NRD Herbicide Use Shoots Up in 2020 in San Francisco

As we have been doing for many years now, we compiled the pesticide usage data  for San Francisco Recreation and Parks Department for 2020.  It’s getting worse year by year. Toxic herbicide use (i.e. herbicides classified as “More Hazardous” or “Most Hazardous”) has risen for the fifth year in a row.

(We exclude Harding Park – but not the other golf courses – from this analysis because it’s externally-managed under a PGA contract to be kept tournament-ready at all times.)


San Francisco’s parks are increasingly doused in toxic herbicides. In 2020, SFRPD applied herbicides 295 times, up from 243 in 2019. It’s actually the highest number since 2013, when we started compiling these data.

Of these, 201 applications were by the NRD in “Natural Areas” (this includes PUC areas managed in the same way – i.e. use of toxic herbicides against plants they dislike). The Natural Resources Department (NRD, formerly the Natural Areas Program or NAP) is the entity that in trying to bring “native” plants to more than a thousand acres of our parks, cuts down trees and restrict access to people and their pets. This is up from 144 NRD/ PUC applications in 2019. NRD, which accounts for perhaps a fourth of the land area, used nearly one half of the pesticides measured as active ingredients in fluid ounces.

NRD – and PUC lands that they are managing the same way – have sharply increased their use of triclopyr since the new pesticide Vastlan has been designated Tier II (More Hazardous) instead of Garlon, which was Tier I (Most Hazardous). In both herbicides, the active ingredient is triclopyr. They also increased their usage of other herbicides: Glyphosate, imazapyr, Milestone.


The NRD’s continually growing usage of the herbicides is a sign that this strategy is failing. They have been using hazardous chemicals on some 50 target species year after year. Theoretically, the point of  using toxic herbicides on unwanted species is to allow the desired species to replace them.  Instead, the growing usage of these chemicals shows that if anything, the situation is only made worse.

This stands to reason; “invasive” plants are successful because they are better adapted to current conditions. If they are destroyed with herbicides, the replacement is likely to be the next best adapted (thus, invasive) species. Given 50 target species, the bench is deep. This leads to a vicious cycle of hazardous herbicide use, clearly visible in the graph above.


Besides NRD, the rest of San Francisco Recreation and Parks Department also increased their usage of pesticides to the highest level since 2013. In the last couple of years, they have been using a range of herbicides all classified as Tier II. These include Axxe, Suppress, Clearcast, Lifeline and Sapphire.



San Francisco’s Department of the Environment (SFEnvironment) assigns Tier hazard ratings to the various pesticides it uses. Tier III is Least Hazardous, Tier II is More Hazardous, and Tier I is Most Hazardous.  Over the years we have been following this usage, we have seen various chemicals being moved from one Tier to another. Milestone was moved from Tier I to Tier II; Glyphosate (Roundup, Aquamaster)  from Tier II to Tier I; and triclopyr (Garlon, Garlon 4 Ultra, Turflon, Vastlan) from Tier I to Tier II (for Vastlan and Turflon). Avenger has been moved from Tier II to Tier III, which we think makes sense and makes analysis easier.

We analyze the usage of Tier I and Tier II herbicides.


SF Forest Alliance has been trying to encourage SF Environment to spearhead a reduction in herbicide use. Some years ago, it appeared that pesticide usage was declining, especially after the Roundup revelations. When we wrote our Pesticides report for 2016, the other areas of SFRPD had slashed their herbicide use; the NRD accounted for 74% of pesticide usage. By 2017, hazardous herbicide use was creeping up again.

In August 2019, we attended the annual meeting of the SF Environmental Commission about certifying the so-called Reduced Risk Pesticide List. When we spoke about the risks of pesticide use, we were rebuked by a Commissioner, who said the matter should be left to the experts.

We were dismayed. Aside from questions about why bother with public hearings – or indeed an Environment Commission – if it’s all to be left to “experts”, we were concerned the comment gave permission for much more pesticide use.

It seems the 2020 data have borne out that fear

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