Vandalism by native plant advocates

In 2010, Timothy Paine, an entomologist at University of California, Riverside, published an article (1) about the introduction of Australian insect predators of eucalyptus into California.  Eucalyptus is native to Australia.  It was introduced to California in about 1850 and was virtually pest free until 1983.  Since then 15 insect predators of the eucalyptus have been found in isolated locations in California. 

Professor Paine observes that, “The spatial and temporal patterns of introductions [of these insect pests] do not seem to be random, particularly when taken in perspective of the geographic distribution of the insects in Australia.”  For these and other reasons explained in his publication, Professor Paine speculates that “…with no definitive proof, we suggest that the multiple patterns may be nonrandom; instead they suggest the possibility of intentional introductions.”

In a recent interview  Professor Paine explains, “We took all of the available information we had on the introduction of eucalyptus pests into California and the conclusion we drew is that there is a very high probability that someone was intentionally introducing [the insect pests of eucalyptus]…There is likely intentional movement of insect pests of eucalyptus into the state.  The patterns suggest that.”

Professor Paine agonized about publishing his study.  Responsible people are appropriately reluctant to make accusations in the absence of proof.  He decided to publish because of the implications of his findings: 

“Intentional introductions of insect herbivores onto crop plants, or organisms pathogenic to plants or domestic animals, represent an insidious threat that could severely damage the national agricultural economy, endanger a safe and abundant food supply, threaten water quality or quantity, increase the risk of wild fires, or degrade environmental quality across massive areas.” 

Professor Paine has had some success with finding biological controls of these insect pests of the eucalyptus.  However, as fast as he can find an effective antidote species of insect, a new pest arrives to attack the eucalyptus.  His research is controversial because the native plant advocates who despise eucalyptus and demand its eradication are opposed to any attempt to control the insect infestation.  Jake Sigg, our local, prominent native plant advocate is quoted as saying, “I think the University ought not to be going ahead with this research without considering all of the ramifications and hearing from all parties.” 

Jake Sigg is a big fan of biological controls to eradicate non-native plants, so we find it ironic—even hypocritical–that he is opposed to research needed to save the eucalyptus from its insect predators.   In his Nature News of February 18, 2011, he said, “On this scale, biological control offers the most promise, and–take note–would obviate the need for herbicides.  Unfortunately, it is inadequately funded.  The beauty of biocontrol is that if the necessary rigorous (and expensive) research is successful the problem of that plant is taken care of for all time–which means it is really inexpensive in the long run.”

So apparently biological controls are highly desirable if they are used to eradicate non-native plants and trees.  If they are used to save non-native trees, they are verboten, in Mr. Sigg’s opinion.

The long track record of vandalism by native plant advocates

We can’t prove that Australian insects were intentionally imported to California to kill eucalypts.  However, if they were it would not be the first time that native plant advocates have used vandalism to eradicate our eucalypts.

The historical record of vandalism of non-native trees in San Francisco goes back nearly 20 years.  In 1994, the Sacramento Bee published an article (2) about non-native Monterey pines and eucalyptus being cut down in public parks by a native plant advocate by the name of Greg Gaar.  According to the Sacramento Bee, Mr. Gaar had planted these trees and then changed his mind some 20 years later. (For the record, we note that we don’t approve of such unauthorized plantings any more than unauthorized destruction.)  

The California Native Plant Society apparently convinced Mr. Gaar that the trees were a threat to San Francisco’s “natural heritage.”  He cut down trees on Mount Davidson and Tank Hill in San Francisco and was sent a bill for $10,996.27 by the Recreation and Park Department.  The Bee reported that Mr. Gaar was unemployed and had no intention of paying the bill.  Getting caught was apparently the end of that particular method of destroying non-native trees. 

Native plant advocates then found a more surreptitious method of destroying the trees. They began girdling the trees in the public parks of San Francisco.  Girdling is a method of killing a tree slowly.  A band of bark is hacked off the circumference of the trunk with an axe or chainsaw.  This prevents water and nutrients from traveling from the roots of the tree into the tree.  The tree slowly starves to death.  The bigger the tree, the longer it takes to die.

Girdled trees, Bayview Hill, San Francisco

After girdling the tree, native plant advocates stacked up vegetation around the scar so that it was not visible to the public.  Even if the public noticed the scar, they didn’t know what it meant until the tree began to die.  By the time the trees started to die several years after the girdling began, about 1,200 trees had been girdled in the parks of San Francisco.  Most of them were on Bayview Hill, and many are still visible on Mount Davidson. 

According to an article in The Independent, some of the girdling was done by city employees of the Natural Areas Program in the Recreation and Park Department, but much of it was done by native plant advocates, described as “volunteers” by their supporters and “vandals” by their critics.  The Independent quotes the head of the urban forestry division of the Recreation and Park Department as saying that trees were also being killed by dousing them with pesticides.

There was a noisy outcry when the public figured out what they were doing.  The native plant advocates paid a public relations price for their vandalism and they quit doing it.  They are no less dedicated to destroying all of our eucalypts.  Perhaps they have moved on to even more nefarious methods such as introducing deadly insects.

We wouldn’t be at all surprised.  One of our more memorable debates with a prominent local nativist was about the plan of the Natural Areas Program to reintroduce a legally protected native turtle to a local park that is heavily forested with eucalypts.  We knew that rare turtle requires unshaded nesting habitat within 500 feet of its water source.  Providing that habitat to this legally protected turtle would have required the destruction of all the trees in that park.

When we objected to the reintroduction of that turtle, the nativist smirked and said, “You know nothing can stop us from putting that turtle in that park whenever we want.  And the law provides the same legal protection to that turtle whether it is found there naturally or put there by man.”

Some of these people will stop at nothing.  They are appropriately called eco-terrorists.


(1)    Timothy Paine, et. al.,  “Accumulation of Pest Insects on Eucalyptus in California:  Random Process or Smoking Gun,”  Journal of Economic Entomology, 103(6): 1943-1949, 2010

(2)    “San Francisco garden guerrillas axing alien plants in San Francisco,” Sacramento Bee, February 19, 1994.  This article is not available free on-line.  However, it can be purchased inexpensively from Sacramento Bee Archives.

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