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The Northwest Fire Science Consortium works to accelerate the awareness, understanding, and adoption of wildland fire science. We connect managers, practitioners, scientists, and local communities and collaboratives working on fire issues on forest and range lands in Washington and Oregon.

Learn more about NWFSC...

JFSP Regions


NWFSC is one of
fifteen regional exchanges
sponsored by the Joint Fire Science Program.


Seeking consensus in post-fire management: The Canyon Creek example

Hot Topics

Do insect outbreaks reduce the severity of subsequent forest fires?

Authored by G.W. Meigs; Published 2016

Understanding the causes and consequences of rapid environmental change is an essential scientific frontier, particularly given the threat of climate- and land use-induced changes in disturbance regimes. In western North America, recent widespread insect outbreaks and wildfires have sparked acute concerns about potential insect–fire interactions. Although previous research shows that insect activity typically does not increase wildfire likelihood, key uncertainties remain regarding insect effects on wildfire severity (i.e., ecological impact). Recent assessments indicate that outbreak severity and burn severity are not strongly associated, but these studies have been limited to specific insect or fire events. Here, we present a regional census of large wildfire severity following outbreaks of two prevalent bark beetle and defoliator species, mountain pine beetle (Dendroctonus ponderosae) and western spruce budworm (Choristoneura freemani), across the US Pacific Northwest. We first quantify insect effects on burn severity with spatial modeling at the fire event scale and then evaluate how these effects vary across the full population of insect–fire events (n = 81 spanning 1987–2011). In contrast to common assumptions of positive feedbacks, we find that insects generally reduce the severity of subsequent wildfires. Specific effects vary with insect type and timing, but both insects decrease the abundance of live vegetation susceptible to wildfire at multiple time lags. By dampening subsequent burn severity, native insects could buffer rather than exacerbate fire regime changes expected due to land use and climate change. In light of these findings, we recommend a precautionary approach when designing and implementing forest management policies intended to reduce wildfire hazard and increase resilience to global change.

NWFSC Fire Facts: What is? A Fire Adapted Community

Authored by N.W.Fire Scien Consortium; Published 2016

A Fire Adapted Community acknowledges and takes responsibility for its risk of wildfires and takes appropriate actions at all levels of the community. Read more at Fire Facts: What is? A Fire Adapted Community

Ignition patterns influence fire severity and plant communities in Pacific Northwest, USA, prairies

Authored by A. Martin; Published 2016

In the prairies of the Pacific Northwest, USA, fire has been reintroduced as a tool for reducing non-native, invasive plant cover and promoting the growth and establishment of native plant communities.  Head fires and backing fires are the two primary ignition patterns used to complete most prescribed burns, but the relative effectiveness of these two methods on invasive plant control and native enhancement is unknown.  A clear understanding of the relationship between fire behavior, fire severity, and fire effects on vegetation and how these metrics are affected by fire ignition patterns could help managers fine tune burn prescriptions to better achieve ecological objectives.  We used observations from five prescribed burns in the south Puget Sound prairies of western Washington, USA, to evaluate the relationship between intensity, severity, and effects.  Additionally, we collected data from two burns on how ignition patterns affected these relationships.  We found a significant positive correlation between maximum surface temperature and fire severity, and a decline in perennial taxa with increasing fire severity.  We also found that surface temperatures did not differ between ignition patterns, but a greater area burned at moderate severity in backing fires than in head fires.  Ignition patterns differentiated plant communities by changing the number of species present within different life form categories.  However, this response was contingent upon site history and pre-burn conditions.  Native perennial forbs were associated with head fires in a site with high pre-existing native plant species richness.  Native and exotic forbs were associated with backing fires at a site with low pre-existing native plant species richness.  Thus, managers may want to consider ignition patterns when planning burn prescriptions in order to achieve particular ecological objectives.

Using native plants in fuel breaks

Fuel breaks are common treatments on rangelands where the spread of invasive annuals and subsequent wildfire are a threat to sagebrush ecosystems. Fuel breaks are often seeded with non-native plants such as crested wheatgrass or forage kochia. However, there are alternatives using native grasses and forbs which have been shown to be effective. Mark Williams, BLM, Winnemucca, NV, will discuss the advantages and disadvantages of using native plants in fuel breaks.

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NWFSC Fire Facts: The National Cohesive Strategy

Authored by N.W.Fire Scien Consortium; Published 2016

The National Cohesive Wildland Fire Management Strategy is a collaboration effort involving federal and state agencies, local governments, tribes, and interested stakeholders throughout the nation to improve coordination across the various jurisdictions for managing wildfire. Read more at Fire Facts: What is? The National Cohesive Strategy

The ability of winter grazing to reduce wildfire size and fire-induced plant mortality was not demonstrated: a comment on Davies et al. (2015)

Authored by A.M. Smith; Published 2016

A recent study by Davies et al. sought to test whether winter grazing could reduce wildfire size, fire behaviour
and intensity metrics, and fire-induced plant mortality in shrub–grasslands. The authors concluded that ungrazed
rangelands may experience fire-induced mortality of native perennial bunchgrasses. The authors also presented several
statements regarding the benefits of winter grazing on post-fire plant community responses. However, we contend that the
study by Davies et al. has underlying methodological errors, lacks data necessary to support their conclusions, and does not
provide a thorough discussion on the effect of grazing on rangeland ecosystems. Importantly, Davies et al. presented no
data on the post-fire mortality of the perennial bunchgrasses or on the changes in plant community composition following
their experimental fires. Rather, Davies et al. inferred these conclusions based on their observed fire behaviour metrics of
maximum temperature and a term described as the ‘heat load’. However, we contend that neither metric is appropriate for
describing the heat flux impacts on plants. This lack of post-fire data, several methodological errors and the use of
inappropriate thermal metrics limit the authors’ ability to support their stated conclusions

Dormant season grazing may decrease wildfire probability by increasing fuel moisture and reducing fuel amount and continuity

Authored by K.W. Davies; Published 2015

Mega-fires and unprecedented expenditures on fire suppression over the past decade have resulted in a renewed focus on presuppression management. Dormant season grazing may be a treatment to reduce fuels in rangeland, but its effects have not been evaluated. In the present study, we evaluated the effect of dormant season grazing (winter grazing in this ecosystem) by cattle on fuel characteristics in sagebrush (Artemisia L.) communities at five sites in south-eastern Oregon. Winter grazing reduced herbaceous fuel cover, continuity, height and biomass without increasing exotic annual grass biomass or reducing bunchgrass basal area or production. Fuel moisture in winter-grazed areas was high enough that burning was unlikely until late August; in contrast, fuels in ungrazed areas were dry enough to burn in late June. Fuel biomass on perennial bunchgrasses was decreased by 60% with winter grazing, which may reduce the potential for fire-induced mortality. The cumulative effect of winter grazing from altering multiple fuel characteristics may reduce the likelihood of fire and the potential severity in sagebrush communities with an understorey dominated by herbaceous perennials. Dormant season grazing has the potential to reduce wildfire suppression expenditures in many rangelands where herbaceous fuels are an issue; however, increasing woody vegetation and extreme fire weather may limit its influence.

Synthesis of Knowledge of Extreme Fire Behavior: Volume II for Fire Behavior Specialists, Researchers, and Meteorologists

Authored by P.A. Werth; Published 2016

The National Wildfire Coordinating Group’s definition of extreme fire behavior indicates a level of fire behavior characteristics that ordinarily precludes methods of direct control
action. One or more of the following is usually involved: high rate of spread, prolific crowning/ spotting, presence of fire whirls, and strong convection column. Predictability is difficult
as such fires often influence their environment to some degree and behave erratically, sometimes dangerously. Alternate terms include “blow up” and “fire storm.” Fire managers
examining fires over the last 100 years have come to understand many of the factors necessary for extreme fire behavior development. This effort produced guidelines included in
current firefighter training, which presents the current methods of predicting extreme fire behavior by using the crown fire model, which is based on the environmental influences of
weather, fuels, and topography. Current training does not include the full extent of scientific understanding nor does it include the most recent scientific knowledge. National Fire Plan funds and the Joint Fire
Science Program have sponsored newer research related to wind profiles’ influence on fire behavior, plume growth, crown fires, fire dynamics in live fuels, and conditions associated
with vortex development. Of significant concern is that characteristic features of extreme fire behavior depend on conditions undetectable on the ground, namely invisible properties
such as wind shear or atmospheric stability. No one completely understands all the factors contributing to extreme fire behavior because of gaps in our knowledge. These gaps, as well as the limitations as to when various
models or indices apply should be noted to avoid application where they are not appropriate or warranted. This synthesis summarizes existing extreme fire behavior knowledge. It
consists of two volumes. Volume 1 is for fire managers, firefighters, and others in the fire community who are not experts or specialists in fire behavior but need to understand the
basics of extreme fire behavior. Volume 2 is more technical and is intended for fire behaviorists and fire researchers.

Winter grazing decreases the probability of fire-induced mortality of bunchgrasses and may reduce wildfire size: a response to Smith et al.

Authored by K.W. Davies; Published 2016

A recent commentary by Smith et al. (2016) argues that our study (Davies et al. 2016) contained
methodological errors and lacked data necessary to support our conclusions, in particular that winter grazing may reduce
the probability of fire-induced mortality of bunchgrasses. Carefully reading Davies et al. (2016) and relevant literature
provides strong evidence that the comments of Smith et al. are unfounded. Most notably, Smith et al. (2016) state that
thermocouples placed in the air have no correlation to temperatures experienced by vegetation. However, in our study,
thermocouples were placed inside the centre of meristematic crowns of bunchgrasses, as was clearly stated in the methods.
Nowhere in the manuscript does it say that thermocouples were placed in the air. Duration of elevated temperatures has
been repeatedly linked to an increased risk of fire-induced mortality of vegetation in the literature, contrary to claims by
Smith et al. (2016) that no evidence of a relationship exists. The conclusion that winter grazing may decrease the likelihood
of perennial bunchgrass mortality was not based solely on data collected in this experiment, but also Davies et al. (2009),
where post-fire bunchgrass density and production in ungrazed areas were less than half those of grazed areas.

Does prescribed fire promote resistance to drought in low elevation forests of the Sierra Nevada, California, USA?

Authored by P.J. van Mantgem; Published 2016

Prescribed fire is a primary tool used to restore western forests following more than a century of fire exclusion, reducing fire hazard by removing dead and live fuels (small trees and shrubs).  It is commonly assumed that the reduced forest density following prescribed fire also reduces competition for resources among the remaining trees, so that the remaining trees are more resistant (more likely to survive) in the face of additional stressors, such as drought.  Yet this proposition remains largely untested, so that managers do not have the basic information to evaluate whether prescribed fire may help forests adapt to a future of more frequent and severe drought.

During the third year of drought, in 2014, we surveyed 9950 trees in 38 burned and 18 unburned mixed conifer forest plots at low elevation (<2100 m a.s.l.) in Kings Canyon, Sequoia, and Yosemite national parks in California, USA.  Fire had occurred in the burned plots from 6 yr to 28 yr before our survey.  After accounting for differences in individual tree diameter, common conifer species found in the burned plots had significantly reduced probability of mortality compared to unburned plots during the drought.  Stand density (stems ha-1) was significantly lower in burned versus unburned sites, supporting the idea that reduced competition may be responsible for the differential drought mortality response.  At the time of writing, we are not sure if burned stands will maintain lower tree mortality probabilities in the face of the continued, severe drought of 2015.  Future work should aim to better identify drought response mechanisms and how these may vary across other forest types and regions, particularly in other areas experiencing severe drought in the Sierra Nevada and on the Colorado Plateau.

1984–2010 trends in fire burn severity and area for the conterminous US

Authored by J.J. Picotte; Published 2016

Burn severity products created by the Monitoring Trends in Burn Severity (MTBS) project were used to analyse historical trends in burn severity. Using a severity metric calculated by modelling the cumulative distribution of differenced Normalized Burn Ratio (dNBR) and Relativized dNBR (RdNBR) data, we examined burn area and burn severity of 4893 historical fires (1984–2010) distributed across the conterminous US (CONUS) and mapped by MTBS. Yearly mean burn severity values (weighted by area), maximum burn severity metric values, mean area of burn, maximum burn area and total burn area were evaluated within 27 US National Vegetation Classification macrogroups. Time series assessments of burned area and severity were performed using Mann–Kendall tests. Burned area and severity varied by vegetation classification, but most vegetation groups showed no detectable change during the 1984–2010 period. Of the 27 analysed vegetation groups, trend analysis revealed burned area increased in eight, and burn severity has increased in seven. This study suggests that burned area and severity, as measured by the severity metric based on dNBR or RdNBR, have not changed substantially for most vegetation groups evaluated within CONUS.

Post-fire logging produces minimal persistent impacts on understory vegetation in northeastern Oregon, USA

Authored by D.W. Peterson; Published 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 logging
treatments – 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 cover
and species diversity on 10–11 sampling plots within each of nine experimental treatment units to see if post-fire logging treatments produced any lasting effects on understory plant cover, species diversity,
community composition, or exotic species cover. Post-fire logging treatments produced no significant effects on understory vegetation cover, diversity, or community composition 15 years after treatment.
We found no significant treatment effects on graminoid, forb, woody plant, or exotic plant cover and species richness, and differences among treatment means were generally small. Differences in treatment
means were larger at the individual species level, but were only statistically significant for one native grass, California brome (Bromus carinatus), which responded differently to the two logging treatments.
Multivariate analysis of understory plant communities across 91 sample plots found two major gradients in understory plant community composition, one correlated with regenerating forest (sapling) density
and one correlated with residual overstory tree density, suggesting that initial fire severity (tree mortality) and post-fire regeneration may have greater long-term impacts on post-fire understory vegetation
than post-fire logging. This study demonstrates that understory vegetation can be resilient to post-fire logging, particularly when best management practices, like logging over snow, are used to limit damage
to soils and understory vegetation. Further research is needed to establish the generality of our results and to identify sources of variability in understory plant community responses to wildfire and postfire
logging. If further research confirms our findings, post-fire logging debates will be able to focus more on how to mitigate short-term disturbance impacts and manage fire-killed trees to meet wildlife habitat,
fuel reduction, and economic objectives, and less on concerns over long-term ecosystem degradation.

NWFSC Fire Facts: What is? Red Flag Warning

Authored by N.W.Fire Scien Consortium; Published 2016

A Red Flag Warning is issued by the National Weather Service (NWS) to alert land management agencies about the onset, or possible onset, of critical weather and fuel moisture conditions that could lead to rapid or dramatic increases in wildfire activity. Read more at Fire Facts: What is? Red Flag Warning

Forest fuels and potential fire behaviour 12 years after variable-retention harvest in lodgepole pine

Authored by J.S. Crotteau; Published 2016

Variable-retention harvesting in lodgepole pine offers an alternative to conventional, even-aged management. This harvesting technique promotes structural complexity and age-class diversity in residual stands and promotes resilience to disturbance. We examined fuel loads and potential fire behaviour 12 years after two modes of variable-retention harvesting (dispersed and aggregated retention patterns) crossed by post-harvest prescribed fire (burned or unburned) in central Montana. Results characterise 12-year post-treatment fuel loads. We found greater fuel load reduction in treated than untreated stands, namely in the 10- and 100-h classes (P = 0.002 and 0.049 respectively). Reductions in 1-h (P < 0.001), 10-h (P = 0.008) and 1000-h (P = 0.014) classes were greater in magnitude for unburned than burned treatments. Fire behaviour modelling incorporated the regenerating seedling cohort into the surface fuel complex. Our analysis indicates greater surface fireline intensity in treated than untreated stands (P < 0.001), and in unburned over burned stands (P = 0.001) in dry, windy weather. Although potential fire behaviour in treated stands is predicted to be more erratic, within-stand structural variability reduces probability of crown fire spread. Overall, results illustrate trade-offs between potential fire attributes that should be acknowledged with variable-retention harvesting.

Incorporating Anthropogenic Influences into Fire Probability Models: Effects of Human Activity and Climate Change on Fire Activity in California

Authored by M.L. Mann; E. Batllori; M.A. Moritz; E.K. Waller; P. Berck; A.L. Flint; L.E. Flint; E. Dolfi; Published 2016

The costly interactions between humans and wildfires throughout California demonstrate the need to understand the relationships between them, especially in the face of a changing climate and expanding human communities. Although a number of statistical and process-based wildfire models exist for California, there is enormous uncertainty about the location and number of future fires, with previously published estimates of increases ranging from nine to fifty-three percent by the end of the century. Our goal is to assess the role of climate and anthropogenic influences on the state’s fire regimes from 1975 to 2050. We develop an empirical model that integrates estimates of biophysical indicators relevant to plant communities and anthropogenic influences at each forecast time step. Historically, we find that anthropogenic influences account for up to fifty percent of explanatory power in the model. We also find that the total area burned is likely to increase, with burned area expected to increase by 2.2 and 5.0 percent by 2050 under climatic bookends (PCM and GFDL climate models, respectively). Our two climate models show considerable agreement, but due to potential shifts in rainfall patterns, substantial uncertainty remains for the semiarid inland deserts and coastal areas of the south. Given the strength of human-related variables in some regions, however, it is clear that comprehensive projections of future fire activity should include both anthropogenic and biophysical influences. Previous findings of substantially increased numbers of fires and burned area for California may be tied to omitted variable bias from the exclusion of human influences. The omission of anthropogenic variables in our model would overstate the importance of climatic ones by at least 24%. As such, the failure to include anthropogenic effects in many models likely overstates the response of wildfire to climatic change.

Outcomes of fire research: is science used?

Authored by M.E. Hunter; Published 2016

An assessment of outcomes from research projects funded by the Joint Fire Science Program was conducted to determine whether or not science has been used to inform management and policy decisions and to explore factors that facilitate use of fire science. In a web survey and follow-up phone interviews, I asked boundary spanners and scientists about how findings from a random sample of 48 projects had been applied and factors that acted as barriers or facilitators to science application. In addition, I conducted an investigation of recent planning documents to determine whether products from the sampled projects were cited. All lines of evidence suggest that information from most (44 of 48) of these projects have been used by fire and fuels managers in some capacity. Science has mostly been used during planning efforts, to develop treatment prescriptions, and to evaluate current practices. Lack of manager awareness was commonly identified as a barrier to application of science. Conversely, activities and organisations that foster interaction between scientists and managers were identified as facilitating the application of science. The efforts of the Joint Fire Science Program to communicate science findings and engage managers has likely contributed to the application of fire science.

Vegetation Response to Piñon and Juniper Tree Shredding

Authored by J. Bybee; Published 2016

Piñon (Pinus spp.) and juniper (Juniperus spp.) expansion and infilling in sagebrush (Artemisia L.) steppe communities can lead to high-severity fire and annual weed dominance. To determine vegetation response to fuel reduction by tree mastication (shredding) or seeding and then shredding, we measured cover for shrub and herbaceous functional groups on shredded and adjacent untreated areas on 44 sites in Utah. We used mixed model analysis of covariance to determine significant differences among ecological site type (expansion and tree climax) and treatments across a range of pretreatment tree cover as the covariate. Although expansion and tree climax sites differed in cover values for some functional groups, decreasing understory cover with increasing tree cover and increased understory cover with tree reduction was similar for both ecological site types. Shrub cover decreased by 50% when tree cover exceeded 20%. Shredding trees at ≤ 20% cover maintained a mixed shrub (18.6% cover)−perennial herbaceous (17.6% cover) community. Perennial herbaceous cover decreased by 50% when tree cover exceeded 40% but exceeded untreated cover by 11% (20.1% cover) when trees were shredded at 15−90% tree cover. Cheatgrass (Bromus tectorum L.) cover also increased after tree shredding or seeding and then shredding but was much less dominant (< 10% cover) where perennial herbaceous cover exceeded 42%. Sites with high cheatgrass cover on untreated plots had high cheatgrass cover on shredded and seeded-shredded plots. Seeding and then shredding decreased cheatgrass cover compared with shredding alone when implemented at tree cover ≥ 50%. Vegetation responses to shredding on expansion sites were generally similar to those for tree cutting treatments in the SageSTEP study. Shredding or seeding and then shredding should facilitate wildfire suppression, increase resistance to weed dominance, and lead toward greater resilience to disturbance by increasing perennial herbaceous cover.

Seeking consensus in post-fire management: The Canyon Creek example

Webinar from Northwest Fire Science Consortium

Seeking consensus is a challenging process. But the Blue Mountains Forest Collaborative and the USFS are beginning to find common ground.

The interagency fuels treatment decision support system: Functionality for fuels treatment planning

Authored by S.A. Drury; Published 2016

The Interagency Fuels Treatment Decision Support System (IFTDSS) is a web-based software and data integration framework that organizes fire and fuels software applications into a single online application. IFTDSS is designed to make fuels treatment planning and analysis more efficient and effective. In IFTDSS, users can simulate fire behavior and fire effects using the scientific algorithms and processes found in desktop applications including FlamMap, Behave, FOFEM, and Consume. Strategic-level goals of IFTDSS are to
• simplify the fuels treatment planning decision-support process;
• improve the overall quality of analysis and planning;
• control long-term costs;
• encourage scientific collaboration;
• reduce agency information technology (IT) workload in deploying and maintaining fuels applications and data; and
• promote interagency collaboration within the fire and fuels community.

This paper discusses the tools and processes IFTDSS offers to fire, fuels, and resource managers responsible for planning fuels treatment within a framework of hazard analysis and risk assessment. We outline how fire and
fuels treatment planners can use IFTDSS to identify areas of high hazard and risk, evaluate the potential burning risk and hazard level for valued resources (values at risk) within the area of interest, and simulate the effectiveness of fuels treatments in reducing the potential harm to values at risk.