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Pacific Northwest Research Station

Pacific Northwest Research Station
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2011 Fire and Smoke Research

Key Findings and Products

A new book, The Landscape Ecology of Fire, analyzes wildfire in western North America at the spatial scales most relevant for management, with an emphasis on how fire regimes may evolve in an era of rapid global change.

Intensive thinning treatments are needed to reduce crown fire hazard in dry forests of the western United States.

The MC1 Fire Forecasting System provides the basis for experimental forecasts of annual firefighting expenditures and optimal timing for prescribed fire.



New book analyzes landscape fire regimes across western North America

Understanding wildfire dynamics across a broad range of spatial scales is critical in an era of rapid climate change. Ecologicalfire science is most complex at intermediate scales (e.g., watersheds or national forest districts). The recently published book The Landscape Ecology of Fire presents new work on the theoretical context of landscape fire, including cross-scale analyses; fire climatology specifically applied to landscapes; effects of fire on biogeochemistry, wildlife populations, and other ecosystem elements; and management and the human dimension of landscape fire in a warming climate. For example, cross-scale analysis of fire regimes from watersheds to ecoregions suggests that shifting controls on fire occurrence and spread (climate, topography, fuels) can be quantified and projected into new climate regimes. On the human side, regional-scale adaptation strategies are presented along with a West-wide analysis of the effects of population growth on wilderness fire management.

The book is written for university students, agency scientists, and land managers with jurisdictions from local watersheds to broad ecoregions e.g., Forest Service regions). Two new lines of research stem from this book: the ecohydrology of fire and landscape fire theory.

Contact: Don McKenzie,, Threat Characterization and Management Program

Partners: University of Arizona, University of Washington, USDA Forest Service Rocky Mountain Research Station

For more information: McKenzie, D.; Miller, C.; Falk, D.A., eds. 2011. The landscape ecology of fire. Ecological Studies. V. 213. New York: Springer Science. 312 p.


Simulating fuel treatments on 40,000 stands yields quantitative guidelines for resource managers


June 2011 Wallow Fire, Apache-Sitgreaves National Forest, Arizona (Photo by Jason Coil).Dry forest ecosystems prevalent in western North America historically exhibited high-frequency and low- to moderate-severity fire regimes. Several decades of fire exclusion have made these forests more susceptible to active crown fire and higher burn severity. Fuel treatments are often implemented to reduce fire hazard caused by increased stem densities in low- to moderate-severity fire regimes. With millions of hectares of dry forests in the western United States requiring fuel treatment, forest and fire managers need information to support science-based decisionmaking for fuel management.

In the largest study ever evaluating the effectiveness of fuel treatments, researchers used simulation results from over 40,000 stands to infer that thinning to 50 to 100 trees per acre followed by prescribed burning to remove slash was the most effective treatment combination to reduce crown fire hazard in dry forest types throughout the western United States. These quantitative guidelines for thinning and fuel treatment provide resource managers and fire managers with the scientific basis for reducing stand densities and surface fuels.

This study received significant media coverage; it was featured in Greenwire, Land Letter, National Public Radio, and the Arizona Daily Sun, among others.

Contact: Morris C. Johnson,, Threat Characterization and Management Program

Partner: University of Washington


Fire forecasting system provides basis for expenditure forecast and timing of prescribed fire

Station scientists produce continuously updated 7-month forecasts of fire potential and drought for the conterminous United States for use in fire management planning. As of 2010, these high-resolution forecast models are routinely run at the Arctic Region Supercomputer Center in partnership with the University of Alaska. Along with summary maps of predicted drought and fire potential, the MC1 Fire Forecasting System now also predicts area burned, the moisture content of several live and dead fuel classes, and measures of potential fire behavior including rate of spread, fireline intensity, and the energy release component. These detailed data are being provided as input to two new experimental forecasting systems under development by researchers at the Rocky Mountain Research Station and Western Regional Climate Center (WRCC).

The Rocky Mountain Research Station is using MC1 burn forecasts to predict annual firefighting expenditures with results that are significantly better than the professional judgments currently made at the National Interagency Fire Center. The WRCC is using MC1 forecasts of fuel moisture and fire behavior to predict optimal timing for prescribed fire and posting them monthly to a WRCC-sponsored Web site.

Contact: Jim Lenihan,, and Ray Drapek,, Ecological Process and Function Program

Partners: Desert Research Institute, Oregon State University, National Interagency Fire Center, University of Alaska, USDA Forest Service Rocky Mountain Research Station, Western Regional Climate Center


Station expertise helped predict smoke from Southwest fires


June 2011 Wallow Fire, Apache-Sitgreaves National Forest, Arizona.

Use: National Interagency Fire Coordination Center uses expertise to issue daily smoke forecasts.

This year , numerous large wildfires burned across the southwestern United States. Fueled by historically low fuel moistures, these fires exhibited explosive growth and grew to unprecedented size—the Wallow Fire is the largest in contemporary Arizona history. The smoke from these fires created a significant public health challenge, blanketing large swaths of Arizona and New Mexico with unhealthy air quality conditions.

Federal, state, tribal, and local government agencies pooled resources to create a coordinated smoke and health effects outlook that was disseminated to the public. Expertise from the PNW Research Station was requested and was a key component of this effort. Station scientists provided a core set of customized advanced smoke modeling results and expert analyses to the group on a daily basis. Their efforts were instrumental in determining the daily smoke outlook.

These reports were linked to the Web site that lists information about all active fires in the Nation (Inciweb) and accessed thousands of times by involved agencies and the public. The reports were redistributed by up to 20 agencies that coordinated their message through daily consultations. The smoke outlooks were also picked up by television stations around the region and were used by the public for such things as rescheduling sporting events to avoid times of peak smoke.

Contact: Sim Larkin,, Threat Characterization and Management Program

Partners: Desert Research Institute; Lawrence Livermore National Laboratory’s National Atmospheric Release Advisory Center; Mazama Science; National Weather Service; Sonoma Technology, Inc.; USDA Forest Service Southwestern Region Fire and Aviation Management, Wildland Fire Research Development and Application


Analysis of atmospheric thermal troughs suggests why they cause more active fire behavior

Thermal troughs are atmospheric structures found along the west coast of the United States, characterized by high surface temperatures and low pressure. They typically form along the coast or in Oregon’s Willamette Valley and eventually move eastward across the Cascade Range. They are associated with active, highly variable fire behavior at all times, but most notably as they cross the ridge of the Cascades. Analysis of historical thermal troughs using atmospheric models revealed characteristic wind patterns aloft, patterns that are not detectable on the ground but capable of intensifying winds and fire behavior. Continuing, more detailed analysis of a small set of thermal trough events and the associated fire behavior is clarifying finer scale structure and the forces causing the wind patterns.

A prototype Web page has been created and shared with the Northwest fire weather community for their use and evaluation. The numerical prediction maps and atmospheric cross-sections displayed were chosen based on ongoing discussions with the National Weather Service and the Northwest Interagency Coordination Center.

Contact: Brian Potter,, Threat Characterization and Management Program

Partners: National Weather Service, Northwest Interagency Coordination Center, University of Washington, USDA Forest Service Washington office

For more information:


Summer prescribed burns can reduce acorn production by Oregon white oak


A prescribed  burn in a stand of Oregon white oak will keep fuel level low and help prevent conifers from encroaching.The Oregon white oak is a sun-loving tree. Without fire, conifers increasingly dominate the stand, and oak is eventually shaded out. Prior to Euro-American settlement, American Indians who gathered acorns for food frequently burned Oregon white oak woodlands to favor the tree. This killed the young conifers and led to grassy understories. These low-intensity grass fires often caused only minor canopy damage to oaks. Prescribed fire is once again being used in many Pacific Northwest woodlands to control competition from woody vegetation. Understory conditions have changed, however. Where shrubs have replaced grass, fire burns hotter and causes more tree damage.

Because white oak flowers and leaves form inside the buds one year prior to actual flowering, researchers found that buds are particularly vulnerable to summer fire damage. Researchers were able to relate fire intensity to acorn production. Even when tree buds are not killed, flowering and acorn production the following year may be reduced. This information will help land mangers effectively use prescribed burns to manage oak woodlands and wildlife that depend on acorns for food.

Contact: David Peter,, Threat Characterization and Management Program

Partner: U.S. Department of Defense, Joint Base Lewis-McChord


Postfire management influences later plant communities

Restoring burned forests on federal lands in southwest Oregon may have multiple objectives, including protecting site productivity, maintaining diversity of species in the near and long term, and developing structurally complex mature stands. Station scientists have monitored various reforestation methods that were applied to burned plantations following the 2002 Timbered Rock Fire. They observed that removing competing vegetation had a greater effect on the composition of plant communities than did planting conifer seedlings.

Woody shrubs were cut back repeatedly during the first 3 years following conifer planting. This did not remove shrubs from the sites, but the temporary reduction in their abundance resulted in the early development of different postfire vegetation communities, when compared to sites where woody shrubs were not cut back. Initial increases in the occurrence of nonnative invasive species were very small, suggesting that the reforestation treatments were not likely to directly lead to invasive species problems.

This information may be useful to land managers in southwest Oregon who are preparing postfire strategies for reforestation, vegetation, and fuel management. It can also be applied more broadly by modelers interested in predicting postfire vegetation and fuel dynamics at stand and landscape scales.

Contact: Paul D. Anderson,, Land and Watershed Management Program

Partners: Oregon State University, USDI Bureau of Land Management




Fuel Characteristic Classification System(FCCS) v. 2.2

Description: The Fuel Characteristic Classification System (FCCS) was designed to build and catalog fuelbeds by using inventoried fuel data, photo series, or literature. Fuelbeds span the canopy to the ground and have been mapped for the continental United States. The system predicts surface fire behavior including reaction intensity, flame length, and rate of spread; and surface fire behavior, crown fire, and available fuel potential using a 9-point index. Version 2.2 was released in 2011 with refined fire behavior equations, a total carbon calculator, and options for both metric and English units. Station scientists are working with the University of Aveiro, Portugal, and the University of Alcala, Spain, to build FCCS fuelbeds representing Portugal and the world.

Use: The FCCS is used to build and characterize fuels for specified areas at any scale of interest. FCCS fuelbeds have been created for the Okanogan-Wenatchee National Forest, central Oregon, the Lake Tahoe Basin, and the U.S. Department of Energy’s Savannah River Site. The associated fire behavior predictions and total carbon represented by the fuelbeds for these areas also have been mapped. This information is being used for fire hazard planning and evaluating fuels treatment effectiveness.

How to get it:

Contact: Roger Ottmar,, Threat Characterization and Management Program


Fuel Characteristics Classification System/Forest Vegetation Simulator Postprocessor

Description: The Forest Vegetation Simulator (FVS) is used to predict forest stand dynamics. It is used extensively throughout the United States. The Fire and Fuels Extension to FVS, when combined with the Fuel Characteristic Classification System (FCCS), has the potential to model fire effects and succession more realistically and with higher resolution. Postprocessors are stand-alone pplications that extend the capabilities of a model. This new postprocessor will integrate the effects of silvicultural and surface fuel treatments, using realistic fuels and making the fuels component more visible, user friendly, and flexible within the modeling system.

Use: The FVS is the standard model used by various government agencies including the USDA Forest Service, USDI Bureau of Land Management, and USDI Bureau of Indian Affairs. The new interface provided by this postprocessor will allow managers to more accurately determine the outcomes of fuel treatments, especially with respect to duration of treatment effectiveness.

How to get it: Tool will be distributed with the FVS program, or download from

Contact: Morris C. Johnson,, Threat Characterization and Management Program


Modeling the Effect of Fire on Aquatic Systems

Description: These models predict the potential of fire to alter critical in-stream salmon habitat by modeling a fire’s potential to facilitate delivery of sediment and large wood to stream channels. The models are also used to consider road impacts following fires.

The analysis tools incorporate the physical attributes of hillslopes and of stream channels with models of fire behavior and fire intensity across the landscape. These tools are designed to be used with output from FlamMap—a fire behavior mapping and analysis program. The models are available in the ArcGIS version of NetMap and some portion of them will become available in a Web browser in 2012.

Use: These tools are intended for land and natural resource management.

How to get it:

Contact: Rebecca Flitcroft,, Land and Watershed Management Program

Partner: Earth Systems Institute


US Forest Service - Pacific Northwest Research Station
Last Modified: Tuesday,18November2014 at14:53:02CST

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