Resilient Landscapes

at the Wildland Urban Interface

William Stratton & Julie Johnstone

November 11, 2025

Great Ecology provides a suite of fire resilient landscape services, ranging from community wildfire protection plans, brush management plans to long-term wildfire planning. Our specialists, including ecologists, scientists, planners and landscape architects, collaborate on projects to ensure long term community and site viability.

This blog is part of our Fire Resilient Landscapes blog series so stay tuned for additional content exploring fire and similar climate change driven impacts.

San Diego's landscape is a complete gradient of urban to wild, with wild canyons and rolling hills never far from a subdivision or urban core. San Diego has over 500 linear miles of Wildland Urban Interface, some seen here from a hike on Cowles Mountain. Source: Billy Stratton

The Wildland Urban Interface (WUI) is the edge or interface, between urban development and wild open spaces. In southern California, it exists where homes are perched above wild canyons and where neighborhoods and businesses abut rolling hills of chaparral, coastal sage scrub, and other wild open spaces. San Diego has over 500 linear miles of WUI. As development expands, pushing outward and especially inland toward drought-afflicted and fire-suppressed open space, the WUI also shifts and expands. Wildfires pose an increasing threat to urban areas in southern California and elsewhere, tragically demonstrated by the Palisades and Eaton fires in January 2025; it is up to homeowners to understand laws, guidelines and their ultimate responsibility to tend their land and prevent excessive damage to their property from wildfires.

Wildfire prevention at the WUI is coded at various state and local levels. Under 2022 California Fire Code, owners of properties in Local Responsibility Areas designated as Very High Fire Hazard Severity Zones (San Diego zones are identified on a map located here: https://www.sandiego.gov/fire/community-risk-reduction/fire-hazard-severity-zones) must manage their property to prevent damage from wildfires. Under the state-wide fire code, fire code officials require a fire protection plan for most new development in this zone, including additions and some remodels for existing homes. San Diego Municipal Code requires brush management in all areas which contain native or naturalized vegetation and are within 100’ of a structure. Additionally, San Diego law requires a brush management plan as part of any proposed development in the Very High Fire Hazard Severity Zones requiring discretionary entitlements, grading, and/or building permits.

Very High Fire Hazard Severity Zone map for San Diego, 2025. From https://www.sandiego.gov/fire/community-risk-reduction/fire-hazard-severity-zones.

The goal of brush management is to minimize the fuel load while preserving some habitat function and natural beauty. Effective brush management makes a natural landscape look fresh, tidy and safe. Fires spread vertically and horizontally, so brush management is focused on both thinning vegetation and cutting it down to low heights. Brush management is prioritized from the face of a home or building outward, so the tightest restrictions occur nearest the home and the perimeter of a property appears more natural to blend with the wild or naturalized land outside the property line. Brush management plans divide a property’s landscape into 2 or 3 Zones: Zone 0 (sometimes included as part of Zone 1), Zone 1, and Zone 2.

Zone 0 is the first 5’-10’ from the face of a home or building outward into the landscape. Zone 0 should be an apron of pavement and/or fireproof hardscape such as DG, gravel, concrete, or bare dirt. Firewood, combustibles, and plants should be excluded from Zone 0. The tight restrictions in this zone prevent flames from reaching under the eave and radiating heat against walls.

Zone 1 is the first 35 feet between a home or building and a wild or naturalized area. This Zone is effectively the ornamental landscape and outdoor space of a home or property. Zone 1 should contain only non-combustible hardscape and permanently irrigated ornamental plantings. In southern California, northern coastal manzanita, ceanothus, clinopodium, erigeron, epilobium and other showy and evergreen native species function well in Zone 1. Trees and tree branches should not extend within 10’ of a home or building- in Zone 1, trees should be pruned to keep the canopies high and the branches as far as possible from combustible materials and buildings. All other landscaping must be limited to 4’ max height in Zone 1. In addition to maintaining a permanent irrigation system, Zone 1 should be regularly thinned and pruned.

Zone 2 is the next 65 feet between Zone 1 and a wild or naturalized area. Most properties within the WUI are not large enough to include this zone. Where it is applicable, Zone 2 maintains native habitat function and blends the property with the surrounding wild landscape while minimizing fuel load and the probability of an intense, spreading fire. Zone 2 should be comprised of heavily thinned, non-irrigated native vegetation. Plants must be under 24” height, except for trees and large shrubs. A vertical gap must be maintained between the top of shrubs and the lower branches of trees; the gap should equal 3x the height of the shrub beneath the tree canopy.

With proper care, planning, and dedication, homes in the Wildland Urban Interface have fire-safe and beautiful landscapes, nestling them into their wild context. As a multi-disciplinary practice of landscape architects, planners, biologists, and ecologists, Great Ecology can expertly craft brush management plans for home and property owners to achieve fire resilient, beautiful and functional landscapes.

Learn More About Our Fire Resilience Services

Great Ecology provides habitat restoration, landscape design, and other ecological services to leading corporations, governments, and nonprofits throughout the United States and around the world.

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