Evidence of fuels management and fire weather influencing fire severity in an extreme fire event.

Following changes in vegetation structure and pattern, along with a changing climate, large wildfire incidence has increased in forests throughout the western United States. Given this increase, there is great interest in whether fuels treatments and previous wildfire can alter fire severity patterns in large wildfires. We assessed the relative influence of previous fuels treatments (including wildfire), fire weather, vegetation, and water balance on fire-severity in the Rim Fire of 2013. We did this at three different spatial scales to investigate whether the influences on fire severity changed across scales. Both fuels treatments and previous low to moderate-severity wildfire reduced the prevalence of high-severity fire. In general, areas without recent fuels treatments and areas that previously burned at high severity tended to have a greater proportion of high-severity fire in the Rim Fire. Areas treated with prescribed fire, especially when combined with thinning, had the lowest proportions of high severity. The proportion of the landscape burned at high severity was most strongly influenced by fire weather and proportional area previously treated for fuels or burned by low to moderate severity wildfire. The proportion treated needed to effectively reduce the amount of high severity fire varied by spatial scale of analysis, with smaller spatial scales requiring a greater proportion treated to see an effect on fire severity. When moderate and high-severity fire encountered a previously treated area, fire severity was significantly reduced in the treated area relative to the adjacent untreated area. Our results show that fuels treatments and low to moderate-severity wildfire can reduce fire severity in a subsequent wildfire, even when burning under fire growth conditions. These results serve as further evidence that both fuels treatments and lower severity wildfire can increase forest resilience.

[1]  S. Stephens,et al.  Novel characterization of landscape-level variability in historical vegetation structure. , 2015, Ecological applications : a publication of the Ecological Society of America.

[2]  Philip N. Omi,et al.  Theory and Practice of Wildland Fuels Management , 2015, Current Forestry Reports.

[3]  Carl H. Key,et al.  Landscape Assessment (LA) , 2006 .

[4]  Brandon M. Collins,et al.  Fire weather and large fire potential in the northern Sierra Nevada , 2014 .

[5]  Jay D. Miller,et al.  Trends in Wildfire Severity: 1984 to 2010 in the Sierra Nevada, Modoc Plateau, and Southern Cascades, California, USA , 2012, Fire Ecology.

[6]  Scott L. Stephens,et al.  Challenges and Approaches in Planning Fuel Treatments across Fire-Excluded Forested Landscapes , 2010, Journal of Forestry.

[7]  Peter H. Singleton,et al.  Restoring fire-prone Inland Pacific landscapes: seven core principles , 2015, Landscape Ecology.

[8]  Joshua H. Viers,et al.  Modern departures in fire severity and area vary by forest type, Sierra Nevada and southern Cascades, California, USA , 2013 .

[9]  Charles W. McHugh,et al.  Numerical Terradynamic Simulation Group 10-2011 A simulation of probabilistic wildfire risk components for the continental United States , 2017 .

[10]  M. Rollins.  LANDFIRE: a nationally consistent vegetation, wildland fire, and fuel assessment , 2009 .

[11]  S. Stephens,et al.  Historical and current landscape‐scale ponderosa pine and mixed conifer forest structure in the Southern Sierra Nevada , 2015 .

[12]  S. Stephens,et al.  Impacts of fire exclusion and recent managed fire on forest structure in old growth Sierra Nevada mixed-conifer forests , 2011 .

[13]  Maggi Kelly,et al.  Interactions Among Wildland Fires in a Long-Established Sierra Nevada Natural Fire Area , 2009, Ecosystems.

[14]  Robert J. McGaughey,et al.  Mixed severity fire effects within the Rim fire: Relative importance of local climate, fire weather, topography, and forest structure , 2015 .

[15]  C. Skinner,et al.  Probability of tree survival after wildfire in an interior pine forest of northern California: Effects of thinning and prescribed fire , 2007 .

[16]  Matthew P. Thompson,et al.  Negative consequences of positive feedbacks in US wildfire management , 2015, Forest Ecosystems.

[17]  Jay D. Miller,et al.  Quantifying burn severity in a heterogeneous landscape with a relative version of the delta Normalized Burn Ratio (dNBR) , 2007 .

[18]  Michael C Wimberly,et al.  Assessing fuel treatment effectiveness using satellite imagery and spatial statistics. , 2009, Ecological applications : a publication of the Ecological Society of America.

[19]  Lloyd P. Queen,et al.  Characterizing Fire-on-Fire Interactions in Three Large Wilderness Areas , 2012 .

[20]  Andrew T. Hudak,et al.  Burn Severity of Areas Reburned by Wildfires in the Gila National Forest, New Mexico, USA , 2010 .

[21]  A. Taylor,et al.  Fire regimes, forest change, and self-organization in an old-growth mixed-conifer forest, Yosemite National Park, USA. , 2010, Ecological applications : a publication of the Ecological Society of America.

[22]  P. Hessburg,et al.  DETECTING CHANGE IN FOREST SPATIAL PATTERNS FROM REFERENCE CONDITIONS , 1999 .

[23]  S. Stephens,et al.  Spatial patterns of large natural fires in Sierra Nevada wilderness areas , 2007, Landscape Ecology.

[24]  A. Taylor,et al.  Changes in forest structure, fuels and potential fire behaviour since 1873 in the Lake Tahoe Basin, USA , 2014 .

[25]  N. Stephenson,et al.  Apparent climatically induced increase of tree mortality rates in a temperate forest. , 2007, Ecology letters.

[26]  Jay D. Miller,et al.  Relating Fire-Caused Change in Forest Structure to Remotely Sensed Estimates of Fire Severity , 2016 .

[27]  Jarred D. Saralecos,et al.  Ponderosa Pine Forest Restoration Treatment Longevity: Implications of Regeneration on Fire Hazard , 2016 .

[28]  Carol Miller,et al.  Wildland fire as a self-regulating mechanism: the role of previous burns and weather in limiting fire progression. , 2015, Ecological applications : a publication of the Ecological Society of America.

[29]  M. Brooks,et al.  Short- and Long-Term Effects of Fire on Carbon in US Dry Temperate Forest Systems , 2011 .

[30]  Nicole M. Vaillant,et al.  Analyzing the transmission of wildfire exposure on a fire-prone landscape in Oregon, USA , 2014 .

[31]  A. Symstad,et al.  Fire and forest history at Mount Rushmore. , 2008, Ecological applications : a publication of the Ecological Society of America.

[32]  Brandon M. Collins,et al.  Severity of an uncharacteristically large wildfire, the Rim Fire, in forests with relatively restored frequent fire regimes , 2014 .

[33]  Carol Miller,et al.  Wildland fire limits subsequent fire occurrence , 2016 .

[34]  Scott L. Stephens,et al.  Variability in vegetation and surface fuels across mixed-conifer-dominated landscapes with over 40 years of natural fire , 2016 .

[35]  Charles W. McHugh,et al.  Simulation of long-term landscape-level fuel treatment effects on large wildfires , 2006 .

[36]  M. Meyer.  Forest Fire Severity Patterns of Resource Objective Wildfires in the Southern Sierra Nevada , 2015 .

[37]  S. Stephens,et al.  Beyond reducing fire hazard: fuel treatment impacts on overstory tree survival. , 2014, Ecological applications : a publication of the Ecological Society of America.

[38]  Malcolm P. North,et al.  Water balance and topography predict fire and forest structure patterns , 2015 .

[39]  Charles W. McHugh,et al.  Stand- and landscape-level effects of prescribed burning on two Arizona wildfires , 2005 .

[40]  E. Kalies,et al.  Tamm Review: Are fuel treatments effective at achieving ecological and social objectives? A systematic review , 2016 .

[41]  Jan W. van Wagtendonk,et al.  Factors Associated with the Severity of Intersecting Fires in Yosemite National Park, California, USA , 2012 .

[42]  A. Latimer,et al.  Fuel treatment effectiveness in California yellow pine and mixed conifer forests , 2012 .

[43]  Carol Miller,et al.  Previous Fires Moderate Burn Severity of Subsequent Wildland Fires in Two Large Western US Wilderness Areas , 2013, Ecosystems.

[44]  J. Kane,et al.  Duration of fuels reduction following prescribed fire in coniferous forests of U.S. national parks in California and the Colorado Plateau , 2016 .

[45]  Brandon M. Collins,et al.  Constraints on Mechanized Treatment Significantly Limit Mechanical Fuels Reduction Extent in the Sierra Nevada , 2015 .

[46]  M. C. Kennedy,et al.  Fuel treatment prescriptions alter spatial patterns of fire severity around the wildland–urban interface during the Wallow Fire, Arizona, USA , 2014 .

[47]  David Saah,et al.  Modeling hazardous fire potential within a completed fuel treatment network in the northern Sierra Nevada , 2013 .

[48]  A. Taylor,et al.  Topography, Fuels, and Fire Exclusion Drive Fire Severity of the Rim Fire in an Old-Growth Mixed-Conifer Forest, Yosemite National Park, USA , 2015, Ecosystems.

[49]  B. Collins,et al.  Early forest dynamics in stand-replacing fire patches in the northern Sierra Nevada, California, USA , 2013, Landscape Ecology.

[50]  Erin McCormick,et al.  FireFamily Plus user's guide, Version 2.0 , 2000 .

[51]  Tapash Das,et al.  Climatic Correlates of Tree Mortality in Water- and Energy-Limited Forests , 2013, PloS one.

[52]  Robert J. McGaughey,et al.  Assessing fire effects on forest spatial structure using a fusion of Landsat and airborne LiDAR data in Yosemite National Park , 2014 .

[53]  M. Fromm,et al.  The 2013 Rim Fire: Implications for Predicting Extreme Fire Spread, Pyroconvection, and Smoke Emissions , 2015 .

[54]  Jan W. van Wagtendonk,et al.  The History and Evolution of Wildland Fire Use , 2007 .

[55]  T. Spies,et al.  Factors associated with crown damage following recurring mixed-severity wildfires and post-fire management in southwestern Oregon , 2010, Landscape Ecology.

[56]  H. Preisler,et al.  Climate change and growth scenarios for California wildfire , 2011 .

[57]  David J. Parsons,et al.  Impact of fire suppression on a mixed-conifer forest , 1979 .

[58]  E. Natasha Stavros,et al.  Regional projections of the likelihood of very large wildland fires under a changing climate in the contiguous Western United States , 2014, Climatic Change.

[59]  Brian J. Harvey,et al.  Drivers and trends in landscape patterns of stand-replacing fire in forests of the US Northern Rocky Mountains (1984–2010) , 2016, Landscape Ecology.

[60]  J. Negrón,et al.  The effectiveness of vegetation management practices for prevention and control of bark beetle infestations in coniferous forests of the western and southern United States , 2007 .

[61]  Jay D. Miller,et al.  Wildfire impacts on California spotted owl nesting habitat in the Sierra Nevada. , 2016 .

[62]  Angela M. White,et al.  Avian community responses to post‐fire forest structure: implications for fire management in mixed conifer forests , 2016 .

[63]  M. C. Kennedy,et al.  Fuel treatments and landform modify landscape patterns of burn severity in an extreme fire event. , 2014, Ecological applications : a publication of the Ecological Society of America.

[64]  P. Fulé,et al.  Interactions of fuel treatments, wildfire severity, and carbon dynamics in dry conifer forests , 2015 .

[65]  Kevin Barnett,et al.  Beyond Fuel Treatment Effectiveness: Characterizing Interactions between Fire and Treatments in the US , 2016 .

[66]  A. Flint,et al.  Fine-scale hydrologic modeling for regional landscape applications: the California Basin Characterization Model development and performance , 2013, Ecological Processes.

[67]  Philip N. Omi,et al.  Fuel treatments and fire severity: A meta-analysis , 2013 .

[68]  Scott L. Stephens,et al.  U.S. federal fire and forest policy: emphasizing resilience in dry forests , 2016 .

[69]  Joseph W. Sherlock,et al.  Calibration and validation of the relative differenced Normalized Burn Ratio (RdNBR) to three measures of fire severity in the Sierra Nevada and Klamath Mountains, California, USA , 2009 .

[70]  T. Swetnam,et al.  Warming and Earlier Spring Increase Western U.S. Forest Wildfire Activity , 2006, Science.

[71]  Michelle Coppoletta,et al.  Post-fire vegetation and fuel development influences fire severity patterns in reburns. , 2015, Ecological applications : a publication of the Ecological Society of America.

[72]  Jay D. Miller,et al.  Climate, lightning ignitions, and fire severity in Yosemite National Park, California, USA. , 2009 .

[73]  C. Rheinberger,et al.  Comment on "Significance of "high probability/low damage" versus "low probability/high damage" flood events" by Merz et al. (2009) , 2010 .

[74]  Carl N. Skinner,et al.  Basic principles of forest fuel reduction treatments , 2005 .

[75]  Jay D. Miller,et al.  Differences in wildfires among ecoregions and land management agencies in the Sierra Nevada region, California, USA , 2012 .

[76]  Susan J. Prichard,et al.  Prior wildfires influence burn severity of subsequent large fires , 2016 .

[77]  A. Latimer,et al.  Long-term climate and competition explain forest mortality patterns under extreme drought. , 2017, Ecology letters.

[78]  T. Swetnam,et al.  Managing Forests and Fire in Changing Climates , 2013, Science.

[79]  Matthew P. Thompson,et al.  Quantifying the influence of previously burned areas on suppression effectiveness and avoided exposure: A case study of the Las Conchas Fire , 2016 .

[80]  Joseph Buongiorno,et al.  Adaptive economic and ecological forest management under risk , 2015, Forest Ecosystems.

[81]  Brad Quayle,et al.  Calibration and Validation of Immediate Post-Fire Satellite-Derived Data to Three Severity Metrics , 2015, Fire Ecology.

[82]  H. Safford,et al.  Effects of fuel treatments on fire severity in an area of wildland-urban interface, Angora Fire, Lake Tahoe Basin, California , 2009 .

[83]  P. Hessburg,et al.  Dry forests and wildland fires of the inland Northwest USA: Contrasting the landscape ecology of the pre-settlement and modern eras , 2005 .

[84]  Lisa M. Holsinger,et al.  Influences of prior wildfires on vegetation response to subsequent fire in a reburned Southwestern landscape. , 2016, Ecological applications : a publication of the Ecological Society of America.

[85]  Alistair M. S. Smith,et al.  Vegetation, topography and daily weather influenced burn severity in central Idaho and western Montana forests , 2015 .

[86]  David S. Pilliod,et al.  Pattern and process of prescribed fires influence effectiveness at reducing wildfire severity in dry coniferous forests , 2012 .

[87]  Angela M. White,et al.  Evaluating potential trade-offs among fuel treatment strategies in mixed-conifer forests of the Sierra Nevada , 2016 .

[88]  Donald McKenzie,et al.  Climate, fire size, and biophysical setting control fire severity and spatial pattern in the northern Cascade Range, USA. , 2014, Ecological applications : a publication of the Ecological Society of America.

[89]  Scott L. Stephens,et al.  Using Fire to Increase the Scale, Benefits, and Future Maintenance of Fuels Treatments , 2012 .

[90]  D. Loftsgaarden,et al.  Evaluation of fire danger rating indexes using logistic regression and percentile analysis , 2003 .