2014 Wrap-Up and 2015 Preview

Our last post of 2014 will summarize wins and losses in our effort to save our urban forest and preview the local issues that remain unresolved.  2014 has been a year of many accomplishments, but there have been disappointments as well.

2014 Accomplishments

Good news always comes first!  We are most grateful for the hard work of the San Francisco team with whom we collaborate.  After herculean effort, they completed most of the presentations to the members of the Board of Supervisors about the forthcoming approval process for the Environmental Impact Review of San Francisco’s Natural Areas Program, which has been in the works for eight years…and still counting.  We are advocating for the Planning Commission and the Board of Supervisors to approve the “environmentally superior” Maintenance Alternative, which would enable the Natural Areas Program to maintain the native gardens they have created in the past 15 years, but would prohibit expansion of those gardens.  The Maintenance Alternative could save about 18,500 healthy non-native trees from being needlessly destroyed and significantly decrease herbicide use in our parks.

Because native plant advocates have succeeded in convincing many politicians that their projects are “science-based,” the San Francisco team was particularly glad to have three lectures at the Commonwealth Club by academic scientists, which challenged the unfounded assumptions of the native plant ideology:

These presentations were very well attended, including by native plant advocates.  They were entirely successful from our standpoint, though they seem to have had little influence on the opinions of native plant advocates, many of whom seemed not to understand the scientific information being presented.

The dense and healthy Sutro Forest
The dense and healthy Sutro Forest

 In March 2014, UCSF announced that they have put their plans to destroy most trees on Mount Sutro on indefinite hold.  This decision was made in response to the public’s overwhelming opposition to these plans during the public comment period for the Draft Environmental Impact Report in March 2013.  However, UCSF has destroyed about 1,200 trees during the past 18 months which they claimed would mitigate immediate hazards.  UCSF has also made a commitment to not using herbicides on Mount Sutro.  UCSF has provided no estimated time frame for announcing a new plan. Please visit Save Mount Sutro Forest for a more detailed description of that announcement.  We consider this a “holding pattern” because we know that UCSF is under constant pressure from those who want the Sutro Forest to be destroyed.

Invasion biology is being revised by academic scientists who inform us that empirical studies do not support the hypotheses of invasion biology.  Here are a few of the highlights from the scientific literature:

Likewise, mainstream media has become more even-handed in its coverage of invasion biology and native plant “restorations.”  Here are a few specific examples:

2014 Disappointments

The publication of the final Environmental Impact Statement for FEMA projects in the East Bay Hills was the biggest disappointment of 2014.  There were over 13,000 public comments on the draft and they were overwhelmingly opposed to the proposed projects.  Yet, the projects are fundamentally unchanged by the final EIS, which will be officially approved by a “Decision of Record” on January 5, 2015.  We are grateful to the Hills Conservation Network for their continuing opposition to these projects and we urge our readers to support their effort.

Some of the hundreds of trees destroyed by UC Berkeley in August 2014
Some of the hundreds of trees destroyed by UC Berkeley in August 2014

We were outraged by UC Berkeley’s destruction of hundreds of non-native trees on their property in August 2014, prior to the approval of these FEMA grants.  And we were also appalled by the letters sent to FEMA by elected officials in the East Bay in July, demanding that funding be immediately released and approved for use to destroy all non-native trees on their properties.

In San Francisco, our biggest disappointment of 2014 was the approval of the revised Recreation and Open Space Element (ROSE) of the city’s General Plan, which has committed the city to managing all open space as “natural areas.”  The ROSE defines “natural areas” so broadly that it includes not only areas that currently contain existing remnants of SF’s pre-settlement habitat, but also areas that could support native plants if they were planted there, or, in other words, nearly all open space in SF, including people’s back yards. This policy commits the city to managing nearly ALL open space in San Francisco, including that in private hands, the same way as the Natural Areas Program manages its lands.  As disappointing as that decision was, it was also instrumental in producing one of the biggest accomplishments of 2014.  We were successful in convincing the State of California to decline to fund a grant application which would have implemented the plans to convert all open space in San Francisco to native plant gardens.  That so-called “biodiversity program” continues, but is presumably handicapped by the loss of that fund source.

Looking forward in 2015

In the past six months, the San Francisco team has devoted a great deal of time and effort to influencing the city’s Urban Forestry Council (UFC) to adopt “best management practices” that would discourage the destruction of healthy trees.  The UFC has hosted a “listening series” of presentations by those who advocate for the eradication of eucalyptus forests as well as those who are opposed to that destruction.  Native plant advocates have introduced new justifications for destroying the eucalyptus forests:

  • They claim that eucalyptus forests are dying of disease, drought, old-age, etc. We have sought the advice of many professional arborists and academic ecologists who assure us these claims are inaccurate.
  • They claim that the health of the eucalyptus forests would be improved by radical “thinning.” The scientific literature informs us that mature forests do not benefit from thinning because mature trees are unable to respond positively to increased light and wind.  Thinning is only beneficial to young trees and even then, the disturbance can damage the trees that remain.  Radical thinning of the mature eucalyptus forest is likely to destroy the few trees that will remain.

The UFC has completed its listening series and will probably reach its conclusions in 2015.  Based on the meetings we have attended and the conversations we have had with members of the UFC, we are not hopeful about the outcome.  They seem to be sympathetic to the demands of those who want the non-native forests of San Francisco to be destroyed.   In that case, their “best management practices” could be specifically supportive of the plans of the Natural Areas Program to destroy 18,500 trees in San Francisco and Pacifica.  If you would like to express your opinion to the Urban Forestry Council, you can write to them here:  SFUrbanForestCouncil@sfgov.org.

We also expect the final Environmental Impact Report for San Francisco’s Natural Areas Program to be published in 2015.  We will make our best effort to convince the Planning Commission and the Board of Supervisors to approve the Maintenance Alternative.  However, we should all understand that the lack of an approved EIR does not seem to have prevented the Natural Areas Program from destroying trees whenever and wherever they wish.  Many trees (perhaps a few hundred) in Glen Canyon Park, McLaren Park and Pine Lake in Stern Grove have been destroyed without an approved Environmental Impact Report.  In other words, the Environmental Impact Report seems increasingly irrelevant to what is actually being done in our parks.

A few of the trees destroyed recently in Pine Lake "natural area"
A few of the trees destroyed recently in Pine Lake “natural area”

The President of the San Francisco Forest Alliance, Carolyn Johnston, ran for a seat on the Executive Committee of the San Francisco Group of the Sierra Club.  If you follow the controversy about the Natural Areas Program in San Francisco, you may be aware of the Sierra Club’s role in supporting the nativist agenda (HERE is an example of their role).  Carolyn lost by only 6 votes.  If everyone in San Francisco who abandoned the Sierra Club because of its support for turning urban parks into native plant gardens, would renew their membership, maybe we could win a seat next year.  We are grateful to Carolyn for running.

We also expect a final response from the California Invasive Plant Council to our request that Blue Gum eucalyptus be removed from its list of “invasive” plants.

In summary

Science is rapidly revising the unfounded assumptions of invasion biology and climate change is making the concept of “native” meaningless.  But these realities are having no apparent influence on public policy, which seems to be immune to such facts.  Popular culture always lags behind science.

Million Trees is changing its emphasis in response to these political realities.  In 2015, we will focus on the science that is revising invasion biology because that’s where progress is being made.  This type of research is both difficult and time-consuming for us because we do the background reading to understand the scientific literature and produce accurate reports that are accessible to the layperson.  We therefore expect to publish new articles only once each month in 2015.  As always, we invite guest authors to step forward with news of new developments that we are not covering.

Thank you for your readership in 2014 and for any help you gave us in 2014 on our various initiatives.  We wish you all a Happy New Year in 2015.

“Hey, You Calling Me an Invasive Species?”

The New York Times published an op-ed by a member of their Editorial Board on Sunday, September 8, 2013, entitled, “Hey, You Calling Me an Invasive Species?”  It is a spirited defense of non-native plants.  Surely this is an indication that our challenge of the native plant movement is now mainstream.  We will touch on a few of the op-ed’s main themes, but we urge you to read the op-ed here.

Mount Sutro Forest is threatened with destruction because it is not native.  Courtesy Save Sutro Forest.
Mount Sutro Forest is threatened with destruction because it is not native. Courtesy Save Sutro Forest.

Using the eucalyptus forest on Mount Sutro as an example. the Editorial Board member, Verlyn Klinkenborg, makes the point that many of our non-native plants have been here for hundreds of years.  Since they have been here for several generations of humans, most of us no longer consider them foreigners: 

“But the trees on Mount Sutro have been there within the memory of every living San Franciscan, and to the generations who have grown up within view of them, it seems almost perverse to insist that they are alien.” 

The distinction between native and non-native depends upon an arbitrarily selected “snapshot” of our landscape taken just prior to the arrival of Europeans.  On the East Coast, that’s the early 16th Century.  In the San Francisco Bay Area, that’s 1769, when Portola’s men saw the San Francisco Bay.  The Times op-ed reminds us that this particular snapshot is becoming more and more irrelevant because of climate change.  If plants and animals don’t move in response to that change they will not survive: 

“As plants and their pests adjust their range under the influence of global warming, what becomes of the distinction between native and nonnative?  To any individual species, it doesn’t matter whether it’s native or not.  The only thing that matters is whether its habitat is suitable.”

Finally, Mr. Klinkenborg takes us on a verbal tour of Central Park to make the point that our open spaces are a mélange of native and non-native plants and animals.  We can see with our eyes that they are living in harmony and to pluck only those considered non-native from their midst would be needlessly destructive and disruptive of the peace that reigns there:

“Nature in Central Park can’t be divided into native or nonnative species, and neither can it be on Mount Sutro.  The eucalyptus trees that grow there may be naturalized rather than native, but try telling that to all the other creatures that live in those woods or the people who hike there.”

Mr. Klinkenborg’s final sentence reminds us that we are the original “invaders:” 

And when it comes to the distinction between native and nonnative, we always leave one species out:  call us what you will—native, naturalized, alien or invasive.”

The absurdity of nativism is becoming more and more evident.  Our objections to its destructive consequences will eventually be heard.  It’s just a matter of time.

Why does UCSF want to destroy the Sutro forest?

The short answer to that question is “I don’t know.”  However, since many of the over 1,200 signers of the petition to University of California San Francisco (UCSF) to save the forest have asked this question, it seems that they deserve some answer.  So, in this post, we will tell you the reasons that UCSF has given for its plans to destroy the forest.

UCSF makes two erroneous claims about the Sutro forest which it uses to justify its destruction.  They claim that the forest is unhealthy and that destroying most of the forest will benefit the few trees that remain.  They also claim that the forest is very flammable and that destroying most of the forest will make it less flammable.  This is our response to these claims.

The Sutro Forest is not unhealthy

Mount Sutro Forest
Mount Sutro Forest

The Save Sutro website recently posted the professional opinion of two arborists who evaluated the Sutro forest and pronounced it healthy.  We recommend that article as a starting point for anyone who wishes to be reassured on this important point.

The Draft Environmental Impact Report for UCSF’s planned project claims that the forest is old and dying.  If we don’t beat it to the punch and kill it first, it will soon die without our help.  An analogy comes to mind: “We had to destroy the village to save it,” which was the explanation given for the destruction of a village during the Vietnam War.  It didn’t make sense then and it doesn’t make sense now.

The fact is, the Sutro forest is young and in the prime of its life.  Eighty-two percent of the forest is blue gum eucalyptus.  Blue gums live in Australia from 200 to 500 years. (1)  They live toward the longer end of that range in milder climates such as the San Francisco Bay Area.  The blue gum eucalypts were planted on Mount Sutro in the 1880s.  It is still a young forest.

Another indication that the forest is young is that the individual trees are small by blue gum standards.  The study plots used by the Draft Environmental Impact Report (DEIR) to calculate how much carbon is stored in the trees found that 77% of the trunks of the trees are 5 inches in diameter at breast height or less (if the study plots are representative of the entire forest, which is questionable).  It also says that this species of eucalyptus grows very fast and that its trunk is 9 inches in diameter after only three years of growth.  In other words, the DEIR claims that the trees are old and no longer growing, yet it says that most of the trees are very small and it intends to destroy the small trees, not the big ones.  This is just one of many contradictions that we find in the DEIR. 

There is little risk of wildfire in the Sutro Forest

One of the most powerful rhetorical tools used by native plant advocates to justify the destruction of our urban forest and motivate the public to pay for these expensive projects is the fear of fire.  UCSF uses this strategy as well.  Frankly, we doubt that UCSF believes it themselves because they applied for a Federal Emergency Management Agency (FEMA) grant to pay for this project in 2008. FEMA informed UCSF that there is little risk of wildfire on Mount Sutro. UCSF withdrew its grant application rather than answer FEMA’s questions.

FEMA asked UCSF to supply scientific evidence that the project would reduce fire risk despite the fact that the project would reduce fog condensation from the tall trees which moistens the forest floor, making ignition unlikely.  FEMA also asked for scientific evidence that a wind driven wildfire would not be more likely after the destruction of the wind break provided by the forest.  UCSF chose to withdraw its grant application, presumably because they could not answer those questions. 

In 2010, UCSF applied for another fire hazard mitigation grant from the California Fire Safe Council.  The Council has funded 150 such grants in California, but they denied UCSF’s application.  That suggests that the California Fire Safe Council shares FEMA’s opinion.

You might ask, where is UCSF getting the money to pay for this project?  We don’t know, but we consider that a legitimate and important question given that UCSF is a publicly funded enterprise. 

UCSF may not be able to answer FEMA’s questions, but we can, using specific scientific studies.   In 1987, 20,000 hectares burned in a wildfire in the Shasta-Trinity National Forest.  The effects of that fire on the forest were studied by Weatherspoon and Skinner of the USDA Forest Service.  They reported the results of their study in Forest Science. (2)  They found the least amount of fire damage in those sections of the forest that had not been thinned or clear-cut.  In other words, the more trees there were, the less damage was done by the fire.  They explained that finding:

“The occurrence of lower Fire Damage Classes in uncut stands [of trees] probably is attributable largely to the absence of activity fuels [e.g., grasses] and to the relatively closed canopy, which reduces insolation [exposure to the sun], wind movement near the surface, and associated drying of fuels.  Conversely, opening the stand by partial cutting adds fuels and creates a microclimate conducive to increased fire intensities.”

In other words the denser the forest,

  • The less wind on the forest floor, thereby slowing the spread of fire
  • The more shade on the forest floor.
    • The less flammable vegetation on the forest floor
    • The more moist the forest floor

All of these factors combine to reduce fire hazard in dense forest. Likewise, in a study of fire behavior in eucalyptus forest in Australia, based on a series of experimental controlled burns, wind speed and fire spread were significantly reduced on the forest floor.(3)   Thinning the forest will not reduce fire hazard.  In fact, it will increase fire hazard.

Jon E. Keeley of the USGS is a world-renowned expert on the fire ecology of California.  We have read his recently published book (Fire in Mediterranean Ecosystems:  Ecology, Evolution and Management, Cambridge University Press, 2011) and many of his articles.  Anyone with a sincere interest in wildfire hazards in California would be wise to read these publications.  Reference to Keeley’s work is conspicuously absent from the Draft EIR. 

Keeley’s most recently published study  of specific wildfires in the Wildland-Urban-Interface (WUI) of California is most relevant to consideration of wildfire hazard in the Sutro Reserve.  (4) The authors studied the property damage resulting from specific wildfires in California “…and identified the main contributors to property loss.”  Keeley and his colleagues found that steep slopes in canyons that create wind corridors were the best predictors of fire damage and that grassy fuels were more likely to spread the fire than woody fuels.  Applying these observations to Mount Sutro, its topography is the biggest factor in the potential for wildfire and substituting the forest with grassland and scrub will result in more dangerous fuel loads. 

Scripps Ranch fire, San Diego, 2003.  All the homes burned, but the eucalypts that surrounded them did not catch fire.  New York Times
Scripps Ranch fire, San Diego, 2003. All the homes burned, but the eucalypts that surrounded them did not catch fire.

UCSF and native plant advocates make allegations about the flammability of eucalypts by misrepresenting actual wildfires in the Bay Area.  These allegations are addressed elsewhere on Million Trees, which we invite you to visit if you have more questions:

All pain, no gain

So, if the forest is healthy and destroying it does not reduce fire hazards, how can UCSF justify all the damage this project will do to the environment:

    • Releasing thousands of tons of carbon dioxide into the atmosphere that are stored in the trees and significantly reducing the ability of the forest to sequester carbon in the future, thereby contributing to climate change.
    • Increasing air pollution by reducing the ability of the forest to absorb air pollutants.
    • Using pesticides to destroy the vegetation in the understory and preventing the trees that are destroyed from resprouting.
    • Destroying the food and cover of the birds and animals that live in the forest.
    • Eliminating the noise and wind barrier that protects UCSF’s neighbors
    • Increasing the risk of wildfire by eliminating the windbreak, reducing the moisture in the forest, and littering the forest with the dead logs and wood chips of the trees that are destroyed.

We can’t imagine why UCSF wants to destroy its forest.  We understand why native plant advocates support this project because they are making the same demands all over the Bay Area.  They want land managers to destroy non-native trees because they believe that destroying them will result in the return of native plants.  The UCSF project makes no commitment to plant native plants after the forest is destroyed, with the exception of a few small areas and then only if “money is available.”  Native plants will not magically emerge from the wood-chip tomb on the forest floor.  Is it possible that UCSF shares the fantasy of native plant advocates that this destructive project will result in a landscape of grassland and chaparral which is the native landscape on Mount Sutro?  Surely a scientific institution of such distinction knows better.  Or it should. 

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 EIR@planning.ucsf.edu 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 SaveSutro.com for ongoing information and analysis.


(1)     Eucalypt ecology: Individuals to ecosystems, by Jann Elizabeth Williams, John Woinarski ,Cambridge University Press, 1997

(2)     Weatherspoon, C.P. and Skinner, C.N., “An Assessment of Factors Associated with Damage to Tree Crowns from the 1987 Wildfires in Northern California,” Forest Science, Vol. 41, No 3, pages 430-453

(3)     Gould, J.S., et. al., Project Vesta:  Fire in Dry Eucalyptus Forests, Commonwealth Scientific and Industrial Research Organisation and Department of Environment and Conservation, Western Australia, November 2007

(4)     Alexandra Syphard, Jon E. Keeley, et. al., “Housing Arrangement and Location Determine the Likelihood of Housing Loss Due to Wildire.” PLOS ONE, March 18, 2012

“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 EIR@planning.ucsf.edu 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 SaveSutro.com 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, et.al., “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


Biodiversity: Another eucalyptus myth busted

Native plant advocates use many arguments to justify the destruction of non-native species and we have debunked many of those arguments here on Million Trees.  Now we will examine the claim that non-native species must be destroyed because their mere existence reduces biodiversity by out-competing native plants and animals.  Because eucalyptus trees are one of the primary targets for eradication, we will focus on the specific claim that the eucalyptus forest is a “biological desert.”   We are frequently told that “nothing grows” under the eucalypts and that they are not providing food or habitat to insects, birds, and other animals.

Professor Dov Sax (Brown University) tested these claims while a student at UC Berkeley.  He studied the eucalyptus forest in Berkeley, California, and compared it to native oak-bay woodland.  He found little difference in the species frequency and diversity in these two types of forest.
Eucalyptus forest and its thriving understory, Mt. Sutro, June 2009


He studied six forests of about 1 hectare each, three of eucalypts and three of native oaks and bays.  The sites were not contiguous, but were selected so that they were of similar elevation, slope, slope orientation, and type of adjacent vegetation.  He conducted inventories of species in spring and autumn.  He counted the number of:
  • Species of plants in the understory
  • Species of invertebrates (insects) in samples of equal size and depth of the leaf litter
  • Species of amphibians
  • Species of birds
  • Species of rodents

 He reported his findings in Global Ecology and Biogeography*:

“Species richness was nearly identical for understory plants, leaf-litter invertebrates, amphibians and birds; only rodents had significantly fewer species in eucalypt sites.  Species diversity patterns…were qualitatively identical to those for species richness, except for leaf-litter invertebrates, which were significantly more diverse in eucalypt sites during the spring.” 

Professor Sax also surveyed the literature comparing biodiversity in native vs non-native forest in his article.  He reports similar findings for comparisons between non-native forests and local native forests all over the world:

  • In Spain, species of invertebrates found in the leaf-litter of eucalyptus plantations were found to be similar to those found in native forests, while species richness of understory plants was found to be greater in the native forests.
  • In Ethiopia the richness of understory species was found to be as great in eucalyptus plantations as in the native forest.
  • In the Mexican state of Michoacán, species richness and abundance of birds were found to be similar in eucalyptus and native forests.
  • In Australia species richness of mammals and of soil microarthropods were found to be similar in native forests and in non-native forests of pine.

The only caveat to these general findings is that fewer species were found in new plantations of non-natives less than 5 years old.  This helps to illustrate a general principle that is often ignored by native plant advocates.  That is, that nature and its inhabitants are capable of changing and adapting to changed conditions.  In the case of non-native forests in the San Francisco Bay Area, they have existed here for over 100 years.  The plants and animals in our forests have “learned” to live in them long ago. 

Anise Swallowtail, Mt. Sutro, March 2010

We recommend that you visit the SaveSutro website   for a description of the richness of the non-native forest that thrives on Mount Sutro in San Francisco.  It is the perfect illustration of these scientific principles.  We can discuss scientific principles in the abstract, but there is no substitute for a walk in the forest to confirm with our eyes what science tells us.

*Dov Sax, “Equal diversity in disparate species assemblages:  a comparison of native and exotic woodlands in California,” Global Ecology and Biogeography, 11, 49-52, 2002.



FEMA sees through the smokescreen

The Federal Emergency Management Agency (FEMA) has seen through the smokescreen that native plant advocates have created as a pretext for destroying non-native trees in the San Francisco Bay Area.  Native plant advocates claim that destroying non-native trees will reduce fire hazard.  As taxpayers, and as fans of all trees, we commend FEMA for preserving their limited resources for legitimate disaster mitigation.
In February 2010, UC San Francisco (UCSF) announced that it had withdrawn its application for FEMA funding to destroy most of the eucalypts on 14 acres of the Sutro Forest.  When making that announcement UCSF explained that FEMA would require a comprehensive Environmental Impact Study before the grant would be awarded which would result in a two-year delay in the implementation of the project.  UCSF preferred to pay for the project with its own funds rather than delay it during the environmental review.  Therefore, UCSF withdrew its application for FEMA funding.  Since then, UCSF has proceeded with its plans, expanding them to 40 acres, and continues to claim that there is extreme fire hazard in the Sutro Forest which it claims will be mitigated by the project.

Sutro Forest on a typically foggy day in late summer. Courtesy SaveSutro.wordpress.com

We now know there is more to the story than is revealed by UCSF’s announcement.  The neighbors of the Sutro Forest who have been trying to save their forest for over a year, have since obtained correspondence from FEMA regarding UCSF’s grant applications through a public records request.    The correspondence with FEMA indicates that:

  • UCSF misrepresented and exaggerated the fire hazard on Mount Sutro by rating it as “extreme.”  FEMA confirmed with the state’s fire authority that fire hazard on Mount Sutro is moderate, CAL Fire’s lowest rating of fire hazard.  (1) 
  • FEMA asked UCSF to explain how fire hazard would be reduced by eliminating most of the existing forest, given that: (2)
    • Reducing moisture on the forest floor by eliminating the tall trees that condense the fog from the air could increase the potential for ignition, and
    • Eliminating the windbreak that the tall trees provide has the potential to enable a wind-driven fire to sweep through the forest unobstructed.
  • FEMA asked UCSF to consider alternatives to its project, which would have the potential to mitigate fire hazard to the built environment by creating defensible space around buildings, structural retrofits, and vegetation management projects. (3)

UCSF has elected to ignore this advice from FEMA, choosing instead to proceed with its project as originally designed using  its own funds at a time of extreme budgetary limitations.  Clearly this is an indication that fire hazard mitigation is not the purpose of their project.  UCSF chooses to increase fire hazard rather than reduce it, putting themselves and their neighbors at risk.

FEMA is now engaged in a comprehensive Environment Impact Study of four similar projects in the East Bay hills that propose to destroy hundreds of thousands of trees.  The applicants are UC Berkeley, the City of Oakland, and East Bay Regional Park District.  Fire hazard in the East Bay is greater than in San Francisco because the summer is hotter, the frequency of Diablo winds is greater, and there are rare deep freezes that cause some non-natives to die back, creating dead leaf litter on the forest floor.  However, the remaining issues are the same as those on Mount Sutro: 

  • The loss of tall trees will reduce moisture on the forest floor and eliminate the shade that maintains that moisture.  The remaining native landscape will be predominantly grassland studded with scrub, chaparral, and short native trees in sheltered ravines.  This will be a flammable landscape, not less flammable than the existing landscape.
  • The loss of the windbreak provided by the tall trees will enable a wind-driven fire to travel unhindered through the community.
  • The projects in the East Bay hills do not provide defensible space around homes, which would reduce fire hazard to homes and those who live in them, the stated purpose of FEMA grants.

We hope that FEMA will see the similarity between the East Bay projects and those in San Francisco and advise the applicants in the East Bay to revise their projects so that they are appropriately aimed at creating defensible space around homes.  Destroying hundreds of thousands of trees will not make us safer.  In fact, it is likely to increase the risk of wildfire.



(1) Excerpt from FEMA’s letter of October 1, 2009, regarding UCSF’s grant applications:

“In its response to provide a clarification of the wildfire hazard, UCSF inaccurately interprets a map, provides inadequate details regarding the history of wildfires in the Sutro Forest, and provides a simplistic and ineffective comparison of the wildfire hazard in the Sutro Forest to the hazard in other areas that have burned in the San Francisco Bay Area…The 2007 FHSZ [Fire Hazard Severity Zones] map shows the Sutro Forest to have a “Moderate” wildfire hazard in the 2007 FHSZ maps.  “Moderate” is the lowest of the three fire hazard severity zones…”

(2) Excerpt from FEMA’s letter of October 1, 2009, regarding UCSF’s grant applications:

“Commenters argue that the proposed projects would increase wildfire hazard by removing some of the material that collects fog drip and keeps the forest moist and resistant to ignition and fire, thus allowing the forest to dry out more easily and increase the relative hazard for ignition.  Can UCSF specifically address this comment and describe how overall forest moisture content will change after implementation of the proposed projects?  Please provide scientific evidence to support any claims.”

“Additionally, several of these unsolicited public comments have stated that the proposed projects could result in changed wind patterns on Mount Sutro which could also increase the wildfire hazard in the forest.  New wind patterns could reduce biomass moisture as well as reduce the effective windbreak created by the current forest.  These comments argue that the effective windbreak created by the existing forest limits the potential for wildfire spread in the forest and the immediately surrounding area.  As UCSF has stated, winds are a contributing factor in wildfires.  Provide a citable and logical defense regarding how the proposed projects, and the resulting changes in wind patterns, would not result in an increase in the wildfire hazard in the Sutro Forest.”

(3) “Assuming that UCSF has been able to establish a clear need for wildfire mitigation activities, UCSF must conduct a more thorough analysis to identify alternatives to the proposed projects that could mitigate wildfire hazard in the Sutro Forest to the vulnerable built environment.  These alternatives must be technically, economically, and legally practical and feasible and can include activities not eligible for FEMA grant funding.  As described in FEMA’s Wildfire Mitigation Policy…wildfire mitigation grants are available for defensible space, structural retrofit, and vegetation reduction projects.  It would seem reasonable that alternatives to the proposed projects could include defensible space or retrofit projects.”    (emphasis added)