Creating Defensible Space for Fire Safety

Those who have a sincere desire to reduce fire hazards in the Bay Area would be wise to turn their attention away from the distracting and irrelevant debate about the flammability of native compared to non-native plants and trees.   California native ecology is dependent upon and adapted to fire.  The native landscape is not less flammable than non-native plants and trees.  Most firestorms in California are wind-driven fires in which everything burns, including native and non-native trees and plants as well as any buildings in the path of the fire.   

Rather, the creation of “defensible space” immediately around your home is your best defense against the loss of your home in a wildfire.  Creating defensible space means reducing fire fuels around your home by appropriate pruning and maintenance, such as limbing up trees to remove the fire ladder to the tree canopy and removing leaf litter.  Defensible space is intended to slow the progress of fire to your home.

In this post we will visit several reputable sources of information about fire safety that advise homeowners about how to protect themselves, particularly those who live in the Wildland-Urban Interface where fire hazards are greatest.   We will see that all these sources of information have in common that they do not single-out specific species of plants or trees.  Rather they emphasize that how vegetation is pruned and maintained is more important to reducing fire hazard and that materials we use in building our homes are equally important to our safety.  These sources of information are not native plant advocates.  Their advice is not based on a desire to destroy non-native plants and trees in the belief that their destruction will benefit native plants and trees.  

Firewise Communities is an internet resource provided by the National Fire Protection Association and co-sponsored by the US Forest Service and the US Department of the Interior.  This resource offers on-line courses in fire safety.  In the course on “Firewise Landscaping” these criteria are listed as the characteristics of fire-resistant plants:  low leaf litter, high water retention ability, high salt retention ability, lack of aromatic oils, low fuel volume, height and spread that fits well into the intended space.  Some native and some non-native plants fit these criteria and some do not.  For example, although the leaves of eucalyptus contain aromatic oils, so do the leaves of the native California bay laurel.   

Homeowners in the Wildland-Urban Interface should focus on creating defensible space around their homes rather than on choosing particular plant or tree species. CALFire guidelines for creating defensible space do not advise for or against any particular species of plant or tree. Rather CALFire focuses on how to prune and maintain vegetation around your home and create a “defensible space” around your home with low fuel volume, as illustrated in this brochure on their website.

Creating defensible space around your home. CALFire

Likewise the UC Berkeley Fire Center in their brochure “Home Landscaping for Fire” says, “It is important to remember that given certain conditions, all plants can burn…how your plants are maintained and where they are placed is as important as the species of plants that you chooselandscape management (e.g., pruning, irrigation, and cleanup) have a greater impact on whether or not a plant ignites than does the species.” It is ironic that UC Berkeley is engaged in the destruction of every non-native tree and plant on its property, despite the advice on its own website about fire safety, which is obviously being ignored. 

The August 2010 issue of Sunset Magazine includes a comprehensive “Wildfire Survival Guide,” including advice about planting a fire-safe garden. 

The City of Oakland passed an ordinance in 2006 requiring homeowners to maintain defensible space around their homes and voters in Oakland agreed to tax themselves to pay for the enforcement of this requirement.  Unfortunately, a drive in the Oakland hills informs us that these requirements are not being enforced. 

Oakland hills

This home is particularly vulnerable because fire tends to travel up hill.  Firewise says that a 30% slope will accelerate the rate of spread of fire to twice the speed of fire on flat ground. 

Wouldn’t the people of Oakland be better served by enforcement of requirements for defensible space around homes rather than paying shared costs of $662,280 for a FEMA grant to eradicate all non-native vegetation from 325 acres of wildland? (see “Our Mission, Projects in the East Bay”)  Oakland is  flat broke and one of the most violent cities in the country.  Eighty policemen were recently laid off and 120 more are likely to be laid off if voters don’t vote to tax themselves further.  Shouldn’t homeowners be required to create defensible space around their homes where their lives and property are most at risk before “vegetation management” is extended far beyond the perimeter of homes?

3 thoughts on “Creating Defensible Space for Fire Safety”

  1. This is an excellent article that everyone living in the Oakland-Berkeley Hills should read. It is important to note that Oakland residents who live in the area that burned in the 1991 fire pay a parcel tax that includes annual inspections by the fire department to make sure there is defensible space around every house. As the writer of this blog confirms, one can find many areas of the hills where these requirements are not being enforced. Most of the eucs have been removed (in the vain hope that eradicating the eucs would solve all the problems), but there are pines, bays, oaks, redwoods, cypress, and much flammable dry grass and brush close to houses. Fire does not discriminate between native and non-native vegetation. A garden of drying native shrubs and drying native bunch grass is an invitation to disaster.

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