San Francisco Natural Areas and Escalating Pesticide Use

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.

[ETA March 2012: There were 86 applications in 2011, vs 71 in 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.

[Edited to Add 2 July 2012: New York prohibits “Milestone”, too.  Read more about Milestone in this article at Death of a Million Trees: Regretting the Use of Pesticides]

[Edited to Add: Milestone is again sold in the UK, with hazard labeling.]


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.]

[ETA 3 (July 2,2012): The latest figures (as of June 24th) indicate that Shelterbelt is receiving  $123 thousand for FY 2012. (This is probably a final number, since the year ends June 30.) The links don’t see to work, but here’s the report.

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.

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