Landscaping Out of Fire’s Way

There is, without exception, no reason for a structure to be consumed by wildfire.

When these fires break out, we spend millions of dollars per 24-hour period employing Super Scoopers, retardant-dropping fixed-wing aircraft and helicopters, and hundreds of fire engines and firefighters in a vain attempt to save structures that, with forethought, could have survived even the highest intensity blaze.

The key to structural survival in a wildfire is fuel management by entire communities. Although site specific, this includes choosing native, drought-resistant vegetation while declining nonnative species, using fire-safe building materials, selecting appropriate structure placement and providing adequate water. For hillside / canyon residents, fuel management is the most critical fire-safety consideration.

Wildfire professionals in California have coined a new term to denote the wildfire threat at the Urban-Wildland Interface or Intermix. The term is the “I Zone,” for “Interface Zone,” an area that includes wild land vegetation, exotic / ornamental vegetation and structures. Locally, the I Zone includes, among other areas, all of the Santa Monica Mountains, the Verdugos, Santa Susanas, San Gabriels, Whittier Hills, Palos Verdes and the hill areas of Orange County.

In fire parlance, all vegetation--both native and exotic / ornamental is termed “fuel.” The California Department of Forestry and Fire Protection, under auspices of the state fire marshal, in January published the most contemporary text on structural survival from wildfire, appropriately titled “California’s I Zone.” My contribution included the chapter “Fuel Management.”

To a major extent, individual hillside / canyon residents are not in control of their own destiny. Each resident within 300 feet of another must practice effective fuel management to preclude a domino effect from fire jumping from structure to fuel to structure. That is why effective vegetation management must be a community effort.

From 1990 through 1993, I monitored six catastrophic California wildfires that involved extreme or significant structure loss. The fires, by name and location, were: “College” in Glendale; “Paint,” Goleta; “East Bay,” Oakland Hills; “Laguna,” Laguna; “Kinneloa,” Altadena; and “Old Topanga,” Malibu / Topanga. Both the Paint and College fires occurred the same day in 1990, with a loss of more than 600 structures in the Paint fire and more than 60 in College. Before that, the largest loss of structures from wildfire in California was in the Bel-Air fire of 1961. The East Bay fire (1991), moved from parkland into Oakland and consumed more than 3,700 structures and directly caused 25 deaths.

Catastrophic fires in 1993 included Laguna, Kinneloa and Old Topanga, with a total of more than 600 structures lost. In addition, two lives were lost in the Malibu fire.

What carried the fire from house to house? Initial reports implicated wood roofing. However, the first two structures lost in the College fire had noncombustible roofs. And in all of the fires, structures that survived displayed smaller amounts of nearby ornamental vegetation. In addition, one structure, with a wood roof and wood siding, survived the Old Topanga fire in the Big Rock Mesa area due primarily to an aggressive vegetation management program by the property owner as well as owners of adjacent property.

After viewing some of the fires firsthand and the others through news and amateur video, a more significant modus operandi was established: Although wood roofing was a contributing factor, the real culprit turned out to be drought-stressed ornamental vegetation planted by homeowners. The drought-impacted exotic (meaning nonnative) vegetation had taken on the same characteristics as wild land fuel. Six years of drought had created a severe dead-to-live fuel ratio in trees and shrubs.

The use of cultivated exotic trees and shrubs was remarkably similar from Oakland to Laguna: acacia, cypress, eucalyptus, Scotch or French broom, juniper, conifer / pine and palm formed the exotic and explosive pallet near the structures.

A close video review clearly shows the flaming front of the fire moving well ahead of the torching structures. What appears to be carrying the fire is ornamental vegetation. Burning structures were the aftermath or product of the fast-moving flaming front. Planted ornamental vegetation was the wick.

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Ninety-eight percent of the structures lost in the fires I studied were pre-1980 construction. Homes built post-1980 tended to have double-paned windows, tighter, energy-efficient construction--and noncombustible roofing. Most important, ornamental, exotic landscaping had not become decadent, as in the pre-1980 developments. The “wick” effect was not present.

Hillside residents live in chaparral-covered canyons because they enjoy the ambience. But instead of landscaping with deep-rooted native California vegetation, they tend to use shallow-rooted, exotic species.

One of the major recommendations of the Los Angeles County Wildfire Safety Panel, and adopted in the L.A. County fire ordinance in 1994, was establishment of a “Very High Severity Fire Hazard Zone” in areas subject to wildfire. This zone would require a fuel modification plan and preclude the use of acacia, cedar, cypress, eucalyptus, juniper, pine, palm, pampas grass and any other highly flammable exotic or native (such as chamise or sage) species within 30 to 100 feet of any building, depending on the slope. The ordinance also mandates fire department access to all new swimming pools, as emergency sources of extra water.

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I strongly encourage the use of native California vegetation for hillside landscaping, due to its drought resistance, resilience and deep root structure. The California Native Plant Society can provide lists of desirable shrubs and trees. Both L.A. city and county fire departments have brochures depicting appropriate management practices with approved shrub lists, and county fire can provide a registered professional forester to assist in plant selection. In addition, the Theodore Payne Foundation in Sunland and Rancho Santa Ana Botanic Garden in Claremont each has a native plant nursery.

The new Los Angeles County Fire Ordinance is unique because it takes into consideration fuels, terrain and structure placement. Unfortunately, preexisting development is exempt, except for basic brush clearance. Ninety percent of existing construction in the I Zone was built before 1980. If communities in the I Zone employed the county fire code with a vegetation management plan, they would significantly increase their chance of surviving the next fire. And be assured, that fire may well be on the next Santa Ana wind.