The Great Eucalyptus Debate

The Bay Area is deadlocked in a battle over whether its non-native blue gum trees should be felled or protected.

The Tasmanian blue gum, Eucalyptus globulus, is a magnificent tree. That is perhaps the only thing that everyone agrees on. It is, as Jake Sigg puts it, “a big, grand, old tree.” Tall, gnarled, stripey-barked, with white flowers like sea anemones, blue gum eucalyptus are characteristic of the San Francisco Bay area, despite being native to an Australian island half a world away. They just happen to thrive in the Bay climate, and many were planted either for timber or for scenery from the 1850s onwards.

There is, to put it mildly, widespread disagreement about what to do with these trees. The argument is as complex and tangled as the bark streamers that hang from the blue gum’s trunks. In the most general terms, there is a faction of environmentalists that want to see many of these eucalyptus trees removed, because they are a fire hazard close to homes, or because they are non-native and make poor habitat for native species, or both. In this group, place native plant enthusiast Sigg (who nevertheless loves the species and would like to see more of them planted in landscaped, irrigated parks). This faction also includes the local chapter of the Sierra Club.

There is another faction of environmentalists that dispute that the trees are more of a fire hazard than what might replace them, see them as decent or even very valuable habitat, and want to retain them to sequester carbon, provide shade, beauty, and recreation, and to avoid the use of the herbicides that are generally necessary to thoroughly kill them off. This faction includes a longtime correspondent of mine, Mary McAllister, and allies in different groups, including the Hills Conservation Network and the small-but-fierce Forest Action Brigade.

Those are the basic contours, but getting a fuller understanding requires a walk deeper into the woods.

This fight is many years old. There have been lawsuits and there have been letters to the editor pro and con. There have been protests and postcard campaigns and blog posts and newsletters and lots and lots of official public comment on management plans for various eucalyptus forests and groves. It is a classic Bay Area dispute: greens vs. greens, experts vs. experts, and committed amateurs vs. committed amateurs. And it has gotten very hot.

One recent summary of the dispute was this feature in Bay Nature by Zach St. George. The piece seemed pretty even-handed to me, but McAllister sent me a four-page memo with counter arguments against a hypothetical fire scenario described in the article. And that’s not surprising. McAllister, a retired university administrator, is very much engaged in the eucalyptus debate and always ready to rumble. And she and her allies can chalk up some recent wins. The Hills Conservation Network recently settled with the Federal Emergency Management Agency, who, as a result of the settlement, cancelled grants to remove eucalypts in the East Bay.

I became interested in the Great Eucalyptus Debate several years ago. In 2011, I wrote a book, Rambunctious Garden, that reported on new exciting directions in conservation. Among these was a reassessment of non-native species. Maybe not all of them were terrible. In fact, maybe we had been spending too much time and money removing non-natives in a quest for an unobtainable purity, money we could have spent on something else, like land acquisition or climate change mitigation. McAllister read my work and got in touch. People were trying to cut down all the eucalyptus trees just because they were non-native, she said. All the talk about fire risk was just “a cover story.” Recently we spoke on the phone. “They learned that the public is not interested in killing trees or eradicating plants just so it can look like it did 250 years ago,” she says. “They learned that they have to use fear tactics, and their main response is fire.”

McAllister has “reams” of studies that she says shows that the trees aren’t a fire hazard—or any more of one than the native shrubs and trees. She points in particular to the “fog drip” that these large, lanceolate-leaved trees collect and retain making them, in her opinion, a lovely defense against fire.

Sigg actually agrees that fire isn’t the main reason to remove eucalyptus. His central motivation has always been “the importance of saving natural ecosystems”—in this case the oak woodland-grassland that predated the eucalyptus at many sites around the Bay.

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Chris Alexakisparks