California Develops Stricter Wildfire Home Regulations
Following the Eaton and Palisades Fires in Los Angeles, which destroyed over 16,000 structures, California is in the process of drafting new statewide regulations for vegetation management around homes. These proposed rules aim to mitigate wildfire risks in areas prone to such events.
Zone Zero Concept and Proposed Requirements
The core of the new regulations is the "Zone Zero" concept, which mandates clearing plants and flammable materials within five feet of a house. The objective is to prevent ignition and subsequent spread of flames to structures and adjacent areas, particularly given that embers carried by wind are a primary cause of home ignition during high-wind wildfires.
Specific proposals under consideration include:
- Prohibiting flammable items such as firewood, bark mulch, and dead vegetation within five feet of a home.
- Requiring fences and gates in this zone to be constructed from metal or other non-combustible materials.
- Allowing well-maintained trees, provided branches are kept at least five feet above the roofline.
- Regarding other plants, regulators are evaluating options:
- Permitting only potted plants.
- Limiting plants to a maximum height of 18 inches.
- Allowing any well-maintained plants devoid of dead material.
If implemented, these rules would affect approximately 17% of buildings in California. A three-year grace period is anticipated for existing homes, with local fire agencies retaining some discretion for implementation. This initiative could establish a precedent for other Western states facing increasing wildfire activity due to a warming climate.
Public and Expert Responses
Public meetings have revealed concerns among homeowners regarding potential loss of greenery and shade, associated costs, and the belief that some plants may act as protective buffers. Scientific studies generally indicate that vegetation increases a building's fire risk.
Michael Gollner, from the Berkeley Fire Research Lab at UC Berkeley, emphasized the need for adaptation to prevent home losses. Richard Snyder, a retired firefighter and wildfire risk consultant, recounted his experience during the Eaton Fire, noting that wind-blown embers ignited numerous small fires in his Pasadena neighborhood, leading to significant property damage. His home sustained damage, while several others were lost.
Jessica Rogers of the Pacific Palisades Resident Association expressed concerns at a public hearing, suggesting that the "Zone Zero" policies might misaddress the primary causes of fire damage, citing adjacent structures as a factor in her community's losses. Conversely, some residents at the hearings supported clearing Zone Zero as a preventative measure. Martin Hak, a Pacific Palisades resident, testified that well-hydrated hedges at his property appeared to act as a fire break.
Tony Andersen, executive officer for California's Board of Forestry & Fire Protection, acknowledged divergent opinions but underscored the consensus on community protection from wildfires.
Scientific Perspectives on Vegetation and Flammability
Max Moritz, a wildfire specialist at the University of California Cooperative Extension at UC Santa Barbara, suggested that the role of green plants as a protective buffer is not fully understood and warrants further research. He notes that greener plants, containing water, are more difficult to ignite, but agrees that highly flammable species and dead plant material should be prohibited.
Gollner's "burn lab" research at UC Berkeley demonstrates that even well-watered shrubs can ignite once flames reach their leaves, which rapidly dry out and burn. His team's experiments and computer models indicate that if a neighboring structure or vegetation ignites within Zone Zero, the fire can spread to a nearby house. Studies have shown that even seemingly healthy shrubs can contain dry interior material.
Research from the Insurance Institute for Business & Home Safety, based on inspections of over 250 homes affected by the Los Angeles fires, found that homes with vegetation in 25% or more of Zone Zero had an almost 90% chance of being damaged or destroyed. A UC Berkeley study using computer models estimated that Zone Zero rules could reduce structure losses by 17%. Another study examining the 2018 Camp Fire and 2017 Thomas Fire identified vegetation within six feet of walls as a significant factor in building destruction.
Holistic Approach to Wildfire Resilience
While minimizing vegetation is a key component, experts emphasize that home survival also depends on fire-resistant construction materials. Older homes, often featuring wood roofs, wood siding, or single-paned windows, are more susceptible. Recommendations include clearing roof gutters and covering attic vents with fine mesh to prevent ember intrusion.
California's building codes require fire-resistant materials for homes constructed in wildfire zones after 2007. However, much of the existing housing stock predates these requirements. Furthermore, community-wide preparation is considered crucial, as fire can spread from one structure to another, highlighting that the effectiveness of individual measures is amplified by collective action across neighborhoods.