Mount Sutro Forest: 30,000 trees to be cut down

I guess by now, most people in Forest Knolls have some idea that big changes are planned for the forest behind our neighborhood. Essentially, UCSF plans to cut down over 90% of the trees on three-fourths of the forest, and remove 90% of the undergrowth. The only bit to be spared would be 15 acres or so of steep hillside on the western side, above Inner Sunset.

UCSF is having a hearing on Feb 25th at 7 p.m. (They sent around postcards about this.) It’s at the Milberry Union, 500 Parnassus, CA 94134. If you can attend, please do, and speak up. If there’s a big turnout, they may limit each speaker to 2-3 minutes, so have your points ready.



We’re concerned that it would ruin the forest’s character, and Forest Knolls would face consequences like:

  • Changes in wind patterns (the tall, closely-spaced trees are an impressive windbreak);
  • Risk of landslides (the old forest has intertwined and intergrafted roots that function like a living geo-textile and hold up the mountain, while the exposed rock on Twin Peaks has a rock-slide every year or two);
  • Pesticide drift into our neighborhood, affecting us and our pets (right now, Sutro Forest may be the only pesticide-free wildland in the city; the Natural Areas Program, which controls most of it, uses pesticides regularly)
  • Increased noise (the vegetation – the leaves of the trees and the shrubs in the understory are like soft fabrics absorbing sound)
  • Changes in air quality (trees reduce pollution by trapping particle on their leaves until they’re washed down)
  • Environmental impact – (eucalyptus is the best tree species for sequestering carbon because it grows fast, large, is long-lived, and has dense wood; but felled and mulched trees release this carbon right back into the atmosphere).

The implementation would be in two phases; it would start with the “demonstration” plots, around 7.5 acres in Phase I. The largest of these, #1 in the map is a 3-acre strip directly above Forest Knolls. Most of the trees would be cut, and tarping or pesticides used to prevent resprouting. Later, UCSF would extend the same plan to the entire forest (except for the 15 acre piece mentioned).


1. Write to the Board of Regents, who will ultimately decide whether to approve this project. Ask them why they are undertaking this controversial, expensive, and ecologically destructive project, and gutting a San Francisco treasure to achieve a “parklike” environment. You can contact the Regents at their website HERE. (Their email address is: )

2. Write a comment on the Draft Environmental Impact Report. The report is HERE. (It will take some time to load.) The person to write to is Diane Wong, and her email address is at:

3. Sign a petition to ask the Regents not to approve this plan. (And see how many signatures we have already!)

Copy (2) of sign button


The article below has been copied with some modifications from, which is a website set up to inform people about Mount Sutro Cloud Forest and to defend it.

Mount Sutro Forest has approximately 45,000 trees in the 61 acres belonging to University of California, San Francisco (UCSF), and designated as an open space reserve. This dense forest, with an estimated 740 trees per acre, a sub-canopy of acacia, an understory of blackberry and nearly a hundred other plant species, is functionally a cloud forest. All summer long, it gets its moisture from the fog, and the dense greenery holds it in. Where it isn’t disturbed, it’s a lush beautiful forest, providing habitat for birds and animals, and a wonderful sense of seclusion from urban sounds and sights.

(CLICK HERE to see the Google Map of the forest.)

Mount sutro forest greenery


UCSF now has published a Draft Environmental Impact Report (DEIR) on a project to remove over 90% of the trees on three-quarters of the area. Only 15 acres – on the steep western edge of the forest – will remain as they are. Tree-felling could start as early as Fall 2013.

[Edited to Add:

Here is the PDF of the DEIR. Mount_Sutro_EIR_1-16-13_with_Appendices

Comments were due on March 4th, but because of the length and complexity of the document, neighbors asked for, and got, an extension. Comments are now due before March 19, 2013.]

On most of the forest (44 acres), UCSF plans to cut down trees to achieve a spacing of 30 feet between trees – the width of a small road – and mow down nearly all the understory habitat. On another 2 acres, they will space the trees 60 feet apart. The stumps of the trees will be covered in black plastic, or else poisoned with Garlon to prevent re-sprouting. Eventually, this will kill the roots, which will start to decay. We’ll address some of these issues in more detail in later posts.

Right now, we want to talk about the number of trees that will be felled. A spacing of 30 feet between trees gives about 50-60 trees per acre. A spacing of 60 feet gives 12-15 trees per acre.

(The easiest way to think about it is that each tree occupies a 30 x 30 foot space, or 900 sq ft. An acre is 43,560 sq ft, so this would give 48.4 trees to an acre. The DEIR calculates it as 61 trees per acre, assuming each tree occupies a circle that’s 30 feet in diameter, 707 sq ft. But there’s no way to arrange circles without wasted spaces between them, so this doesn’t exactly work.)

So on 44 acres, they will retain maybe 50 trees per acre (or maybe fewer). On two more acres with a 60-ft spacing, they will retain 12-15 trees per acre. All the rest will be cut down. Even using the DEIR’s overly optimistic calculation, they will be felling some 31,000 trees. Our calculations are closer to 32,000. Either way, it’s a huge number.

That means that in the 46 acres where UCSF will be felling trees, they will remove more than 90% of the standing trees.

The DEIR says that they will start by cutting down trees that are dead or dying. Aside from their value as habitat (some birds like woodpeckers depend on them), there are not all that many of them in Sutro Forest, which despite everything that has been claimed to to opposite, is a thriving forest. Next in line will be trees with diameters under 12 inches, or roughly 3 feet around – as thick as an adult’s waist. Then they’ll start on the larger trees. Since it’s going to be 90% of the trees, we expect thousands of large trees to be removed.


However, this is not all. We expect further tree losses for four reasons:

  • Wind throw. Since these trees have grown up in a dense forest where they shelter each other, removing 90% of the trees exposes the remaining 10% to winds to which they’re not adapted. This can be expected to knock down a significant number of the trees not felled. Since the Plan only calls for monitoring the trees and felling any that seem vulnerable to wind-throw, it’s unlikely any vulnerable trees will be saved.
  • Physical damage. Damage done to the remaining trees in the process of removing the ones they intend to fell. With such large-scale felling, damage to the other trees is inevitable, from machinery, erosion, and falling timbers.
  • Something like AvatarPesticide damage. This forest has an intertwined, intergrafted root system. When pesticides are used to prevent resprouting on tree-stumps and cut shrubs and ivy, it is quite possible for it to enter the root system and damage remaining trees.
  • Loss of support. Compounding the effects of the wind-throw, the remaining trees will suffer from a lack of support as the root network dies with 90% of the trees being removed. This could destabilize them, and make them more likely to fail.

What remains will be a seriously weakened forest with a greater risk of failure and tree-loss, not the healthier forest that the DEIR claims. It is likely that the long-term impact of the Project will be the elimination of the forest altogether, and instead will be something like Tank Hill or Twin Peaks plus a few trees.


The project is to be implemented in two phases. In the first phase, trees will be felled and the understory removed in four “demonstration areas” totaling 7.5 acres. They are shown on the map below in yellow, as areas #1-#4. [The 3-acre area #1 is right above Forest Knolls.]  One of these, #4 “East Bowl”, is the two-acre area slated to have only 12-15 trees per acre.

hand-drawn map not to scale

One area (#5 on the map) is supposed to be a “hands off” area to demonstrate the untouched forest. However, a trail has already been punched through it in November 2011, even before the DEIR had been published.

During this phase, they would experiment with the 3 acres on the South Ridge, just above the Forest Knolls neighborhood. On 1 acre, they would use tarping to prevent regrowth of felled trees; on 1 acre, they would use pesticides, particularly Garlon; and 1 acre they would trim off sprouts by hand. They could also use pesticides on the understory “consistent with city standards” – presumably those of the Natural Areas Program (See article on NAP’s Pesticide Use.)

In the Second Phase, the plan would be extended to the remaining forest, with the proviso that not more than a quarter of the forest would be “thinned” at “any given time.”

Why it’s called “Forest” Knolls – and described as “Marin-like”
Digitally-altered image – Forest Knolls without Sutro Forest. Maybe there’ll still be some trees left after this Plan is implemented.

5 thoughts on “Mount Sutro Forest: 30,000 trees to be cut down”

  1. No forest in Forest Knolls? Toxic chemicals in our yards and streets?
    People and tour buses parking on our streets 24 hours a day to go up to the “new twin peaks”?
    New crappy 34-unit development clogging the streets with 100 more cars?
    Bus line eliminated?

    Does anyone else see our property values plummeting? Our neighborhood changed beyond recognition? Anything else to wreck our neighborhood possible? Everyone brokering the above propositions want to just ruin what is and move on – they don’t live here.

    All of these projects must be protested and at least downsized.

    1. What is the reason for this draconian culling? Why 900 sqft per tree? Why not a more reasonable 100 sq ft/tree? Anyone have any ideas why this is so draconian?

      [Webmaster: To be frank, we don’t completely understand why they don’t allow the forest to ‘self-thin’ – the most adaptive form of forest-thinning, so the spacing becomes what is appropriate to that particular terrain. Possibly because they wish to grown sun-loving native plants where the forest is now.]

  2. Very sad. There is most certainly a lot of money driving this, no respect for the tiny bit of wild left here. I am going to protest the ruining of the forest. Please get involved.

  3. I absolutey agree with the plans of the university to restore Mount Sutro. I do live in the neighborhood. My family has lived in the neighborhood since it was built after WW2, and have lived in San Francisco for what is now our 6th generation. We were here before Sutro Forest was planted, and we will be here long after the restoration will bare it’s fruits.

    [Webmaster: Thanks for your comments, and of course individual preferences can differ. The 125-year old Sutro Forest that was planted in the late 1800s. It can never be “restored” to what it was. Even Twin Peaks, which is probably the nearest comparison, has a mix of non-native plants growing naturally, and native plants being introduced there. Also lots of pesticide use.]

    I am far less concerned with property values (considering that we intend on staying in the neighborhood; hopefully for centuries to come) and have no intention on selling our home and moving to some other state were we have no knowledge of the indigenous flora and fauna. I inharetted from my family the knowledge of the names of the plants that are intended to replace the Eucalyptus groves. I know that what is proposed comes from an understanding of the local biology and science, not greed or some alterer motive. This project comes at a price, a sacrafice to nature. It isn’t as if the removed trees can be sold as lumber; they can not.

    [Webmaster: There’s no plan to sell the lumber. It’s going to be mulched and left on the mountain, releasing carbon as it decays. Why not share the names of some of the plants that are intended to replace the Eucalyptus forest?]

    I beleive the spirit of the author is genuine and with good intention, but doesn’t from education, rather it comes for sentimentality and an emotional motivation as apposed to a real understanding of the local enviornment, the local community, and the natural sciences.

    [Webmaster: I would argue that I do in fact understand the local environment, the local community, and the natural sciences. I am not biased in favor of (or against) native plants; I recognize that San Francisco had no real native trees, and I believe that trees have tremendous eco-system benefits. They sequester carbon – and eucalyptus is one of the best trees in the world at doing that. They reduce air pollution by trapping particles on their leaves. This forest, with its intergrafted root system, stabilizes the mountain; Twin Peaks sees rockslides nearly every winter, and so does Forest Knolls from time to time when its steeper hillsides are bared. Right now, the forest is pesticide-free; if this project goes through, it might not be. It’s also an important habitat for forest birds, both resident and migratory. The flowers provide food for honeybees at times when nothing else blooms. If you want more information, try – there’s articles on every aspect, often with links to scientific articles or references to papers.]

    For example, did you all know that native bird species are threatened by the Euctalyptus? Their short beaks and nostrals get clogged in resins and in turn the birds sufocate when they eat from the sweet bloosoms of the trees. It is not uncommon to find dead birds under the Eucalyptus canopy.

    [Webmaster: Actually, that’s a myth. It is uncommon to find dead birds under the eucalyptus canopy, no one has reported any. There’s an article about it HERE: Another Eucalyptus Myth: Bird Death (via Audubon)]

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