Girdling a tree by cutting through the outer layer of bark into the woody trunk eventually kills the tree by interrupting the channel through which the tree receives moisture and nutrients from its roots. The bigger the tree, the longer it takes to die, but the death of a girdled tree is inevitable.
Between about 1998 and 2003, approximately 1,200 non-native trees in San Francisco were girdled by native plant advocates, including a few who were employees of the Recreation and Park Department’s so-called Natural Areas Program. This vandalism was finally stopped after one of the native plant advocates was caught and prosecuted and the Recreation and Park Department was embarrassed by the media coverage.
In addition to killing trees by girdling them, an entomologist has published a study which reports that Australian pests of eucalypts were intentionally and illegally introduced to California for the purpose of killing non-native eucalypts. These stories are told here.
More recently, we have learned that native plant advocates are also spraying non-native vegetation in public parks in San Francisco with herbicides, in violation of San Francisco’s policy regarding pesticide use. The people who are spraying these herbicides are not authorized to do so. They are not posting notices of the application of herbicides as required by law. They are also using herbicides that are not approved for use in San Francisco’s public properties. That story is told here.
Guerilla Gardening in the East Bay
These guerilla tactics have recently spread to the East Bay. Shortly before Christmas in December 2010, the neighbors of Garber Park (Evergreen Lane) in the Oakland hills were shocked when an enormous crane pulled up to their park and began to take down several huge eucalyptus trees. The neighbors had been told nothing about their destruction and they had no idea why they were being destroyed. A little frantic investigation revealed that one of their neighbors had requested that the trees be removed and, because she was willing to pay for their removal, the City of Oakland obliged her without any further consultation with her neighbors. Needless to say, many neighbors were not pleased with this undemocratic method of altering their neighborhood landscape. That story was reported in the Hills Conservation Network newsletter which is available here.
The removal of those trees was the first step in an ambitious project to eradicate non-native plants and trees in Garber Park and replace them with native plants. That project is described on the website of the “Garber Park Stewards.”
On a recent visit to this wild 13-acre park, we saw little evidence of this effort. A rough, barely passable trail meanders through the park. Most of the trees are native oaks, bays, big leaf maples, and buckeyes. The tangled understory is a mix of natives (cow parsnip, horsetail, poison oak, etc) and non-natives (annual grasses, forget-me-knots, etc). The only evidence of the work of the stewards was typical of these projects: a small patch of bare ground with colored flags.
Now more eucalypts are being destroyed in Garber Park by girdling them. A chain saw was apparently used to cut into the cambium of the tree, which is the channel that carries nutrients from the roots of the trees to its canopy. Something was painted or sprayed into the cuts which we speculate is an herbicide that will accelerate the death of the trees.
We speculate that the girdling of these trees was not authorized by the City of Oakland. The neighbors of the park say they were not informed that the trees were going to be destroyed. Therefore, we assume that this is a case of vandalism which we hope will be reported to the police as such.
We have no idea who girdled the trees in Garber Park. We therefore make no accusations. However, based on our experience in San Francisco, we speculate that whoever killed these trees believes their destruction will enhance the native plant restoration project. There are few eucalypts in this park. We saw only one that was not either girdled or a stump. We wonder what harm these few trees could do in this wild place. They are clearly not spreading
We repeat the Million Trees mantra
We say at every opportunity that we like native plants and trees and we encourage native plant advocates to plant them. We ask only that they stop destroying the plants and trees that have lived peacefully in the San Francisco Bay Area for over 100 years and are performing valuable ecological functions. We remind native plant advocates that we live in a democracy and that our public lands belong to all of us. If the landscape is to be permanently altered, a democratic process should be used to reach that conclusion.
Conservation Sense and Nonsense 
What would happen if the first peoples on this continent started girdling all the non-native invasive human species that have totally taken over and destroyed the landscape?
Webmaster: Yes, Susan, your question places the blame squarely where it belongs, on the humans who planted these trees to begin with. The scapegoating of innocent plants for the environmental problems caused by humans is distressing indeed.
Thank you for your visit and for your comment.
Who is in charge of enforcing the law? Thugs are doing this all over, as evidence by this:
http://www.nydailynews.com/new-york/bronx/found-ax-allegedly-girdling-younger-trees-article-1.1202830
Webmaster: Good question. Illegal herbicide applications by “volunteers” in San Francisco were reported to both the Recreation and Park Dept and the Department of the Environment, which is responsible for the city’s pesticide policy. Neither department responded to the reports. In a meeting with the Department of the Environment, we were told to report it to the police. Needless to say, the police have more important things to do. So, I guess the answer to your question is, “No one.”
People feel the same way about black locusts in the East. Even though it is a tree indigenous to North America, anything considered outside its ‘native’ range can be removed under the disguise of restoration. It doesn’t seem to matter to them there are benefits even when you tell them. Their mantra is “It’s invasive. Kill it.”
Webmaster: Trying to keep plants and animals within their historical native ranges is an even more extreme version of nativism, particularly at a time of changing climate.
Moving in response to changing climate is one of the most effective survival strategies for plants and animals. If they are no longer well adapted to the changed climate, we doom them to extinction if we deprive them of their means of adapting.
Props to those that girdle! I have never found a coyote bush, sticky monkeyflower, arboreal salamander, colony of candy caps, nesting acorn woodpeckers or grey foxes lurking in, about or around the dead zone created by Eucalyptus. They occupy land that can provide a multitude of life rather than preventing it. Like a clear cut, they are a slow cut, slowly spreading and destroying native habitat. Please educate yourself and go to our native Oak woodlands and see the myriad of species that these woodlands support from fungi to amphibian. Yes, eucs are great as perches or nests for Great Horned owls and Red Tailed Hawks, but our native woodlands support a far greater amount of species. Please educate yourselves and help replant these areas with natives. Then you will know the joy of nesting songbirds, king snakes and the witches butter fungus amongst thousands of others in hundreds of genre.
The webmaster’s response on the first post is irresponsible, but probably with good albeit misinformed intent. Don’t get me started on Susan’s comment.
Thanks!
Foxenergy
Webmaster: We are grateful for your comment because it demonstrates the ignorance of native plant zealots, rather than the ignorance of the Million Trees blog. Although it is a widely and deeply held belief amongst native plant advocates that the eucalyptus forest does not support wildlife, there is no scientific evidence that supports that claim. In addition to park visitors with an open mind who observe wildlife in the eucalyptus forest, there are two scientific studies which found exactly the opposite.
1) Professor Dov Sax (Brown University) compared species richness in the eucalyptus forest with oak woodlands in Berkeley, California. He found equal numbers of species of plants in the understory, birds, and amphibians in both. He also found equal numbers of species of insects in both in the fall and significantly more in the eucalyptus forest in the spring. That study is reported here: https://milliontrees.me/2013/04/09/biodiversity-of-the-eucalyptus-forest/
2) Professor Robert Stebbins (UC Berkeley) was hired by the East Bay Regional Park District to study the biodiversity of the eucalyptus forest. He summarizes his findings, “Contrary to popular belief, many animals, both vertebrates and invertebrates, have adapted to life in the Eucalyptus groves.” That study is reported here: https://milliontrees.me/2013/04/09/biodiversity-of-the-eucalyptus-forest/
But, this isn’t really the point. Vandalism is vandalism whatever your reasons for doing it. You don’t have the right to destroy our parks. It is a crime, whatever your misguided justification.
“I have never found a coyote bush, sticky monkeyflower, arboreal salamander, colony of candy caps, nesting acorn woodpeckers or grey foxes lurking in, about or around the dead zone created by Eucalyptus.” sez Foxenergy.
Really? Then you haven’t been looking. You’ll never see things when you have an ideological commitment not to see them.
“the dead zone created by Eucalyptus” is pure mythology, countered by scientific studies (two of which are listed above).
Kieth McAllister – The “dead zones” around eucalyti is not mythology, it is allelopathy . But it is a trait shared by many tree species. Eucalypti are only mildly invasive, and as the cited studies demonstrate, (though difficult to find since the author of this blog cites his own bog instead of the actual studies.) species diversity is only mildly reduced in euclyptus vs bay/oak woodlands.
Webmaster: Citations of the studies are provided in the articles on this blog. Look at the footnotes provided.
What I have observed about the pro eucalyptus argument, is a strong confirmation bias. Neither study supports the notion that eucalyptus woodlands are equal to, or preferrable to native bay/oak woodlands. I read the Sax study. And I have observed the sites he studied. What is not mentioned in the abstract, is that although there were similar diversity of species, they were not the same species. Weeds and other invasive species fare much better than native species in a eucalyptus forest.
BTW – Girdling a eucalyptus is not likely to kill it.
Webmaster: There are about one thousand dead trees in San Francisco that were girdled about 10-15 years ago. The bigger they are the longer it takes them to die. A huge girdled tree on Mt.Davidson just fell over during the wind storm on April 8, 2013. It had been dead for some time, but just fell over. Some of the girdled trees have been removed, presumarly because they were considered hazardous. Perhaps you have not been observing girdled trees long enough to watch them die. I assure you they will because nutrients cannot be delivered from the roots to the canopy.
Bob, I’m afraid I don’t understand your first paragraph. You acknowledge that “species diversity is only mildly reduced in eucalyptus vs bay/oak woodlands.” That says to me “NOT a dead zone.”
I have a beautiful coast live oak in my yard; I do virtually no weeding since nothing, neither native nor non-native, wants to grow there. I walk through eucalyptus forest and oak/bay forest. In both types sometimes there is thick undergrowth, sometimes there is moderate undergrowth, and sometimes the forest floor is almost bare. An added wrinkle is that the understory in some euc forest in the East Bay is bay and oak. Scientists debate about the significance of allelopathy in both eucalyptus and oaks. (both leaves contain tannins) Presence of water, sunlight, and the physical barrier of thick leaf litter might be the more important factors in determining whether plants grow under oaks and eucs. I’m not qualified to sort it all out. But I have never heard anyone talk about “the dead zone created by oaks.”
I’m not “pro-eucalyptus.” I just reject many anti-eucalyptus arguments, e.g. “biological desert,” “creates a dead zone,” “eucs kill birds.” And make no mistake, there really is a militant anti-eucalyptus movement. I attended a public hearing in February where a guy walked to the microphone and said, “I hate eucalyptus,” and sat down. Other speakers expressed the same sentiment, just not so concisely. I don’t recommend planting more eucalyptus; I wouldn’t consider trading my oak for a eucalyptus. But I do object to destroying long-existing eucalyptus forests which have well established plant and animal inhabitants, especially when I see the excuses given as largely bogus. We’re not going to return to a pre-European landscape in the Bay Area; it’s just not going to happen. I know of a few small scale native plant restorations but they require intensive, on-going gardening that the larger landscape is not going to get. So I object to massively destructive projects in pursuit of such a quixotic goal.
Sorry about the open link.
I was able to find the studies from the information you provided. Just suggesting that a to the cited study is more convenient for the reader.
Webmaster: Thanks for the link. I have added it to the post about biodiversity of the eucalyptus forest. The study was not available on the internet when I posted that article or I couldn’t find it. I usually provide links when they are available.
I had heard that eucalytus sprout new shoots from the roots and trunk when girdled. But I will defer to your experience.
Webmaster: I have watched hundreds of girdled trees over a long period of time and never seen any resprouts from the roots.
Garbor park is a native park. The eucalypti are messy, invasive weeds in that environment. I have pictures to demonstrate.
Webmaster: I have been to Garber Park, so I don’t need photos. There were only a handful of eucalypts in Garber Park when the huge trees were destroyed and there was no evidence that they had spread. They had probably been there for over 100 years. If they didn’t spread in 100 years, they weren’t likely to spread in the next 100 years.
I don’t know what you mean by a “native park.” Yes, most of the trees are native. There are also many non-native shrubs, annual grasses, etc, as there are in any urban park.
But that is not the point of the article on which you are commenting. The point of this article is that killing trees without authorization is vandalism and whatever your motivation for doing so, it is a criminal act. You don’t have the right to impose your personal vision on public property because it does not belong to you. Those who do not share your personal vision for our urban parks own these parks as much as you do.
(Wish this site had a preview)
If it were not for the pictures, I would think you were talking about a different park. While the trails are rough, I would hardly characterize them as “barely passable”, but I am fit and strong, so perhaps for someone with physical issues, they might seem to be barely passable. I find your discounting the work of the stewards and their volunteers also offensive. Those of us who live near Garber are very appreciative of the efforts of the stewards.
Some person or person’s went along the trails in Garber Park, beating the vegetation with a stick or something. They made a huge mess, leaving a trail of broken and bashed plants. The stewards and their volunteers (I was one of them) cleaned up the mess. Searching the internet for “garber park vandalism” is what led me to your page.
Webmaster: Interesting that you object to some forms of vandalism and support others. That you can’t see the hypocrisy of that, is the problem. This is the last comment I will post because it has become repetitive.
There are at least 16 eucalypti in Garber Park. There would be more, except the stewards remove saplings and shoots, A few of the big ones have been removed, and a few of the medium sized have fallen down.
Webmaster: And now some of them are girdled and will eventually die.
With all the problems the world faces, I have to wonder about what motivates you to fight with your neighbors about an invasive species that poses an unacceptable risk to their property.
Webmaster: Garber Park is just one of many similar projects. The cumulative impact of these projects is what makes them controversial. I am not “fighting with my neighbors.” I am fighting with the destructive element of the entire native plant movement. If native plant advocates would plant natives and quit destroying everything else, they would hear no criticism from this website.
As for how I choose to spend my time, I could say the same of whoever is girdling trees.