Escalating pesticide use by the unnatural Natural Areas Program

Webmaster: We are grateful to Save Mount Sutro Forest for their research on pesticide use by San Francisco’s misnamed Natural Areas Program and for giving us permission to reprint this update on NAP’s pesticide use in 2011.


We spent a couple of hours, the other day, in the beautiful McLaren Lodge, leafing through a thick binder of pesticide reports for the San Francisco Rec and Park Department. It was so thick in part because it contained a lot of nil reports… supervisors of various sections writing in to say things like “No Roundup used in this complex.

The monthly reports from the Natural Areas weren’t nil. Far from it.

Some months ago, we wrote that the pesticide use in the Natural Areas seemed to have increased sharply in 2010 compared with 2009. Oh, said a critic, don’t focus on an individual year. It might go back down next year, it might just be a blip.

If so, we’re not blip-free yet. According to our preliminary figures (which we will update if we get better information) pesticide applications in 2011 were up 20% from 2010.

The NAP continues to use glyphosate regularly (38 39 times in 2011). It’s mostly switched from Roundup to a different formulation, Aquamaster. This alternative provides better control over the adjuvant, the stuff that the pesticide is mixed with. It still contains glyphosate, with its attendant risks.


Part of the reason for switching to Aquamaster is that POEA, the adjuvant in Roundup, is actually toxic instead of being inert. But it’s not just the POEA. Glyphosate itself has problems, particularly in terms of pregnancy problems and birth defects. A 2005 article published in the journal of the National Institutes of Health noted that glyphosate was toxic to placental cells (and Roundup was even more so):

“… glyphosate is toxic to human placental JEG3 cells within 18 hr with concentrations lower than those found with agricultural use, and this effect increases with concentration and time or in the presence of Roundup adjuvants.”

In addition, it’s an endocrine disruptor. French scientists published an article in the journal Toxicology titled, “Glyphosate-based herbicides are toxic and endocrine disruptors in human cell lines.”

According the the guidelines from San Francisco’s Department of the Environment, Aquamaster is to be used “Only as a last resort when other management practices are ineffective.” Since this last resort occurs some 40 times in a year, we suggest the DoE consider reclassifying Aquamaster as Tier I to reflect the latest research on glyphosate.


The big change this year was the move from Garlon (triclopyr) to Polaris or Habitat (imazapyr). According to the record, Garlon was only used thrice in 2011, while imazapyr was used 40 times.

This is somewhat of an improvement in that Garlon is a very toxic chemical, classified as Tier I; imazapyr is less toxic and classified as Tier II.

Unfortunately, it’s possible that the best thing about imazapyr is that it isn’t as bad as Garlon. It is very persistent, and doesn’t degrade easily. It moves around, being exuded by the roots of the plants it’s meant to poison. And its break-down product is a neurotoxin – it poisons the nervous system. It’s banned in the European Union.

The NAP also used Milestone four times. (That does sound like a last resort.) Fortunately. Milestone is an extraordinarily persistent chemical that has been withdrawn from sale in the UK, and is rightly classified as Tier I, Most Hazardous.


The NAP also continued to violate pesticide guidelines. In August 2011, they used Aquamaster against ludwigia (water primrose) in Lake Merced — a lake that is considered red-legged frog habitat. The guidelines ask for a 60-foot buffer zone. Since the water primrose is in the water (and so, we presume is the frog), this buffer zone’s not happening.

Some readers will remember this post about the dateless sign threatening pretty much all the vegetation near the Twin Peaks reservoir with Garlon and Aquamaster. We never got to the bottom of that. The pesticide records don’t mention it.

[Edited to Add (22 Jan 2012): One of our readers asked about this Glen Canyon notice, too, listing the use of Glyphosate and Imazapyr against ivy and acacia.

Again, we don’t know what happened but it’s not in the pesticide records.]


Shelterbelt Builders, the contractor the Natural Areas uses for pesticide application, earned more fees from Rec & Park as pesticide applications increased:

  • In fiscal 2009-10 (year ending June 30), it earned $51 thousand;
  • In fiscal 2010-11, it was paid $78 thousand;
  • In fiscal 2011-12, it’s been paid (or is owed) a total of $84 thousand, and the fiscal year is only half-finished.

[Edited to Add: This is public information from the SF Controller’s website. You can see it here. ETA2: The report on the SF Controller’s website has been changed. Here is the new link. Also, the picture here can be enlarged by clicking on it until it’s readable.]

On Mount Sutro, though the Sutro Stewards’ volunteers have been gutting the understory and destroying habitat, we are glad to say there is still no use of herbicides. Again, our thanks to UCSF for preserving possibly the last pesticide-free wildland in San Francisco. Even if only temporarily.


It’s not a good time to be a plant or a tree in San Francisco. The San Francisco Chronicle reports that the city is handing off 23,000 street trees to homeowners to care for. It estimates it will save $300 thousand. The kind of comments people made on the article don’t bode well for the future of those trees. Meanwhile, it seems to be able to find funding to destroy trees in Natural areas across the city, trash habitat needed by the city’s wildlife, and take out quirky old trees that give some of these wild areas their character.

4 thoughts on “Escalating pesticide use by the unnatural Natural Areas Program”

  1. We live on the coast in the state of Washington where Japanese eel grass has recently been classified as a class ‘c’ weed. This allows for even more spraying of the chemicals imazapyr and glyphosate (ROUNDUP) on commercial shellfish beds to control this grass, along with spartina grass, which has been sprayed since 1996.
    A new chemical – imadicloprid – is being tested to replace carbaryl (SEVIN) for mud shrimp control on these same beds. SEVIN use started in 1964 and, after 48 years, was outlawed in 2012, more than likely after scientists figured out the long-term effects.
    There are numerous independent university and research facility studies on the potential dangers of these chemicals to humans. “The EPA, FDA and the Department of Health and Human Services (HHS) should immediately order more extensive and unbiased testing for all chemicals in these products — sprayed or otherwise — and, if appropriate, set consumption limits especially for pregnant women and children as they do on other many foods like freshwater fish and other seafood.
    Please tell all your family members and friends of the potential dangers of eating chemical/water filtering GMO shellfish that have been exposed to these chemicals. Don’t be the guinea pigs for the next new and improved poison.
    Whales are dying and autism is becoming epidemic. Could there be a connection?

  2. Pesticides and herbicides are toxic. They kill bugs and plants. And if improperly handled they can make you sick. They should not be used unless there is a clear benefit for doing so. However, this article unnecessarily plays into chemical phobia.The laboratory cell studies can be misleading. You can find toxic effects from almost any substance depending on the dose. There have been dozens of long-term studies on the health effects on people who are exposed to these chemicals occupationally, especially applicators, with no or little negative health impacts. As with anything, the risk must be weighed against the benefit. I think the point is there is little benefit in this case and there is some risk even if minimal. These chemicals should not be used for to create natural areas. However, fear mongering is not necessary to make your case and could be a distraction and harm your credibility.

    Webmaster: Your point is well-taken. We agree that there is no need to exaggerate the dangers of pesticide use. This article is reprinted from a source that uses resources from a wider variety of publications than we do on Million Trees.

    When Million Trees publishes an article about pesticide use, we usually confine ourselves to studies conducted by the Environmental Protection Agency and those reported on the manufacturers’ labels. We assume these are the most conservative sources of information and hopefully the most credible.

    For example, we are using many pesticides here in the United States that have been approved by the EPA that have been banned by the European Union. Also, some of the pesticides being used by the misnamed Natural Areas Program–such as imazapyr–were approved for use without the usual tests being completed by the EPA. Imazapyr was put on an “accelerated” approval track in response to advocates for the eradication of non-native Spartina grass.

    I hope this information assures you that we are very conservative in our assessment of pesticide use. However, despite your misgivings you conclude, as we do, that the risks associated with pesticide use cannot be justified for the purpose of creating places called “natural areas.”

    Thank you for your visit and for your comment.

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