Research Database
Displaying 41 - 60 of 106
Effects of season and interval of prescribed burns on pyrogenic carbon in ponderosa pine stands in the southern Blue Mountains, Oregon, USA
Year: 2019
In ponderosa pine (Pinus ponderosa) forests of the western United States, prescribed burns are used to reduce fuel loads and restore historical fire regimes. The season of and interval between burns can have complex consequences for the ecosystem, including the production of pyrogenic carbon (PyC). PyC plays a crucial role in soil carbon cycling, displaying turnover times that are orders of magnitude longer than unburned organic matter. This work investigated how the season of and interval between prescribed burns affects soil organic matter, including the formation and retention of PyC, in a…
Publication Type: Journal Article
Wildfires as an ecosystem service
Year: 2019
Wildfires are often perceived as destructive disturbances, but we propose that when integrating evolutionary and socioecological factors, fires in most ecosystems can be understood as natural processes that provide a variety of benefits to humankind. Wildfires generate open habitats that enable the evolution of a diversity of shade‐intolerant plants and animals that have long benefited humans. There are many provisioning, regulating, and cultural services that people obtain from wildfires, and prescribed fires and wildfire management are tools for mimicking the ancestral role of wildfires in…
Publication Type: Journal Article
Recovery of ectomycorrhizal fungus communities fifteen years after fuels reduction treatments in ponderosa pine forests of the Blue Mountains, Oregon
Year: 2018
Managers use restorative fire and thinning for ecological benefits and to convert fuel-heavy forests to fuel-lean landscapes that lessen the threat of stand-replacing wildfire. In this study, we evaluated the long-term impact of thinning and prescribed fire on soil biochemistry and the mycorrhizal fungi associated with ponderosa pine (Pinus ponderosa). Study sites were located in the Blue Mountains of northeastern Oregon where prescribed fire treatments implemented in 1998 and thinning treatments in 2000 included prescribed fire, mechanical thinning of forested areas, a combination of…
Publication Type: Journal Article
Fire frequency drives decadal changes in soil carbon and nitrogen and ecosystem productivity
Year: 2018
Fire frequency is changing globally and is projected to affect the global carbon cycle and climate. However, uncertainty about how ecosystems respond to decadal changes in fire frequency makes it difficult to predict the effects of altered fire regimes on the carbon cycle; for instance, we do not fully understand the long-term effects of fire on soil carbon and nutrient storage, or whether fire-driven nutrient losses limit plant productivity. Here we analyse data from 48 sites in savanna grasslands, broadleaf forests and needleleaf forests spanning up to 65 years, during which time the…
Publication Type: Journal Article
Pyro-Ecophysiology: Shifting the Paradigm of Live Wildland Fuel Research
Year: 2018
The most destructive wildland fires occur in mixtures of living and dead vegetation, yet very little attention has been given to the fundamental differences between factors that control their flammability. Historically, moisture content has been used to evaluate the relative flammability of live and dead fuels without considering major, unreported differences in the factors that control their variations across seasons and years. Physiological changes at both the leaf and whole plant level have the potential to explain ignition and fire behavior phenomena in live fuels that have been poorly…
Publication Type: Journal Article
Towards an understanding of the evolutionary role of fire in animals
Year: 2018
Wildfires underpin the dynamics and diversity of many ecosystems worldwide, and plants show a plethora of adaptive traits for persisting recurrent fires. Many fire-prone ecosystems also harbor a rich fauna; however, knowledge about adaptive traits to fire in animals remains poorly explored. We review existing literature and suggest that fire is an important evolutionary driver for animal diversity because (1) many animals are present in fire-prone landscapes and may have structural and phenotypic characters that contribute to adaptation to these open landscapes; and (2) in some cases, animals…
Publication Type: Journal Article
The influence of fire history on soil nutrients and vegetation cover in mixed-severity fire regime forests of the eastern Olympic Peninsula, Washington, USA
Year: 2018
The rain shadow forests of the Olympic Peninsula exemplify a mixed-severity fire regime class in the midst of a highly productive landscape where spatial heterogeneity of fire severity may have significant implications for below and aboveground post-fire recovery. The purpose of this study was to quantify the impacts of wildfire on forest soil carbon (C) and nitrogen (N) pools and assess the relationship of pyrogenic carbon (PyC) to soil processes in this mixed-severity ecosystem. We established a 112-year fire chronosequence with nine similar forest stands ranging in time since lastfire (TSF…
Publication Type: Journal Article
Recent post-wildfire salvage logging benefits local and landscape floral and bee communities
Year: 2018
Understanding the implications of shifts in disturbance regimes for plants and pollinators is essential for successful land management. Wildfires are essential natural disturbances that are important drivers of forest biodiversity, and there is often pressure to respond to wildfire with management like post-wildfire logging (i.e., removal of dead trees for economic value immediately following wildfire). We investigated how local floral and bee density, species richness, and community composition and dispersion were influenced by post-wildfire logging, and how these effects differed between an…
Publication Type: Journal Article
Using fire to promote biodiversity
Year: 2017
Fire profoundly influences people, climate, and ecosystems (1). The impacts of this interaction are likely to grow, with climate models forecasting widespread increases in fire frequency and intensity because of rising global temperatures (2). However, the relationship between fire and biodiversity is complex (3, 4). Many plants and animals require fire for their survival, yet even in fire-prone ecosystems, some species and communities are highly sensitive to fire. Recent studies (2, 3, 5, 6) are helping to define fire regimes that support the conservation of species with different…
Publication Type: Journal Article
Diversity in forest management to reduce wildfire losses: implications for resilience
Year: 2017
This study investigates how federal, state, and private corporate forest owners in a fire-prone landscape of southcentral Oregon manage their forests to reduce wildfire hazard and loss to high-severity wildfire. We evaluate the implications of our findings for concepts of social–ecological resilience. Using interview data, we found a high degree of "response diversity" (variation in forest management decisions and behaviors to reduce wildfire losses) between and within actor groups. This response diversity contributed to heterogeneous forest conditions across the landscape and was driven…
Publication Type: Journal Article
Emissions from prescribed burning of timber slash piles in Oregon
Year: 2017
Emissions from burning piles of post-harvest timber slash (Douglas-fir) in Grande Ronde, Oregon were sampled using an instrument platform lofted into the plume using a tether-controlled aerostat or balloon. Emissions of carbon monoxide, carbon dioxide, methane, particulate matter (PM2.5), black carbon, ultraviolet absorbing PM, elemental/organic carbon, filter-based metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzodioxins/dibenzofurans (PCDD/PCDF), and volatile organic compounds (VOCs) were sampled to determine emission factors, the amount of pollutant formed per amount…
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
Forest management scenarios in a changing climate: trade-offs between carbon, timber, and old forest
Year: 2016
Balancing economic, ecological, and social values has long been a challenge in the forests of the Pacific Northwest, where conflict over timber harvest and old-growth habitat on public lands has been contentious for the past several decades. The Northwest Forest Plan, adopted two decades ago to guide management on federal lands, is currently being revised as the region searches for a balance between sustainable timber yields and habitat for sensitive species. In addition, climate change imposes a high degree of uncertainty on future forest productivity, sustainability of timber harvest,…
Publication Type: Journal Article
Wildfire, climate, and invasive grass interactions negatively impact an indicator species by reshaping sagebrush ecosystems
Year: 2016
Iconic sagebrush ecosystems of the American West are threatened by larger and more frequent wildfires that can kill sagebrush and facilitate invasion by annual grasses, creating a cycle that alters sagebrush ecosystem recovery post disturbance. Thwarting this accelerated grass–fire cycle is at the forefront of current national conservation efforts, yet its impacts on wildlife populations inhabiting these ecosystems have not been quantified rigorously. Within a Bayesian framework, we modeled 30 y of wildfire and climatic effects on population rates of change of a sagebrush-obligate species,…
Publication Type: Journal Article
Restoring forest structure and process stabilizes forest carbon in wildfire-prone southwestern ponderosa pine forests
Year: 2016
Changing climate and a legacy of fire-exclusion have increased the probability of high-severity wildfire, leading to an increased risk of forest carbon loss in ponderosa pine forests in the southwestern USA. Efforts to reduce high-severity fire risk through forest thinning and prescribed burning require both the removal and emission of carbon from these forests, and any potential carbon benefits from treatment may depend on the occurrence of wildfire. We sought to determine how forest treatments alter the effects of stochastic wildfire events on the forest carbon balance. We modeled three…
Publication Type: Journal Article
Does increased forest protection correspond to higher fire severity in frequent-fire forests of the western United States?
Year: 2016
There is a widespread view among land managers and others that the protected status of many forestlands in the western United States corresponds with higher fire severity levels due to historical restrictions on logging that contribute to greater amounts of biomass and fuel loading in less intensively managed areas, particularly after decades of fire suppression. This view has led to recent proposals—both administrative and legislative—to reduce or eliminate forest protections and increase some forms of logging based on the belief that restrictions on active management have increased fire…
Publication Type: Journal Article
Post-fire logging produces minimal persistent impacts on understory vegetation in northeastern Oregon, USA
Year: 2016
Post-fire forest management commonly requires accepting some negative ecological impacts from management activities in order to achieve management objectives. Managers need to know, however,whether ecological impacts from post-fire management activities are transient or cause long-term ecosystem degradation. We studied the long-term response of understory vegetation to two post-fire loggingtreatments – commercial salvage logging with and without additional fuel reduction logging – on a long-term post-fire logging experiment in northeastern Oregon, USA. We sampled understory plant coverand…
Publication Type: Journal Article
Burning the legacy? Influence of wildfire reburn on dead wood dynamics in a temperate conifer forest
Year: 2016
Dynamics of dead wood, a key component of forest structure, are not well described for mixed- severity fi re regimes with widely varying fi re intervals. A prominent form of such variation is when two stand- replacing fi res occur in rapid succession, commonly termed an early- seral “reburn.” These events are thought to strongly infl uence dead wood abundance in a regenerating forest, but this hypothesis has scarcely been tested. We measured dead wood following two overlapping wildfi res in coniferdominated forests of the Klamath Mountains, Oregon (USA), to assess whether reburning (15- yr…
Publication Type: Journal Article
Positive effects of fire on birds may appear only under narrow combinations of fire severity and time-since-fire
Year: 2016
We conducted bird surveys in 10 of the first 11 years following a mixed-severity fire in a dry, low-elevation mixed-conifer forest in western Montana, United States. By defining fire in terms of fire severity and time-since-fire, and then comparing detection rates for species inside 15 combinations of fire severity and time-since-fire, with their rates of detection in unburned (but otherwise similar) forest outside the burn perimeter, we were able to assess more nuanced effects of fire on 50 bird species. A majority of species (60%) was detected significantly more frequently inside than…
Publication Type: Journal Article
Long-term effects of wildfire on greater sage-grouse - integrating population and ecosystem concepts for management in the Great Basin
Year: 2015
Greater sage-grouse (Centrocercus urophasianus; hereinafter, sage-grouse) are a sagebrush obligate species that has declined concomitantly with the loss and fragmentation of sagebrush ecosystems across most of its geographical range. The species currently is listed as a candidate for federal protection under the Endangered Species Act (ESA). Increasing wildfire frequency and changing climate frequently are identified as two environmental drivers that contribute to the decline of sage-grouse populations, yet few studies have rigorously quantified their effects on sage-grouse populations across…
Publication Type: Report