I began studying the native plant movement and the “restoration” projects it spawned over 20 years ago, when I learned about a proposal to change my neighborhood park in San Francisco in ways that were unacceptable to me. Virtually all the trees in the park were non-native and the original proposal would have destroyed most of them. The trees provide protection from the wind as well as a visual and sound screen from the dense residential neighborhood. A treeless park in a windy location is not a comfortable place to visit.
The original plans would have made the park inhospitable to visitors for several other reasons, particularly by reducing recreational access to the park. The prospect of losing my neighborhood park turned me into an activist. I eventually learned there were similar plans for most major parks in San Francisco. My neighborhood organized to prevent the destruction of our park and to some extent we succeeded. However, we were unable to prevent the city-wide plan from being approved in 2006, after fighting against it for nearly 10 years.
When I moved to the East Bay, I learned that similar projects are even more destructive than those in San Francisco, I have spent the last 20 years informing myself and others of these plans, visiting those places, and using whatever public process that was available to oppose the plans. The following paragraphs are brief descriptions of the projects I have studied for over 20 years.
Tree Destruction Projects in the East Bay
East Bay Municipal Utilities District (EBMUD) is the public utility that supplies our water in the East Bay. To accomplish that task, EBMUD manages 28,000 acres of watershed land. Like most open space in the Bay Area, the vegetation on EBMUD’s land is a mix of native and non-native species. EBMUD destroys non-native trees which it believes to be a fire hazard. EBMUD uses herbicides to “control” non-native vegetation, but it does not use herbicides on tree stumps to prevent resprouting. EBMUD reports using 409 gallons of herbicide and 6 gallons of insecticide in 2019. Of the total amount of herbicide, 338 gallons were glyphosate-based projects. EBMUD says “minor amounts of rodenticide were applied by contractors.”
The East Bay Regional Park District (EBRPD) approved the “Wildfire Hazard Reduction and Resource Management Plan” and its Environmental Impact Report in 2009. This plan is removing most eucalyptus, Monterey pine, and acacia from several thousand acres of parkland. Forests are being thinned from an average density of 600 trees per acre to approximately 60 trees per acre. These plans are being implemented and funding for completion of the project has been secured. Herbicides are used to prevent the trees from resprouting and to destroy vegetation deemed “invasive.”
UC Berkeley clear-cut over 18,000 non-native trees from 150 acres in the Berkeley hills in the early 2000s. UCB applied for a FEMA grant to complete their clear-cutting plans. The FEMA grant would have clear cut over 50,000 non-native trees from about 300 acres of open space in the Berkeley hills.
In 2016, FEMA cancelled grant funding as a result of a lawsuit and subsequent appeals from UCB were defeated several years later. In 2019, UCB revised its original plans. With the exception of clear-cutting ridgelines, the revised plan will thin non-native forests. Herbicides will be used to prevent the trees from resprouting.
The City of Oakland applied for a FEMA grant in collaboration with UC Berkeley to clear cut non-native trees on over 120 acres in the Oakland hills. That FEMA grant was cancelled at the same time UC Berkeley lost its grant funding. Oakland has also revised its plans for “vegetation management” since the FEMA grant was cancelled. The revised plan will thin non-native forests on over 2,000 acres of parks and open space. The plan is undergoing environmental review prior to implementation. Herbicide use to implement the plan is being contested.
Tree Destruction Projects in San Francisco
The Natural Areas Program (now called Natural Resources Division) of the City of San Francisco has destroyed thousands of trees in 32 designated areas of the city’s parks since the program began in 1995. The management plan for the Natural Areas Program was approved in 2006, after 10 years of opposition. The plan proposes to destroy an additional 18,500 trees over 15 feet tall and untold numbers of smaller trees that the plan chooses not to define as trees. Herbicides are used to “control” non-native vegetation and prevent trees from resprouting after they are cut down.
University of California at San Francisco (UCSF) began its effort over 20 years ago to destroy most non-native trees on 66 acres of Mount Sutro. UCSF applied for a FEMA grant to implement those plans based on their claim that the Sutro Forest is a fire hazard. UCSF withdrew the grant application after FEMA asked for evidence that the forest is a fire hazard. San Francisco is cool and foggy in the summer, making fires rare and unlikely.
UCSF’s plans to destroy most trees on Mount Sutro were approved in April 2018. Many trees on Mount Sutro have been destroyed since the project was approved and more will be destroyed before the project is complete. UCSF made a commitment to not use pesticides in the Sutro Forest. Many of the trees that have been destroyed have therefore resprouted. Unless the resprouts are cut back repeatedly, the forest is likely to regenerate over time.
Tree Destruction Projects on Federal Lands
The federal government is one of the largest landowners in the Bay Area. Golden Gate National Recreation Area (75,500 acres), Point Reyes National Seashore (28,800 acres), and Muir Woods National Monument are operated by the National Park Service. The Presidio in San Francisco is a National Park that is presently controlled by a non-profit trust. These parks have engaged in extensive tree-removal on the public lands they control. Information available on their websites does not enable us to quantify the acres or number of trees that have been removed or are planned for removal in the future. Therefore, we will describe those projects in the broad terms available to us.
There are two main categories of tree-destruction projects on these federal lands. There are many large-scale “restoration” efforts that have required the removal of all non-native vegetation, including trees. These attempts to eradicate non-native plants are based on a misguided belief native plants will magically return. Herbicides are used by National Park Service to destroy non-native vegetation, although specific information is difficult to obtain because NPS is not responsive to inquiries and the federal public records law can take years to respond.
Eradication efforts fail regardless of method used
In “Lessons learned from invasive plant control experiments: a systematic review and meta-analysis,” scientists analyzed 355 studies of attempts to eradicate non-native plants from 1960 to 2009. The scientists determined the methods used and the efficacy of those methods. More than 55% of the projects used herbicides, 34% used mechanical methods (such as mowing, digging, hand-pulling), 24% burned the vegetation, and 19% used all three methods. The study found that herbicides most effectively reduced “invasive” plant cover, but this did not result in a substantial increase in native species because impacts to native species are greatest when projects involve herbicide application. Burning projects reduced native coverage and increased non-native coverage. In other words, it doesn’t matter what method is used, eradicating non-native plants does not result in the return of native plants. We didn’t need a study to tell us this. We can see the results with our own eyes.
Flammability of plants is unrelated to nativity
The other, larger category of tree-removal projects on these federal lands are the so-called “fuel management projects.” The flammability of non-native plants and trees is exaggerated in order to justify their destruction. Native plants are not inherently less flammable than non-native plants.
In fact, native vegetation in California is fire adapted and fire dependent for germination and survival. The California Native Plant Society recently revised its “Fire Recovery Guide. The Guide now says, “California native plants are not inherently more likely to burn than plants from other areas.” This statement is the mirror image of what defenders of our urban forest have been saying for 25 years: “Non-native trees are not inherently more flammable than native trees.” Both statements are true and they send the same message: flammability is unrelated to the nativity of plants. “Think instead about characteristics of plants,” according to the CNPS “Fire Recovery Guide.”
There are undoubtedly many other similar projects of which we are unaware. I report only on projects that I have direct knowledge about and that I have visited.
Why I opposed these projects
The San Francisco Bay Area was nearly treeless before early settlers planted non-native trees. Non-native trees were planted because they are better adapted to the harsh coastal winds than native trees. The treeless grassland was grazed by deer and elk and burned by Native Americans to promote the growth of plants they ate and fed the animals they hunted. Grazing and burning maintained the grassland, preventing natural succession to shrubs and trees.
Modern land use and management policies have suppressed fire and reduced grazing in the Bay Area. Consequently grasslands are naturally converting to chaparral and scrub. Although managers of public lands often describe these changes in the landscape as “invasions,” Jon Keeley (Ph.D. biologist, USGS) considers them a natural succession: “These changes are commonly referred to as shrub invasion or brush encroachment of grasslands. Alternatively, this is perhaps best viewed as a natural recolonization of grasslands that have been maintained by millennia of human disturbance.”
Early settlers planted trees to protect their residential communities and their crops from wind. The urban forest also provides sound and visual screens around parks that are surrounded by dense residential neighborhoods. Urban forests are storing carbon that is released as greenhouse gas when they are destroyed. They also reduce air pollution by filtering particulates from the air.
When trees are destroyed, the unshaded ground is quickly colonized by weeds that are then sprayed with herbicide. Even environmental organizations that support the destruction of non-native trees agree about the results of these projects:
- The California Native Plant Society predicted the post-project landscape in its written public comment on the Draft Environmental Impact Statement (DEIS) of the FEMA project in the East Bay hills with this rhetorical question: “What mechanism is being instituted by FEMA in this DEIS to guarantee a commitment of money and personnel for management of greatly increased acreages of newly created annual weedy grassland?”
- The Audubon Society predicted the post-project landscape in its written public comment on the DEIS: “There is no support for the conclusion that native vegetation will return on its own. This plan may not result in an increase in native trees and plants…Heavy mulching will delay or prevent the growth of native species.”
To summarize: I am opposed to destroying our urban forests because they perform many important ecological functions, including providing habitat for wildlife. Furthermore, the herbicides used to destroy the forest and control weeds that thrive in the absence of shade, damage the soil and create unnecessary health hazards to humans and other animals.