Wednesday, June 4, 2025

California Accelerates Wildfire Plant Ban Despite Scientific Opposition

Gov Gavin Newsom

Governor expedites regulations requiring homeowners to clear vegetation within five feet of structures, but researchers question the science behind blanket prohibitions

California is fast-tracking controversial regulations that would ban most plants and vegetation within five feet of homes in high-risk wildfire areas, following Governor Gavin Newsom’s executive order to accelerate implementation of long-delayed Zone 0 rules. The regulations aim to create “ember-resistant zones” around structures to prevent wind-blown embers from igniting homes during wildfires.

“These steps will spur proactive actions to defend the most vulnerable homes and eliminate combustible material within five feet of homes to reduce the risk of a home igniting in an ember-driven fire,” said Wade Crowfoot, California Natural Resources Secretary.

The State Board of Forestry and Fire Protection must complete rulemaking by December 31, 2025, under Newsom’s Executive Order N-18-25 signed February 6. The regulations stem from Assembly Bill 3074, authored by Assemblymember Laura Friedman and passed unanimously in 2020, but implementation has been delayed over two years from its original 2023 deadline.

State officials cite research showing embers are responsible for 90% of structures destroyed by wildfire. The rules would prohibit grass, shrubs, mulch, wooden fences and many trees within the five-foot zone, though mature trees without low-hanging branches may be allowed.

However, prominent wildfire scientists are raising concerns about the scientific basis for blanket vegetation bans.

“As scientists who study how vegetation ignites and burns, we recognize that well-maintained plants and trees can actually help protect homes from wind-blown embers and slow the spread of fire in some cases,” wrote Max Moritz of University of California, Santa Barbara and Luca Carmignani of San Diego State University in The Conversation.

The researchers argue California’s proposed regulations “oversimplify complex conditions in real neighborhoods and go beyond what is currently known from scientific research regarding plant flammability.” Post-fire analysis from January 2025 Los Angeles wildfires showed thick green vegetation survived between closely spaced homes during the Palisades Fire.

The scientists emphasize that “what matters more for keeping plants from becoming fuel for fires is how well they’re maintained and whether they’re properly watered.” Well-maintained plants can serve as “heat sinks,” absorbing energy and blocking embers.

“We understand that it’s not going to be a very easy change for some homeowners. But the science is very simple: even a green, well-maintained plant will catch on fire and it’s going to destroy your home,” said Daniel Berlant, California Department of Forestry and Fire Protection’s state fire marshal.

The regulations will apply immediately to new construction when finalized, with existing homes receiving a three-year phase-in period.