The evidence against EMBER
EMBER opposition relies on three documents to justify its scientific position. Why only three? Other wildfire science research articles, when dealing with defensible space, have backed defensible space (i.e. Zones 0, 1 and 2 concepts) requirements.
The Syphard and Keeley paper
The 2019 Syphard and Keeley paper is a solid wildfire science research paper that is easy to misinterpret. Syphard herself disavowed the use of her research against Zone 0,and came out in favor of Zone 0: “I am sorry to learn that my work is being somewhat misrepresented in a way that could make residents more at risk to wildfire. […]
My study found significant benefits of defensible space, particularly the closer you are to the structure. It is my thought that the Zone Zero requirements are one of the most important things residents can do to protect their property from wildfire.”
The Longcore/Ossola letter
This letter was sent in spring 2025 to the Zone Zero Regulatory Advisory Committee of the California Board of Forestry and Fire Protection (CalFire). The authors are not wildfire scientists, and rely primarily for wildfire science on (a) the 2019 Syphard article and (b) a critique on a Gollner paper favorable to Zone 0 requirements. However, Syphard disavowed the use of her research for this purpose (see above) and, in a recent letter to Calfire, Gollner and Syphard (both wildfire scientists) jointly disagreed with the interpretation by LongCore and Ossola (who are not wildfire scientists) of the Gollner paper.
The Moritz/Carmignani op-ed
This 2025 magazine article, while an opinion piece, is stronger than it appears, because it was authored by two wildfire scientists with solid track records. However, it is tentative in its evidence discussion (“how often vegetation buffers homes from igniting during urban conflagrations is still unclear”), and a painstakingly detailed study of its references and sources finds no evidence to support either the authors’ conclusions or their various assertions supporting the article title. In fact, when evidence is provided, it supports the enforcement of a strict Zone 0, or evidence in support of a strict Zone 0, such as removing herbaceous growth in Zone 0 and leaving moist trees. What the article does, however, is point out that there are gaps in existing vegetation combustibility research, which may, unfortunately, need many years to supply evidence one way or another.
Consequently, there is no scientific evidence to support opposition to EMBER. What about EMBER support?
The evidence for EMBER
There are several tens of wildfire science research papers in support of defensible space that have been published in the past 25 years. These papers provide two different types of evidence: (a) analysis of past fires (correlative evidence) and (b) experimental research (causal evidence).
Example of correlative evidence: the 2021 Institute for Loss Reduction—Data from Camp Fire article identifies the existence of a wood roof and the lack of defensible space (Zones 0, 1 and 2) as the two leading causes of home ignitions.
Example of causal evidence: Wildfire Research Near-Building Noncombustible Zone, Technical Report Dec 2018 [PDF]". The study confirms that "the current 0–5 ft noncombustible zone recommendation provides a proper noncombustible zone.”
Every wildfire scientist and every firefighter testifying at the May 12, 2025 CalFire Zone 0 workgroup testified in favor of strict Zone 0 requirements.
IBHS, the leading insurance company consortium, which has funded a large part of the wildfire research projects of the past 30 years, requests homeowners to implement strict Zone 0 (among other things) for its lowest certification
The CA Department of Insurance, which provides the CA FAIR plan, requests that homeowners implement strict Zone 0. It has started enforcing some of its homeowner requirements through non-renewals.
Professor Michael Gollner, of the UC Berkeley Fire Research Lab, explains why he supports strict Zone 0 requirements.
This study shows that the implementation of EMBER in the Grizzly Peak Mitigation Area is likely to result in approximately 2.3 acres of vegetation removal in total.
Dave Winnacker, nationally recognized wildfire expert, who recently became a part of BFD, believes that we can win against an ember fire in the Berkeley Hills but that EMBER is required:
- Is the Berkeley Ridge defensible today? Would BFD position assets there and endeavor to defend it?
BFD will do what it can, but we have a low probability of success. - Can we survive a wildfire on the Ridge in Extreme Fire Weather ?
Yes. If we are prepared, puny little men with tools can stop it. - Can we defend the Berkeley Ridge without EMBER?
I dont think so.