The California Chaparral Field Institute

Why we are concerned about over exuberant clearance regulations...

Creating a "Survivable Space" Around Your Home: The Difference Between Rational Action and Overreaction

There is no question that dense/flammable vegetation should be removed from the area immediately around a home in order to reduce the risk of structural ignition during a wildfire. The question is how to properly do so without causing additional problems. The basic rule is to eliminate flammable materials (fire-prone vegetation, wood stacks, wood decking, patio furniture, umbrellas, etc.) from within 30 feet of the home. Then for structures near wildland open space, an additional 70 feet should be modified in such a way as to remove dead wood from shrubbery, thin and trim trees and shrubs (lower limbs removed), and prevent the growth of weedy grasses. Maintaining a modified canopy of vegetation to shade the ground is important to reduce weed growth.

Unfortunately the term "clearance" is used in California state law when referring to this 100 foot zone, leading people to think all vegetation must be removed down to bare soil. This is why the city of San Diego Fire and Rescue Department has replaced the word "clearance" to "thinning" when referring to vegetation management around homes. Officials in the California Department of Forestry and Fire Protection (CDF) are continually trying to help citizens understand that clearance doesn't mean the removal of all native plants. Bare soil clearance not only unnecessarily compromises large amounts of native wildlands and increases erosion, but will lead to the growth of weeds in the now disturbed soil. These weeds are considered "flashy fuels" which actually increase fire risk because they ignite so easily.

WHAT'S WRONG WITH THE ABOVE PHOTO?

This photograph has been widely distributed by San Diego County as proof that draconian clearing will save your house from a wildfire. It is an example of trying to prove a favored theory by ignoring other important variables. While some may think the "best" way to reduce fire risk is by striping down to bare ground wide areas around your house and replacing part of it with lawn or ice plant as shown above, the important question to ask is "considering the total costs, is this the most effective way to protect my house?" The answer is No. It may be the easiest strategy for politicians to demand, but by no means does it guarantee your safety.

WHY?

1. The primary mechanism for homes igniting during a wildfire is through ember attack, not radiation from a wall of flame. Embers can travel a mile or more from the fire front. This is why wildfires jump ten-lane Interstate Highways and over large lakes. The reason the home above did not burn down could have been due to the presence of firefighters, shift in the direction or speed of the wind, fire resistant construction, time of day the fire reached the property (evening weather typically moderates fires), or just simple probability. We do not know from just looking at this photo.

2. The concept of "defensible space" by itself is not an adequate solution for Southern California. It presumes wildfires are small and firefighting resources will always be available. This is not realistic. The most damaging wildfires are typically large events that tax firefighting agencies. Chances are there may not be a firefighter available to use the defensible space. It is best to create a "survivable space" in which the home can survive on its own. This means fire-safety needs to focus on fire-resistant construction as well as proper vegetation management.

3. Striping the land of native vegetation as the owner did above leads to erosion and the growth of invasive weeds. Weeds demand continual maintenance to control. Once dried, they pose an extended fire risk since they are much more flammable than properly thinned native vegetation. See the impact of such type-conversion on our Threats to Chaparral page.

4. Lightly irrigated, properly thinned and spaced shrubs can act as a "green" fire barrier, absorbing heat and deflecting oncoming embers. Bare, open space can not do this.

5. There are a number of reasons one decides to live next to a natural environment; peacefulness, enjoyment of wildlife, uncluttered vistas, native wildflowers, a chance to take an evening stroll through nature. While surrounding one's self with ice plant and other non-native additions may appeal to some, it is generally not supportive of these types of values. Although an easy target, native vegetation is not the enemy. We are next to it because of it. Therefore, it makes sense to build a home that is adapted to the environment in which it exists. Consequently, the first place to start when trying to protect your home from wildfire is from the structure out, not from the wildland in which includes:

     a. Proper attic vent construction (to keep out embers), non-combustible roofing (to resist embers), enclosed eaves (to defend against embers), and the removal of flammable objects such as wood fences, patio furniture, wood decking, etc. (to prevent ignition by embers).

     b. Making sure the first 30 feet around the home is free of flammable materials and is landscaped with fire resistant vegetation is the next step. Pines, palm, and Eucalyptus trees do not belong anywhere near a house.

     c. The next 70 feet should not be stripped to bare ground as the photo above suggests. Selectively thin the native vegetation, remove the dead wood, maintain a loose canopy, without disturbing the soil.

Once these three basic steps are accomplished, only minimal yearly maintenance needs be done and the reason you live next to nature in the first place is preserved. The use of goats as is currently being implemented in some areas to create 200 feet of bare dirt clearance is more of a political response than one based on science. Not only will such action unnecessarily damage native plant communities, but it fails to address the main reason homes ignite in the first place, flying embers.

We have just completed a study of the July 2006 Sawtooth desert fire that burned more than 50 homes in and around Pioneertown, a small community west of Yucca Valley and northwest of Palm Springs. Numerous homes with 100 feet+ of bare dirt clearance burned to the ground. An interesting observation concerning the numerous homes that burned without the necessary survivable space zone relates to the condition of the vegetation around the structure. In many cases, the only portion of the shrubs and trees that showed fire damage were the sides facing the home. It was the burning structure that ignited the vegetation, not the other way around. A complete report will be available soon.

No Turning Back...

Once native vegetation is cleared and the soil is disturbed the homeowner is permanently shackled with a number of negative consequences:

1. Continual maintenance costs

2. The introduction and growth of invasive weeds

3. Increased soil erosion and the formation of gullies

4. Surrounding aesthetics seriously damaged

5. Natural habitat destroyed

6. Reduction of native animal life

7. Potential legal costs if “clearance” is done improperly or on public/private land without proper authorization

8. Failure to account for future changes in vegetation management laws

9. Failure to account for changes in personal tastes. Do you think you’ll always want your home surrounded by dirt and weeds?

10. False sense of security that “clearance” will prevent your home from burning

The important point to understand about fire behavior and why some homes burn while other do not is that there are multiple variables involved. "How do I prevent my home from burning?" is NOT a one answer question. While vegetation management will reduce the risk of home ignition, depending on it alone to protect your home in a firestorm is wishful thinking at best. The other thing to appreciate is that no matter what you do, nothing will guarantee that your home will remain standing after a California wildfire. If you live in California's fire-prone environment, all you can do is take steps to reduce risk.

So...What are California's new requirements for "clearance" around structures according to Public Resources Code 4291?

The new state law passed in response to the 2003 fires in California is confusing to most homeowner's, is poorly written, and its interpretation depends on who is enforcing it. What is demanded by one inspector or "clearance" contractor will be different from what another may require. Some will say "clearance" means just that, down to mineral soil. This is not only a misinterpretation of the law, but has the potential of causing a increased fire risk by encouraging the growth of alien weeds which are much more flammable that the shrubs they have replaced. The resulting erosion of the bare earth will cause additional problems.

What does it mean that you are required to remove all "flammable vegetation" within 100 feet of your home if you live in a very high fire hazard severity zone (usually meaning next to any wild open space)?

1. You are NOT required to remove all native vegetation, but rather remove the flammable material (dead wood and litter) that has accumulated around the shrubbery within 100 feet of your home.

2. Thin ornamental or native shrubs and trees into umbrella-like forms in order to maintain most of the canopy to help reduce the invasion of weeds.

3. Do NOT disturb the soil by disking or ripping out shrubs. This will only allow weeds to invade, creating increased fire risk later on.

4. Vegetation up to18 inches high in ADDITION to well maintained and trimmed shrubs and trees are allowed within the 30-100 foot zone where necessary to stabilize the soil and prevent erosion.

Here's the law (Public Resource Code 4291)

Know the difference between the law and an interpretation of the law

Home owners in areas subject to wildfire, as defined by state and local officials pursuant to existing state law:

1.  Must create a firebreak by clearing all flammable vegetation or combustible growth within 30 feet of a structure, or to the property line, whichever is less.

2.  May be required to create additional fire protection or firebreaks within 100 feet of a structure, or more, if ordered by local agencies on larger parcels.

3.  May keep, within either zone, "single specimens of trees or other vegetation that is well-pruned and maintained so as to effectively manage fuels and not form a means of rapidly transmitting fire from other nearby vegetation, buildings or structures." Note that ornamentals are not the only trees and plants allowed within these zones. Native trees and plants can be grown if they are appropriately spaced, pruned and maintained.

4.  May grow, beyond 30 feet from a structure, "vegetation maintained to stabilize soils and prevent erosion...."  if those plants are less than 18 inches high.  So, for those with a natural landscape, local officials may not order the wholesale clearance of low growing natives interspersed with native trees and other plants.  And clearly, a mixture of natives and non-natives is permissible.

5.  May not be required to manage their neighbors' vegetation.

6.  May be required to assent to larger fire breaks or fire protection zones by their insurance carriers, however, it does not appear the insurance carrier can require owners to clear all vegetation.

7.  Be allowed, if a structure is built from nonflammable exterior materials, to modify or eliminate these fire break and fire protection zones, after exterior and interior inspections and the approval of local officials.

The state's definition of weeds no longer singles out native plants. Weeds now include all plants: (a.) whose seeds are of a "downy or winged nature", (b.) that create a fire hazard to adjacent improved property and certain urbanized but unincorporated areas, (c.) are dry and brittle, (d.) are litter or rubbish, (e.) or are poison oak or poison ivy that is deemed a menace to public health.

- Contributed by the San Diego Chapter of the California Native Plant Society

To see the latest research on how to prepare for wildfire from the community outward instead of from the wildland inward, see the ONLINE WILDFIRE RISK ASSESMENT TOOL from UC Berkeley. Here is the press release for further details:

Fire researchers at the University of California, Berkeley, are launching a new set of interactive online tools to help homeowners, community leaders and researchers assess the risk of wildfire damage to their homes and communities.

The interactive site, officially called the Fire Information Engine Toolkit, debuts today (Wednesday, Sept. 13) and can be found HERE. It was developed by researchers at the Center for Fire Research and Outreach, based at UC Berkeley's College of Natural Resources. Users can type in a specific address to see if they live in a region at risk for wildfires, as well as obtain information about historic fires that have occurred in the area since 1950.

Homeowners can also use the site to get a science-based assessment of their vulnerability to wildfire based upon the answers they provide on an online form.

"What's new about these tools is that homeowners and community officials can get an individualized assessment of a specific building's fire risk based upon such factors as the material used in their roof construction or the density of vegetation near the structure," said Max Moritz, UC Berkeley cooperative extension wildland fire specialist and lead researcher for the fire toolkit project. "The toolkit then provides immediate feedback that helps identify areas where people would get the biggest payoff in mitigation.""There are no other sites like this that allow people to get suggestions for reducing fire risk that are targeted to their own homes," added Faith Kearns, associate director of the Center for Fire Research and Outreach.

The researchers reviewed a number of the most widely used fire hazard ranking methods - each dealing with different risk factors including dense vegetation, installation of attic vent screens, or the width of the roads leading to the homes - as well as the latest wildfire research to create one comprehensive risk assessment tool. In addition, the researchers are utilizing geographic information systems (GIS) and Google Maps to display fire hazard information.

Locations of major wildfires active within the previous week are also mapped on the fire center site, and readers can link from there to recent fire-related news stories.

Local officials and decision makers can also download forms to complete a community-wide assessment on fire risk, and easily upload the results to a Web map. Such information could be used to plan education and risk reduction campaigns, the researchers said.

"One of our goals with this project is to raise grassroots awareness of the fire risk of one's home or neighborhood among the public, since we are ultimately most concerned with the loss of lives and property in fire-prone areas," said Moritz.

The site contains useful information for fire researchers, as well. Scientists can get background information on fuel models and fire behavior, and download the HFire computer modeling software used to predict the speed and direction of fire spread. The program, developed by Marco Morais when he was a graduate student in geography at UC Santa Barbara, can also be used for multi-year simulations of wildfires.