FIRE!!! The Cover Story
Native plant advocates have used many different arguments to justify the destruction of non-native trees (eucalypts are the primary target) and we will examine them all in A Million Trees. However, their most effective argument has been a bogus claim that non-native trees and plants are more flammable than native vegetation. This justification has been effective because fear is a powerful motivator for all public policy.
The most frequently cited “evidence” of the flammability of eucalypts is the 1991 firestorm in the Oakland/Berkeley hills. The conventional wisdom is that eucalypts were the cause of that fire. The role the eucalypts played in the 1991 fire in the East Bay is greatly exaggerated.
As FEMA notes in its analysis of that fire, the fire started in dry grass (“On…October 19, 1991…a brush fire was reported…the vegetation on the slope was mostly grass with some brush and a few trees.” page 22) and only leapt out of control when a spark reached nearby brush (On October 20, 1991, “Very suddenly, the fire flared up…Burning embers had been carried from one of the hot spots to a patch of tinder dry brush.” page 26). During a wildfire accelerated by high wind, everything will burn, including eucalyptus. That does not mean the eucalypts were the cause of the fire.
Eucalyptus contributed more fuel to the fire than they normally do because of the deep freeze that occurred the winter preceding that fire: “The unprecedented drought was accompanied by an unusual period of freezing weather, in December 1990, which killed massive quantities of the lighter brush and eucalyptus. Dead fuel accumulated on the ground in many areas and combined with dropped pine needles and other natural debris to create a highly combustible blanket. Due to the fiscal cutbacks, governmental programs to thin these fuels and create fuel breaks were severely curtailed, so the fuel load was much greater than normal by the second half of 1991.” (page 6) Such freezes, sufficiently deep and sustained, causing eucalypts (and other plants) to die back are very rare in the Bay Area. There has not been such a freeze since 1990 and its predecessor was in the early 1970s. Since they are rare, they can be easily mitigated by clearing the dead debris after such a freeze, a significantly more cost-effective and less destructive measure than eradicating a million trees.
Weather is an important factor in creating the conditions for fires. In addition to deep freezes resulting in dead leaf litter, high winds from the hot interior—called Diablo winds in the Bay Area—are an important factor. These Diablo winds are associated with high temperatures. If a fire ignites during a Diablo wind, it is quickly fanned into a conflagration and quickly spreads. These weather conditions are rare occurrences on the San Francisco peninsula because of the moderating influence of the ocean. In San Francisco, the winters are warmer and the summers cooler than the East Bay. For that reason, the fear of fire in San Francisco is irrational.
University of California at San Francisco (UCSF) applied for a FEMA pre-disaster mitigation grant to remove eucalypts from Mt. Sutro, based on a claim that these trees are a fire hazard. FEMA’s scientists were able to evaluate UCSF’s grant applications. Their knowledge of the local conditions led to questions about the grant applications which ultimately resulted in UCSF’s withdrawal of their applications for fire mitigation grants.
The FEMA report on the 1991 fire in the East Bay is consistent with the Mayors’ “Task Force on Emergency Preparedness & Community Restoration.” Officials from all jurisdictions in the fire area participated in this analysis of the causes of the 1991 fire. They were assisted by nearly 100 citizens, experts, and scientists. Participants included “experienced fire ecologists, firefighters, foresters, arborists, landscape architects, park naturalists, geologists, writers, editors, and homeowners.” The recommendations of the Forestry and Vegetation Committee of the Task Force were unanimous.
Their “Primary Findings” included, “The current emphasis on Blue gum…and Monterey pine…as primary culprits in the recent fire, and calls for quick removal of them are an oversimplification that can lead to negative environmental consequences.” (Page 31) And their “Policy Recommendations” included, “Do not target specific species, such as Blue gum eucalyptus, or Monterey pine, for eradication…” (page 37)
The public record does not support the claim that eucalypts are to blame for the 1991 fire in the East Bay hills.
Read more about fire in posts: