Fine-scale assessment of cross-boundary wildfire events in the western United States

Abstract

Abstract. We report a fine-scale assessment of cross-boundary wildfire events for the western US. We used simulation modeling to quantify the extent of fire exchange among major federal, state, and private land tenures and mapped locations where fire ignitions can potentially affect populated places. We examined how parcel size affects wildfire transmission and partitioned the relative amounts of transmitted fire between human and natural ignitions. We estimated that 85 % of the total predicted wildfire activity, as measured by area burned, originates from four land tenures (Forest Service, Bureau of Land Management, private, and state lands) and 63 % of the total amount results from natural versus human ignitions. On average, one-third of the area burned by predicted wildfires was nonlocal, meaning that the source ignition was on a different land tenure. Land tenures with smaller parcels tended to receive more incoming fire on a proportional basis, while the largest fires were generated from ignitions in national parks, national forests, and public and tribal lands. Among the 11 western states, the amount and pattern of cross-boundary fire varied substantially in terms of which land tenures were mostly exposed, by whom, and to what extent. We also found spatial variability in terms of community exposure among states, and more than half of the predicted structure exposure was caused by ignitions on private lands or within the wildland–urban interface areas. This study addressed gaps in existing wildfire risk assessments that do not explicitly consider cross-boundary fire transmission and do not identify the source of fire. The results can be used by state, federal, and local fire planning organizations to help improve risk mitigation programs.

Fostering collective action to reduce wildfire risk across property boundaries in the American West

“…state, family forest) experience more incoming fire transmitted from other ownerships than large parcels (e.g. USFS) (Palaiologou et al 2019). Federal landowners in our cases were usually slower than other landowner types to complete treatments, a concern among nonfederal owners who worried a wildfire would occur and compromise their efforts.…”

“…Wildfire risk reduction in multi-ownership landscapes is a collective action problem for both ecological and social reasons. From an ecological standpoint, wildfires can burn large areas (>40 000 ha) and wildfire transmission occurs across land ownerships , Hessburg et al 2015, Palaiologou et al 2019. It is neither practical nor necessary to treat hazardous fuels everywhere to reduce wildfire risk; nevertheless, thousands of hectares must be treated to change fire behavior and reduce its severity (Finney et al 2007, North et al 2012, Krofcheck et al 2017, Tubbesing et al 2019.…”

“…To be most effective, treatments should be strategically-placed and target high-hazard locations where wildfires are most likely to ignite and to burn (Finney et al 2007, Tubbesing et al 2019. Uncoordinated fuels treatments on individual land ownerships do not necessarily add up to, or optimize, landscape-scale wildfire risk reduction (Finney et al 2007, North et al 2012, Loudermilk et al 2014, Hessburg et al 2015, Palaiologou et al 2019.…”

Understanding the Impact of Different Landscape-Level Fuel Management Strategies on Wildfire Hazard in Central Portugal

“…The simulation for the BAU option was run 100,000 times. The fireshed (e.g., [26]) was estimated as the convex area for which a potential ignition could lead to a wildfire that would partially burn the Alvares parish. To reduce computational time, only the ignitions overlapping the fireshed area (ca.…”

“…Science can contribute with knowledge and tools for more effective landscape fuel management, thus improving planning and decision-making. Previous research has shown how fire spread simulation tools can be used to assess wildfire exposure at the landscape level [19][20][21], quantify associated risk [22][23][24], study wildfire transmission [25,26] and identify optimal fuel treatment location [27,28]. These simulation tools have also proven useful to quantify the potential impact of climate change on wildfire incidence [29] and of mitigation measures on post-fire erosion and water contamination [30,31].…”