McLaren Park walk: Looking at the Future, Minus 800 Trees

[Apologies: Some glitch on the website caused Draft versions of this post to be published. Please ignore the earlier posts.]

On a Saturday in late August 2015,  the San Francisco Forest Alliance organized a walk in John McLaren Park – Natural Areas for a  group of our supporters and other interested people. It wasn’t just about a walk through this fascinating park on San Francisco’s southern edge – we all wanted to understand what was planned for its future.


The group wanted to learn about the San Francisco Recreation and Parks Department (“SFRPD”) plans for the Park:  elimination of 8.3 acres of dog play areas; the removal of 809 trees ( eucalyptus, Monterey cypress and Monterey pine);  and using herbicides to poison the  “non-native, invasive” vegetation. The idea is to expand native plants – mainly scrub – in the Park.

In McLaren Park, nearly all the areas that are not actually built up or used for sports, are designated as “Natural Areas.”The Natural Area covers 165.3 acres and is made up of grassland, scrub, and blue gum eucalyptus trees. These are subject to the “Significant Natural Resource Areas Management Plan” – or SNRAMP (pronounced Sin-Ramp).

mclaren NAP Map 1

All the colored areas in the map above – brown, tan, and olive – are subject to SNRAMP.

SNRAMP McLaren Map

Outlined areas (with diagonal lines) will be “restored.”  Trees and shrubs are to be removed. Native species will be planted.

The walk was led by Tom Borden, bicyclist, and Ren Volpe, long-time dog walker both of whom know the park and RPD’s plans for McLaren.


So with SNRAMP maps in hand the group walked 3+ miles around the Park to see the trees that the city wants to remove. According to the SNRAMP document for McLaren Park:    “… Tree removal at McLaren Park is planned mostly for individual trees or small groups of trees within grasslands. …”

We started the walk parallel to the Mansell St corridor, where the city plans to change 4 lanes of traffic into 2 lanes for vehicles and 2 lanes for pedestrians and bikes.

We believe the city will remove these trees along Mansell.  See link to the City’s plans here.

Trees along the north and south side of Mansell will be removed

Trees along south side of Mansell Street will be removed ” to preserve the grasslands … “

These other trees will likely be cut in this area along Mansell:


Trees to be removed to “…allow coastal scrub and oak woodland communities to become established…”

“... In the area downslope of Mansell Street, near the water tanks, the overall plan is to remove enough trees to preserve the grasslands and allow coastal scrub and oak woodland communities to become established. This would involve thinning the stand, which would leave the edges intact and would not result in a substantial change in ground‐level wind hazards and windthrow.

We walked along the trail to the Upper Reservoir and saw where the removal of “invasive” trees is planned and the reintroduction of native plants will be undertaken.

Guide Tom points out the area

Our guide points out where “invasive” trees will be removed … to be replaced by “sensitive plants to prevent the extinction of rare or uncommon grassland plants”

According to the SNRAMP document for McLaren Park: “… in some locations, trees would be replaced by native scrub or grassland species, which would open up views that are currently blocked by trees….

We diverted our walk to take in the magnificent views from this part of the Park.  The views from the Water Tower provided us with a 270 degree view looking west and north to the downtown skyline:

We walked along the Philosophers Way trail where Tom noted that trees along the sides of John Shelly Drive will be removed. This is presumably to open up to yet more views of the downtown skyline  – and to the wind.


At the east end of the Redwood Grove and picnic area, Tom shows which trees are likely to be removed


We observed signs around the Jerry Garcia Amphitheater that dogs would be allowed off-leash around the amphitheater “unless there is a permitted event“.   Someone pointed out that dog-walkers needed to know when there is a “permitted event’ so that they could avoid the area or leash their dogs.  No one knew how SFRPD planned to communicate a  “permitted event.”

According to the SNRAMP document for McLaren Park: “… DPAs [Dog Play Areas – off leash] would be reduced by 14%. The existing DPAs at this park are 61.7 acres…

Our walk continued to the open grassland area  south of the Jerry Garcia Amphitheater and parallel to Mansell Street.  This photo show where grasslands will created by cutting down trees, and will be closed to people (and dogs).

Open grassland with threatened trees

Grassland, now open as a dog play area, will be restricted use and probably fenced off

More dog walkers will be coming to McLaren Park when the GGNRA clamps down on dog access in areas controlled by the National Park system (the Presidio, Fort Funston, etc).  This will force more dog walkers into an ever smaller area. It’ll be smaller still if NAP further restricts the existing boundaries that NAP is planning for the off leash dog area (now within the John Shelley Drive loop) – which is entirely possible.


Tom reminded us that the SF Urban Riders and McLaren Bike Masters had donated thousands of hours for trail-building in McLaren Park – and then were shut out of the trails they’d helped to build.  (We wrote about that HERE.)

Our tour included the grasslands area that looks down to Visitacion Valley and the Gleneagles Golf Course. We were informed that trails have been closed to bicycles where previously biking was allowed.

Looking down to Vistitacion Valley

Looking down to Visitacion Valley and the Gleneagles Golf Course

Lower trails closed

This portion of the Philosopher’s Way trail has been closed to bicyclists since earlier this year

In the area south of Mansell Street, near the 2 water tanks, NAP plans to remove enough trees to allow establishment of a coastal scrub community. That means many of the trees in the picture above will be removed.


Local residents of San Francisco (people, bicyclists, dogs and wildlife) get enormous benefits from the beauty of McLaren Park.  It’s a  welcome respite for a very urban population, surrounded on all sides by freeways and boulevards. Local residents come here to enjoy the serenity and beauty that is just a few minutes from their homes.  A lot of that ambiance will be taken away when the City removes hundreds of trees.

It’s not just beauty. The trees in McLaren Park provide valuable ecosystem services. They fight climate change by sequestering carbon; and mature trees absorb more carbon than smaller young ones. They help fight urban pollution by trapping particles on their leaves, keeping them out of the air and our lungs. It cleans the air, especially fighting particulate pollution, by trapping particles on its leaves that eventually get washed onto the ground. They regulate water run-off and reduce the load on our sewer system.

In San Francisco, we have few wildland fires – and when we do, they’re grass fires. When the fog rolls in over the trees of McLaren Park, moisture drops on the ground, allowing for a dense damp understory that fights drought and resists fire. Trees  provide wind breaks, thus reducing the impact of wind on surrounding neighborhoods, and also reducing fire hazard.


Trees are good for our health. A New Yorker article linked here references a recent study that shows that ten additional street trees on a city block had the same health impact as giving each household $10,000 – or making all the adults seven years younger. Other studies have shown trees improve mental health, reduce stress, and aid healing.

SNRAMP is bad for health. Aside from blocking opportunities for outdoor exercise and recreation, it would require the use of large quantities of poisonous herbicides to prevent resprouting of the felled trees – herbicides that are likely get washed down the hillsides and into surface and ground water.

The City plans to remove 809 trees in this park since they are labelled “invasive”.  We strongly oppose this action.   Aside from the beauty of the Park, and the undisturbed wildlife habitat that would both be destroyed, we think it is environmentally irresponsible. Trees sequester carbon; eucalyptus, with its dense wood, its size, and its 400-500-year life-span, is particularly effective.


We plan to organize more such small-group walks through beautiful areas that will be impacted by SNRAMP.  They are always free, and no donations are expected. They’re guided by people who know the place well.  (HERE is a post about our recent visit to Sharp Park in Pacifica.) If you would like to know about the planned walks, as well as get updates about issues of trees and access restrictions, please stay in touch. We encourage you to enter your email address at the top right (“sign me up”) in order to receive our updates directly to your email.

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Roundup Reclassified as Tier I – SF Dept of Environment

A few weeks ago, we reported that the World Health Organization (WHO) had found that Roundup (glyphosate) was “probably carcinogenic.” It’s the herbicide the Natural Areas Program (NAP) uses most, either by the name Roundup or the name Aquamaster. The chart shows glyphosate use as olive green bars. (NAP is a program of the San Francisco Recreation and Parks Department – SFRPD)

We were interested in how San Francisco’s Department of the Environment (SFDoE) would respond to this finding. They regulate what pesticides may be used on city property, including the Natural Areas.

NAP Herbicide use by active ingredient 2014SFDoE called a public meeting in response. They have reclassified glyphosate from Tier II (more hazardous) to Tier I (most hazardous).  We received notes from someone who attended and found it encouraging. This is based on those notes, and is not a comprehensive report on this meeting.  It focuses on issues the observer considered important.



by a Concerned Citizen

This meeting drew a huge crowd.  I’d say there were 100 people in the room.  Chris Geiger [of the SFDoE] asked how many people were employees of public land agencies.  Most were.  When he asked how many people were “concerned citizens,” fewer than 10 people raised their hands.  I did not see Lisa Wayne [who heads NAP] nor any NAP gardener.

Chris Geiger said the meeting was organized in response to the recent categorization of glyphosate as a “probable human carcinogen” by the International Agency for Research on Cancer (IARC) of WHO.  He said the purpose of the meeting was informational as well as to consider the question of how the city’s Integrated Pest Management (IPM) policy should respond to the new classification.  In that regard, Geiger announced that the city has reclassified glyphosate as a Tier I pesticide (most toxic).

The presentation was made by Susan Kegley, Ph.D. Chemist and Executive Director of Pesticide Research Institute.  She is the author of the risk assessments of herbicides for Marin Municipal Water District and California Invasive Plant Council.

[Read the presentation HERE: sfe_th_kegley_sf_ipm_glyphosate_7-2-15 ]

Dr Kegley described the process used by IARC of WHO to classify pesticides.  Usually, they publish a monograph which details all of the studies they reviewed in making their decision.  In this case, they have yet to publish the monograph and so much of what Dr Kegley said was speculation about what studies they used to reach their decision.  Based on the studies she summarized, the evidence of glyphosate causing cancer in humans is “limited” but the evidence of glyphosate causing cancer in laboratory rats and mice is stronger.

The most significant thing that Dr Kegley said was one of her last slides when she expressed her opinion of an appropriate policy reaction to the WHO classification.  Basically, she said that landscape decisions should be re-evaluated with the goal of reducing the need for herbicide use.  Her final recommendation was one she uses in her own garden, that is, to create shade in the garden which suppresses weed growth.  (The obvious example of that strategy is TO QUIT DESTROYING THE TREES THAT CREATE SHADE.)

[Edited to Add: Another observer present at the meeting drew our attention to an important point in Dr Kegley’s presentation – that glyphosate was present in the urine of 44% of tested subjects in European Union countries where glyphosate-tolerant crops are not grown. In the US, the percentage would likely be considerably higher because of the greater use of glyphosate.]

An employee of SF’s Public Utilities Commission (PUC) demanded that the IPM program tell the PUC they must continue to use glyphosate because he can’t deal with weeds without it.  He was disruptive and behaved inappropriately.  Mr Geiger asked him politely to “stand down.”  This employee illustrates how the use of pesticides is in the hands of irresponsible public employees.

Natural Areas Program pesticide notice - Roundup on fennelMr Geiger then asked employees of public lands to explain what they are using glyphosate for.  Kevin Woolen of SFRPD described his efforts to reduce herbicide use by SFRPD.  He sounded responsible and convincing.  Good public relations for SFRPD.

A concerned citizen asked an excellent question about climate change.  Basically she asked why herbicides are being used to kill non-native plants that are better adapted to the changed climate and asked if it is still realistic to try to re-establish native plants that may not be adapted to the changed climate.

Mr Geiger invited Peter Brastow [of the “Office of Biodiversity” in the SFDoE] to answer that question.  Mr Brastow said that there are many “microclimates” in San Francisco and that in some of those microclimates, it is still possible to maintain native plants.  He claimed the city is not trying to establish native plants everywhere, but he claimed that native plants will continue to be with us for the foreseeable future  because “evolution does not happen in our time frame.”



We thank the observer for that report.  We are pleased that glyphosate has been reclassified as Tier I; we have been asking for this for some years.

More importantly, we ask that NAP stops using herbicides in the Natural Areas.  Trying to kill off the plants that grow naturally in order to introduce others that have difficulty surviving in our city is a waste of resources and a poor reason to add toxins to our wild lands. We are pleased that Dr Kegley focuses on alternatives to using herbicides. We suggest that in Natural Areas, the best alternative is – let them be.

Incidentally, Mr Brastow is wrong; evolution happens all around us all the time. We’re reminded of the talk by Dr Scott Carroll at the Commonwealth Club last year. Evolution is visible in the bugs that develop resistance to antibiotics, in the weeds that develop resistance to herbicides, and even in creatures that evolve to adapt themselves to newly available natural resources.

Signs of Annoyance – Natural Areas Program

Recently, the San Francisco Recreation and Parks Department (SFRPD) spent an estimated half-million dollars on signage, most of which listed various Don’ts (though ironically, they start with “San Francisco Recreation & Parks Welcomes You”). All our parks and open spaces are peppered with them. Many park users, who earlier had no idea that the Natural Areas Program (NAP) was designed to restrict access and usage, are upset. They’ve started “fixing” the signs. Someone sent us these pictures:

Natural Areas Program fixed sign

The sign has been “edited” to warn people of toxic pesticide use and wryly note that most of the park is off-limits except to staff and supervised volunteers.

Of course, we have been talking about toxic pesticides, but here’s a recent picture. Roundup (glyphosate) has been identified as “probably carcinogenic” by the World Health Organization.

Natural Areas Program pesticide notice

Here, it’s been used to destroy (non-native)  fennel, the pleasant-smelling feathery-leaved plant that is, incidentally, the host plant to the Anise Swallowtail, a beautiful butterfly that happens to be native.

Anise swallowtail butterfly breeds on fennel

In fact, as the altered sign below points out, nearly all the plants you see in San Francisco – including the grasslands NAP is ostensibly seeking to protect with its use of herbicides – are non-native. They still add to the beauty of the landscape, the greenery of our parks, and provide habitat for wildlife from insects to birds to mammals. The herbicides do nothing but poison these plants, leaving space for the next most aggressive plant to move in – most likely also non-native.

Fixed sign - whats wrong with Natural Areas Program

Five Reasons it’s Okay to Love Oxalis – and Stop Poisoning It

The oxalis season is over, and the perky yellow flowers have vanished for another year. These Bermuda buttercups will be back next year to herald the spring, bringing joy to those who love them, irritation to those who hate them, and Tier I herbicides targeted at them in San Francisco’s so-called “Natural” Areas.

oxalis in glen canyon feb 2011


These flowers are so visible in spring that Bay Nature magazine did an article about them in March 2015: A Natural History of the Little Yellow Flower that’s Everywhere Right Now. It quoted Jake Sigg, the retired SF Recreation and Parks gardener who is considered the doyen of San Francisco’s native plant movement. He hates oxalis pes caprae, which he considers extremely invasive. The article quotes him as saying that, without intervention, “in X many years Twin Peaks would just be one solid mass of yellow, and there wouldn’t be any other plants there…” The article suggested that an oxalis-dominated landscape “drives away coyotes, hawks and owls that feed on grassland foragers, and the situation is especially dire for endangered Mission blue butterflies, which depend heavily on native wildflowers.” Most of those ‘facts’ about oxalis are mistaken as we’ll explain below.

Mr Sigg’s theories align with those of the Natural Areas Program (NAP) of the San Francisco Recreation and Parks Department (SFRPD), which uses the herbicide, Garlon (triclopyr) to battle oxalis  despite its dubious efficacy for the purpose.  San Francisco’s Department of the Environment San Francisco’s Department of the Environment classifies Garlon 4 Ultra as Tier I: Most Hazardous. It’s listed as HIGH PRIORITY TO FIND AN ALTERNATIVE (their caps). Since oxalis is the main reason NAP uses Garlon, the alternative we propose is – don’t use Garlon or anything else on oxalis.

An article on, based on a detailed study by the Marin Municipal Water Department, describes some of the issues with Garlon:

  • Garlon “causes severe birth defects in rats at relatively low levels of exposure.” Baby rats were born with brains outside their skulls, or no eyelids. Exposed adult females rats also had more failed pregnancies.
  •   Rat and dog studies showed damage to the kidneys, the liver, and the blood.
  •   About 1-2% of Garlon falling on human skin is absorbed within a day. For rodents, its absorbed twelve times as fast. It’s unclear what happens to predators such as hawks that eat the affected rodents.
  • Dogs  may be particularly vulnerable; their kidneys may not be able to handle Garlon as well as rats or humans.  Dow Chemical objected when the Environmental Protection agency noted decreased red-dye excretion as an adverse effect, so now it’s just listed as an “effect.”
  •  It very probably alters soil biology. “Garlon 4 can inhibit growth in the mycorrhizal fungi…” ( soil funguses that help plant nutrition.)
  •  It’s particularly dangerous to aquatic creatures: fish (particularly salmon); invertebrates; and aquatic plants.
  •  Garlon can persist in dead vegetation for up to two years.
twin peaks - jan 2015 - imazapyr and garlon for poison oak cotoneaster oxalis

Natural Areas Program uses Garlon on oxalis

First, a little about the actual natural history of oxalis. This plant doesn’t set seed in California, and spreads entirely by sending out roots and forming little bulbils (like tiny potatoes) underground. It’s usually found where the soil has been disturbed by activities such as road-building, gardening, or trail-building. In some cases, the disturbance come from landslides or something similar. It can’t stand frost. If we do nothing,  it would tend to die down rather than spreading uncontrollably.

In disturbed landscapes, it can spread fast. For this reason it can be a nuisance in gardens. People don’t want to leave their gardens alone for years to let nature take its course with the oxalis, and not every garden design includes brilliant yellow as the dominant color for a few weeks. The only way to eradicate it in the short term is to dig it out carefully every time you see it, and make sure you get most of the bulbils. Or use strong herbicides, which may not work.

In a natural landscape, though, it’s a different story and here’s why.


Oxalis is actually an excellent plant for bees and butterflies.  When blooming, it provides “copious nectar.” In fact, it generously gives away its nectar. Since it doesn’t set seed, it doesn’t benefit from pollinators – but it’s a food source for honey bees, bumblebees and butterflies. (You can read a rather technical description of the plant HERE in a 2-page PDF note from UCLA’s Barry A. Prigge and Arthur C. Gibson.)

In fact, a recent 2014 study shows that plant communities with exotic plants had more plant species as well as more pollinators, that pollinators didn’t prefer native plants, and that even some specialist pollinators depended on introduced plant species.

It’s true the Mission Blue butterfly needs (native) lupine as its nursery plant. (It doesn’t depend on any other native wildflowers – only three varieties of lupine.  Incidentally, one of the key nectar sources for the Mission Blue butterfly is an invasive non-native Italian thistle: Carduus pycnocephalus).

Lupine has been planted on Twin Peaks as NAP attempts to reintroduce the Mission Blue butterfly there. But lupine is also a plant of disturbed areas, which means that NAP must maintain it or it will die out as the area stabilizes. They have to keep planting it, weeding, and trimming the grass around the lupine patches to make it attractive to the butterfly. An SFRPD report on the reintroduction project said “unmanaged habitat deteriorates quickly.” Presumably, they don’t use Garlon near the lupine patches, since it would likely kill that too. Despite what is implied in the Bay Nature article, it’s not oxalis that’s the issue. The real problem is another native plant, the coyote bush which takes over grasslands in a natural succession.


Oxalis bulbils are a food source for wildlife. Gophers and other rodents eat them. In fact, the Bay Nature article says, “Their spread is abetted by pocket gophers and scrub jays, which have been spotted carrying the bulbs and caching them in the ground—effectively planting them in new areas.”

Since gophers are a foundation species in the food web, being dinner for predators from hawks to coyotes to great blue herons, these plants actually provide habitat benefits whether or not they’re flowering, because the bulbils are there all year.

gopher-twin-peaksWhere there are gophers, the predators follow. Like the coyotes in these pictures, which clearly haven’t been driven away by a landscape dominated by oxalis.

coyote pouncing in oxalis field - copyright Janet Kessler

coyote pouncing in oxalis field – copyright Janet Kessler

coyote in oxalis field - copyright Janet Kessler

coyote in oxalis field – copyright Janet Kessler


The article says that oxalis leaves “bare ground during the six months of the year oxalis doesn’t flower.” That’s not true either.

oxalis interspersed with grasses and other plants

oxalis in glen canyon feb 2011The spectacular yellow bloom of the oxalis – valuable because it the mass of color attracts honey bees and bumblebees – gives the impression that it’s the only plant there.  But though it visually takes over the landscape when it’s in bloom, it naturally grows interspersed with grasses and other plants. Like in the picture above.

In fact, oxalis tends to enrich the soil with phosphorus, which is good for grass.

So when it finishes blooming, as it has by now – you don’t get bare ground. The picture below shows the same area as the first picture in this article – but it’s after the oxalis bloom is over. It’s a grassland.

glen canyon after the oxalis season


One argument – related  to the ‘bare ground’ argument – is that oxalis takes over grasslands and destroys them, particularly the native grasses. However, grasslands in most of California including San Francisco are dominated non-native grasses. The change occurred over 100 years ago, when these grasses were planted for pasture. So the grassland that NAP is defending with herbicides are primarily non-native anyway.

oxalis and california poppies sm But anyway, what’s the evidence that oxalis is actually damaging native plants?

It’s true some European studies do suggest that an increase in oxalis is associated with a decrease in native plants diversity -though whether it’s a cause is unclear. It may just be benefiting from human activities that disrupt the landscape. Another study put oxalis head-to-head with a native annual grass, lolium rigidum. The native grass tended to dominate. Their conclusion: “Oxalis is a poor competitor. This is consistent with the preferential distribution of Oxalis in disturbed areas such as ruderal habitats, and might explain its low influence on the cover of native species in invaded sites.

The California Invasive Plant Council rates its invasiveness as “moderate,” considering it as somewhat invasive in sand dunes and less so in coastal bluff areas.

In San Francisco, every place where oxalis grows is already a disturbed environment, a mix of non-native grasses and plants with native plants (some of which have been artificially planted).  Here,  oxalis appears to grow happily with other plants – including, for instance, the native California poppy in the picture above.


Children love oxalis, both for its pretty flower and for the sour taste of its edible stems.

Even small children love gathering posies of Bermuda buttercups (though picking flowers is technically prohibited in Natural Areas). The flowers are surprisingly hardy for wildflowers, and in a glass of water last quite well as cut-flowers.

The plant is edible, and its tart leaves make a nice addition to salad. People enjoy snacking on its sour stems. Besides Bermuda buttercup, it’s also called ‘sourgrass’ and ‘soursob.’ It does contain oxalic acid (as does spinach, for instance), and so you probably wouldn’t want to make a meal of it. Though in South Africa it’s made into soup.

Adding Garlon to it is probably a bad thing.

Photo credit: Badjonni (Creative Commons - Flickr)

Photo credit: Badjonni (Creative Commons – Flickr)


From our current evidence, there’s no sign that oxalis has a negative impact on wildlife, and plenty of evidence it’s already part of the ecological food web of our city.  The evidence also suggests it’s not having a negative effect on other plants in San Francisco either. Lots of people find this flower attractive; one writer described it as the city smiling with Bermuda buttercups.

In any case, even Doug Johnson of the California Invasive Plant Council doesn’t think it’s worth attacking at a landscape level: the payoff isn’t worth the expense. Removing it from the hundreds of acres in Natural Areas isn’t as simple as eradicating it from a small yard where it’s clashing with the garden design. It requires a lot of work, a lot of powerful herbicides, a multi-year effort – and for what?

The justification for using strong pesticides like Garlon to control it is weak. We call on NAP to stop using Tier I and Tier II herbicides altogether.

World Health Organization: Roundup “Probably Carcinogenic”

The World Health Organization (WHO) recently declared that glyphosate is “probably carcinogenic” to humans. Specifically, it links the herbicide to non-Hodgkin lymphoma. (You can read their press release here: WHO glyphosate MonographVolume112)

Though SFRPD Natural Areas Program’s use of herbicides declined in 2014, it rose quite sharply before that. Roundup and Aquamaster, with active ingredient glyphosate, is one of the most frequently used herbicides in their arsenal. (The others are Garlon 4 Ultra, i.e. triclopyr; Polaris, Stalker or Habitat,  i.e. imazapyr, and Milestone VM – aminopyralid.)

Three of the Four on Mt Davidson

Three of the Four on Mt Davidson

We’re glad that WHO has come out with this statement, but we’re not surprised. We’ve been following the literature for some years. In 2013, Dr Morley Singer alerted us to an article in the highly-respected peer-reviewed and journal, CA: A Cancer Journal for Clinicians. The article said that people who applied pesticides – or were around pesticides – were more likely to get cancer. [HERE’s the link to the article:  Increased cancer burden among pesticide applicators and others due to pesticide exposure.] We wrote about it here: Pesticides and Cancer, Glyphosate and Gut Bugs. NAP Herbicide use by active ingredient 2014


We hope that the WHO’s determination will make the Natural Areas Program (NAP) re-think its use of herbicides. Glyphosate, i.e. Roundup/ Aquamaster is possibly carcinogenic, and is on the list of herbicides to be evaluated as an endocrine disruptor. Besides the risk to the public and their pets, their own staff are in the front lines here.

The San Francisco Department of the Environment (SFDoE) assigns a ‘Tier” ranking to all the pesticides that are legal for use on City-owned property. Tier III is Least Hazardous, Tier II is More Hazardous, and Tier I is Most Hazardous. Roundup/ Aquamaster is Tier II. We again ask SFDoE to consider reclassifying it as Tier I. But we would be disappointed if NAP merely substituted other herbicides instead.

We have concerns about all the herbicides they use. (See this summary article: Toxic and Toxic-er )

  • Triclopyr (Garlon) is possibly more hazardous than Roundup; it’s already classified as Tier I, and for years has been listed as “High Priority to find a substitute.” NAP is a major user of Garlon, mainly to fight Bermuda Buttercups – yellow oxalis. (We’ll discuss that trade-off another time.)
  • Imazapyr (Polaris), classified as Tier II, is problematic because it doesn’t go away. It can continue to poison plants and impact the environment for a long time after it’s applied. Also, it moves around – it’s mobile in the soil. Some plants actually push it out through their roots. Its breakdown product is a neurotoxin.
  • Milestone VM – aminopyralid – is also classified as Tier II, and it’s even more persistent than Imazapyr. It’s so persistent that animals can eat it, and their poop is poisonous to plants. It’s banned in several places because of its threat to groundwater.

Besides the risk to humans and their pets, pesticide use doesn’t benefit native wildlife – whether insects including butterflies, birds, or animals. It doesn’t benefit native plants, either. All that happens is that other plants best-suited to the area take over, and those are usually other ‘invasives.’ Or worst of all – nothing grows there, leaving bare poisoned slopes. We call on the Natural Areas Program to stop using herbicides.

McLaren Park's Flowered Grassland and Forest

McLaren Park’s Flowered Grassland and Forest

Two Cheers for NAP’s Herbicide Use in 2014

[Note: This article has been edited to add a section on dead birds near Kezar Stadium.]

NAP Herbicide use by active ingredient 2014We’ve been following the use of hazardous herbicides by the Natural Areas Program (NAP) for some years now – and it’s been rising steadily. We recently compiled the data for 2014. For the first time since 2009, 2010, NAP’s use of Tier I and Tier II herbicides actually declined. (San Francisco’s Department of the Environment – SFDOE – sorts acceptable herbicides into three tiers. Tier III is Least Hazardous; Tier II, More Hazardous; and Tier I, Most Hazardous.) It’s even below 2010 levels, though considerably higher than 2009. We consider this an encouraging development.

The main herbicides NAP uses are:

  • Garlon 4 Ultra (triclopyr),
  • Stalker (imazapyr)
  • Aquamaster, also called Roundup Custom (Glyphosate)
  • Milestone VM (Aminopyralid)

Garlon is Tier I, and the other three are Tier II. NAP uses no Tier III herbicides. All these herbicides have downsides, but Garlon is the most problematic. SFDOE considers it a ‘high priority to find an alternative.’ Why?

  • Risks to humans – and the risk to women of child-bearing age is 20 times higher than to men
  • Risks to birds – relatively small amounts can reduce birds’ breeding success
  • Risk to animals – dogs may be especially sensitive to Garlon because their kidneys take longer to process the chemical.
  • Persistence – it can remain in the soil for years.

In 2008, Marin Municipal Water Department made a thorough review of several pesticides. The triclopyr chapter chapter from their draft report is linked here: Chap4_Triclopyr_8_27_08

A presentation from the California Invasive Plant Council (which supports the use of herbicides) has an interesting assessment of risk factors for various herbicides – including triclopyr. It’s linked here: Law_Johnson 2014 presentation toxicity

McLaren Park's Flowered Grassland and Forest

McLaren Park’s Flowered Grassland and Forest

The Natural Areas program is still the largest user of  Tier I herbicides in the SFRPD, (with one exception we’ll discuss below). It’s mainly Garlon used on oxalis, the yellow-flowering plant that covers San Francisco hillsides in spring, and which they consider an invasive non-native plant (together with about 35 species of plants, including fennel).

Oxalis flowers early and spectacularly in Spring, providing abundant nectar to bees, butterflies and other insects. It then dies back, making way for other plants. In any case, knocking back the oxalis merely opens the niche to the next most adapted plant, most likely also non-native, to expand into the vacated area.


number of herbicide applications by NAP 2014The first graphs showed a comparison based in the volume of the active ingredient, which is the metric the Department of the Environment prefers. This second graph show NAP’s herbicide use in terms of number of applications (which is a proxy measure of breadth of exposure to the herbicides). The number of applications in 2014 rose slightly from 2013, but not close to the 7-year high in 2012.

NAP herbicide applications by volume 2014The third graph shows the volume of herbicides used (which includes both the active ingredient and the so-called ‘inert’ compounds that are not always in fact inert). Here too NAP has reduced its usage in 2014. By this measure, NAP still hasn’t dropped back to 2010 levels, mainly reflecting the changed product mix with less Garlon in 2014.


In 2013, NAP used nearly as much herbicide as all of the rest of SFRPD put together. (We exclude Harding Golf Course, which is managed by the PGA Tour under contract and not by SFRPD.)

In 2014, NAP actually used a lot less herbicide than SFRPD. (Not as low as the 4% quoted by Mr Ginsberg, but only 26%. Since NAP has about a quarter of the total acreage owned by SFRPD within the city, this is more or less in line with the rest of the park.)

SFRPD overall (ex NAP and ex Harding) used a lot more herbicide than in 2014 than in 2013. Here’s why:

  • A mistake in Gleneagles.  In March 2014, Gleneagles golf course used a huge amount of triclopyr (512 fl ounces), while its normal usage is little or nothing. In fact, except for NAP, triclopyr is little used by SFRPD. Gleneagles also used 36 fl oz of Sapphire, a golf-specific product that is supposed only to be used when getting ready for a tournament. At the annual pesticide review meeting, SFRPD’s Integrated Pest Management Coordinator confirmed that it was a mistake by an outside contractor.
  • Kezar Stadium soccer field’s new herbicide. Kezar Stadium used Drive XLR8 (quinclorac) on the soccer field in November and December 2014.  This required an exception, because it’s not approved for use on city-owned property. The stadium was closed for three months, so SFDoE considered the risk acceptable. We wondered why, if the stadium was closed, they could not just plow the thing under and start anew, but apparently that would be a capital budget issue. We hope these kinds of questions do get asked somewhere in SFRPD. Coincidentally, Golden Gate Audubon reported a number of dead birds showing up in the area, but Drive XLR8 is not considered especially toxic to birds and there’s no indication the two things are related. [Edited to Add: Actually, they may be related. See section at the end.] Anyway, Chris Geiger of SFDOE confirmed Drive XLR8 was a Tier I pesticide that would not be moved on to the approved list; this usage was a one-off.

Adjusted for the two incidents above, SFRPD reduced its non-NAP herbicide use by about 20% from 2013 to 2014. In fact, its usage this year was below NAP’s herbicide usage for 2013, and it used only a tiny amount of Tier I herbicide. But for exceptional incidents like the ones described about, NAP remains the single largest user of Tier I herbicides in SFRPD.

NAP vs other SFRPD 2014 n 2013

We applaud NAP’s reduction of herbicide use in 2014, and call for it to eliminate use of all Tier I and Tier II herbicides.


[This section was added 22 Feb 2015.]

As we mentioned above, there were reports of dead birds around Kezar Stadium. We learned that they were mostly robins (but Golden Gate Audubon also mentioned blackbirds and sparrows), and the person who found them spotted several dead birds where ordinarily even one is unusual. We assumed that the relationship with the Drive XLR8 used on the turf was unrelated, because our research indicated no especial threat to birds.

But further investigation suggest that the problem chemical could be not the active ingredient, but ethylene glycol used in the formulation. Ethylene glycol is better known as anti-freeze, and it’s toxic to mammals and birds. The Cornell University College of Veterinary Medicine says the following on its “Consultant” website:

“Ethylene glycol, antifreeze, toxicity is often fatal in birds. Oxalate crystals are found in renal tissue at necropsy.” It lists the signs, which include sudden death: “Anorexia, Ataxia, Diarrhea, Dullness, Dysmetria, Neck weakness, Seizures or syncope, Sudden death, Torticollis, Trembling, Tremor.”

Robins love digging in the grass for worms and such, and with the stadium closed they would have had undisturbed access. If the worms on the field were poisoned by ethylene glycol, so would the robins.  There’s no way to tell for sure, because as far as we know none of the dead birds was kept for a necropsy (like an autopsy for animals).

But anyway, the good news is that the Department of the Environment does not plan to use this product again.




Relentless War on Eucalyptus – The Example of Glen Canyon

This article is reproduced from – the website of Death of a Million Trees with permission and minor formatting changes.

A new front has opened in the relentless war on eucalyptus in California. The drought has given native plant advocates an opportunity to develop a new narrative to justify their demands for eradication of eucalyptus. The opening gambit in this new strategy is an item in Jake Sigg’s “Nature News” of May 16, 2014:

“The prolonged drought of the last 2-3 years seems to be taking its toll. The Tasmanian blue gums in Glen Canyon along O’Shaughnessy Boulevard strongly show drought stress. The stress is more evident from the high cliffs above O’Shaughnessy than it is at ground level. Thinning crowns and discolored foliage was striking. And that was before the recent heat wave. Barring substantial rains–unlikely, but not impossible–the trees are in serious trouble. The City could have an emergency situation and no money to address it.”


When public land managers began the war on eucalyptus in the 1980s it did not occur to them that the public would object. So deep was their prejudice against eucalyptus, that they assumed the public shared their opinion. The first two massive projects in the 1980s on National Park Service and State Park properties were greeted with angry public protests. Land managers quickly learned that it was not going to be as easy to eradicate eucalyptus as they had thought. They developed a series of story-lines to justify their projects, which were designed to convince the public that the eradication of eucalyptus is both necessary and beneficial. This is a summary of some of their cover stories with links to articles that debunk them:

Based on our experience, we were immediately suspicious of the new claim that San Francisco’s eucalyptus forest is dying of drought. We know that our predominant species of eucalyptus—Tasmanian blue gum—grows successfully throughout California, all the way to the Mexican border in climates that are much hotter and drier than the Bay Area. We also know that the central and north coast of California is foggy during the dry summer months, which doubles the amount of annual precipitation in the eucalyptus forest. All reliable sources of horticultural information describe blue gum eucalyptus as drought tolerant. Frankly, we couldn’t see how our eucalyptus could be dying of drought.


The picture became clearer when Jake Sigg posted the following on his “Nature News” on June 12, 2014:

“The June 10 newsletter [see below*] included an editorial on an evolving catastrophe, mostly involving our numerous plantations of Tasmanian blue gums. The editorial focused primarily on the plantations on O’Shaughnessy Blvd in Glen Canyon and on Mt Sutro, and included a photo of a grove of Mt Sutro dying trees. Here is a photo of the Glen Canyon plantation, taken from above the high cliffs on O’Shaughnessy. The damage is most visible from high, looking down. The discoloration of leaves was very dramatic, but the foliage color and condition is not fully conveyed in the photograph. Some trees defoliated entirely in the prolonged winter dry spell. Look very closely at the juvenile blue leaves of the coppice shoots; anything that appears faintly bluish are new coppice shoots which grew in response to the late rains we had in February and March. Once you see coppice shoots on old trees you know the trees are in trouble. These trees are in double jeopardy, as they invested energy in new shoots, but were betrayed by another dry spell which, under normal circumstances, will last until autumn. Note that you can now see the grassland through the trees; that slope was not previously visible. Even a casual inspection of these groves reveals dead, dying, and stressed trees, and under normal circumstances we will have four or five months of dry. The fire situation is serious right now and is likely to become worse.”


View of west side of Glen Canyon Park from Marietta Drive, June 2014

View of west side of Glen Canyon Park from Marietta Drive, June 2014

With more specific information in hand about what Jake Sigg is looking at, we went to see for ourselves. We could see what he was describing from a vantage point on Marietta Drive, west of Glen Canyon Park. We could see lighter colored leaves, but they were more localized than Jake Sigg’s description implied. We didn’t feel qualified to speculate about why the leaves were lighter colored so we recruited an arborist to help us figure out what is happening there. We were fortunate to enlist the help of a certified arborist who has been responsible for urban forests on public lands in the Bay Area for several decades. This is what we learned.


Looking through binoculars from our vantage point on Marietta Drive, the arborist said immediately, “Those are epicormic sprouts.” The leaves of epicormic sprouts are distinctively lighter colored than the darker green of mature eucalyptus leaves. They are also a more rounded shape than the long, pointed mature leaves of eucalyptus. This is how Wikipedia describes epicormic sprouts: “Epicormic buds lie dormant beneath the bark, their growth suppressed by hormones from active shoots higher up the plant. Under certain conditions, they develop into active shoots, such as when damage occurs to higher parts of the plant. Or light levels are increased following removal of nearby plants.”

Epicormic sprouts on trees in Glen Canyon Park, June 2014

Epicormic sprouts on trees in Glen Canyon Park, June 2014

The remaining question was why some of the eucalypts, were producing these epicormic sprouts, when most were not. We went down to O’Shaughnessy Blvd to get a closer look, hoping to answer that question. This is what we learned:

  • The understory of non-native shrubs between O’Shaughnessy Boulevard and the trees with epicormic sprouts has been cleared in the past year. We could see the dead brush piled up next to the trees. We had to wonder how people who claim to be concerned about fire hazard could think such huge piles of dead brush were nothing to be concerned about.


Remains of dead non-native brush destroyed along O'Shaughnessy Boulevard, June 2014

Remains of dead non-native brush destroyed along O’Shaughnessy Boulevard, June 2014

  • We could see the stumps of some of the dead brush and we wondered if the stumps had been sprayed with herbicides after they were cut. Pesticide use reports for Glen Canyon indicate that O’Shaughnessy was sprayed several times in the past year, twice with products containing imazapyr. Imazapyr is known to be harmful to trees if sprayed in proximity to their roots. The trees with epicormic sprouts were downhill from the understory shrubs that were destroyed, in the probable direction of water and herbicide flow.
  • We found several trees that had been girdled in the past and are now dead.
Girdled tree in Glen Canyon Park, now dead, June 2014

Girdled tree in Glen Canyon Park, now dead, June 2014


Then we walked into Glen Canyon Park from its southern end. It’s not a pretty sight. Many huge, old eucalypts have been destroyed. When they were destroyed, their stumps were immediately sprayed with herbicide to prevent them from resprouting. The stumps are simultaneously painted with dye so that workers can tell which trees have been sprayed. The dye is no longer visible, but regular visitors took photos of the painted stumps before the dye faded. The spraying of the stumps do not appear on the pesticide use reports of the Recreation and Park Department. We assume that’s because the spraying was done by the sub-contractors who destroyed the trees.

Poisoned and dyed eucalyptus stump, Glen Canyon Park, 2013.  Courtesy San Francisco Forest Alliance

Poisoned and dyed eucalyptus stump, Glen Canyon Park, 2013. Courtesy San Francisco Forest Alliance

The arborist who walked in the forest with us said, “The painting of stumps with RoundUp or Garlon in proximity to trees that are being preserved can kill the neighboring preserved tree. Stumps near living, residual (preserved) trees should not be painted with RoundUp or Garlon if the stumps are within 40’ of mature, blue gums that are slated for preservation.” If the remaining trees are damaged by herbicides, their mature leaves fall and epicormic sprouts will then emerge as the tree recovers.

Some of the stumps of the trees that were destroyed in Glen Canyon Park in 2013.  Taken June 2014

Some of the stumps of the trees that were destroyed in Glen Canyon Park in 2013. Taken June 2014

While the trees were being destroyed in 2013, the Natural Areas Program was eradicating non-native vegetation in the Canyon. They sprayed ivy, blackberry, and valerian with Milestone, which is another herbicide that is known to damage trees if sprayed near their roots. In addition to these official applications of herbicide in this park, there is a long history of unauthorized, illegal herbicide applications by “volunteers,” more appropriately called vandals. We saw a lot of epicormic growth in the Canyon, sprouting from stumps that must be cut back and resprayed with herbicides. It usually takes several retreatments to successfully kill the roots of eucalypts that are destroyed. We also saw epicormic growth from eucalypts that had been severely pruned and were also exposed to a great deal more light because they had lost the shelter of their neighboring trees.

Epicormic growht, Glen Canyon Park, June 2014

Epicormic growth, Glen Canyon Park, June 2014


The trees in Glen Canyon are reacting to the traumas to which they have been subjected: the loss of their neighbors that were either girdled or cut down thereby exposing them to more light and wind, the loss of the shelter of their understory, the application of herbicides known to be harmful to trees. The good news is that there are still plenty of trees in Glen Canyon that have not yet been destroyed and they are in great shape. Here is the view of the tree canopy in Glen Canyon taken from the east side of the park near Turquoise Way. The first picture was taken in December 2012 (before the current round of tree destruction in Glen Canyon Park) and the second picture was taken in May 2014.

Eucalyptus canopy on east side of Glen Canyon Park, taken from Turquoise Way December 2012, before tree destruction began.  Courtesy San Francisco Forest Alliance

Eucalyptus canopy on east side of Glen Canyon Park, taken from Turquoise Way December 2012, before tree destruction began. Courtesy San Francisco Forest Alliance

Same perspective of Glen Canyon tree canopy, taken May 2014.  Courtesy San Francisco Forest Alliance.

Same perspective of Glen Canyon tree canopy, taken May 2014. Courtesy San Francisco Forest Alliance.

These trees are doing just fine because the Natural Areas Program has not yet gone that deeply into the park. But NAP intends to destroy many more trees in Glen Canyon (and elsewhere) when the Environmental Impact Report (EIR) for their management plan (SNRAMP) is finally approved. Then we will see more consequences of the destructive practices of the Natural Areas Program and we will probably hear more bogus explanations for that damage. We expect the EIR to finally be considered for approval at the end of 2014. We will do whatever we can to convince San Francisco’s policy makers that they should approve the “Maintenance Alternative” which would enable NAP to continue to care for the native plant gardens they have created in the past 15 years, but prevent them from expanding further. We hope that our readers will help to accomplish this important task.

*Jake Sigg’s Nature News of June 10, 2014, introduced the theories of Craig Dawson about the health of the Sutro Forest. Mr. Dawson’s speculations are different from Mr. Sigg’s and we will not address them in those post.


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