This is an extensive excerpt from an article by Peter Gray Scott on the subject of the myths surrounding Eucalyptus and fire [with emphasis added]. It is quoted here with permission.
One by one, myths about eucalyptus are pitched at us and, one by one, we must knock ’em down. Like the WMD myth, the apparent intent of those who pitch these myths is to keep propping up the fear factor, to support the eucaphobia that unfortunately grips some of our neighbors. Repeat something scary enough times and in some peoples’ minds it becomes fact.
Myth 1: Eucalypts were responsible for, and exacerbated, the ’91 [Oakland, CA] fire.
The truth is that eucs were nowhere near the origin of the fire on Saturday, October 19. The fire started in dry brush, grass and scrub oak on a steep slope above Buckingham Boulevard. There were some pines nearby but the fire did not jump into them. The fire restarted on Sunday, October 20, as flare-ups in dry brush within and just beyond the area that burned on the previous day. It spread first into oak trees. By the time the flames reached the first grove of eucs (1/6 mile away, just above Charing Cross) the conflagration was no longer a vegetation-fueled fire; it was a full-fledged structure-fueled fire that consumed everything in its path.
Myth 2: Blue gum eucalyptus trees are uniquely hazardous because they are oily, and explode in a fire.
Tree experts disagree with this myth. The leaves of blue gum eucalyptus trees contain oil; so do the leaves of bays and many species of chaparral. However, the trunks of eucalyptus trees are described as “fire-resistant (like redwoods).” Their trunks resist ignition, and the leaves are close to 50% water (koalas live off them). When, finally, the tree’s temperature reaches an ignition point, the euc will outgas a flammable haze, producing a sudden bright flare . . . but this is not an “explosion.” It poses no extraordinary risk, and it occurs significantly after other species have already burned.
Myth 3: Eucalypts are responsible for advancing the fire-front by “spotting”—projecting burning bits ahead of the flames.
In the first version of this myth, the leaves were blamed because they were said to be uniquely aerodynamic. However, experiments demonstrated that a) the leaves don’t fly very well, b) they don’t fly at all once burned, and c) they are incapable of maintaining an ember. So that myth was modified. Now it’s claimed that the euc’s bark strips are the culprits. This assertion appears in serious presentations, like Jerry Kent’s history of the hills fires and EBRPD’s Environmental Impact Report, but it is unsupported by any evidence, and it denies common sense and actual experience. Why should eucalyptus bark embers fly but not burning oak twigs, bay branches and coyote brush limbs?
The truth is: all loose material flies in a Diablo wind. During the 1991 fire, a fire-fighting pilot reported seeing a burning sheet of plywood at 2000 feet!
Myth 4: Eucalyptus forests are prone to dangerous crown fires.
The opposite is true. Because the mature trees’ lowest limbs tend to be more than 8 feet above the forest floor, no “fire ladder” sends the flames into the crowns; because the eucalypt’s wood and leaves naturally resist ignition, the underbrush and surface fuel is consumed before the euc reaches ignition temperature. Films of Australian wildfires show the fire sweeping through the understory, but leaving the eucalypts’ crowns green and intact. Photos of the ’91 fire indicate the same fire behavior in Gwin Canyon. The 2006 Broadway Terrace fire demonstrated this same characteristic.
In conclusion, he points out that “In an effort to forestall climate change, cities and nations around the globe are busy protecting and planting thousands of trees. Ironically, organizations that historically have supported protection of the environment and the health of the planet—the Sierra Club, the Audubon Society and others — are actively supporting tree removal projects. But it is clear they are advocates for a very different agenda: Although they superficially support fire risk mitigation, their true mission is restoration of native plants.”