less agreement about longer term impacts. We present results of a re-study of a set of communities affected by the largest wildfire in Arizona history. The re-study uses structuration theory to suggest that while local…
Publication Type: Journal Article
Woodpecker Habitat After the Fire
Year: 2011
Public land managers are asked to minimize fuel levels after fires, including using techniques such as salvage logging. They are also responsible for maintaining suitable wildlife habitat, especially for species of concern to state and federal agencies. An area where these responsibilities could conflict is in the use of salvage logging in burned-over areas that also represent good habitat for certain wildlife such as woodpeckers. Controversy over this conflict has led to litigation. Public land management agencies need consistent design criteria to maintain suitable habitats for these birds…
Publication Type: Report
Vegetation recovery after fire in the Klamath-Siskiyou region, southern Oregon
Year: 2011
This overview is intended to facilitate decisions regarding forest regeneration in the Klamath-Siskiyou Ecoregion. It summarizes the results of several scientific investigations that took place in the ecoregion. Some of the research occurred in areas without post-fire management, and other research occurred in moderately or intensively managed areas. Some of the research also occurred immediately after a wildfire, and other work occurred several decades later.
Publication Type: Report
Prescribed fires as ecological surrogates for wildfires: A stream and riparian perspective
Year: 2010
Forest managers use prescribed fire to reduce wildfire risk and to provide resource benefits, yet little information is available on whether prescribed fires can function as ecological surrogates for wildfire in fire-prone landscapes. Information on impacts and benefits of this management tool on stream and riparian ecosystems is particularly lacking. We used a beyond-BACI (Before, After, Control, Impact) design to investigate the effects of a prescribed fire on a stream ecosystem and compared these findings to similar data collected after wildfire. For 3 years after prescribed fire treatment…
Publication Type: Journal Article
The fire pulse: wildfire stimulates flux of aquatic prey to terrestrial habitats driving increase in riparian consumers
Year: 2010
We investigated the midterm effects of wildfire (in this case, five years after the fire) of varying severity on periphyton, benthic invertebrates, emerging adult aquatic insects, spiders, and bats by comparing unburned sites with those exposed to low severity (riparian vegetation burned but canopy intact) and high severity (canopy completely removed) wildfire. We observed no difference in periphyton chlorophyll a or ash-free dry mass among different burn categories but did observe significantly greater biomass of benthic invertebrates in both high severity burned and unburned reaches versus…
Publication Type: Journal Article
Response of antelope bitterbrush to repeated prescribed burning in Central Oregon ponderosa pine forests
Year: 2009
Antelope bitterbrush is a dominant shrub in many interior ponderosa pine forests in the western United States. How it responds to prescribed fire is not well understood, yet is of considerable concern to wildlife and fire managers alike given its importance as a browse species and as a ladder fuel in these fire-prone forests. We quantified bitterbrush cover, density, and biomass in response to repeated burning in thinned ponderosa pine forests. Low- to moderate-intensity spring burning killed the majority of bitterbrush plants on replicate plots. Moderately rapid recovery of bitterbrush…
Publication Type: Journal Article