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.