Factors related to building loss due to wildfires in the conterminous United States

Abstract

Wildfire is globally an important ecological disturbance affecting biochemical cycles and vegetation composition, but also puts people and their homes at risk. Suppressing wildfires has detrimental ecological effects and can promote larger and more intense wildfires when fuels accumulate, which increases the threat to buildings in the wildland-urban interface (WUI). Yet, when wildfires occur, typically only a small proportion of the buildings within the fire perimeter are lost, and the question is what determines which buildings burn. Our goal was to examine which factors are related to building loss when a wildfire occurs throughout the United States. We were particularly interested in the relative roles of vegetation, topography, and the spatial arrangement of buildings, and how their respective roles vary among ecoregions. We analyzed all fires that occurred within the conterminous United States from 2000 to 2010 and digitized which buildings were lost and which survived according to Google Earth historical imagery. We modeled the occurrence as well as the percentage of buildings lost within clusters using logistic and linear regression. Overall, variables related to topography and the spatial arrangement of buildings were more frequently present in the best 20 regression models than vegetation-related variables. In other words, specific locations in the landscape have a higher fire risk, and certain development patterns can exacerbate that risk. Fire policies and prevention efforts focused on vegetation management are important, but insufficient to solve current wildfire problems. Furthermore, the factors associated with building loss varied considerably among ecoregions suggesting that fire policy applied uniformly across the United States will not work equally well in all regions and that efforts to adapt communities to wildfires must be regionally tailored.

Where wildfires destroy buildings in the US relative to the wildland–urban interface and national fire outreach programs

“…Without such spatial data on buildings at a national extent, the details of these non-WUI environments remain somewhat unknown, but the low housing densities within these Census blocks (less than 0.5 housing units km À2 ) and lower rates of loss in wildfire events suggest that these states and environments may be substantially different than popular conceptions of the WUI. Here, a more varied approach to fire prevention and outreach may be necessary, given the diversity of communities at risk to wildfire (Alexandre et al 2016;Paveglio and Edgeley 2017;. More detailed information on building locations could help communities generate local assessments of WUI risk (e.g.…”

“…Numerous factors other than the existence of nearby fire resources influence a resident's decision to reduce fire susceptibility on their property (Price and Bradstock 2013;Olsen et al 2017), including differences in social vulnerability (Collins and Bolin 2009;Ojerio et al 2010;Gaither et al 2011;Wigtil et al 2016). Additionally, factors outside a landowner's control can have a major effect on the survivability of a building, such as topography, nearby vegetation, and nearby buildings (Price and Bradstock 2013;Syphard et al 2013;Alexandre et al 2016;Clark et al 2016), as well as differences in values among neighbours in a community (Collins and Bolin 2009;Skowronski et al 2016;Singer et al 2017). However, programs such as CWPPs can create important partnerships and build relationships that are critical for communities after a wildfire (Jakes and Sturtevant 2013).…”

“…For example, throughout the north-eastern United States, buildings are adjacent to and intermixed with dense forests that have a low probability of burning (Finney et al 2011;Haas et al 2013). Furthermore, in those areas that are prone to fire, several factors determine the overall likelihood of building loss, including building design and maintenance, spatial configuration of flammable wildland vegetation, and suppression capabilities and response (Radeloff et al 2005;Price and Bradstock 2013;Alexandre et al 2016;Westhaver 2016). Despite the role of local-and landscape-level factors in building loss, the WUI as a whole remains a focus area for federal wildfire programs (United States Congress 2003;Wildland Fire Executive Council 2014), including a recent Executive Order (Obama 2016).…”

Human-Related Ignitions Increase the Number of Large Wildfires across U.S. Ecoregions

“…Of the large wildfires, a greater percentage were started by humans in the eastern U.S. (Figure 1) compared to the western U.S. and this was likely tied to population density, infrastructure, and the wildland-urban interface (WUI) [34,[61][62][63][64]. This pattern for large fires mirrored the human contribution to overall numbers of ignitions [5].…”

Adapt to more wildfire in western North American forests as climate changes

“…Another promising approach for increasing adaptive resilience of WUI residents to wildfire is the promotion of fire-adapted planning in communities. Providing incentives for counties, communities, and homeowners to plan fire-safe residential development for both existing and new homes and discouraging new development on fire-prone lands will make communities safer (89,(94)(95)(96). Communities can use land-use and development codes that encourage developers to set aside open space and recreational trails as fuel breaks and require ignition-resistant construction materials in fire-prone settings.…”