Portland State University PDXScholar Dissertations and Theses Dissertations and Theses 3-17-2020 Tending the Fire: Wildfire Risk Management at the Interface Cody Randolph Evers Portland State University Follow this and additional works at: https://pdxscholar.library.pdx.edu/open_access_etds Part of the Environmental Sciences Commons Let us know how access to this document benefits ou.y Recommended Citation Evers, Cody Randolph, "Tending the Fire: Wildfire Risk Management at the Interface" (2020). Dissertations and Theses. Paper 5416. https://doi.org/10.15760/etd.7289 This Dissertation is brought to you for free and open access. It has been accepted for inclusion in Dissertations and Theses by an authorized administrator of PDXScholar. Please contact us if we can make this document more accessible: [email protected]. Tending the Fire: Wildfire Risk Management at the Interface by Cody Randolph Evers A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Earth, Environment and Society Dissertation Committee: Max Nielsen-Pincus, Chair Alan Ager Andres Holz Vivek Shandas Antonie Jetter Portland State University 2020 i © 2020 Cody Randolph Evers ii Abstract Escalating loss from wildfire in the American West has made clear the need to rethink wildfire risk, including how such risks result from the unique interaction of social and natural dynamics within the wildland urban interface. Unfortunately, techniques for studying these interactions remain limited. The intent of this research is to address this gap. In each of four chapters, I examine different aspects of wildfire risk management through a coupled human-natural lens. I document how wildfire activity has shifted over three decades across forest and shrubland systems in the western US and connect these changes to the simultaneous growth in development within fire-prone wildlands. Using wildfire models, I then examine the transmission of wildfire risk from public land into nearby communities to quantify both the magnitude and geographic extent of wildfire exposure across the American West. These results show how community exposure has become geographically concentrated within several dozen regional hotspots, each featuring a distinct mix of exposure conditions. The dissertation then shifts its focuses to wildfire management within one specific hotspot, North Central Washington. Here I map where wildfire risk management crosses ownership boundaries to address risk and how the resulting organizational diversity appears to shape the roles that different organizations play. Finally, I look at the network structure of relationships among those managing wildfire risk and show that geographic proximity and shared risk lead to collaboration. Together, this work represents a cohesive body of research that expands coupled social and biophysical knowledge of wildfire risk management. i Dedication To my parents for their unconditional support To my wife for her courage and perseverance To my daughter for a love I never imagined ii Acknowledgments The research presented in this dissertation would not have been possible without the guidance and support of many. A special thanks goes to Max Nielsen-Pincus, the chair of my dissertation committee, for his reliably, timely, and sage advice. The work of Alan Ager provided the foundation for much of this research. I deeply appreciate his drive and curiosity. Thanks goes to Andres Holz for inspiring the work in Chapter 1 and for the intellectual engagement and honesty that he applies to all of his work. I thank Vivek Shandas for our early conversations on community resiliency and ecosystem services. His enthusiasm and creativity always inspired. The Rocky Mountain Research Station of the USDA Forest Service provided financial support for much of this research. I also wish to acknowledge the training and support provided by the National Science Foundation Integrated Graduate Research and Education Traineeship (IGERT) program. A dissertation is a long journey influenced by many colleagues and friends. Thanks goes to numerous classmates and colleagues at Portland State University, Oregon State University and University of Oregon. iii Table of Contents Abstract ................................................................................................................................ i Dedication ........................................................................................................................... ii Acknowledgments .............................................................................................................. iii List of Tables ................................................................................................................... viii List of Figures .................................................................................................................... xi Introduction: Wildfire Risk Management at the Interface ...................................................1 Risk at the interface ........................................................................................................ 2 Chapter overview ........................................................................................................... 4 Chapter 1: Shifting Fire Regimes in the American West ....................................................9 1. Shifting Fire Regimes in the American West ........................................................... 11 2. Methods .................................................................................................................... 15 2.1. Classifying vegetation and fire regimes ....................................................................... 16 2.2. Classifying social dimensions of fire activity ............................................................. 17 2.3. Analytics ..................................................................................................................................... 18 3. Results ...................................................................................................................... 19 3.1. Shifts in fire activity among vegetation systems ...................................................... 19 3.2. Shifts in wildfire regimes within vegetation systems ............................................ 22 3.3. Social dimensions of shifting fire regimes. ................................................................. 24 4. Discussion ................................................................................................................ 27 4.1. Implications .............................................................................................................................. 31 iv 5. Conclusion ................................................................................................................ 32 6. Figures ...................................................................................................................... 34 Chapter 2: Archetypes of Community Wildfire Exposure ................................................44 1. Archetypes of Community Wildfire Exposure ......................................................... 46 2. Methods .................................................................................................................... 50 2.1. Study Area ................................................................................................................................. 50 2.2. Simulation exposure to communities ............................................................................ 51 2.3. Characterizing wildfire exposure .................................................................................... 53 2.4. Gradient and cluster analysis of wildfire exposure ................................................. 55 3. Results ...................................................................................................................... 56 3.1. Community exposure to wildfire originating from national forests ................ 56 3.1. Variation in conditions among highly exposed communities ............................. 58 3.2. Archetypes of community wildfire exposure ............................................................. 59 4. Discussion ................................................................................................................ 62 4.1. National forest sources areas ........................................................................................... 63 4.2. Community exposure areas ............................................................................................... 65 4.3. Connecting multiple scales of exposure ....................................................................... 66 4.4. Limitations and Future Research .................................................................................... 67 5. Conclusion ................................................................................................................ 69 6. Figures ...................................................................................................................... 70 7. Tables ....................................................................................................................... 75 Chapter 3: Organizational Geography of Wildfire Risk Management ..............................81 v 1. Organizational Geography of Wildfire Risk Management ...................................... 82 1.1 Wildfire risk and land tenure ............................................................................................