Defensible Space 411

Fire usually burns uphill. As discussed, fire burns more intensely on hillsides as well. Hillside sites should be avoided, since they are difficult to protect. The increased flame length of fires burning upslope can directly expose structures to flames.

If building occurs on a ridge, structures should be set back at least 30 feet from the edge of the downhill slope in order to limit the same effects. It is sometimes possible to provide your site a southern exposure, on a ridge top or setback, while the downhill slope is a northern exposure. Northern exposures are less likely to burn with the intensity of other exposures and tend to be characterized by shade-tolerant, less flammable vegetation.

Building should not be undertaken in saddles or at the top of steep draws in order to avoid the fire chimney effect of concentrated heat.

Sites adjacent to large areas of continuous vegetation that are not managed to reduce fire hazard are also ill considered.

The road and/or driveway to your home must offer a safe evacuation route as well as reasonable ingress for firefighters to respond quickly. Access roads should be two lanes with frequent turnouts. It is a poor idea to purchase property in the wildlands interface that is located on a dead end road.

Driveways should be as short as possible with vegetation trimmed back 20 feet from the road edge. Large trees in this zone should be limbed no lower than 15 feet. Road surfaces must provide good traction for a large fire engine, with sufficient room for a turnaround and parking, in order for its crew to protect your house.

Driveways longer than 50 yards should have turnouts at their midpoints or every hundred feet that allow vehicles to safely pass. Bridges and culverts must be adequate in width and load capacity to support a 20-ton engine. The drive must not be too steep for an engine and be certain it can negotiate any sharp curves.

Road names must be posted at intersections with 6-inch white letters on a reflectorized background. When the house cannot be seen from the road, the address must be posted at the driveway entrance. The house must have its address clearly visible in at least 6-inch numbers.

If your home is not part of a community water storage and distribution system, and you do not have a summer stream or spring on or adjacent to your property, you should have at least 2500 gallons of water storage in either a water tank, pond or pool. Your well is probably not adequate to deliver the volume of water necessary for firefighting. Wildland fire engines have limited water-carrying capacity and require on-site water supply to effectively protect your home. A gas-powered pump can be valuable if an engine is not available and you decide to protect your home yourself. If you do depend on a well, consider purchase of a gas-powered, backup generator in the event of power failure.

Most home losses are due to roofs catching fire. Wind-blown embers from a fire will find a hospitable burning environment among wooden shakes and shingles. A fire-resistant roof installation is perhaps the most important wildfire safety precaution a homeowner can take.

Roofing is rated from A to C, based upon fire resistance, with C the least resistant. Communities with Class A roofs are a world safer than communities with mixed class roofing. Clay, metal and concrete tile roofing, as well as metal panels and composition shingles, can last decades. A fire resistant subroof is essential. Roofing must be installed so that embers cannot blow or fall into spaces between covering material.

When designing a home, one consideration should be that steep roofs permit embers to slide off more readily and allow less accumulation of tree litter. Pulsating rooftop sprinklers may be also be invaluable. Additionally, all eaves should be enclosed.

Vents should be screened with galvanized steel hardware cloth. This applies to foundation vents as well. Gutters must be metal and gutter screens help prevent debris build-up. Spark-arresting screening and/or chimney caps are required by law.

Windows and skylights are easily broken at low levels of fire intensity. Thermal pane glass should be used in all windows and skylights. It is preferable that there be no skylights at all. Window size and the number of windows should be reduced on sides of the house facing heavily vegetated areas. Operable metal shutters and fire resistant curtains should be considered.

With the obvious exception of shingle siding, wood siding itself is relatively fire resistant, but vulnerable to embers in vertical joints or where planks may overlap. Stained or painted siding retains higher fuel moisture content than untreated siding. Vinyl siding melts at relatively low temperatures and should be avoided.

Stucco, stone and metal exterior walls are most desirable and should be backed by sheathing in order to prevent fire entry.

Solid metal doors, or steel-jacketed, insulated doors, while perhaps aesthetically unpleasing, offer maximum fire resistance. Solid core wood doors are a good second choice.

Decks and porches should be treated with retardant and enclosed beneath with fireproof materials. Awnings and covers of metal and fiberglass are fire resistant, while canvas invites ignition. Materials such as outdoor furniture, firewood and lumber should never be stored below. When decks are built over a slope, posts, girders and joists must be steel.

Outbuildings, fences and arbor trellises can offer wildfire a route to your house. All three can be constructed of metal or other fire resistant material. Outbuildings should be sited only after consideration of whether their ignition will compromise defense of the house. All of the above factors must be considered in the construction of outbuildings.

It is a good idea to install outbuilding sprinkler systems. Flammable materials such as paint and gas should be stored in metal or concrete block buildings well away from other structures. Propane tanks should not be enclosed and have at least 15 feet of clearance around them. The area beneath tanks must also be kept clean.

Hardware cloth should be installed in back of the cooler pads to prevent embers from entering the house.

If you must have pet doors, they should be installed so that they can be sealed closed when you are away, or in the event of wildfire.

The California Department of Forestry and Fire Protection and the U.S. Forest Service conduct fire prevention property inspections through Eastern Sierra communities.

Public Resources Code section 4119 authorizes California fire protection agencies to inspect all properties, with the exception of home interiors, in order to achieve compliance with state fire laws. The primary inspection objective is to achieve property owner compliance with Public Resource Code section 4291 requirements.

Eastern Sierra Regional Fire Safe Council volunteers assist both agencies with inspections. Inspections are recorded on California Interagency Fire Prevention Inspection form LE-38 and volunteers are trained in its use. LE-38s are legal notices as well as public documents.

Fire law violations are noted on the forms and used as a basis for follow-up inspections and possible legal action by CDF and the USFS. It should be emphasized that ESRFSC volunteers act only in an advisory capacity. Inspectors must receive permission to enter private property.

PRC section 4291 mandates minimal fire defense measures. As discussed earlier, these measures provide inadequate protection in areas of high fire risk and greater clearances must be created to assure greater fire safety. Fire Safe property is not only reasonably protected from serious losses by wildfire entering the property, but can lessen chance of escape onto adjacent lands by fire ignited on the property

An outreach, or community education project that provides information to residents of the wildlands interface, is a secondary objective of volunteer inspections. ESRFSC volunteers offer information about how to live more safely with both the threat and reality of wildfire by discussion of elements of the Fire Safe Plan:

Firescaping is defensible space landscaping. It is landscape design that limits the vulnerability of home and property to wildfire. An appropriate landscape may be the primary factor in whether your home survives wildfire. The goal is to create an environment surrounding the house that is not likely to burn in any but the most extreme conditions.

An effective firescape can be as attractive as traditional landscape design and need not appear substantially different. It simply integrates defensible space concepts into the landscaping objectives of aesthetics, erosion management, entertainment environment, and wildlife habitat considerations.

Through careful selection, location and maintenance of plants, firescaping reduces:

The first priority in plant selection is the plant's capacity to reduce your property's vulnerability to wildfire--we choose a plant that is "FireSmart." Appearance, erosion control and value to wildlife are secondary considerations. Popular evergreen shrubs and trees, such as junipers, conifers and broadleaf ornamentals, contain oils, waxes and resins that burn with tremendous intensity. Ornamental grasses and berries also burn with intensity. These are not FireSmart choices.

FireSmart plants are low growing, with high moisture content, and their plant tissue is not readily flammable. Hardwood, or deciduous trees for example, are more desirable than conifers because they have higher moisture content and less fuel volume during dormancy.

Plant selection inevitably involves choosing between native and non-native, or exotic, species. There has been a growth in awareness of both the value of native plantings and the threat posed by exotics in our Eastern Sierra ecosystems. Many residents have moved to the Eastern Sierra because of their affinity for and love of its native vegetation, an affinity shared by many life-long residents. Remodeling an existing landscape by thinning and pruning creates a healthier ecosystem with less competition for moisture and nutrients.

Many exotic species such as cheatgrass and tamarisk have "escaped" into formerly pristine areas and wrought havoc in the ecosystem. Weedy species that spread onto wildlands can displace native vegetation. They may also hybridize and contaminate local gene pools. When non-native species are used, they should not be related to local plants.

Within at least ten feet of buildings, as previously suggested, all plants should be irrigated, with low-growing ground cover mowed to no more than five inches in height. Review the sections on plant spacing and ladder fuels prior to plant selection. As discussed, boulders, decorative rock, gravel, and steppingstones used in paths and as ground cover will disrupt fuel continuity and may function as fire barriers and control lines.

Larger shrubs and trees should have 10 to 30 feet of spacing between islands of plantings. FireSmart plants contain low fuel volumes and as a rule of thumb are less than two feet in height. Mulches effectively limit weed growth and provide a major boost in conserving fuel and soil moisture.

When thinning trees, select the healthiest, most defect-free, dominant trees as leave-trees. Plants have a defined lifespan and an ecosystem is dynamic rather than static—it’s always changing. Preserve some of the healthiest, sprouting tree seedlings to eventually replace their parents.

The Bristlecone Chapter of the California Native Plant Society holds an annual native plant sale. CNPS members are happy to provide information concerning native plants.

Local nurseries also encourage native plantings. When purchasing plants from a local nursery, employees should be consulted regarding appropriateness of plants for their intended locations. Consider the amount and type of required maintenance, elevation, seasonal temperatures, amount of sun and shade on the site, deer resistance, drought tolerance and tolerance to wet conditions. Local State and Federal Fire Prevention Officers can visit your site and offer additional advice.

National Forest special use permitees and recreational residence lessees must remember that they are required to landscape using only local native plants.

Key Planting Tip!

Most native plants begin their growing seasons in fall, not spring. This is the best time for many plantings, since new plantings are active enough that they are less susceptible to transplant shock. They then enjoy an extended, cooler growing season during which they become established, sending out deeper roots prior to next summer’s heat stress.