Fire-Wise Landscape Design

This video give a brief summary of Resilient Landscapes principles.

This video provides a deeper, more detailed treatment of resilient landscape design.

A resilient, fire-wise landscape design uses sustainable practices, hardscape, and plant selection hand in hand to reduce the risk of fire in the defensible space zone, while creating a beautiful garden.

A well designed landscape can be very beautiful while providing fire resilience and ecosystem benefits.

Fuel breaks can be created by walkways, areas with decorative rock, and low-water use lawns.

Create fuel breaks by providing space between planting areas.

Ladder Fuels: the distance between the understory plant and lowest tree limb is recommended to be 3x the understory plant height

Defensible Space Zones

Sustainable Landscape Practices will keep plants healthy and so less prone to ignition. At the same time, sustainable practices can lower maintenance needs, and encourage native wildlife to enter the garden to pollinate and provide other ecosystem services:

Keep plants well pruned and hydrated to reduce risk of combustibility.
Keep soil in place, and promote and support soil microorganisms, using compost and mulch.
Conserve water: Use drought tolerant (where possible, native) plants; where irrigation is needed, adjust seasonally; slow, spread, and sink water into the soil; mulch.
Minimize pesticides: use non-toxic pest control methods, using chemical pesticides only as a last resort
Support biodiversity: a more biodiverse landscape is more resilient, as bird species such as hummingbirds, swallows or bluebirds, for instance, provide services like pollination, and pest control.
Sequester carbon: Plants and soil absorb and store vast quantities of CO2, and soils alone are the most effective carbon sink. In fact, soils with a healthy microbiome can store more CO2 than the atmosphere and plants combined.

For more information: http://sonomamg.ucanr.edu/Sustainable_Home_Gardening/

Fire resistant landscaping is landscape design that integrates proper plant selection, placement and maintenance, with features such as retaining walls, paths, fencing, and open areas to reduce a property’s vulnerability to wildfire. Careful planning and design will reduce the possibility of ignition, lower fire intensity, and slow the spread of fire – all factors which will increase a home’s survivability during a wildfire. As a reminder, however, review and follow the recommendations in the Home Hardening section (to come https://sonomacounty.ca.gov/General-Services/Energy-and-Sustainability/Benefits-of-Sustainability/Construction-Hardening/) as a critical first step in protecting your property.

Creating a sustainable, fire-wise garden takes careful planning, and it may be helpful to consult with a local landscape professional knowledgeable about the techniques described in this section.

Within the 100’ defensible space, “fuel breaks” are a vital component in firewise design. Create fuel breaks with driveways, low-water use lawns, walkways, patios, parking areas, areas with inorganic mulches such as decorative rock, and with fences or walls of nonflammable materials such as rock, brick, metal or concrete to slow the spread of fire and separate your home from ignition sources. Leaving open space around the home and within the landscape also allows firefighters leeway to fight a fire safely and effectively. While bare soil can’t burn, it is not promoted as a firewise element due to aesthetic and soil erosion concerns, although some small patches of bare earth can provide habitat for native bees.

Create fuel breaks by:

providing space between planting areas. A rule of thumb between planting areas is the space should be twice the height of the adjacent plants. (see diagram), but the space will increase with steeper slopes. Such spaces can include patios, pathways, drives, walls, or well-hydrated & drought tolerant grasses (http://sonomamg.ucanr.edu/Lawn_Replacement/Lawn_Alternatives_Table/), or low-growing herbaceous plants
eliminating “fuel ladders” under tall shrubs and trees. A rule of thumb is the distance from the lowest branches should be twice the height of the shrub or groundcover below
pruning plants to remove dead foliage and to keep an open growth habit

Keep tree limbs at least 10 feet from chimneys. Minimize ladder fuels that will take fire from the ground into the tree canopy; make sure that only low growing shrubs and groundcovers are under the tree branches.

Defensible Zones & Plant Selection - Right Plant, Right Place
Within the 100’ defensible space there are typically 3 zones with different approaches to plant selection. Consider the species, height, and width at maturity when selecting new plants. Closer to the house, it’s best to reduce potential fuel for fire by choosing lower-growing plants, and within 5’ of the house it’s best to use only hardscape. (see plant list section of this website)

0-5’ from the house: no plants recommended
5-30’ from the house: lower growing plants (3’ or less) with individual larger shrubs or trees. A good place for patios, herbaceous perennials, and groundcovers.
30-100’ from the house: this is a transition zone to the wider landscape, and provides for wildlife and biodiversity support through larger plant groupings than the 5-30’ zone.

Focus on locally native plants, since they are best adapted to this climate, and are better able to remain well hydrated with less water than many non-native plants. A mix of at least 70% native plants provides excellent habitat for wildlife biodiversity, and allows plenty of room for other favorites.

Awareness of the micro-climate (sun, shade, wind, marine influence) and climate zone at your property will help determine plants that will remain healthy with the least maintenance. In choosing plants, it also helps to know the local plant communities of your watershed.

Avoid Invasive Species which are often dry and combustible in fire season https://www.cal-ipc.org/plants/profiles/)

Plant Maintenance
Keeping plants healthy with proper seasonal pruning, irrigation and mulching is of primary importance in a firewise garden. A proper maintenance program should incorporate annual maintenance based on the life cycle of the plant and work that should be done every few years. During fire season, particularly during Red Flag Warnings, a good thorough clean up around your plants is recommended along with a good soak

Pruning: As plants grow, the spacing between them “shrinks.” Regular pruning helps maintain spacing, and removes the dead twiggy materials that can make a plant burn. Several favorite California native plants such as manzanita, coyote brush, ceanothus, salvias and buckwheat - which are beautiful and provide abundant food and shelter for wildlife - appear on some lists of fire prone plants. In fact, if pruned properly, well hydrated, and separated from adjacent plants, these plants can grace your garden as effective elements in a firewise landscape. Please see the firewise plant list for instructions on optimal pruning of different species. Most of the herbaceous perennials can be cut back to about 6” from the ground every 2-3 years to discourage woody growth. Alternating years for maintenance between groups of plants conserves cover for habitat.
- Prune to remove lower limbs and foliage, dead and dying vegetation, dry undergrowth,
- Shear herbaceous perennials annually to remove old foliage and encourage next season’s growth and flowering.
- Prune larger shrubs to remove dead wood and foliage and eliminate ladder fuels from adjacent plants.
- http://marinmg.ucanr.edu/Choose_Plants/Native_Plants_574/Pruning_California_Native_Plants/;
Mulching: mulch cools the soil, conserves water, and suppresses weeds.
- Use only non-combustible mulch like pea gravel within 5' of the home, and Arbor Mulch up to 2' depth from 5-30' of the home.
- Do not use fine bark or shredded redwood mulch which is highly combustible, and ignites easily from embers.
- For information about mulch and fire: https://ucanr.edu/sites/fire/Prepare/Landscaping/Mulch/
Irrigation: Proper irrigation amounts and timing will keep plants hydrated. Drip irrigation is the standard, however there is emerging information that in summer, most native plants appreciate bi-weekly light overhead watering from low pressure pop-up sprinklers to clean leaves and hydrate the plant.
For general information on watering and mulching: http://sonomamg.ucanr.edu/Firewise_Landscaping/Watering_and_Mulching/
Clean-up: Trees drop leaves regularly, especially in the fall when fire-season is at its worst. Clean up as often as needed, and pay careful attention to your roof and the base of your home. Clean up aggressively when fire weather is extreme.

Tree Maintenance
Consult a licensed arborist to help maintain your trees in good health.
Most trees can be maintained to reduce ignitability, and the shade they provide can suppress weeds while retaining moisture, cooling your house and enhancing your property’s Defensible Space. Certain species such as Italian cypress, however, cannot be maintained in a way that reduces ignitability, and the buildup of dead material behind their foliage is dangerous year-round.
Remove lower limbs of trees so that no foliage is within 6’ of the ground (or 1/3 the height of the tree if it’s less than 30’ tall). Preserve single specimens or groupings of well-pruned trees, while keeping vertical spacing between lower branches and understory plants equal to 3x the height above the understory plant.

Continuous Canopy in Forests and Woodlands
Many residential areas are located within forests or woodlands, in which mature tree canopies are touching overhead. As long as there are no ladder fuels that can carry a fire from the ground up into the canopy, this intertwining canopy should be no problem. Also note that it is wise to create a break in the canopy at least 30' from the house to reduce the risk spread to the house if a canopy fire occurs. If there is enough sunlight, lower growing shrubs (to 3’) and groundcovers can be beneficial in these woodlands to provide wildlife habitat. All trees should be pruned to remove dead or dying branches, and lower branches should be pruned to 3x the height above the understory plant.

Plant Communities and Habitat
Plant Communities are groups of plants that grow together because of similar adaptations to microclimates, rainfall, soils and slopes, and other factors. Some typically found in Sonoma County are listed below. For more detail go to: https://www.laspilitas.com/comhabit/california_communities.html

Oak woodland or savannah: An oak savannah is characterized by trees that are widely spaced, often with grassland between, while an oak woodland is characterized by trees growing closer together with canopies often touching. Live Oak (Quercus agrifolia), Blue Oak (Quercus douglasii) and Black Oak (Quercus kelloggii) are dominant species in Sonoma County. The understory can be sparse or more dense with a diversity of shrubs, depending on how much shade the oaks provide. Some oak woodland understory plants are: Blue Wildrye grass (Elymus glaucus), California Honeysuckle (Lonicera hispidula), Iris (Iris douglasiana), California Melic (Melica torreyana), and Golden Yarrow (Eriophyllum lanatum). Northern Oak Woodland is occupied by many birds but most conspicuously by the acorn woodpecker. A very gregarious bird, the acorn woodpecker lives in large, extended, talkative families collecting and storing acorns.
Grassland plant community: this plant community is composed of perennial bunch grasses, annual grasses, sedges and rushes as well as legumes, like lupine, and other wildflowers. These plants also occur in Oak Woodlands in open areas among trees.
Chaparral or Coastal Sage Scrub. Chaparral occurs on the west-facing slopes which typically are hotter and drier, and features few trees, but very drought tolerant shrubs with hard waxy evergreen leaves or needles. Coastal Sage Scrub, found on the cooler, moister coastal climates, features soft-leaved, drought-deciduous shrubs.
Riparian Woodland: The riparian plant community is found along streams. Common plants include Spicebush, Willow, Dogwood, Alder, Big Leaf Maple, Box Elder, Oregon Ash, Valley Oak, Black Walnut and Cottonwood. Riparian plants are generally more water-loving than those of the other California plant communities. Riparian habitat runs through other plant communities, as water flows from higher elevations through tributaries.
Redwood forest: This plant community is found along the ocean side of the coast ranges of California. Common species include Coast Redwood (Sequoia sempervirens), Douglas Fir (Pseudotsuga menziesii), California rose-bay (Rhododendron macrophyllum), Western Azalea, (Rhododendron occidentale) and Tanbark Oak (Notholithocarpus densiflorus), The keystone species of the Redwood Forest, the Coast Redwood tree (Sequoia sempervirens), can live for more than a thousand years.
Mixed evergreen forest: This plant community is found mostly in the northern coastal mountains of California, and is usually found on the cooler, damper north-east facing slopes. Some of the component species include Tanbark Oak (Notholithocarpus densiflorus), Madrone (Arbutus menziesii), Douglas Fir (Pseudotsuga menziesii), California Bay (Umbellularia californica), Bigleaf Maple (Acer macrophyllum), Canyon Live Oak (Quercus chrysolepis), Black Oak (Quercus kelloggii), Coast Live Oak (Quercus agrifolia) and California Hazelnut (Corylus californica). This forest is filled with leafy trees and fewer conifers.

FIRE HAZARDOUS PLANTS
Highest Hazard Species
Certain fire prone shrubs and trees, like juniper, Italian cypress, pampas/jubata grass and bamboo are so combustible that they should be removed from the Defensible Space area and replaced with more appropriate plant selections. Eucalyptus trees, as well as conifers like pine, cedar, and fir trees should be removed or maintained aggressively for fire resistance.

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