Gardening : Drought and Winds Add to Danger of Wildfire : Protection: Homeowners on hillside can limit danger by cutting back bone-dry plants and selectively thinning chaparral.
On a clear day you can see Catalina Island, and most any day red-tailed hawks soar above and deer nibble your rosebuds. Indian paintbrushes, woolly-blue-curls and other wildflowers bloom on the sage-scented slopes.
These are some of the perks of living in Southern California’s hillside areas.
Scott Franklin, who retired in Marchafter 10 years as the Los Angeles County Fire Department’s vegetation management officer, knows it’s that love of flora and fauna as well as the dramatic views that draw people to live in the hills and canyons.
He has a somewhat different perspective, though, one molded by 36 years of fighting and studying wildfires:
“It’s like sitting in a room filled with vaporized gasoline, just waiting for a spark. Each pound of dry vegetation releases as much heat when it burns as a cup of gasoline.”
The awesome destructive potential has made Franklin an advocate of what could be called “preventive pruning.”
Seven of the last eight years have had below-average rainfall, making hillside brush tinder-dry. With water-rationing now in effect, even cultivated garden plants start to take on the characteristics of wild vegetation--low moisture content and a buildup of dead twigs, branches and leaves.
In a year when everything seems to go wrong, even last December’s severe cold weather contributed to the Southland’s fire hazard.
Laurel sumacs (Rush laurina), common native shrubs that are as tender as lemons and avocados, were heavily damaged by the frosts. When summer’s heat returns, those frost-killed branches will be just that much more dry fuel on the hillsides. The same is true of frost-damaged garden plants--a large mound of frozen bougainvillea is highly flammable.
At the U.S. Forest Service’s Forest Fire Laboratory in Riverside, Philip Riggan reports that fire danger has increased dramatically because a mysterious canker fungus has killed thousands of acres of chaparral in the past decade and because drought-stressed trees are falling prey to insect pests.
Native conifers in parts of San Diego’s Cleveland National Forest are being destroyed by five species of pine-bark beetles, Riggan said.
Eucalyptus trees from San Diego to San Francisco are being infested with another deadly beetle, accidentally introduced from Australia several years ago.
In years of normal rainfall, pines and eucalyptuses respond to insect attacks by exuding sap that expels the invaders. In prolonged droughts the trees just don’t have enough sap to defend themselves and death can result, adding to the already huge fuel load.
In La Canada Flintridge’s Palm Canyon, Franklin designed a model fuel-reduction project to help fire departments learn to cope with wildland vegetation, but the project’s methodology is applicable to home landscapes.
The goal is to thin the chaparral selectively rather than cutting it all down and exposing the hillsides to erosion. Small shrubs such as sage, buckwheat and chamise are thinned along with taller shrubs because these low, fine-leaved bushes can also carry a fire readily.
The lower branches of trees and tall shrubs are removed, eliminating “ladder fuels” that allow a fire to spread into the crowns of trees.
Wild vegetation is only part of the fuel-load problem. The role of cultivated plants is often overlooked, according to Franklin, but the June, 1990, fire in the Chevy Chase area of Glendale was carried mostly by planted ornamental vegetation.
After studying the 1988 Porter Ranch Fire, Franklin and Riggan both point the finger at planted junipers with a buildup of dead leaves and twigs as the major element in spreading the fire. Aleppo and Monterey pines also were a problem.
The destruction led Franklin to issue a stern warning, “I tell homeowners that if they have conifers with a lot of dead material in them, their house is history.” Neither researcher advocates banning conifers from the landscape, just keeping them pruned.
Looking ahead to the coming fire season, Franklin says with an edge of frustration to his voice, “It’s hard to get across to homeowners what a huge amount of dead material there is in their landscapes. Nobody thinks about it during cool spring weather, but when we start having weather episodes with low humidity and high temperatures plus wind, we’re really in trouble.”
With the fire season just around the corner, the time to act is now.
Last year a colleague of Franklin from Santa Barbara suggested they cooperate on a research program on overgrown, 80-year-old chaparral on the coastal side of San Marcos Pass. Franklin agreed but said, “We’d better hurry. That area is ready for a big blow-out.”
The next day the Paint Fire swept down from the pass, devastating the outskirts of Goleta and leaving nothing but ashes in its path.
A booklet entitled “Homeowner’s Guide to Fire and Watershed Safety at the Chaparral/Urban Interface” is available from the Los Angeles County Fire Department, 1320 N. Eastern Ave., Los Angeles, 90063. The booklet is free to Los Angeles County residents and $1.50 to non-residents.
