[This section has been updated, Dec 2013.]

UPDATE: In November 2013, UCSF declared it would pursue a different Plan – and use no herbicides in the forest.

UCSF logo with herbicide statementThanks, UCSF. In view of all that we’ve learned about herbicides, we are grateful that they will not be used in the forest, especially since it is high ground from where it could get into the ground water, surrounding neighborhoods, and the Bay.


Sutro DEIR pesticides

Native Plant restorations in San Francisco are inevitably associated with toxic herbicides because their primary goal is war on invasive plants. Unfortunately, it can cause real harm to animals, birds, and people.  The Natural Areas Program has used increasing amounts of toxic pesticides since 2009.

Meanwhile, no pesticides were used in the Mount Sutro Open Space Reserve after 2008 (or in the student housing area from November 2009). This may have been the only pesticide-free wildland in the city.

The proposed Plan for removing thousands of trees and 90% of the understory will change that; herbicide use is about to start.

At present, no chemicals are needed in the forest.  Once it has been felled, Aquamaster (glyphosate) and Garlon (triclopyr) will be used to prevent resprouting of the eucalyptus, blackberry, and ivy. This will introduce toxic chemicals where there are none. Thousands of applications will be needed, since it will be used on thousands of tree-stumps, vines, and blackberry stems. It will be necessary over many years, because all these things resprout – eucalyptus for 7-9 years after being chopped down.

The amounts required will be huge, according to estimates from UCSF’s Draft Environmental Impact Report, reported HERE: Bucketloads of Pesticides for Sutro Forest.] The amounts will be 5-15 times as much as even the Natural Areas Program used in its peak year (2012) across its entire 1100 acres.

Even in the first year, where it will be used on only one experimental acre, they could use as much as one-third of NAP’s entire 2012 use in all its parks. If this is found to be the best way of preventing regrowth, it would be extended to all the demonstration areas in the second year – using  as much pesticide on 7.5 acres as NAP used in all its parks. As the acreage being felled grows, so will the amount of pesticides.

(We’ve been asked about ‘herbicides’ vs ‘pesticides.’ These are all herbicides, designed to kill plants. However, it’s a distinction without a difference, since they also have toxic effects on animals and people. San Francisco’s Department of the Environment refers to all chemicals used in this way as pesticides.)

Despite the manufacturer’s claims, there is evidence that these herbicides are not safe. Our article summarizing this is HERE: Natural Areas Program: Toxic and Toxic-er.


(Classified as a Tier II – More Hazardous – chemical by the San Francisco Department of the Environment; active ingredient ‘Glyphosate.’)

  1. Toxic to human cells, particularly embryonic and placental cells. Here’s an article in Scientific American, about the effect of Roundup on human cells – not just the active ingredient, Glyphosate, but the “inert” one, POEA. (Aquamaster does not contain POEA.)
  2. Damage to liver, red blood cells, lymph system. Here’s a series of research articles detailing some of illnesses caused by Roundup.
  3. Linked to cancer, specifically, Non-Hodgkins Lymphoma. A 1999 article on research linking Roundup to cancer, specifically non-Hodgkins lymphoma, and HERE is a follow-up published in 2008 in the International Journal of Cancer.
  4. Dangerous to amphibians. This article cites University of Pittsburgh research showing Roundup is highly lethal to amphibians.
  5. heart breaking

    heart breaking

    Link to birth defects. Here’s an abstract of a  May 2010 article in the journal Chemical Research in Toxicology. It indicates that Roundup increased retinoic acid activity in vertebrate embryos, causing “neural defects and craniofacial malformations.” The actual article, which we read elsewhere describes some of the birth defects: microcephaly (tiny head); microphthalmia (tiny undeveloped eyes); impairment of hindbrain development; cyclopia (a single eye in the middle of the forehead); and neural tube defects. Our summary of this article is HERE.


(Classified as a Tier I – Most Hazardous – chemical by the San Francisco Department of the Environment; active ingredient ‘Triclopyr.’)

Based on a pretty thorough multi-source review of Garlon, here are the risks: birth defects; kidney damage; liver damage; damage to the blood. It very probably alters soil biology. Garlon can persist in dead vegetation for up to two years. It’s particularly dangerous to aquatic creatures: fish (particularly salmon); invertebrates; and aquatic plants, which makes it an especially nasty chemical to use on one of the highest points above the bay.

Here’s our article based on the Garlon chapter of Draft Vegetation Management from the Marin Muncipal Water District (which can be found here as a PDF file).

  1. Here’s a description of Garlon and what it does.
  2. Here’s a discussion between commenters on Garlon. (Scroll down after clicking on the link.)
  3. Here’s the “specimen label” for Garlon 4 Ultra from the website of the Armed Forces Pest Management Board. It details use precautions, including taking off and washing any contaminated clothing, and avoiding use where it could get into waterbodies or groundwater.


(Classified as a Tier II – More Hazardous – chemical by the San Francisco Department of the Environment.)

Imazapyr is now being used by the “Natural Areas Program” in San Francisco. For the present,  UCSF does not expect to use this. Nevertheless, we include it in case this changes later on. Here’s our article on Imazapyr.

The main issues with it are that plants push it out through their root system, so that it can affect other plants; it is very persistent. Its breakdown product is neurotoxic. It’s banned in Europe.


(Classified as a Tier II – More Hazardous – chemical by the San Francisco Department of the Environment; active ingredient, ‘Aminopyralid’)

This chemical has recently been added to the Natural Areas Program’s toxic arsenal. It is even more persistent that Imazapyr, and can survive being ingested by animals. Thus, if it is used to treat plants and animals eat and excrete them, they spread the poison. It is banned in New York for fear it will get in the groundwater, and was for a time banned in the UK.


Can’t we assume that big companies like Monsanto and Dow would never release chemicals that harmed the environment and peoples’ health? And if not, isn’t that what the EPA is there for? Well, not always. We have a series of links below that suggest that they are more lenient than many other countries’ regulatory bodies

  1. Here’s an article on why EPA clearance doesn’t mean safety; and a link to an article about the dangers of the “inert” chemical, POEA in Roundup.
  2. And here’s a petition by Change.org, which notes: “…the 33 year-old law that is supposed to protect Americans from exposure to toxic chemicals is so outdated that China legally exports toxic materials into the U.S. that are not only banned in Japan and Europe, but can’t even be used domestically in China.”
  3. And here’s one pointing out a loophole by which the EPA allows chemicals to be described as “inert” even if they’re toxic.
  4. Here’s the consent order against Dow AgroSciences (which makes Garlon) in the matter of alleged misleading advertising for another pesticide, and here’s the article from the Office of the Attorney General about the $2 million fine.
  5. This article from Yale Environment 360 (from the Yale School of Forestry & Environmental Studies) notes that low level long term exposure to pesticides many be causing die-offs of bats, amphibians and bees. Title: “Behind Mass Die-Offs, Pesticides Lurk as Culprit”
  6. Here’s an article about Dr Phillip Landrigan of Mount Sinai Medical Center saying that more research was needed into the environmental causes of autism – including pesticides.
  7. Here’s the Environmental Defense Fund’s assessment of the EPA’s efforts on the “Voluntary Chemicals Program.”


San Francisco has an additional line of defense – the SF Department of the Environment. It restricts the use of pesticides on city property. However, it does not apply to UCSF’s portion of the forest, though it would apply to the Interior Greenbelt.

The SFDoE provides guidelines as to which pesticides can be used under its Integrated Pest Management (IPM) program, but has no enforcement capability. It relies on compliance by other Departments. Also, it does not regulate quantities used (though it does compile a record). And it does permit the Natural Areas the use of Tier I and Tier II chemicals – which has been rising, despite public concern.

This suggests that any kind of Native Plant introduction is impossible without pesticide. However, the 1.5 acre Native Plant garden at the summit of Mount Sutro is maintained by volunteers entirely without pesticide use.  The key is to recognize that Native Plant areas need the same kind of maintenance as any garden. They cannot merely be planted and forgotten.

Trying to extend this regime to 7.5 acres of the Demonstration Projects will be a stretch; to the planned 46 acres will be impossible.

13 Responses to Herbicides

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  12. Nathalie Paven says:

    It is posted at the Stanyan Street entrance that they will be applying Imazapyr (an herbicide) between Jan 3 -10. I don’t get this since they just announced they will not use herbicides.

    [Webmaster: That would be in the Interior Greenbelt – the portion managed by SF RPD, not UCSF. Please write to Phil Ginsburg and Mayor Lee about this. They have not used herbicides in that area for *years*. It is distressing they are starting now.]

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