Why San Francisco’s Natural Areas Are — Unnatural

WHEN I first heard about San Francisco’s Natural Areas Program (SF NAP) some years ago, I was charmed. Over 1000 acres of city-owned land would be left to Nature, more wild and free than the orderly, gardened lawns and playgrounds (which I also appreciated, in a different way). Kudos to the San Francisco Recreation and Parks Department (SFRPD) — which owns the SF NAP — was my reaction.

These would be spaces, I thought, where plants and animals and people could interact naturally. Birds and animals could safely breed in tangled thickets; so could bees and butterflies and other insects. They’d provide enough cover for birds and animals to hide from dogs, cats, hawks, coyotes, raccoons — and people. These spaces would be free of the toxic chemicals used in managing parks. Dogs could be allowed to romp through areas wild enough to tolerate disturbance. The only intervention, I assumed, would be to maintain some degree of safety on trails that animals and people would blaze through these areas.

If like me, you thought that Natural Areas were going to be, well, natural… then like me, you were mistaken.


San Francisco’s “Natural Areas” program is really about is Native Plants, most of which no longer grow in these places naturally. These plants grew (or may have grown) in these 46.9 square miles some 300 years ago. Some are still there. Others, even though common elsewhere, aren’t found in the city any more. Instead, other plants grow there, adding to the biodiversity of the area. According to Peter Kareiva of the Nature Conservancy, there are 25% more species in California than there were before “non-native” plants got here.

What we’re actually getting, then, is Native Plant Gardens, 32 of them. Trying to push these spaces back in time means they must be managed and maintained, because San Francisco now is a different place and a different ecology from the windblown hills and sand-dunes of its pre-colonial past.

What does this management and maintenance imply?


Since there’s a lot of area, and a lot of plants, this means a lot of pesticides. According to the records, Natural Areas had 69 applications of pesticides in 2010, most of them Tier I and Tier II pesticides like Garlon and Roundup. (San Francisco groups permissible pesticides into three tiers, with Tier I being the most dangerous and Tier III the least. The SF NAP hasn’t used Tier III pesticides, they’re all Tier I or II.)

Some — including Native Plant doyen Jake Sigg — have argued that one or two applications in a decade are all that’s needed, and are thus justified. That hasn’t been our experience. Two nearby Native Areas — Twin Peaks and Glen Canyon — have been sprayed many times annually for many years. According to their communications with some concerned neighbors, the SF NAP does not expect to stop.


Some years ago, we ran an article on museum-ification. This is the fate of many of these “natural” areas: they come with more, not fewer, restrictions than gardens and parks. Many of the paths animals and people made naturally, called “social trails” are blocked. There are formal trails, and people must stay on them. They are discouraged from actually interacting with these environments, except as gardening or trail-building volunteers.

Some 86% of the city’s dog-play off-leash areas are in areas controlled by the SF NAP. They plan to close several of these. (This comes on the heels of a plan to ban all dogs from the Golden Gate National Recreation Area.)


Trees are being chopped down.  San Francisco had some wonderful eucalyptus forests, many of them over a century old with a complex habitat and dense understory. Most of these are already gone.

The eucalyptus trees — defined as “invasive trees” despite the evidence that they are not invading anything — are non grata. So too the Monterey pine and the Monterey cypress; those are native to distant Monterey, all the way down the peninsula.  Many trees have already been felled, and many thousands more are doomed. (That’s only counting those over 15 feet tall; the SFNAP counts smaller trees as “saplings” or “seedlings” and cuts them at will.)

The plan, for “urban forests” is to cut down trees until they’re down to a “basal area” of 200-600 feet per acre. This gives an estimated 60-200 trees per acre. (By comparison, Sutro Forest averages 740 trees per acre.)

In addition, the plan calls for removing blackberry thickets, one of the richest and safest habitats for birds and animals. It calls for removing fennel, another tall and dense habitat plant which, just incidentally, is the nursery plant for the native Anise Swallowtail butterfly. It calls for removing vines from the trees, all of which provide some of the complex habitat small birds need.

In fact, it seems to call for removing anything that grows lush and dense and useful to birds and animals. The result wouldn’t be a forest (urban or otherwise);  it would be a garden with some trees in it.


We’d like to clarify:

We are for preservation of existing habitats and ecosystems. We think places like the coastal scrub area on the slope above Laguna Honda Reservoir, (which has not been invaded by the contiguous eucalyptus forest!) deserve protection. This area is, incidentally, owned by the SF Water Department, not the SF Recreation and Parks Department. It’s visible from the road, but is not publicly accessible.

We’re fine with planting scrappy semi-industrialized areas like Heron’s Head Park into Native Plant gardens; that area had a recent win when Clapper Rails nested there and successfully produced chicks.


  • We object to converting parks devoted to other uses into such Native Gardens by imposing numerous restrictions.
  • We object to habitat destruction; birds, insects and animals all use these “non-native’ habitats.
  • We object to felling thousands of trees.
  • Most of all, we object to the use of toxic pesticides in areas that should, naturally, be free of chemicals.


The Draft Environmental Impact Report (DEIR) for San Francisco’s Natural Area’s Program has recently been opened for public comment. It has a “proposed project” — with tree-death and pesticides — as well as four other options. (Our post here, republished from Death of a Million Trees, examines some of the issues. We will be posting more on the DEIR soon.)

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6 Responses to Why San Francisco’s Natural Areas Are — Unnatural

  1. Nancy Wuerfel says:

    This is one of the best articles I have read lately on the SF Natural Areas Program. It tells the tale of this initially well intentioned program to preserve the wild in the city, only to morph into a native-centric program with noticeable contempt for the non-native species.

    All of a sudden the word natural has been co-opted to be mean only native, with an arbitrary date to determine when native ended. The trade winds and birds long ago helped determine what seeds would go where in the world, casting them about with only mother nature to determine what survived. So native is really only a snapshot in time of what was here, when the circumstances favored that life. Circumstances change, and what life will thrive here reflects that change. There must be tolerance for both the new and the old forms of nature. Pesticides are not the answer, nor is gutting our urban forest of non-native trees, nor is the intolerance of what grows naturally in SF now, that is fostered by the ideology of our Park Dept. to control, control, control that which cannot be controlled.


  2. Keith McAllister says:

    The male clapper rail at Heron’s Head was originally spotted and photographed by Richard Drechsler. The bird had previously been trapped and fitted with a radio transmitter at Colma Creek, about 10 kms to the south of Heron’s Head. Colma Creek is the site of a project to eradicate non-native Spartina, which is great clapper rail habitat. So, it appears this clapper rail came to Heron’s Head when it was displaced from its original habitat by a “native plant restoration” project. I don’t see anything “natural” about that.

    • webmaster says:

      Yes, I read about that clapper rail with the radio transmitter hanging around Heron’s Head. But then… there was a female, and there were chicks!
      At first the birders assumed the rails migrated in, but then they determined the chicks were too young, and must have been born there.

      One swallow doesn’t make a summer, and one clapper rail family doesn’t prove a habitat — but surely it’s a good sign?

      (… Though of course not if the main reason they’re there is they got evicted from more desirable habitat in the Colma Creek spartina and are now slumming it at Heron’s Head… I haven’t really researched clapper rails, and will defer to those more knowledgeable.)

  3. milliontrees says:

    The eradication of Spartina alterniflora (smooth cordgrass) on the west coast is doing a great deal of harm. It is native on the East and Gulf Coasts of the US and is considered valuable habitat for the Clapper rail there as well as performing other important ecological functions. The entire West Coast of the US is being sprayed—sometimes from helicopters–with Imazapyr to eradicate this species of Spartina, which has lived here for over 100 years without doing any of the damage of which it is accused by the native plant advocates who demand its eradication. No tests have been conducted on the affect of Imazapyr on any shore bird, including the Clapper rail. This destructive eradication effort cost us $12 million in the past 10 years and is projected to cost us $16.3 million in the next 10 years. Read more about this pointless, destructive effort to eradicate this plant that is native to most of coastal US: http://milliontrees.wordpress.com/2011/06/06/spartina-alterniflora-treasured-on-the-east-coast-reviled-on-the-west-coast/
    I am glad that this family of Clapper rails has found refuge at Heron’s Head, but it is still a shame if man’s need to eradicate their orginal home forced them to move from it.

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