title: Network analysis of wildfire transmission and implications for risk governance.
abstract: We characterized wildfire transmission and exposure within a matrix of large land tenures (federal, state, and private) surrounding 56 communities within a 3.3 million ha fire prone region of central Oregon US. Wildfire simulation and network analysis were used to quantify the exchange of fire among land tenures and communities and analyze the relative contributions of human versus natural ignitions to wildfire exposure. Among the land tenures examined, the area burned by incoming fires averaged 57% of the total burned area. Community exposure from incoming fires ignited on surrounding land tenures accounted for 67% of the total area burned. The number of land tenures contributing wildfire to individual communities and surrounding wildland urban interface (WUI) varied from 3 to 20. Community firesheds, i.e. the area where ignitions can spawn fires that can burn into the WUI, covered 40% of the landscape, and were 5.5 times larger than the combined area of the community core and WUI. For the major land tenures within the study area, the amount of incoming versus outgoing fire was relatively constant, with some exceptions. The study provides a multi-scale characterization of wildfire networks within a large, mixed tenure and fire prone landscape, and illustrates the connectivity of risk between communities and the surrounding wildlands. We use the findings to discuss how scale mismatches in local wildfire governance result from disconnected planning systems and disparate fire management objectives among the large landowners (federal, state, private) and local communities. Local and regional risk planning processes can adopt our concepts and methods to better define and map the scale of wildfire risk from large fire events and incorporate wildfire network and connectivity concepts into risk assessments.
authors.affiliation: Missoula Fire Sciences Laboratory, Rocky Mountain Research Station, Forest Service, United States Department of Agriculture, Missoula, Montana, United States of America.
authors.forename: Alan A
authors.initials: AA
authors.lastname: Ager
authors.affiliation: Department of Environmental Sciences and Management, Portland State University, Portland, Oregon, United States of America.
authors.forename: Cody R
authors.initials: CR
authors.lastname: Evers
authors.affiliation: Department of Forest Ecosystems & Society, College of Forestry, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Day
authors.affiliation: Pacific Southwest Research Station, Forest Service, United States Department of Agriculture, Albany, California, United States of America.
authors.forename: Haiganoush K
authors.initials: HK
authors.lastname: Preisler
authors.affiliation: Department of Forest Engineering, Resources & Management, College of Forestry, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: Ana M G
authors.initials: AM
authors.lastname: Barros
authors.affiliation: Department of Environmental Sciences and Management, Portland State University, Portland, Oregon, United States of America.
authors.forename: Max
authors.initials: M
authors.lastname: Nielsen-Pincus
mesh_terms: D003247:Conservation of Natural Resources; D004190:Disasters; D005390:Fires; D006076:Government; D006801:Humans; D009922:Oregon; D018570:Risk Assessment; D012308:Risk Management