San Franciscans come to the defense of the Sutro Forest

Mount Sutro Forest
Mount Sutro Forest

The San Francisco Chronicle recently published an op-ed by Joe Mascaro about the Sutro Forest (available here). He is a professional ecologist at the Carnegie Institution for Science who studies the ecological functions of forests (his research is described here). He is also a San Franciscan and a fan of the Sutro Forest. He tells us in his op-ed that the Sutro Forest is a unique, “novel” forest that is thriving and that destroying it will increase the risk of wildfire, contrary to the claims of UCSF.

As we approach the March 19, 2013 deadline for submitting public comments on the Draft Environmental Impact Report for UCSF’s proposed plan to destroy 90% of the forest and its understory on 75% of the 61 acres of the Mount Sutro Reserve, we appeal to our readers to take a few minutes in their busy day to write your own comment (see below for details of where to send comments).

About 200 people came to the community meeting at UCSF last night.  Nearly 60 people spoke; the overwhelming majority spoke in opposition to UCSF’s proposed plans to destroy most of the forest.  Everyone spoke respectfully but with passion about what this forest means to the community.  Many spoke about the loss of trees and habitat where similar projects already have been implemented by the Natural Areas Program and the GGNRA.

Over 1,700 people have signed the petition to save the Sutro Forest. If you haven’t signed yet, please do so here. We’re going to quote a few of the astute and well-informed comments that people have written on the petition in the hope that it will inspire you to write your own comment. (Grammatical edits only.)

Comment #1575:

“Among many other reasons not to hurt this forest- it is healing to people in need of healing at the UCSF hospital. The sight of it sustained me through a difficult labor during which I gazed on it for 13 hours. It is a vibrant, healthy, and sacred forest, and the people who love it will not stand by idly and quietly if it is in harms way”

Scientific studies corroborate this patient’s personal experience. Here is a report of these studies.

Comment #1528:

“Please nooooo!!! do not destroy the habitat for hundreds of creatures. WHY the destruction FOR NOTHING!!! I live in the neighborhood and I am sick and tired to see the city and UCSF cutting down trees and not replacing them.. but only with shrubs and small plants”

This is another San Franciscan who has noticed that the UCSF project is one of many in San Francisco which is destroying trees in order to return the landscape to native grassland and scrub.

Comment #1519:

“The reasons for tree removal are inaccurate. The effort is a waste of resources. The forest is healthy and most importantly serves the needs of the population of the city. UC has indicated its willingness to destroy trees for its own gain, but what the people of SF need is the unique ecosystem that provides wind relief, beauty, and comfort. Native plant restoration is a myopic, militant effort that does not take into consideration the needs of the people who live in SF. This is another effort to waste and destroy for misconceived ideals.”

This San Franciscan understands that the Sutro forest is performing important ecological functions.

Comment #1518:

“The trees in Sutro forest provide immense value to the neighborhood and the city in which we live. It is a wind break, it is a visual stimulus, it is a wonderful place to walk, it is home to a large number of hummingbirds, it isolates a busy hospital from the neighborhood and it provides a tremendous source of ground water to neighboring houses. Save the forest.”

This Sutro neighbor understands that the loss of this forest will harm both the neighborhood and the animals that live in the forest.

Comment #1471:

“Destroying 90% of the trees will destroy the forest – its beauty, its Cloud Forest aspect, and its habitat value. The trees, which sequester tons of carbon, will no longer do so, and instead the dead chipped trees will release carbon dioxide into the atmosphere. PLEASE DO NOT REMOVE THESE TREES!”

This commenter understands that the forest is storing carbon which will be released into the atmosphere as carbon dioxide when the trees are destroyed. Carbon dioxide is the predominant greenhouse gas which is causing climate change.

Comment #1277:

“For environmental reasons please do not cut the forest of Mount Sutro. 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).”

This San Franciscan is aware of the pesticides being used by the Recreation and Park Department’s so-called “Natural Areas Program.” UCSF’s proposed project will use pesticides to prevent the resprouting of the trees that they destroy. Pesticides used by native plant “restorations” are described here. She also understands that trees stabilize steep slopes and reduce air pollution.

Here’s what you can do to help save the Sutro Forest:

• Sign the petition to save the forest. Available here.

• Submit a written public comment by 5 PM, March 19, 2013 to UCSF Environmental Coordinator Diane Wong at or mail to UCSF Campus Planning, Box 0286, San Francisco, CA 94143-0286. Include your full name and address.

• Write to the Board of Regents to ask why a public medical institution is engaging in such a controversial, expensive, and environmentally destructive act. Address: Office of the Secretary and Chief of Staff to the Regents,
1111 Franklin St., 12th Floor, Oakland, CA 94607
 Fax: (510) 987-9224

• Subscribe to the website for ongoing information and analysis.

Message to UCSF: Do the math!!

UCSF has sent an email to its neighbors about its plans for the Sutro forest in which they say, “Contrary to rumors being circulated, there is no plan to cut down 30,000 trees in the Mount Sutro Open Space Reserve, and it is unfortunate that this misinformation continues to spread.”

Our response is, Do the math!!

The Draft Environmental Impact Report (DEIR) claims that the thinned forest will have 62 trees per acre. (DEIR Appendix F) The DEIR arrives at this figure by assuming that each tree will occupy a circle with a radius of 15’. In fact, it is not possible to pack circles into another geometric space, whether it is a bigger circle, a rectangle or a square without wasting space. Therefore, this calculation arrives at a bogus answer which is larger than is physically possible.

We have calculated the number of trees remaining in the thinned forest based on the number of squares in an acre that are 30’ X 30’. Such calculations of tree density are found in books regarding arboriculture, which corroborates that we are using a standard calculation used by the timber industry and the DEIR is not. (1)


43560/900 = trees per acre if 30 feet apart (the proposed plan)


43560/3600 = trees per acre if 60 feet apart (the proposed plan)


Total number of trees existing now on 61 acres (according to UCSF)


46 acres X 740 trees/acre = Number of trees existing in project area


44 acres X 48 trees/acre = thinned forest with 30’ spacing


2 acres (Demo Area #4) X 12 trees/acre = thinned forest with 60’ spacing


Existing Trees – Thinned Forest = Trees Removed in Project Area


Trees Removed/Existing Trees in total forest = Percent of Trees Removed in Total Forest

If UCSF wishes to reduce the number of trees that will be removed by the proposed plan, it can do so by reducing the spacing between the trees or the number of acres to be “thinned.” All other numbers used to arrive at an estimated number of tree removals are straight-forward mathematical calculations based on the information provided by UCSF.

UCSF would be wise to read the DEIR for its project, which says, “Under full-implementation or worst-case implementation of management activities under the proposed project, approximately 60% of all existing trees, including large and small trees, could be removed.” UCSF reports that there are 45,000 trees in the Mount Sutro Reserve presently. Sixty-percent of 45,000 is 27,000 trees. We think UCSF’s estimate of tree removals is just a few thousand trees less than what is actually planned. What are we quibbling about?

Once again, we invite UCSF to revise its proposed project to reduce the number of trees that will be removed.

(1) Ecology and Silviculture of Eucalypt Forests, R.G. Florence, CSIRO, Australia

“When Trees Die, People Die”

We often hear people say that a walk in the woods is restorative, but is there any scientific evidence of this relationship between nature and our mental and physical well-being?  Apparently there is.  Here are brief summaries of the many studies that found such a relationship:

  • Patients recovering from gall bladder surgery recovered faster in a room with a natural view than those with a view of a brick wall. (1)
  • Mortality—particularly from cardio-vascular illness—in England was found to be lower amongst those living in “green” environments (after controlling for socio-economic status). (2)
  • In Japan, a positive association was found between survival rate amongst seniors and access to walkable green space. (3)
  • In Holland, those living in greener areas were less likely to be diagnosed with 15 of the 24 health outcomes examined.  These results were strongest for anxiety and depression and for children. (4)
  • In New York City, children living in areas with more street trees were less likely to have asthma. (5)

Intervening variables probably influenced these outcomes.  For example, since trees reduce air pollution by absorbing many of the pollutants in the air, that is a probable explanation for reduced asthma rates where there are more trees. 

The survey of San Francisco’s urban forest conducted by the US Forest Service provides an estimate of how much pollution these trees are now removing from San Francisco’s air.  This survey estimates that there are 669,000 trees in San Francisco.  According to the survey, trees and shrubs in San Francisco are removing 260 tons of pollutants from the air every year:  “Pollution removal was greatest for particulate matter less than 10 microns (PM10), followed by ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), and carbon monoxide (CO).”

The US Forest Service survey also informs us that San Francisco has one of the smallest tree canopies in the country, covering less than 12% of it’s land.  Only Newark, New Jersey has a slightly smaller tree canopy.  We should not be surprised by the small size of our urban forest.  It is an inhospitable climate for trees, which is why there were virtually no native trees in pre-settlement San Francisco.  If we want trees in San Francisco, most will be non-native trees that tolerate the harsh conditions.

The relationship between the death of trees and the death of people

Now there is a new study which found a statistical relationship between the death of millions of trees and increased death rates of people living in the vicinity of those trees:  “The Relationship between Trees and Human Health.”  (6)

White Ash or American Ash.  Creative Commons
White Ash or American Ash. Creative Commons

This study reports that there are 22 species of ash trees native in North America and 7.5 billion ash trees in the country.    In 2002, the emerald ash borer from East Asia was discovered in North America.  It was first seen in Detroit, Michigan and Windsor, Ontario.  Since its arrival, it is said to have killed 100 million ash trees.

The study estimated the correlation between emerald ash borer presence and county-level mortality from 1990 to 2007 in 15 US states while controlling for demographic variables.  The study found an increase in mortality related to cardiovascular and lower-respiratory-tract illness (pneumonia) in counties infested with emerald ash borer.  The relationship was stronger where the infestation of the emerald ash borer was greatest.  The study concluded that “Across the 15 states in the study area, the borer was associated with an additional 6113 deaths related to illness of the lower respiratory system, and 15,080 cardiovascular related deaths.”  

Atlantic magazine was impressed with these findings.  Shortly after the study was published, Atlantic informed their readers in an article entitled, “When Trees Die, People Die.”

Sticking our heads in the sand

Unfortunately, native plant advocates choose to ignore the valuable functions our trees perform in our environment, including how they remove pollutants from the air we breathe.  As we informed our readers recently, native plant advocates in San Francisco have convinced the University of California at San Francisco to destroy over 30,000 trees on their 61 acre open space reserve.  UCSF does not plan to replace most of these trees.

The Draft Environmental Impact Report for this project says nothing about the probable increase in air pollution resulting from this destruction.   In the legally mandated chapter regarding possible impact of the project on air quality, the Draft EIR speaks only of the fossil fuel pollution associated with the use of mechanized equipment needed to destroy these trees. 

The University of California at San Francisco is a medical institution.  It educates medical practitioners.  It provides patient care and it conducts medical research.  We find it deeply ironic that this medical institution would seemingly be unaware of the damage they will do to the health of its neighbors by destroying one of the few forests that exists in San Francisco.  Or worse, they are aware of the damage this project will do to the public’s health, but choose to hide it. 


Here are the things you can do to help us save this beautiful forest:

  • Sign the petition to save the forest.  Available here.
  • Attend and speak at a UCSF hearing about the project:  Monday, February 25, 2013, 7 pm, Millberry Union Conference Center, 500 Parnassus Ave, Golden Gate Room                                                                             
  • Submit a written public comment by 5 PM, March 19, 2013 to UCSF Environmental Coordinator Diane Wong at or mail to UCSF Campus Planning, Box 0286, San Francisco, CA 94143-0286.  Include your full name and address.
  • Write to the Board of Regents to ask why a public medical institution is engaging in such a controversial, expensive, and environmentally destructive act.  Address:   Office of the Secretary and Chief of Staff to the Regents,
1111 Franklin St., 12th Floor, Oakland, CA 94607
  Fax: (510) 987-9224
  • Subscribe to the website for ongoing information and analysis.


(1)    Ulrich, RS, “View through a window may influence recovery from surgery,” Science, 1984:224:420-421

(2)    Mitchell, R, Popham, F, “Effects of exposure to natural environment on health inequalities:  an observational study,” Lancet, 2008, 372:1655-1660

(3)    Takona, R., et. al., “Urban residential environments and senior citizens’ longevity in megacity areas,” J Epidemiol Community Health, 2002, 56(2):9013-918

(4)    Maas, J, et. al., “Morbidity is related to a green living environment,” J Epidemiol Community Health, 2009, 63(12):967-973

(5)    Lovasi, GS,, “Children living in areas with more street trees have lower prevalence of asthma,” J Epidemoil Community Health, 2008, 62(7):647-649

(6)    Donavan, GH, et. al., “The Relationship between Trees and Human Health,” American Journal of Preventive Medicine, 2013, 44(2):139-145