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Creating (Defensible) Space

Updated: Apr 20, 2022

The Wildland Urban Interface (WUI) is the fastest growing land use type in the United States. From 1990 to 2010 the number of houses in the WUI grew by 41% and the land area grew by 33% (Radeloff, 2018). In the 90’s, average acreage burned in the US was 3.3 million acres; From 2011-2020 that figure increased twofold to 7.5 million; In 2020 the area burned was 10.1 million acres(Hanson 2021). These figures tell a story: more people are migrating to the WUI despite an increase in risk to life and property. Why?

There are several factors driving WUI migration. Homeowners are both pulled by an attractive way of life and pushed by policy decisions. Proximity to wildland increases access to outdoor recreation, provides more space and privacy, and holds an idealized aesthetic value. Astronomical housing costs have promoted housing development, which, constrained by preventative zoning ordinances, has been channeled out rather than up or in. Additionally, the threat of wildfire is tempered by an overconfident trust in fire suppression tactics. Decades of aggressive fire suppression have drastically increased fuel levels while putting fire fighters on an omnipotent pedestal. This has created an impossible job for today’s fire fighters: protect communities with unrealistically high expectations of human capacity to control unprecedented mega-fires.

To recap: people are attracted to the standard of living in the WUI and driven by a shortage of alternative housing options. This has driven a mass migration of people with unrealistic expectations of fire suppression in an era with more acres burning at higher intensity. How can this be addressed?

The most obvious solutions come from the top down: rezoning to allow for more infill development of multifamily housing units. In September, three California Senate Bills (SB 8,9 and 10) were signed into law that will nudge the state in the right direction. SB 8 extends the tenure of an existing bill that reduces local capacity to downzone and increases access and efficiency of housing development. SB 9 allows for the subdivision of lots from single family to multifamily except in areas of fire risk. SB 10 allows for 10 housing units to be approved on any parcel in a transit-rich area(Regalia, 2021). However, these are only incremental steps in solving a monumental problem. Berkeley’s Terner Center for Housing Innovation states that SB9 will “modestly accelerate the addition of new units relative to the status quo”(Demsas, 2021). Infill development remains choked at the local level across California.

The process for housing allocation in California starts with the Department of Housing and Community Development. They evaluate statewide housing needs and distribute housing allotments for four strata of household income to regional Councils of Governments (COGs). The COGs then determine how those allotments will be subdivided throughout their constituent cities(Knapp, 2007). In Marin (where I have been serving with Marin Wildfire Prevention Authority) this final step has been met with obstinance. Marin County and 9 of its 11 municipalities have appealed the 2021 housing edict from their COG, Association of Bay Area Governments (ABAG). The allotments are generally seen as excessive, appellants citing reasons such as market-based barriers to housing development, drought and, ironically, wildfire risk (Halstead, 2021).

Now I don’t pretend to be an expert on the housing crisis, land use and zoning ordinances. These issues are complex and the municipalities likely have valid reasons for concern. The point here is that the top-down approach is slow and controversial; it will be of little help for the time being. Fortunately, it’s not the only approach.

Regardless of housing shortages, living adjacent or among nature is a strong driver of WUI migration, especially in a place as beautiful and pristine is Marin County. I grew up in San Diego, land of scrub and sand and some occasional oak woodland. The stark contrast of Marin’s lush redwood forests is incredible. They are not the only fire adapted ecosystem here in Marin, but to this moisture deprived desert boy, they sure call the loudest. If given the opportunity, I would want to live among them too. But I can’t be a bystander as a resident in an ecosystem.

I understand the ethic of living passively amongst the trees with as little footprint as possible.

That ethic of preservation is born of a long tradition of human caused environmental degradation. But preservation is not an option where there is an exchange of resources, and living in the WUI, while not extractive, is an exchange of resources. Dense, untamed greenery encroaching in upon homes and communities is not a symbiotic relationship between ecosystem and infrastructure.

It is, unfortunately, the prevailing characteristic of Marin’s WUI. To protect homes there has to be some degree of fire suppression combined with a heavy dose of fire prevention. The general theme of this preventative work is to space things out. That applies on both a landscape level and directly around people’s homes. My, co-fellow, Rose Joseph, wrote a wonderful post on the history and dynamics of landscape level vegetation management, definitely give it a read if you haven’t already. This work is crucial for the health of our ecosystems and communities and certainly a part of Marin Wildfire Prevention Authority’s overarching mission. But each year we center our work around a core theme, one that showcases our most pressing objective, and this year’s is “House Out.”

Marin is dominated by natural landscapes, all of which have been affected by an unnatural fire regime. These landscapes are overgrown, and drought stricken. Reducing fuels across all that acreage is unrealistic in the short term. There is neither the funding, labor nor bandwidth. The long-term goal is to chip away at these landscapes, gradually returning them to what they looked like before decades of fire suppression. The short-term strategy is to start from the walls of homes and buildings and work outward.

It starts with walls:

It is estimated that as many as 90% of homes are burned from embers or fires started by embers near a structure (Jergler, 2019). Additionally, embers or burning brands can be cast many miles ahead of a wildfire front. This stresses the importance of non-combustible building materials and impenetrability of embers. Unfortunately, these renovations are costly and inaccessible to many homeowners. There are grant programs across the state that can help, but there is much work to be done in providing equitable access to these renovations.

And work outward:

While there is no consensus on a fire safe plant list (all plants can be fuel if held to flame for long enough) there is agreement around those of high risk. Plants like juniper, Italian cypress or rosemary, that conceal lots of dead plant matter behind a thin covering of oily greenery, can rapidly exacerbate fire behavior. Unfortunately, these and other plants like it, have long been recommended in California for drought resistant landscaping. The conflicting messaging is understandably frustrating to homeowners. Nonetheless, these problematic plants can be a threat to entire communities.

The MWPA Executive Director, Mark Brown, recently gave my Co-Fellow, Maria Schmitt and I a tour of his community in Santa Rosa with commentary on how the 2017 Nuns fire moved through it. With a high degree of specificity, he was able to identify places in which these high-risk plants were responsible for the destruction of multiple homes: A gap on the crest of a windswept ridge where there had been two cypresses, and the larger gap across the street, where there had been three houses. A transparent backyard fence where there had once been an ivy privacy screen, offering a view of the house in reconstruction just behind it.

In recognizing these shared threats, some communities have been proactive. A Firewise community in Marin recently spent a day removing a neighbor’s hedgerow of Juniper. Adjacent to the evacuation route, the community recognized this private hedgerow as a public threat and addressed it together rather than placing responsibility on the individual homeowner. Actions like these take little effort, equipment or expertise but greatly reduce the threat to life and property. Much of this work doesn’t take the equipment or guidance of agencies like MWPA or local fire departments, just the recognition of a communal threat, and the communal action that follows.

Beyond the removal of risky plants, the general principle remains the same: space it out.

The reduction of clutter in any space can give people peace of mind. Whether it be clearing a desk or tackling a tower of dishes, the restorative act of creating space can provide mental clarity. A yard, or ecosystem for that matter, should be no different. The reduction of dead vegetation and intentional spacing between plants not only helps protect a home from wildfire, but creates a cleaner aesthetic and a more inviting space to live in. This idea: the connection, between physical, mental, and defensible space, is the new aesthetic paradigm we are trying to promote. It is an alternative to passive residence in the WUI which allows the encroachment of untamed greenery.

In exploring this concept of space and how it applies across mediums, I spent time thinking of the word in various colloquial contexts. We, “take some space” from something when it is distressing us. Any source of stress in our lives, whether it be from work, a relationship, or the general bustle of a fast-paced world, provokes a need for space. We “hold space” for others when they need to be seen and heard without judgement. We seek out tools to cultivate a positive mental space, such as journaling, exercise or meditation. In many ways, this mental concept of space spills over into its physical cultivation. As mentioned above, we clear a cluttered desk to clear our minds. The same goes for an email inbox or a computer desktop. Architects, designers, and artists spend their careers organizing space to have certain personal and interpersonal effects. And us aspiring forest and fire professionals will spend ours creating space with the goal of resource protection and wildfire adaptation.

Works Cited

Demsas, J. (September 17, 2021). California is ending a rule that helped cause its housing crisis.

Vox. Retrieved November 14 from

Halstead, R. (July 27, 2021). Marin County, nine communities appeal housing assignments.

Hanson, L. (October 4, 2021). Wildfire Statistics. Congressional Research Service. Retreived

Jergler, D. (March 20, 2019). “Burning Down a House to Show How to Build for Wildfire

Defense.” Insurance Journal. Retrieved November 16, 2021 from

Knaap, G. et al. (July 2007). Zoning as a Barrier to Multifamily Housing Development. Planning

Advisory Service, Report Number 548, Retreived November 14, 2021 from

Radeloff, V. et al. (March 27, 2018). Rapid Growth of the Wildland Urban Interface Raises

Wildfire Risk. PNAS. Retrieved from

Regalia, M. (October 1, 2021). California Enacts New Housing Legislation to Increase Supply and

Address Housing Crisis. JDSupra. Retrieved November 14, from.

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