Ecology – Page 33 – Conservation Sense and Nonsense

Wind and Trees

The public comment period for the Draft Environmental Impact Report (DEIR) for UCSF’s plans to destroy 90% of the forest and its understory on 46 acres of the Mount Sutro Open Space Reserve ended on March 19, 2013. We studied that document carefully to evaluate its accuracy and form our own opinion of the impact this project will have on the environment. Because Mount Sutro is a very windy environment, we paid particular attention to the influence of the wind for the consequences of UCSF’s proposed plans to destroy most of the forest. In the process, we learned something about the interaction between wind and trees that we would like to share with our readers.

The wind on Mount Sutro

Mount Sutro is a 900+ foot hill that is directly exposed to the wind from the west, coming off the ocean. Steep slopes accelerate the wind as it moves uphill. On the leeward side of a steep hill the wind breaks into turbulent gusts. This is an oversimplification of the movement of wind over a hill because in a complex topography such as Mount Sutro, the movement of the wind is as complex as the topography. For example, Mount Sutro is penetrated by a number of steep canyons that funnel the wind as it moves uphill.

Anyone who has visited the UCSF campus on the top of the hill knows that it is a cold, miserable, windy place much of time. But if you walk in the dense forest on Mount Sutro, you are often unaware of the wind because the trees are shielding you from the wind.

UCSF plans to destroy its windbreak by reducing the density of the forest from 740 per trees acre to only about 15-50 trees per acre. The campus and the neighborhoods on the leeward side of Mount Sutro are going to be subjected to a great deal more wind. They will also experience more fog which is now being “caught” by the tall trees and condensed as moisture to the forest floor. That fog is now going to flow freely from the ocean to the neighborhoods on the leeward side of Mount Sutro.

The consequences for the few trees that remain

UCSF would like the public to believe that it doesn’t intend to destroy the entire forest. However, that is the likely consequence of destroying 90% of the trees on 46 acres because trees develop their defenses against the wind in a specific environment with a specific amount of wind and they often fail when they are exposed to more wind than they are adapted to.

Wndthrow caused by adjacent clearcut, Britain. Creative Commons

UCSF’s own written plans for this project acknowledge that thinning the forest will increase the likelihood of the remaining trees failing: “Individual trees that suddenly become more exposed to high winds are also more likely to fall. For this reason, any thinning of the forest that is considered must not be so extensive that it will subject remaining trees to increased windfall.” (1, page 15) Ignoring its own advice, UCSF proposes to destroy over 90% of the trees on 46 acres of the reserve.

The DEIR also acknowledges that the trees remaining after the forest is thinned will be vulnerable to windthrow for some unknown period of time during which they adjust to the changed environment. The DEIR suggests that it is possible to mitigate for this potential for windthrow by monitoring the remaining trees to identify potential hazards. In other words, the DEIR claims that it is possible to accurately identify trees that might fall before they fall.

This is a fiction. If it were indeed possible to accurately predict that a tree will fall, we wouldn’t read reports of thousands of trees falling all over the country every year. Over 5,400 tree failures were reported to the University of California’s “California Tree Failure Report Program” in 2012. Since reporting is voluntary, we assume that is an underestimate of all tree failures in California in 2012. (Oaks (Quercus) were the most frequently reported genus to have failed in 2012: 22.7% of 5,415 reported tree failures were oaks. Failures of eucalyptus were nearly half that (11.90%).)

Any reputable arborist will tell you that evaluation of trees for potential hazards is an art, not a science. That is, it is a subjective judgment and this is reflected in the wide numerical range used to rate trees for potential hazards. When an arborist agrees to a contract to conduct such an evaluation, he/she usually does so with a liability caveat, making it clear that he/she cannot accept legal responsibility for trees that fail which haven’t been identified as hazardous by their evaluation.

For these reasons, the mitigation offered by the DEIR looks like a trap. If the evaluation is applied conservatively, the ultimate destruction of the entire forest seems likely. In other words, the few trees that remain will be declared hazardous and destroyed. Since those who demand this project have made it perfectly clear that they want the entire forest destroyed, that seems the likely scenario. If, on the other hand, the evaluation is not applied conservatively, unpredicted tree failures are likely. In either case, the ultimate outcome is a forest with fewer trees than projected by the DEIR.

In a consultation with Professor Joseph McBride of UC Berkeley, we were provided with two specific examples to illustrate this trap. Professor McBride evaluated two extreme windthrow events in the San Francisco Presidio and Sea Ranch. This study is cited by the Sutro DEIR. (2) Professor McBride told us that of the 6,000 trees that failed in the Presidio in an extreme weather event in 1993, most would not have been identified in advance as being vulnerable to windthrow. Healthy, structurally sound trees fail in extreme weather events. Conversely Professor McBride told us of an evaluation of all trees on the Berkeley campus in 1976 that judged about 3% of the trees as hazardous for which removal was recommended. Shortly after the evaluation was conducted, UC went through a period of budgetary constraints (much like the one UC is having presently) which prevented the removal of the trees judged to be hazardous. Over 35 years later, about 80% of those trees are still standing. In other words, trees judged healthy by professional arborists sometimes fail and trees judged hazardous often do not fail.

On April 7, 2013, the Bay Area experienced high winds that demonstrated both our windy environment and the consequences for our trees. Winds of 75 miles per hour were recorded in San Francisco. At the San Francisco airport, on the eastern (leeward) side of the City, winds of 35 miles per hour or more were recorded for 21 consecutive hours, an unusually sustained high wind. Both the strength of the wind and its duration caused many trees to fail. In San Francisco, 75 fallen trees were reported to the Department of Public Works. Here’s a brief article in the San Francisco Chronicle about this destructive wind, including photos of some of the many trees that fell.

How wind affects the health of trees

The DEIR would like the public to believe that the thinned forest will be capable of growing sufficiently to compensate for the loss of the existing capability to sequester carbon and recoup the loss of much of the existing stored carbon because the remaining trees will be released from competition. One of the reasons why this is wishful thinking is that the trees that remain will be subjected to a great deal more wind and that wind is going to reduce the trees’ ability to grow:

“As the magnitude of the stress (windspeed) increases, so do the resulting strains, resulting in a cascade of physiological strain responses. The physiological responses range from rapid changes in transpiration and photosynthesis at the foliar level, to reduced translocation, callose formation and ethylene production in the phloem and cambial zone. Long-term developmental and structural changes occur in canopy architecture and biomechnical properties of the xylem. “(3)

This same article explains that the canopy of a tree that is subjected to a great deal of wind tends to be narrower than one subjected to less wind and its leaves are smaller, which is one of the reasons why photosynthesis and transpiration are suppressed in a windy environment.

We turn to Joe McBride’s wind study of the Presidio (4) for a specific, local example that illustrates these general principles. This is what Professor McBride observed at the Presidio:

“Wind at the Presidio affects tree growth, form, and mortality. Exposure to winds in excess of 5 mph usually results in the closure of the stomata to prevent the desiccation of the foliage (Kozlowski and Palhardy, 1997) Photosynthesis is thereby stopped during periods of moderate to high wind exposure resulting in a reduction in tree growth…Eucalyptus showed the greatest reduction in growth with trees at the windward edge being only 46 percent as tall as trees on the leeward side.” (4, page 6)

The plans to destroy 90% of the trees on 46 acres of Mount Sutro will subject the few trees that remain to a great deal more wind. The growth of the few trees that remain will be significantly retarded by the wind. The claim of the DEIR that those trees will grow significantly larger when released from competition from their neighbors is fallacious because it does not take into account that the trees will be subjected to significantly more wind.

Why, oh why?

We cannot imagine why UCSF wants to destroy most of its forest. These are a few of the most mysterious questions that we cannot answer:

Why does UCSF want to subject its students, its patients, and its staff to more wind? Why does it want to subject its neighbors to more wind and fog?

Does UCSF really believe that destroying 90% of the forest on 46 acres of the Sutro Reserve will not result in the destruction of the entire forest?

Does UCSF really believe that the few trees that remain will grow so large and so fast as to compensate for the loss of the ability of the forest to sequester carbon?

We are speaking of a world-class scientific institution. Could it really be so ignorant? Or is there some ulterior motive that is not visible to us? Conspiracy theories abound in the public comments that have been submitted. We cannot verify any of those theories, so we won’t repeat them. We actually prefer to believe the latter explanation, because the thought of such an important scientific institution being so ignorant of scientific facts is too painful to contemplate.

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(1) “Mount Sutro Open Space Reserve Management Plan,” EDAW (consultant to UCSF), 2001

(2) McBride and Leffingwell, “Assessing windthrow potential in urban forests of coastal California,” Society for American Forests Newsletter, 2006

(3) F. W. Telewski, “Wind induced physiological and development responses in trees,” in Wind and Trees, edited by MP Coutts and J Grace, Cambridge University Press, 1995

(4) Joe R. McBride, “Presidio of San Francisco, Wind Study, First Phase,” circa 2002

Biodiversity of the eucalyptus forest

Although they can provide no scientific evidence, native plant advocates claim that the eucalyptus forest is a “biological desert” in which nothing grows and nothing lives. We can see with our own eyes in the Sutro forest that a diverse understory thrives in the eucalyptus forest, but it is more difficult to quantify the biodiversity of wildlife in the forest. For that we turn to scientists.

We published some time ago a summary of a research study by Dov Sax (Brown University) in which he compared the species richness (number of species) living in the eucalyptus forest with species richness in native oak woodland in Berkeley, California. He found equal numbers of amphibians, insects, plants in the understory, and birds in the eucalyptus forest compared to oak woodland in the fall and significantly more species of insects in the eucalyptus forest in the spring.

Eucalyptus around the world

Professor Sax also reported similar studies all over the world that reached the same conclusions, i.e., the introduced eucalyptus forest is just as biodiverse as the native forest all over the world. According to the Encyclopedia of Biological Invasions there are about 40 million acres of eucalypts planted in tropical, sub-tropical, and temperate countries. We have had the opportunity to observe them in several counties.

Much of Argentina is a treeless grassland prairie, called pampas. They imported eucalyptus to provide their economy with pulp. We observed many acres of densely growing eucalyptus forest throughout Argentina during our visit there. They also seemed to be used on the perimeter of agricultural lands, presumably as windbreaks.

Eucalypts used an agricultural windbreak, Argentina, 2010 — Eucalypts used as agricultural windbreak, Argentina, 2010

We also saw many eucalypts growing in Sicily. We were told by our guides that they were planted by Mussolini in the 1930s as the means of draining swampland to reduce the population of malaria-carrying mosquitoes.

We found more eucalypts in Morocco where they also were being widely used as landscape trees. There seemed to be more diversity of eucalyptus species and they were obviously considered valuable for horticultural purposes. We also saw eucalypts sheltering agricultural crops from the wind.

Eucalypts are obviously considered valuable trees in many countries all over the world. We marvel at the hatred they have generated in California.

More evidence of the biodiversity of the eucalyptus forest

Professor Robert Stebbins (Professor of Zoology and Emeritus Curator in Herpetology, Museum of Vertebrate Zoology, University of California, Berkeley) was hired to study the eucalyptus forest in Berkeley, California for the Nature Conservancy’s California Field Office. This is an excerpt from his report which was published in 1983. (It is available at wiki.bugwood.org)

Garter snake in euclypatus leaf litter — Garter snake in eucalyptus leaf litter. Courtesy urbanwildness.com

“Contrary to popular belief, many animals, both vertebrates and invertebrates, have adapted to life in the Eucalyptus groves. Moisture from the air condenses on the leaves and the drippage keeps the groves moist and cool even during the dry season. This is a suitable ground habitat for a wide variety of animal life. Amphibians such as arboreal salamander, California slender salamander, ENSATINA, California newt, rough skinned newt, and Pacific tree frog live in the forest, primarily under fallen logs and duff. Amphibians feed on such invertebrates as millipedes, centipedes, sow bugs, COLLENBOLA, spiders and earthworms.

“Several snakes such as the ring-necked snake, rubber boa and sharp tailed snake have adapted to Eucalyptus groves. The ring-necked snake feeds on the California slender salamander, the rubber boa feeds on meadow mice, and the sharp tailed snake feeds strictly on slugs. Other common reptiles include the northern and southern alligator lizards, which live under fallen logs, and the western fence lizard and western skink, which live in the less densely forested groves.

“Over 100 species of birds use the trees either briefly or as a permanent habitat. The heavy-use birds feed on seeds by pecking the mature pods on trees or fallen pods; so they must wait for the pods to disintegrate or be crushed by cars. Among the birds that feed on seeds in the trees are: the chestnutback chickadee and the Oregon junco. Examples of birds that feed on ground seeds are the song sparrow, the fox sparrow, the brown towhee, and the mourning dove. Birds that take advantage of the nectar from blossoms either by drinking the nectar or by feeding on the insects that are attracted to the nectar include Allen’s hummingbird, Bullock’s oriole, redwinged blackbird, and blackheaded grosbeak. Birds that use the trees as nest sites include the brown creeper, which makes its nest under peeling shags of bark and feeds on trunk insects and spiders, the robin, the chickadee, the downy woodpecker, and the red shafted flicker. The downy woodpecker and the red shafted flicker peck into the trunk of dead or dying trees to form their nests. When these nests are abandoned, chickadees, Bewick wrens, house wrens and starlings move in. Downy woodpeckers use dead stubs to hammer out a rhythmic pattern to declare their territories.

Owl nesting in eucalyptus, courtesy urbanwildness.com

“The red-tailed hawk prefers tall trees for a nesting site. It therefore favors eucalypts over trees such as oak or bay. Great horned owls use nests that have been abandoned by red-tail hawks or they nest on platforms formed between branches from fallen bark. The brown towhee and the golden crowned sparrow are birds that use piles of debris on the ground for shelter during rains.

“Several mammals have adapted to Eucalyptus. Deer find concealment in dense groves where there are suckers, coyote brush, and poison oak; moles live in the surface layer of the soil; meadow mice, gophers, and fox squirrels are found in the forest.

“A Eucalyptus grove is not a sterile environment. The population density of the animals mentioned can be partially attributed to the presence of eucalypts. With a program of cutting trees and burning debris, some animal residents will disappear because they have restricted home ranges or are sedentary. If an animal’s living area (leaf litter, logs, bark) and food supply are destroyed, the animal will either die or attempt to move to another area which is already fully occupied. ‘The wildlife section draws heavily upon conversations with Professor Robert Stebbins. No errors which may exist should be attributed to the professor.’”

Refusing to see the evidence

We stumbled upon this new information in the on-line comments on SFGATE (the San Francisco Chronicle’s website) on an article about the “tree wars of San Francisco.” (Available here) A defender of the forest was responding to the usual claims about the eucalyptus forest being a sterile environment. The defender of the forest was quickly attacked by a native plant advocate who called the commenter a “creepy imbecile.” The native plant advocate also attempted to discredit the source of information on the grounds that Professor Stebbins is apparently now dead. Obviously he was alive when he wrote his report, but the native plant advocate apparently believes that anything he wrote before he died is not credible. Or at least I think that was his/her “reasoning.” Oddly, another native plant advocate then chimed in, complaining that native plant advocates are being “demonized.” Wait! Who called whom a “creepy imbecile?”

Update: When we published this article we assumed that the native plant advocate who claimed that Professor Stebbins was dead at the time was correct about that. Since then we have learned that that was inaccurate information. Professor Stebbins died on September 23, 2013, according this obituary in the New York Times. So, the name-calling native plant advocate was fabricating “information” as well as engaging in ad hominem attacks. We are embarrassed that we assumed the native plant advocate was at least factually correct.

Unfortunately the name-calling comment has been removed from SFGATE which I suppose is consistent with their policy. However, it is a loss because it illustrated the low standards for civility and quality of information being used by native plant advocates to defend their destructive projects. (We are quoting from that comment only the portion for which evidence remains in replies to it.)

We saw these same low standards used by native plant advocates at the February 25, 2013 public hearing at UCSF about their plans to destroy the Sutro forest. There were only about 15 speakers in defense of the project, but their comments were devoid of information. One fellow walked to the microphone and said simply, “I hate eucalyptus” and walked away. Another claimed that the Angel Island fire of 2008 was evidence of the flammability of eucalyptus although 80 acres of eucalypts were destroyed over 12 years before that fire. Only 6 acres of eucalypts remain. The grass fire stopped at the edge of that small remaining stand of eucalypts.

One wonders where people find the energy to hate anything, let alone a tree. We struggle to understand the motivation of these crusaders against the forest. We believe that the most highly motivated amongst them are earning their living on these projects and are simply defending their economic interests. Nothing else makes sense to us.

Professor Arthur Shapiro’s Review of Emma Marris’ Rambunctious Garden

Professor Arthur Shapiro is Distinguished Professor of Evolution and Ecology at University of California Davis and a renowned expert on the butterflies of California. His public comment on the Draft Environmental Impact Report for the Natural Areas Program is one of the most popular articles on Million Trees.

Professor Shapiro has written a review of Emma Marris’ Rambunctious Garden and given us permission to reprint it here. We share his high opinion of Ms. Marris’ book and we urge you to give it the careful read it deserves.

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Rambunctious Garden: Saving Nature in a Post-Wild World by Emma Marris

Review by: Arthur M. Shapiro
The Quarterly Review of Biology, Vol. 88, No. 1 (March 2013), p. 45
Published by: The University of Chicago Press
Stable URL: http://www.jstor.org/stable/10.1086/669328

“Several years ago, I attended a seminar on the psychology of the animal-liberation movement. The speaker observed that although very few animal-lib activists were actually religious, most such people scored very highly on the “religiosity” scale in personality inventories. He suggested that animal liberation served the same functions for such people as religion did for many more: it gave life meaning and conferred a group identity centered on shared moral superiority over others. After years of interacting with “weed warriors”—people who spend their free time trying to eradicate “invasive species” from parks and public lands—I would advance the same hypothesis about most of them. They tend to be absolutely convinced of the righteousness of their cause and highly resistant to any suggestion that naturalized exotics might not be all bad. They also tend to be oblivious to the disconcerting degree to which their rhetoric converges to that of racists and xenophobes, and highly defensive if you point that out to them. After all, they are on the “green” side, right?

In the face of such popular enthusiasm for the alarmist viewpoint on exotics, Emma Marris, a professional science writer, has produced an eminently reasonable, well-researched, and engagingly written defense of the notion that human beings have changed the world and the most sensible way to deal with that is to manage it for the greatest good. She demonstrates very convincingly that communities and ecosystems have always been in flux as the physical world changes around them. The idea of freezing them at some arbitrary moment in time is as wrongheaded as it is impractical. Some naturalized exotics present serious threats to human beings or their support systems: we call them pests, pathogens, and vectors, and they are not what is at issue. Some are such radical ecological gamechangers that they need to be assessed with an eye to the full scope of their impacts (think cheatgrass in the desert and its impact on fire ecology). Most, however, are trivial, and in a world of limiting resources where we must assign priorities to our actions, they do not merit serious attention. But it is not merely a matter of using our management resources effectively. Much of our “invasive species” discourse simply ignores the evolutionary creativity consequent on community reorganization.

Yet we know both in theory and from the fossil record that precisely such creativity is essential for long-term survival in a changing physical context. Ecotypes or ecological races arise in response to novel challenges, both biotic and abiotic. The future of endangered species is likely to depend on such processes. Failure to appreciate this is the single biggest flaw in the “climatic envelope” or “niche modeling” approach to conservation biology. Much of California’s lowland butterfly fauna is now dependent on nonnative larval host plants. When I tell garden clubs—or public land managers—that successful eradication of invasive “weeds” would drive their beloved backyard butterflies to extinction, they stare at me in disbelief. But it is true and emblematic of the larger problem explored very well in this volume.

Shortly after Marris’s book appeared there was a flurry of articles in the professional literature advancing precisely the same ideas. Among the best are by Carroll (2011. Evolutionary Applications 4:184–199) and Thomas (2011. Trends in Ecology and Evolution 26:216 –221). But Marris got there first, and with luck her wise words will be read and acted upon far and wide.”

Arthur M. Shapiro, Center for Population Biology, University of California, Davis, California

San Franciscans come to the defense of the 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 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.

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)

48.4	43560/900 = trees per acre if 30 feet apart (the proposed plan)
12.1	43560/3600 = trees per acre if 60 feet apart (the proposed plan)
45000	Total number of trees existing now on 61 acres (according to UCSF)
34040	46 acres X 740 trees/acre = Number of trees existing in project area
2112	44 acres X 48 trees/acre = thinned forest with 30’ spacing
24	2 acres (Demo Area #4) X 12 trees/acre = thinned forest with 60’ spacing
31904	Existing Trees – Thinned Forest = Trees Removed in Project Area
70.9%	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.

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

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

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., 12^th Floor, Oakland, CA 94607  Fax: (510) 987-9224
Subscribe to the website SaveSutro.com for ongoing information and analysis.

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(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

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., 12^th Floor, Oakland, CA 94607  Fax: (510) 987-9224
Subscribe to the website SaveSutro.com for ongoing information and analysis.

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(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

Plans to destroy over 30,000 trees on Mount Sutro

We are reprinting with permission Save Sutro’s announcement of the Draft Environmental Impact Report for the project to destroy over 30,000 trees on Mount Sutro in San Francisco.

Here are the things you can do to participate in the effort to 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.

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Mount Sutro Forest has approximately 45,000 trees in the 61 acres belonging to 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.

THE TREE REMOVAL PLAN

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 the 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.

IT GETS WORSE

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.
Pesticide 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.

IMPLEMENTING THIS PLAN

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. (One of these, #4 “East Bowl”, is the two-acre area slated to have only 12-15 trees per acre.

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 year, 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 are native plant installations often failures?

We have been watching attempts to eradicate non-native plants and replace them with native plants on public lands in the San Francisco Bay Area for over 15 years. Few of these efforts have been successful. Non-native plants are repeatedly eradicated, then natives are planted. Within months the natives are dead and non-natives have returned.

The few projects that are successful are usually fenced, irrigated, and intensively planted and weeded. Few managers of public lands have the resources to achieve success. We have identified here on the Million Trees blog many reasons why attempts to return native plants to places in the Bay Area where they have not existed for over 100 years are often failures. Many of those reasons are related to the changes in the environment:

Higher levels of CO2 and associated climate change are promoting the growth of non-native plants. A USDA weed ecologist (1) studied the effects of higher temperatures and CO2 on the growth of non-natives (AKA weeds) by growing identical sets of seeds in a rural setting and an urban setting with higher temperatures and CO2 levels. Seeds grown in the urban setting produced substantially larger plants with much more pollen and therefore greater reproductive capability.
The growth of non-native annual grasses is encouraged by higher levels of nitrogen in the soil found in urban environments as a result of the burning of fossil fuels. (2)

The methods used by the projects undermine success

With the exception of the project on Mount Sutro in San Francisco, all of the projects use herbicides to eradicate the non-native plants and trees. Most of the non-native trees will resprout if their stumps are not sprayed immediately with herbicide and this must be done repeatedly to kill the roots of the trees. Many of these herbicides persist in the ground for years and probably suppress subsequent plant growth.

This problem is illustrated by a USDA study of the effects of a one-time aerial spraying of herbicides on grassland after 16 years. Although the herbicide is assumed to “dissipate” within a few years, the negative effect on the natives persisted 16 years later: “…the invasive leafy spurge may have ultimately increased due to spraying. Conversely, several desirable native herbs were still suffering the effects of the spraying,,,”

Anyone who is familiar with native plant restorations in the Bay Area knows that most are covered in a thick layer of mulch. When tree removals are required for a project, the mulch is usually composed of the chips of the trees that have been cut down. The projects of UC Berkeley for which UC is applying for FEMA funding (based on its claim that the clear-cutting of all non-native trees will reduce fire hazards) say specifically that the clear-cut areas will be covered with 24 inches of mulch composed of the chips of the destroyed trees.

The UC Berkeley projects also claim that native vegetation will return to these clear-cut areas without being planted based on an assumption that the seeds of native plants are dormant in the soil. One wonders how these seeds would be able to germinate when covered with 24 inches of mulch, or how the sprouts could penetrate it. Their proposal contains the fanciful suggestion that squirrels will plant the acorns of oaks in the mulch, which may be true of the oaks, but is an unlikely scenario for the many other native plants and trees which UC claims will populate their “restorations” without being planted.

Chips of destroyed trees, UC Berkeley project. Photo courtesy Hills Conservation Network

These heavy mulches prevent native bees from nesting in the ground, as most native bees do. This reduces the population of pollinators which are essential to the germination of a new generation of the plants. If long-term sustainability is the goal of these projects, an environment that is friendlier to pollinators would be helpful.

Lack of horticultural knowledge is also handicapping these projects

One of 5 native oaks that survive on Tank Hill 10 years after 25 oaks were planted.

The managers of these projects often display a profound ignorance of basic horticultural knowledge. For example, we have seen them plant natives that require full sun in the deep shade of trees where they will not survive. We have seen them plant native trees that will not tolerate wind on the slopes of windy hills, only to watch the trees wither and die.

The managers of these projects are apparently unaware of the fact that hundreds of species of California native plants require fire to germinate their seeds and that most of the population will die within 5 years of the fire. (3) These are examples of such “pyroendemics” that sprout after a fire and are almost entirely gone within 5 years:

UC Berkeley and East Bay Regional Park District do not plan to plant any natives after eradicating non-native plants and trees. Their plans say that they expect seeds that are dormant in the ground to sprout when the ground is cleared of non-native plants. Unless they set fire to that ground, many seeds will not germinate and most of the plants that are germinated by that fire will disappear within 5 years unless another fire germinates another generation of plants.

UC Berkeley does not use prescribed burns on its property. East Bay Regional Park District (EBRPD) conducts only a handful of small prescribed burns every year, which they claim are solely for the purpose of reducing fuel loads. In an article about prescribed burns conducted by EBRPD, the District’s “Resource Analyst” is quoted as saying, “’This is not a restoration project. Our primary goal is fuels reduction.’” (4) Ironically, both of these owners of public lands claim that their objective in the eradication of non-native plants is to reduce fire hazard, yet they are trying to reintroduce a landscape that is dependent upon fire for survival.

The Natural Areas Program in San Francisco has never conducted a prescribed burn and the DRAFT Environmental Impact Report for their plan says they do not intend to do so in the future.

New and growing evidence that soil is altered by plants

In addition to these issues which have contributed to the failed attempts to reintroduce an historical landscape to the San Francisco Bay Area, we are reporting today on a new issue. Plants can change the microbial composition of the soil, including mycorrhizal fungi which have symbiotic relationships with plants.

Researchers tested soil for changes in composition after just three growth cycles. Several species of non-native annual grasses were grown in native soils. They reported that the non-native species reduced the population and changed the composition of the mycorrhizal fungi, which reduced the ability of native species to establish and persist in modified soils. (5)

The Berkeley Meadow is a 72-acre native plant garden on a former garbage dump on landfill.

These changes in the soil were observed after only three growth cycles. Our local projects are attempting to eradicate plants which occupied the soil for more than 100 years. In some cases such as the former garbage dumps in the East Bay on landfill, the soil was never occupied by native plants. Surely, the alteration of soil composition is a likely factor in the failure of attempts to turn these properties into native plant gardens.

How many more decades and how much more taxpayers’ money must we spend on these projects before land managers acknowledge their failures?

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(1) Lewis Ziska, USDA Scientist, Beltsville, MD

(2) US Fish & Wildlife, Recovery Plan for Mission Blue butterfly

(3) Jon Keeley, et. al., Fire in Mediterranean Ecosystems, Cambridge University Press, 2012

(4) Wendy Tokuda, “Taming the Flames,” Bay Nature, July-September 2012

(5) Nicholas Jordan, et. al., “Soil-Occupancy Effects of Invasive and Native Grassland Plant Species Composition and Diversity of Mycorrhizal Associations,” Invasive Plant Science and Management, October-December 2012

Bats in Glen Canyon Park are being evicted NOW!

We are reprinting with permission an article about bats in San Francisco’s parks from the San Francisco Forest Alliance. The article reports observations of bats as well as a study of bat populations in San Francisco’s parks. The study found that both the number of bats as well as the number of species of bats was related to the amount of forest edge in each park and the availability of water. The study reports that the forest edge contains more insects which are the primary food of the bats.

We are posting this story today because hundreds of trees in Glen Canyon Park in which bats and many other creatures live are being destroyed as we speak. Here is a video of the destruction which started yesterday and continues today, along with a narrative of how and why this needless destruction is happening. Please watch this moving video to understand why we are so committed to opposing the pointless destruction of our trees by extremist agendas that are damaging the environment and harming the animals that live in our open spaces. (Edited to Add: And here is a video showing the second day of the demolition project.)

The study did not find any relationship between the number of bats nor the number of species of bats with the percent of native plant coverage. We speculate—although the study does not—that the absence of correlation between bat populations and native plant populations suggests that there are not more insects in native plants than at the forest edge. Although native plant advocates claim that more insects are found in native plants, this is yet more evidence that this claim is not true.

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Bats are insect-eating machines. According to the USGS, “Bats normally eat about half their weight in flying insects each night.” So even for those who don’t find these night-flying mammals charming, it’s good to know there are bats among us.

San Francisco has at least four species of bats, all of which eat insects. According to research by Jennifer Krauel, which involved recording bat sounds to determine which species they were, Mexican Free-tailed bats are the most common. Parks with water – like Glen Canyon – also have Yuma Myotis bats. The other two species she found (more rarely) were Western Red Bats, and Little Brown Bats, and she found them in just a couple of places.

Her research indicated that “amount of forest edge and distance to water were the factors best explaining species richness and foraging activity.” It also showed that bats in San Francisco remain active through the winter and don’t hibernate or move elsewhere.

If you’re interested in reading her paper, it’s here as a PDF: Jennifer Krauel thesis on bats in SF

BATS IN GLEN CANYON PARK

Glen Canyon’s bats are often visible at dusk. They’re most evident in the Fall, though they’ve been seen at other times of the year. (The pictures above are from February and April, those below from October.)

Here’s a note on bat-viewing from one visitor to Glen Canyon.

“It was late in the afternoon, and late in October. We were standing around the entrance to the park on Alms Rd. As dusk fell, bats emerged from the tall eucalyptus trees. Quite suddenly they were in the air right above us. I pulled out my camera, which is not really good in poor light but I tried to take some pictures anyway. Here’s one:

“They’re difficult to spot in the picture, but all those black smudges are bats that were moving too fast for my pocket-camera. Here’s the same picture, cropped, with the bats circled in yellow:

“They dispersed over the canyon. Here’s another picture from a few minutes later (and the one below it shows where the bats are).

“It was fantastic. I haven’t seen this many bats anywhere in San Francisco.”

LARGE TREES ARE IMPORTANT

We did a little research, and found a Stanford report that emphasized the importance of large trees to a particular species of bats, Yuma Myotis… bats that Krauel’s research had actually found in Glen Canyon Park.

“Yuma bats that forage in the preserve travel several miles to roost in large trees in Portola Valley and Woodside, suburban communities on the San Francisco Peninsula. The average diameter of the bats’ chosen trees is about a yard across — more than three times wider than the average tree in those areas.”

(The link to the abstract of the actual Stanford research paper is HERE.)

That’s the size of the big eucalyptus trees in Glen Canyon Park – including those that SFRPD wants to chop down.

WHY BATS MATTER

Bats are an important part of an eco-system, and fill a role few other creatures do: They hunt night-flying insects like mosquitoes that birds don’t catch because they’re sleeping. This is especially important now as West Nile virus, a mosquito-borne disease, has been spreading.

Having bats in a landscape contributes to its bio-diversity. All species of bats are protected in California.

(Some people are concerned that bats carry rabies – and it’s true no one should handle bats, especially grounded bats that may be sick, with their bare hands. But according to the California Department of Fish and Wildlife, less than 1% of bats are infected. [Click HERE to see their note.] The risk of getting rabies from a bat is less than the risk of being struck by lightning.)

HOW WILL SF RPD ENSURE THE PRESERVATION OF THE BATS?

We’re concerned about the impact of the planned tree removals on Glen Canyon’s bats.

All species of bats are protected, and removing the trees will impact their habitat by reducing the number of safe roosting spots, especially for Yuma Myotis bats that need both large trees and nearness to water.
The contractor will be chopping down the trees in the daytime. Bats roosting there are likely to be killed – if not in the process of the tree-felling, by being forced to fly blinded and confused in the daytime and fall prey to hawks, crows and ravens.

How is SF RPD going to ensure the protection of these bats?

And in what ways will felling large trees near the stream alter the ecology of the canyon?