Creating a Fire-Resilient Home

5-30 Foot Zone from Structure and Its Attachments

A little more relaxed here, but keep vegetation well-spaced both vertically and horizontally. You don’t want an oncoming crown fire to be fueled right up to your house. A fire-resilient landscape can still be water-conserving and wildlife-friendly. Remember, every decision we make also affects other living creatures.

• Assess the area: Which trees and/or shrubs would you like to keep as specimens? If you choose natives, you will enhance wildlife as well as aesthetics. Large mature trees are generally less prone to burning than smaller, young trees, and can often be kept. Also, oak trees are generally less flammable than conifers.
• For the trees kept, make sure they are well-spaced from each other, and remove any shrubs growing right beneath them (which could act as “ladder fuel,” helping sustain an approaching ground-to-canopy crown fire—a dangerous situation). Limb trees up at least 6 feet from the ground (but not more than 1/3 their height). Limbing trees up can be highly effective in keeping crown fires from sustaining themselves.
• For shrubs kept, are they well-spaced on their own, or might you create small shrub islands, well-spaced from other shrubs and trees? One rule of thumb is to space a shrub or island horizontally so that it is at least twice its height away from another and to keep islands to 10 ft wide or less (Board of Forestry recommendation).

• Landscape interest can be created with nonflammable items like rock/stone, hardscaping, metal benches, etc.
• Dry streams or gravel swales can also be used and have the added benefit of allowing rainwater to slow, spread, and sink into the ground on-site. This can help plants keep their moisture content up longer into the dry season (as well as reducing water needs).
• With bark, chips, or other flammable mulches in this intermediate zone, spread it into well-spaced patches, which can help retain moisture and eliminate weeds while not being a continuous fire path. Compost or composted bark is the least flammable mulch and is recommended.
• Dead leaf litter in the rainy season can be important for overwintering insects and for reducing erosion. In spring, reduce to just one layer. This can help with tree health and moisture retention, thereby reducing fire hazards during the long summer drought ahead.
• Bare ground here and there can be good for native bees, as well as fire resilience. Keep weeds removed or mowed to 4 inches or less. If you have native wildflowers, grasses, or bulbs, weed-eat around them until they have had a chance to set seed (usually early summer). String trimmers are recommended from early summer through fall (mowers have metal blades that can throw sparks).
• Water natives deeply and infrequently (once a month for many) during early mornings in summer and fall to keep plant moisture up and flammability down. Some Southern California experts advocate for 2-3 times a month of light overhead sprinkling instead, mimicking summer thunderstorms.

• Avoid highly flammable plants in this zone altogether. When choosing plants to keep (or to plant): Calscape.org helps you find plants native to your specific area. Signs that a plant might be particularly flammable include aromatic/resinous foliage, a high natural accumulation of dead material, and/or a closed structure that can easily catch embers. You can also try these resources:

  • Bay Area
  • Sierra Foothills
  • Southern California
  • Firescaping Your Home, A Manual for Readiness in Wildfire Country, by Adrienne Edwards and Rachel Schlepper, Timber Press, 2023
• Maintenance: A critical ongoing step! Keep dead plant material pruned out (including deep inside shrubs), trees limbed up, shrubs thinned to a more open structure, vines out of trees, and weeds short or pulled out.
• In spring, avoid disturbing bird or other wildlife nests you might find, delaying pruning till summer. Fall and winter are good times to prune most trees and deciduous shrubs, while summer can be best for pruning evergreen native shrubs. (See California Native Gardening, A Month by Month Guide by Helen Popper for more maintenance of natives information).
• Mature trees often don’t need to be removed – limbing up at least 6 feet is very effective and allowed by CAL FIRE.

Beyond 100 Feet

In chaparral, continuing defensible space beyond 100 feet is probably not necessary based on studies done in Southern California. But in Northern California woodlands, a 2021 study of the Camp Fire showed that keeping canopy cover to roughly 50% for 300 feet may actually be helpful to home survival. And if you live on a hillside, defensible space out 200-300 ft is generally recommended.

In general:

• Focus here on keeping the wildlands of your property healthy and not too badly overgrown from past fire exclusion (unless you live in Southern California chaparral).
• Dead snags can be left for wildlife unless numerous.

Residents near wildlands can be part of the solution by preparing their homes and property to be fire resilient. We CAN learn to live with wildfire and help support the plants and wildlife we share the land with.