Research Database
Displaying 81 - 100 of 114
Recent burning of boreal forests exceeds fire regime limits of the past 10,000 years
Year: 2015
Wildfire activity in boreal forests is anticipated to increase dramatically, with far-reaching ecological and socioeconomic consequences. Paleorecords are indispensible for elucidating boreal fire regime dynamics under changing climate, because fire return intervals and successional cycles in these ecosystems occur over decadal to centennial timescales. We present charcoal records from 14 lakes in the Yukon Flats of interior Alaska, one of the most flammable ecoregions of the boreal forest biome, to infer causes and consequences of fire regime change over the past 10,000 y. Strong…
Publication Type: Journal Article
Modeling wildfire regimes in forest landscapes: abstracting a complex reality
Year: 2015
Fire is a natural disturbance that is nearly ubiquitous in terrestrial ecosystems. The capacity to burn exists virtually wherever vegetation grows. In some forested landscapes, fire is a principal driver of rapid ecosystem change, resetting succession ( McKenzie et al. 1996a ) and changing wildlife habitat (Cushman et al. 2011 ), hydrology ( Feikema et al. 2013 ), element cycles ( Smithwick 2011 ), and even landforms (Pierce et al. 2004 ). In boreal forests, for example, recurring wildfi res are the main cause of compositional and spatial patterns ( Wein and MacLean 1983 ), where a fi re-…
Publication Type: Book Chapter
Effectiveness of fuel treatments for mitigating wildfire risk and sequestering forest carbon: A case study in the Lake Tahoe Basin
Year: 2014
Fuel-reduction treatments are used extensively to reduce wildfire risk and restore forest diversity and function. In the near future, increasing regulation of carbon (C) emissions may force forest managers to balance the use of fuel treatments for reducing wildfire risk against an alternative goal of C sequestration. The objective of this study was to evaluate how long-term fuel treatments mitigate wildfires and affect forest C. For the Lake Tahoe Basin in the central Sierra Nevada, USA, fuel treatment efficiency was explored with a landscape-scale simulation model, LANDIS-II, using five fuel…
Publication Type: Journal Article
Landscape restoration of a forest with a historically mixed-severity fire regime: What was the historical landscape pattern of forest and openings?
Year: 2014
Forest management of dry forests in the western US that historically experienced mixed-severity fire regimes is increasingly focused on landscape-scale restoration. However, this restoration effort is constrained by historic range of variation (HRV) reference conditions that lack information concerning the spatial configuration of these forests at intermediate scales (approximately 0.01–100 ha). I used reconstruction methods to map historical (1860) pattern of ponderosa pine-Douglas-fir forests along twenty 1 km long transects on Colorado’s Front Range and compared pre-settlement opening and…
Publication Type: Journal Article
Severity of an uncharacteristically large wildfire, the Rim Fire, in forests with relatively restored frequent fire regimes
Year: 2014
The 2013 Rim Fire, originating on Forest Service land, burned into old-growth forests within Yosemite National Park with relatively restored frequent-fire regimes (¡Ý2 predominantly low and moderate severity burns within the last 35 years). Forest structure and fuels data were collected in the field 3-4 years before the fire, providing a rare chance to use pre-existing plot data to analyze fire effects. We used regression tree and random forests analysis to examine the influence of forest structure, fuel, fire history, topographic and weather conditions on observed fire severity in the Rim…
Publication Type: Journal Article
Climate, fire size, and biophysical setting control fire severity and spatial pattern in the northern Cascade Range, USA
Year: 2014
Warmer and drier climate over the past few decades has brought larger fire sizes and increased annual area burned in forested ecosystems of western North America, and continued increases in annual area burned are expected due to climate change. As warming continues, fires may also increase in severity and produce larger contiguous patches of severely burned areas. We used remotely sensed burn-severity data from 125 fires in the northern Cascade Range of Washington, USA, to explore relationships between fire size, severity, and the spatial pattern of severity. We examined relationships between…
Publication Type: Journal Article
The climate-wildfire-air quality system: interactions and feedbacks across spatial and temporal scales
Year: 2014
Future climate change and its effects on social and ecological systems present challenges for preserving valued ecosystem services, including local and regional air quality. Wildfire is a major source of air-quality impact in some locations, and a substantial contributor to pollutants of concern, including nitrogen oxides and particulate matter, which are regulated to protect public and environmental health. Since climate change is expected to increase total area burned by wildfire and wildfires affect air quality, which is regulated, there is a need to define and study climate, wildfire, and…
Publication Type: Journal Article
Mixed-severity fire in lodgepole-dominated forests: Are historical regimes sustainable on Oregon's Pumice Plateau, USA?
Year: 2014
In parts of central Oregon, coarse-textured pumice substrates limit forest composition to low-density lodgepole pine (Pinus contorta Douglas ex Loudon var. latifolia Engelm. ex S. Watson) with scattered ponderosa pine (Pinus ponderosa Lawson & C. Lawson) and a shrub understory dominated by antelope bitterbrush (Purshia tridentata (Pursh) DC.). We reconstructed the historical fire regime from tree rings and simulated fire behavior over 783 hectares of this forest type. For centuries (1650-1900), extensive mixed-severity fires occurred every 26 to 82 years, creating a multi-aged forest and…
Publication Type: Journal Article
Contrasting Spatial Patterns in Active-Fire and Fire- Suppressed Mediterranean Climate Old-Growth Mixed Conifer Forests
Year: 2014
In Mediterranean environments in western North America, historic fire regimes in frequent-fire conifer forests are highly variable both temporally and spatially. This complexity influenced forest structure and spatial patterns, but some of this diversity has been lost due to anthropogenic disruption of ecosystem processes, including fire. Information from reference forest sites can help management efforts to restore forests conditions that may be more resilient to future changes in disturbance regimes and climate. In this study, we characterize tree spatial patterns using four-ha stem maps…
Publication Type: Journal Article
Wildfire, Wildlands, and People: Understanding and preparing for wildfire in the wildland-urban interface
Year: 2013
Fire has historically played a fundamental ecological role in many of America’s wildland areas. However, the rising number of homes in the wildland-urban interface (WUI), associated impacts on lives and property from wildfire, and escalating costs of wildfire management have led to an urgent need for communities to become "fire-adapted." We present maps of the conterminous United States that illustrate historical natural fire regimes, the wildland-urban interface, and the number and location of structures burned since 1999. We outline a sampler of actions, programs, and community planning and…
Publication Type: Report
Fire-mediated pathways of stand development in Douglas-fir/ western hemlock forests of the Pacific Northwest, USA
Year: 2013
Forests dominated by Douglas-fir and western hemlock in the Pacific Northwest of the United States have strongly influenced concepts and policy concerning old-growth forest conservation. Despite the attention to their old-growth characteristics, a tendency remains to view their disturbance ecology in relatively simple terms, emphasizing infrequent, stand-replacing (SR) fire and an associated linear pathway toward development of those old-growth characteristics. This study uses forest stand- and age-structure data from 124 stands in the central western Cascades of Oregon to construct a…
Publication Type: Journal Article
The merits of prescribed fire outweigh potential carbon emission effects
Year: 2013
A White Paper developed by Association for Fire Ecology, International Association of Wildland Fire, Tall Timbers Research Station, and The Nature Conservancy.While North American ecosystems vary widely in their ecology and natural historical fire regimes, they are unified in benefitting from prescribed fire when judiciously applied with the goal of maintaining and restoring native ecosystem composition, structure, and function. On a modern landscape in which historical fire regimes cannot naturally occur due to fuel load build-up and resulting public safety concerns, the cornerstone…
Publication Type: Report
Powered by Oregon - The potential for woody biomass
Year: 2013
As a fuel, wood has been with us since humans tamed fire. So what’s the big deal? Why the renewed interest in wood as a source of energy? If we imagine a way to power Oregon that is less dependent on fossil fuels, that is built instead on renewable and homegrown sources of energy, then woody fuel should be a significant part of the picture. Why do we import oil or propane to heat a rural town, for instance, when abundant, clean-burning fuel is a few miles away? Using local fuel creates jobs and keeps money at home. Many small Oregon towns could use more of both. Is it sustainable? Yes. In…
Publication Type: Report
Fire regimes of quaking aspen in the Mountain West
Year: 2013
Quaking aspen, the most widespread tree species in North America, reproduces primarily by resprouting from roots. In some stands, mortality from fire encourages sprouting and prevents conifers from eventually replacing aspen. In other areas, aspen can form stable communities that do not require fire to regenerate or persist. USGS fire ecologist Doug Shinneman and colleagues reviewed literature about aspen populations and fire, summarized research findings, and suggested a classification system for aspen across the western mountainous United States. The scientists proposed five aspen “fire…
Publication Type: Journal Article
Effects of salvage logging and pile-and-burn on fuel loading, potential fire behavior, fuel consumption and emissions
Year: 2013
We used a combination of field measurements and simulation modelling to quantify the effects of salvage logging, and a combination of salvage logging and pile-and-burn fuel surface fuel treatment (treatment combination), on fuel loadings, fire behaviour, fuel consumption and pollutant emissions at three points in time: post-windstorm (before salvage logging), post-salvage logging and post-surface fuel treatment (pile-and-burn). Salvage logging and the treatment combination significantly reduced fuel loadings, fuelbed depth and smoke emissions. Salvage logging and the treatment combination…
Publication Type: Journal Article
Interactions of insects, fire and climate on fuel loads and fire behavior in mixed conifer forest
Year: 2013
Mixed-conifer forests in the interior Pacific Northwest are subject to sporadic outbreaks of the western spruce budworm, the most destructive defoliator in western North America. Such outbreaks usually occur synchronously over broad regions and lead to widespread decreases in growth rates and low to moderate levels of mortality. In the last century, changing land use and fire suppression have led to an increase in the amount and density of host tree species, and changed fire regimes. This has altered the severity and frequency of both fire and western spruce budworm. In spite of the…
Publication Type: Report
Ecological effects of alternative fuel-reduction treatments: highlights of the National Fire and Fire Surrogate study (FSS)
Year: 2012
The 12-site National Fire and Fire Surrogate study (FFS) was a multivariate experiment that evaluated ecological consequences of alternative fuel-reduction treatments in seasonally dry forests of the US. Each site was a replicated experiment with a common design that compared an un-manipulated control, prescribed fire, mechanical and mechanical + fire treatments. Variables within the vegetation, fuelbed, forest floor and soil, bark beetles, tree diseases and wildlife were measured in 10-ha stands, and ecological response was compared among treatments at the site level, and across sites, to…
Publication Type: Journal Article
Characterizing Fire-on-Fire Interactions in Three Large Wilderness Areas
Year: 2012
The interaction of fires, where one fire burns into another recently burned area, is receiving increased attention from scientists and land managers wishing to describe the role of fire scars in affecting landscape pattern and future fire spread. Here, we quantify fire-on-fire interactions in terms of frequency, size, and time-since-previous fire (TSPF) in three large wilderness areas in Montana and Idaho, USA, from 1984 to present, using spatially consistent large fire perimeter data from the Monitoring Trends in Burn Severity (MTBS) dataset. The analysis is supplemented with less consistent…
Publication Type: Journal Article
Testing a pyroclimatic hypothesis on the Mexico–United States border
Year: 2012
The “pyroclimatic hypothesis” proposed by F. Biondi and colleagues provides a basis for testable expectations about climatic and other controls of fire regimes. This hypothesis asserts an a priori relationship between the occurrence of widespread fire and values of a relevant climatic index. Such a hypothesis provides the basis for predicting spatial and temporal patterns of fire occurrence based on climatic control. Forests near the Mexico–United States border offer a place to test the relative influence of climatic and other controls in mountain ranges that are ecologically similar and…
Publication Type: Journal Article
Timing of carbon emissions from global forest clearance
Year: 2012
Land-use change, primarily from conventional agricultural expansion and deforestation, contributes to approximately 17% of global greenhouse-gas emissions. The fate of cleared wood and subsequent carbon storage as wood products, however, has not been consistently estimated, and is largely ignored or oversimplified by most models estimating greenhouse-gas emissions from global land-use conversion. Here, we estimate the fate of cleared wood and timing of atmospheric carbon emissions for 169 countries. We show that 30 years after forest clearance the percentage of carbon stored in wood products…
Publication Type: Journal Article