6.1.4 On the Edge: Life at The Wildland Urban Interface

“Hold tight we’re in for nasty weather,
There has got to be a way,
Burning down the house.”
Byrne, Frantz, Harrison, & Weymouth, 1983.

Over 38.5% of U.S housing stock (Stewart et al, 2006) and roughly 1/3 of its populous (Berg, 2016) reside in the wildland urban interface. Covering roughly 9.5% of the contiguous United States [77 million hectares] (Hamilton, 2018), it is by far the “fastest-growing land-use type” (Whitehouse, 2016, online), accounting for nearly 80% of recent land-use conversion (Mann et al, 2013). Driven by diverse and complex factors including amenity and lifestyle migration, spatial spill-overs, regional economic growth and access to employment, and lower cost housing (Ibid; Paveglio et al, 2015b; Mann et al, 2013, Heimlich and Anderson, 2001), nationally, residential building in the WUI has expanded at a rate of 60% since 1990 (Whitehouse, 2016; Theobald and Romme, 2007), of which, in the western states approx. 70% is privately owned (Schoennagel and Nelson, 2009).

Housing 43.3 million homes (Radeloff et al, 2018), currently, nearly 900,000 thereof, of which the estimated reconstruction costs are $238 billion, are classified at high or very high risk of wildfire (McCrea, 2016). In 2003, analysis of Geographic Information System [GIS] data placed 40 million hectares of WUI at risk of wildfire (Mell et al, 2010). Given the interim rate of development, in combination with current climatological conditions, one can thus assume that, whatsoever the present figure, it exceeds the sum thereof. As the WUI has expanded, so too have the number of properties lost to wildfire. Throughout the 1960s, on average, just over 200 structures a year were destroyed by wildfire (Ibid). By the 1970s the figure had nearly doubled, by the 1980s it had reached 670, and by the 1990s 932 (Ibid). However, between 2000 and 2015 the volume thereof rose to over 3,000 (Maranghides et al, 2015). As discussed earlier, climate change and wildland fire policies are primary contributory factors.

Globally, the relationship between populous and burned area tends be non-monotonic, wherein, initially, rising population density tends incur an increase in burned area, the sum thereof peaking, to then decline (Bistinas et al, 2013). But, in the most fire-prone regions of the U.S., beyond densities of approx. 30 p/km2 burnt area yet again increases (Ibid). A recent study found that between 1992 and 2012, across a sample of 1.5 million U.S. wildfires, the ignition of 84% was attributable to humans (Balch et al, 2017). Furthermore, during that period the “human-caused fire season was three times longer than the lightning-caused fire season”, adding +/- 40,000 wildfires per year (Ibid). Ways in which people accidently start fires include sparks from vehicles, damaged power lines, discarded cigarettes, land clearance, and accidental fire escape (Krawchuk and Mortiz, 2014). In a bid to tackle the issue, arson or otherwise, Californian authorities have increased the number of prosecutions of they that start wildfires (La Ganga, 2016). Yet, at 95%, regionally, wildfire ignitions of which humans are believed to be the cause are yet higher still (CALFIRE, 2018c), the matter thereof contributory in the extending of the state’s fire season by +/- 70 days since the early 2000s (Brunhuber, 2017).

>Continue to Chapter 6.1.5 here.

The thesis is also available in PDF format, downloadable in several parts on Academia and Researchgate.

Note that figures have been removed from the digital version hosted on this site, but are included in the PDFs available at the links above.

Citation: Sterry, M. L., (2018) Panarchistic Architecture: Building Wildland-Urban Interface Resilience to Wildfire through Design Thinking, Practice and Building Codes Modelled on Ecological Systems Theory. PhD Thesis, Advanced Virtual and Technological Architecture Research [AVATAR] group, University of Greenwich, London.