Landscaping & Outdoor Space

Landscaping

In an urban environment, structures are often close together and share defensible spaces with neighboring structures. A combination of fire resilient construction and landscaping can help homes withstand windblown embers, minimize the likelihood of flames or surface fire touching the home or any attachments, and reduce the chance of fire spreading. The primary goal for fire resilient landscaping is reducing fuel by limiting the flammable vegetation and materials surrounding the home and increasing the moisture content of remaining vegetation. The “home ignition zone” or “defensible space” is split up into three different areas. Landscape architects and arborists are additional professionals that can be added to your team. Source 1, 2

Ignition Zones

Structures in a High Fire Hazard Severity Zone are required to adopt a Fuel Modification Plan. However, any property owner can adopt similar measures to improve a structure’s resiliency to future fire.

Zone 0

The area 0-5 feet from a structure should be designed as an ember resistant zone or non-combustible area. The goal is to prevent flames from coming in direct contact with a structure and the accumulation of embers in the immediate area. Fire science studies show this is the most important zone to take immediate action on as it is the most vulnerable to embers. Where you see leaves and other debris accumulating around a structure, is the exact place embers will accumulate.

• Avoid vegetation and dry debris within five feet from any structure
• Use rock or pebbles instead of bark or mulch next to a structure
• Keep other flammable material away from wall exteriors – mulch, flammable plants, leaves and needles, firewood piles, wooden playsets, gas/propane – anything that can burn
• Avoid storing anything underneath decks or porches
• Keep anything that can collect or accumulate embers or debris away from the structure
• Consider fire-resistant, non-plastic material for patio furniture, swing sets, decking, elevated porches, etc. (see Wildland Urban Interface Products linked below in “Other Resource”)

Zone 1

This is the area 5-30 feet from the furthest exterior point of a structure. The goal of this zone is to give an approaching fire less fuel, which will help reduce its intensity as it gets nearer to a structure.

• Create a fuel break with pavers and rock paths around the structure
• Control the density and location of vegetation within five to 30 feet of the structure or up to your property line
• Prioritize fire-resistant, California native plants, and avoid fire prone plants that have a high oil/resin content or accumulate a lot of dead material such as arborvitae, juniper, eucalyptus trees, rosemary, and yew
• Look for plants with high moisture content, low growing, and trees that are deciduous or broad leaf evergreens. See plant selection guides below.
• Prune tree limbs within six feet of the ground
• Prune branches to no closer than ten feet from your building and decking
• Space shrubs apart at a minimum distance of two times the height of the tallest shrub.
• Raise bushes planted along fences or walls, to allow for debris (and embers) to pass through and not accumulate.

Zone 2

This is the area 30-100 feet, from the furthest exterior point of the structure. The goal is not to eliminate fire, nor vegetation, but to interrupt fire’s path and keep flames smaller and on the ground.

• Trees 30-60 feet from the structure should have at least 12 feet between canopy tops.
• Trees 60-100 feet from the structure should have at least 6 feet between the canopy tops.
• The crown spacing needed to reduce/prevent crown fire potential could be significantly greater due to a property’s slope, the species of trees involved and other site-specific conditions. Check with your local arborist and forestry professional to get advice on what is appropriate for your property.

Plant Lists for Landscaping

Selecting the right plants is a critical step in rebuilding a resilient landscape. Choose fire-resistant and water efficient plants that are less likely to ignite. Such plants do not readily ignite from a flame or other ignition source, however, special attention should be considered such as maintenance and irrigation. Some plants can withstand the intense heat and do not readily ignite from a flame or other ignition sources. Avoid highly flammable species and focus on creating defensible space by spacing plants to prevent the spread of fire. Consider layering plant heights to create a natural firebreak.

• East San Gabriel Valley Area Plan Native Plant List
• Recommended List of Native Plants for Landscape in the Santa Monica Mountains
• West San Gabriel Valley Area Plan Native Plant List
• Fuel Modification Plan Selection Guidelines

Trees After a Fire

Wild and urban fires often result in widespread damage to vegetation, with many trees either destroyed or stressed. While the removal of hazardous trees is necessary for public safety, it is also important to evaluate and preserve healthy or recoverable trees. Unnecessary removal of viable trees can hinder post-fire recovery and increase erosion, mudslides, and future fire risk, as well as impacts senses of place and community through long-term recovery.

The vast majority of native trees can survive fires. Regrowth can be evident within a matter of months on most oak trees. A small number may remain dormant for more than a year. The process can vary depending on water availability and other factors. Therefore, unless tree removal is necessary for imminent safety reasons, it is advisable to assume trees may still be alive and should be monitored for up to 2 years following a fire. Consult a certified arborist if you are unsure.

Oak Trees

The Los Angeles County Disaster Recovery Ordinance prohibits the removal of an oak tree damaged by a disaster in the unincorporated areas, unless a County Forester determines that it poses a danger to public safety, or an oak tree permit is obtained. Review the Disaster Recover Ordinance for more details on the management of oak trees damaged by a disaster.

Maintenance

Routine maintenance is a critical part of keeping a fire resilient space. The following are steps you should regularly take:

• Remove leaf litter and other combustible debris from roofs, eaves, rain gutters, abutting structures and fences, etc.
• Maintain areas free of any material known to be receptive to flying embers.
• Remove any plant or portion of a plant that is dead or dying.
• Remove downed, accumulated plant litter and dead wood throughout all zones. Prune to reduce the overall amount and continuity of fuels. Eliminate horizontal and vertical elements that would allow fires to spread.
• Remove invasive species and their parts.
• Ensure irrigation systems are functioning properly.

The failure of neighboring property owners to maintain tier property free of junk, debris, and overgrown vegetation, can have a negative impact on your property. Build community and collective fire resilience by working together and sharing this information. If necessary, to report a nuisance property dial 2-1-1.

Drainage and Water Management

Though in some limited cases the County’s Low Impact Development (LID) requirements for buildings built prior to 2009 and for small residential projects, and gray water ready plumbing requirements may be waived—i.e., only in the unincorporated area of the Eaton Fire impacted area, and only if a “like-for-like” rebuild—it is strongly encouraged to consider such design choices from the start for opportunities for greater water management and conservation, and not to impact adjacent properties. Please also see available resources and incentives for such practices and including water catchment, water efficient landscapes, etc., and consult with your team.

Safe Gardening After a Fire

Residents whose properties have been affected by fire should take extra steps to stay healthy when gardening. Smoke, ash and soot from urban fires, like the Eaton and Palisades fires, that burned structures, vehicles, everyday household products, plastic, rubber and automotive components can produce unhealthy particles and harmful contaminants, such as heavy metals, which can settle in soil and create unsafe conditions for gardens. Below are recommendations to mitigate any potential health hazards safely:

• Wear an N95 mask and gloves when moving or disturbing soil that may contain ash or soot. Anyone with respiratory illnesses is advised to talk with their healthcare provider about what they can do to stay safe and whether they should wear an N95 mask.
• Use a shovel or hoe to scrape and collect surface soil.
• Try to minimize the amount of soil and dirt that is dispersed in the air.
• Dispose of soil, lawn clippings, or other green waste in your trash bin, not your green waste bin.
• Take your shoes off before entering your home and immediately remove and wash clothes in a washing machine.
• Wash your body thoroughly.
• Considering testing your soil, especially if gardening for consumption.
• For homegrown produce, review LA County Public Health Guidelines.

To protect your health, remain current on LA County Public Health advisories and Health Office orders.