All summer we have been reading about wildfires throughout the west. As these fires have burned large areas, the rest of the west has continued to dry out, creating more fuel for future fires. In parts of the Bay Area, the dead and dying oaks add to the problem.

Wildland fires are part of many ecosystems in the west so we need to know how to landscape to minimize this threat in populated areas. As more and more exotic plants have been introduced to the Bay Area we have changed the nature of a wildfire from a low intensity fire useful to the land to a potential blaze of catastrophic proportions. Picture towering eucalyptus torches and then envision the changes in soil chemistry which can affect the way soil absorbs water that result after a eucalyptus fire.

The Oakland fire of 1991 and the Mt. Vision fire in Inverness in 1995 both occurred in October, which can be our most troublesome month: warm, windy and very dry, just before the winter rains. The Oakland fire destroyed over 3400 homes. Unfortunately, Marin is ripe for a similar conflagration as the fuel load on Mt. Tamalpais alone is estimated to be three times that of the Oakland hills before the fire. All it takes is a windy, dry day and a spark. Firefighters, when faced with a large fire, will select the most defensible properties and let others, considered too dangerous because of terrain, architectural features, or landscaping, go.

Q: Are some plants more flammable than others?
A: Pyro(fire)phytes(plant) are plants that ignite readily and burn intensely. Certain characteristics will frequently be found in plants that are volatile:

• leaves that are stiff, woody, small, fine/lacey, needle-like
• contain volatile oils, fats, waxes
• aromatic when crushed; sap gummy, resinous, odorous
• loose or papery bark and other dry leaves/brush
• unwatered plants will be dry and flammable

Q: So what are the best ways to plant and protect my home at the same time?
A: Think of everything you plant as potential fuel and take into account prevailing winds, especially if you live on a hill. Dry grasses and shrubs can ignite easily and winds can push a fire directly up toward a home very quickly. Overhanging branches should be trimmed away from the house, vegetation kept thinned, and plants irrigated. We are encouraged to plant with periodic drought in mind but from a fire safety standpoint, some summer water is a good strategy because a plant with water in its tissues will be less flammable. Mulch is necessary to retain water but it is best to use a wood chip mulch as opposed to shredded bark which can ignite easily if a cigarette is pitched into it. Understory shrubs are best kept under two feet tall and not too densely planted.

• many are broadleaf, deciduous trees which tend to be clean, not bushy, with little deadwood
• leaves supple, moist, easily crushed
• low growing shrubs and taller shrubs with minimal dead, bushy material
• sap is watery, usually without odor

Among the most fire resistant plants available are the succulents such as ice plants (many varities, some of which are invasive and should not be used near the coast), hens and chicks (Escheveria spp), Sedums, Aloes; most require little summer water. Many native trees and shrubs are fire resistant: buckeye (Aesculus californica), alders (Alnus spp), pacific dogwood (Cornus nuttalli), oaks (Quercus spp), willows (Salix spp), coast redwood (Sequoia sempervirens), some Ceanothus, toyon (Heteromeles arbutifolia), some manzanita (Arctostaphylos spp) and rockrose (Cistus spp).

Many commonly used exotic trees and shrubs are safe to plant: maple, (Acer spp), Citrus, Myoporum, mock orange (Pittosporum spp), Escallonia spp, privets (Ligustrum spp), oleander (Nerium oleander), butterfly bush (Buddleia spp), Cotoneaster spp, Lavatera spp, lavender (Lavandula spp) and Lantana spp. Dozens of perennials and groundcovers are good bets: Lirope spp, Santolina spp, Pelargonium spp, Geranium spp, Vinca spp, Agapanthus spp, Heuchera spp, Penstemon spp, Iris spp, lambs ears (Stachys byzantina), California fuschia (Zauschneria californica), common calla (Zantedeschia aethiopica).

The plants mentioned only scratch the surface of hundreds that are safe choices. The University of California Cooperative Extension office (1682 Novato Blvd, Suite 150B, Novato) has copies of an excellent brochure "Pyrophytic vs. Fire Resistant Plants" which lists hundreds of plants to consider. FireSafe Marin publishes brochures which may be available at your local fire station. California Wildfire Landscaping by Maureen Gilmer is available in libraries and goes into detail about proper landscaping with plant lists.

Tip of the Week: Fall is a great time to rework your landscape. New plants will have the benefit of the winter rains to become established and you can improve your garden from a fire safety standpoint by removing selected pyrophytes and putting in some fire resistant plantings.

This article appeared in the Marin Independent Journal on October 7, 2000.

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