2018 Herbicides in San Francisco: NRD Use Rises (Again)

For many years now, we have been obtaining and compiling monthly pesticide use reports from San Francisco Recreation and Parks Department (SFRPD).  This is our report for 2018.

Our analysis omits Harding Park, which is under contract to the PGA and must be tournament-ready at all times. We do include other golf courses, including the nearly pesticide-free Sharp Park in Pacifica (of which more later).

We analyze the data separately for the Natural Resources Department (NRD, formerly the Natural Areas Program or NAP). This is the entity that is 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. (For details, see this LINK.) It  uses toxic herbicides against non-native plants it considers invasive, currently nearly 50 species.

The NRD was the largest single user of herbicides within SFRPD. In fact, it used significantly more herbicides than the rest of SFRPD put together, including all the golf courses except Harding. SFRPD applied herbicides 223 times, of which 175 176 were in “Natural Areas” (this includes PUC areas managed in the same way – i.e. use of toxic herbicides against plants they dislike).

[Edited to Add: We have changed the chart above to correct the data.]



SFRPD (excluding Harding, and excluding NRD) continued to reduce its use of herbicides. Which is good news. They’ve also almost stopped using Tier I products. (SF Department of the Environment – SFEnvironment – groups those pesticides that the city permits to be used on city properties into three Tiers. Tier III is least hazardous; Tier II is More Hazardous; and Tier I is Most Hazardous.) The only usage in 2018 was Roundup Custom on a tree stump in Duboce.

There are some disturbing developments; the drop was a mere 6%, compared to a 34% fall in 2017, a 56% decline in 2016, and 30% in 2015.


NRD dropped its pesticide usage sharply in 2014, and continued the decline through 2016. But in the last two years it started climbing again, and it now is at the highest it’s been in five years (see the graph below).

They’ve added another Tier II pesticide to their arsenal: Axxe, which they tried on oxalis. On the whole, this herbicide is probably not as bad as some others; it has an OMRI listing for organic use. They also used Clearcast on Lake Merced against waterplants.


Honeybee in oxalis flower

The really bad news, though, is the increase in the use of Garlon (triclopyr), the most toxic herbicide that SFEnvironment permits. It’s what they use in their perennial, pointless, and apparently escalating war on oxalis.

The increase is clearer in the graph below. (The orange columns are Garlon.) NRD increased its use of Garlon by about 90% from 2017, and it’s the highest it has been in the last five years.

Oxalis is a beneficial plant: It produces copious amounts of nectar, which is food for bees, butterflies, and other pollinators. Its bulbs provide food for (native!) pocket gophers and some birds. Its brilliant yellow flowers bloom early in spring, before most other flowers. Kids like to chew on its sour stems (it’s also called sourgrass) and even adults have fond memories of this plant. Other than nativist purists, most people love it for its beauty – it’s a sign of spring in San Francisco.


Last year, SFRPD declared war on Cape Marigold, arctotheca. This is a ground-cover plant that’s attractive to butterflies, bees, and other pollinators, but is considered “invasive” – i.e., successful in the urban environment we currently have in San Francisco. In 2018, this attempt resulted in 21 applications of herbicides (of a total of 223), including the first time since August 2010 that pesticides have been used in Sharp Park, habitat for the endangered red-legged frog and the California garter snake.

Nearly all applications were of Milestone VM (aminopyralid) but one was of Sapphire (penoxsulam) – hitherto restricted to golf-courses ONLY in preparation for tournaments. On this occasion, it was being used on the St Mary’s playing field.

Cape Marigold (also called the Plain Treasure Flower) has bright yellow flowers that look like daisies. It’s in the aster family, has a fairly long flowering period, and also provides food for butterflies and bees.


As we said in our half-year report, three new herbicides have been added to the list permissible for use in San Francisco: Axxe (which we mentioned above), Lifeline, and Clearcast.

The list of target species is also growing, and we’ve now counted 47 types of plants that are being sprayed with herbicides. The 2018 newcomers to the list are a couple of succulents: Aeonium, and crassula. Also added to the list is “Cat’s Ear,” an edible plant resembling dandelions and widespread enough that if it’s a target it would provide an excuse for considerable pesticide use. There’s another plant listed as Cape vertigo (sometimes the form is unclear!), which may be an ornamental grass.

We slightly modify our conclusions from our Half-Year report in July: While we are glad that SFRPD has moved to reduce herbicide use (at least in non-Natural areas), we’re disappointed that it continues to consider pesticides a viable strategy. We’re also disappointed at the opening of more battle-fronts against plants, which will inevitably push for more pesticide usage. We’re disappointed at the rising usage by the NRD.

We would like to see SF Environment take the leadership in moving San Francisco to a policy of No Pesticides in our Parks and Watersheds.





Hands Off Mt Davidson’s Forest – Take it Away from NAP

San Francisco Recreation and Parks Department’s Natural Areas Program (NAP) plans to remove 1/3 (10 acres) of the mature and healthy forest on Mount Davidson. We think the 30-acre forested area of the mountain should be removed from NAP’s control to prevent this destruction. The forest should be managed by professional foresters, like those in the Presidio, not gardeners.

In June, 3 years ago, U.C. Berkeley Forestry Management Professor Dr. Joe R. McBride (pdf link: MtDavidson_McBride_Ginsburg(06-29-13)) wrote about his inspection of the Mt Davidson forest, concluding that the Natural Areas Program’s  Significant Natural Resource Areas Management Plan (SNRAMP) for the removal and thinning of different portions of the eucalyptus plantation on Mt. Davidson is NOT justified.

He noted that the forest serves an important role in the history and visual characteristics of the city. Trees and the existing understory provide habitat for wildlife and wind protection for walkers.

mt davidson forest - hiker on trail

Summary of Dr. McBride’s letter to Phil Ginsburg, General Manager of the SF Recreation & Park Dept (parent Department of Natural Areas Program (NAP)):

1) Historic importance and Visual Value.
The eucalyptus forest on Mount Davidson was planted under the direction of Adolph Sutro, philanthropist and former Mayor of San Francisco. The hilltops covered in eucalyptus trees and Monterey cypresses are a distinctive feature of San Francisco’s landscape. They’re been there for a hundred years and are an important historical heritage.

2) Eucalyptus is not invasive.
The Plan frequently refers to these trees as “invasive.” Prof. McBride’s studies indicate that eucalyptus does not invade adjacent grasslands; and this is also obviously true on Mt Davidson, where a stable boundary exists between the forested and unforested areas. [In fact, the California Invasive Plant Council, which had earlier considered eucalyptus as moderately invasive downshifted this classification in April 2015 to “Limited.]

3) Eucalyptus groves are biodiverse.
Eucalyptus groves are richer habitats for vertebrates than either redwood or Monterey cypress/pine forest; and are similar to dry chaparral and grasslands.

4) More Pesticides.
Removing the number of trees shown in the Plan will expose the ground to more light than existing understory plants can tolerate. In the disturbed ground and increase light conditions, existing exotic species will proliferate and will have to be controlled by using even more pesticides.

5) Increased wind-throw and breakage of remaining trees.
Removing trees in this windy area will affect the trees that remain, which are not wind-hardened. More trees will go down.

6) Reducing a wind-break.
This is a very windy part of the city, with winds blowing in straight from the ocean. Walking recreationally on Mt Davidson will be a less pleasant experience.

7) Reduction in habitat.
The Plan’s assumption that birds will quickly adjust to removal of 1600 trees is unfounded. Many birds return to the same nesting site each year. Cutting down large numbers of trees displaces these birds, and also causes a great deal of disturbance. Bird protection plans usually call for a 300-foot radius of protected area around a nest.

Girdled tree Mount Davidson

Girdled tree Mount Davidson

8) The forest is healthy.
The dead trees in the forest have been girdled by someone/s with a vendetta against eucalyptus; few trees – if any – have died naturally.

9) Ivy is not a problem.
English and Algerian ivy climbs up the trees, but cannot smother the trees by growing into the canopy. The only snags covered in ivy were those that had been girdled.

10) Regeneration is a 22nd Century issue.
It’s been argued that the understory of ivy, Cape ivy, and Himalayan blackberry may restrict the establishment of eucalyptus seedlings. If so – and it’s possible – this is a problem for the next century. The forest, though 100 years old, is comparatively young. This could be revisited in another 100 years or so. Meanwhile, the understory provides an excellent food source and cover for wildlife.

Mt Davidson 2 - fuschia flourishing despite drought, watered by the trees catching the fog


Below: Mt Davidson map shows where 10 acres of healthy, mature trees will be removed if the  SNRAMP plans for maximum restoration are approved.  The red, green and yellow notations highlight the information contained SNRAMP plans (as per notes on the lower, bottom left).

SNRAMP. p. 6.2-10, F-14