Sutro Forest – Conservation Sense and Nonsense

Open letter: Does Audubon Society advocate for birds or birders?

Our family was a member of the Audubon Society for decades because we love birds and birding all over the world is our primary hobby. So, it was painful to give up that membership a few years ago when we were unable to convince the Bay Area chapter of Audubon (Golden Gate Audubon Society (GGAS)) that its support for the projects that are destroying hundreds of thousands of trees, are harmful to birds. We didn’t give up easily. We tried for many years to convince GGAS that their policy is harmful to birds. Since leaving Audubon, the GGAS has become progressively more aggressive in its support for these projects. Here are a few recent examples of policy decisions they have made:

GGAS signed a letter of support for the planned project that proposes to aerial bomb 1.3 metric tons of rodenticide on the Farallon Islands to kill mice. You can read about that horrible project HERE.
GGAS is also supporting the US Fish & Wildlife project that is shooting barred owls based on the belief that another native bird will benefit. Read about that project HERE.
Recently they sent a letter to University of California, San Francisco, asking them to proceed with their original plans to destroy approximately 30,000 trees on Mount Sutro. These plans are presently on hold in response to the objections of the public.

Today, we are going to take a closer look at Audubon’s support for the destruction of most trees on Mount Sutro. Jack Dumbacher, member of the GGAS Board of Directors and Chairman of the GGAS “Conservation” Committee, has written an article for the GGAS blog about that project, which gives us this opportunity.

Who are “WE?”

Mr. Dumbacher’s article begins with a litany of “what WE want:”

“We understand that just seeing birds is not enough – we want diversity. It is not enough to have a life list of one species that you’ve seen really well.
“We want a long life list with many species. We want to count as many species as we can on each field trip.
“We want to see birds doing a variety of interesting things.
“We want reasons to visit a variety of habitats and regions. And we love seeing that occasional rare, out-of-place species.”

Many birders and Audubon members have tried unsuccessfully to engage Mr. Dumbacher in a dialogue, so we are resorting to this “open letter” venue to ask these questions:

Who are “WE” in this list of what Mr. Dumbacher claims “WE want?” Does he speak for you? Does he speak for the birds? If not, is he speaking for himself? Is he speaking for all Audubon members? If you are an Audubon member, is he speaking for you?
If this isn’t a list that speaks for you, what do YOU want? Do you want to be able to walk in a forest in which many birds live now? Or do you prefer grassland and dune scrub, which is what the forest in San Francisco is being converted to by native plant advocates?
If Mr. Dumbacher’s wish list doesn’t speak for the birds, what do you think the birds want? Where do you think the owls and raptors will nest if all the tall trees are destroyed? Where do you think the bats will live if the tall trees are destroyed? What do you think the hummingbirds will eat in the winter if all the eucalypts that flower in the winter are destroyed?

Red-tailed hawk nesting in eucalyptus. Courtesy urbanwildness.org

We are too ignorant to understand what THEY want

Mr. Dumbacher wonders how those who share his opinions regarding nature can convince us to want what they want: “…how do we make the case for diversity?” Then he proceeds to try to make the case, by looking back on his childhood experiences in nature and passing judgment on them:

“My father spent much of his spare time in open green spaces. Sometimes I would go with him, and we heard birds and saw squirrels and geese, and we believed that we loved and understood nature. After spending many more years of my life studying biology, I realized that we were just golfers on a relatively impoverished golf course landscape.”

It struck us as unspeakably sad that he would look back on his childhood experience in nature with such condescension. It seems that each of us should have the right to enter nature with whatever level of knowledge we can bring to that experience. Mr. Dumbacher has a Ph.D. degree. Does he think a Ph.D. degree is required to appreciate nature? Such a prerequisite would leave most of us out. Don’t we have a right to enjoy nature too?

Burdened with too much knowledge

We will use our personal experience to present a contrarian viewpoint. A few years ago we had the opportunity to drive the length of the Blue Ridge Highway from the Shenandoah Valley in northern Virginia to the heart of Tennessee. Of course, we had many walks in the woods. It was early spring. The dogwoods were blooming. The birds were actively starting their nesting season. As much as we enjoy a walk in the woods here in California, there was even greater pleasure in those walks in the eastern woods because we have almost no knowledge of what is native or non-native there. It was a great relief to be able to walk without passing judgment, as we have been taught to do in California. There was no need to point fingers and declare that something “doesn’t belong there.” We could accept the beauty of everything we saw on equal terms. Ignorance was bliss.

Monarch caterpillar on milkweed. Tilden Botanical Garden

We will contrast that experience with a more recent experience in the East Bay Regional Park District Botanical Garden in Tilden Park. We were taking a course in which several participants in the class were members of the California Native Plant Society. You might think that a botanical garden in which solely natives are planted, would be a pleasant place for them to walk. It wasn’t. They were outraged by the few non-native “weeds” we saw. They crawled over the plantings to pull the uninvited plants from their roots. One was a lovely scarlet pimpernel, blooming in its bright coral amongst native plants in their dormant, brown phase. Their destructive attitude detracted from our enjoyment of the garden.

The “tiny minority” myth

As the “restoration” projects in the Bay Area have become progressively more destructive, the public has become progressively more opposed to them. Mr. Dumbacher calls us a “vocal minority” in his article. He is mistaken. We consistently outnumber native plant advocates (sometimes ten to one) whenever we have an opportunity to express our opinion in a public venue: in public hearings, on petitions, during written public comment periods. We are not a minority.

Mr. Dumbacher is also mistaken in his description of the project which he is defending in his article. He says, “…a Sutro Management Plan was formed that balanced incremental thinning with incremental planting of native species, in order to increase diversity and reduce the fire threat.” We will give Mr. Dumbacher the benefit of the doubt by assuming that he has not read the Environmental Impact Report of February 2013, in which the project was described in detail. Within ~~a year~~ five years, that project would have destroyed 90% of the trees (about 30,000 trees) and understory on 75% of the acres of Mount Sutro. It proposed no planting of native plants, with the exception of a few small areas if money became available to pay for them. The word “thinning” is used by native plant advocates to describe their plans to destroy the forest because it sounds less destructive. However, it is not a word that accurately describes the destruction of 90% of the forest.

What happens to the birds that are there now?

Blackberries in the Sutro forest. Courtesy Save Sutro Forest

Unfortunately, we can’t share with our readers the lovely pictures in Mr. Dumbacher’s article because we don’t have permission, although you can visit the article to see for yourself. You will see beautiful birds sitting on plants that exist now on Mount Sutro and Mount Davidson. They are native plants that thrive in the understory of the forest and are unlikely to survive the devastation of the destruction of the trees and understory. There are also non-native plants in the understory. Many of them, such as blackberry, are valuable sources of food for birds. There is no evidence, and no reason to believe, that destroying the Sutro forest will increase the number of bird species in San Francisco.

Native red elderberry on Mount Sutro. Courtesy Save Sutro Forest

One wonders if Mr. Dumbacher isn’t aware of this obvious contradiction: he illustrates his article with birds that live in the forest now while trying to make the case that the forest must be destroyed so he can see more birds. Perhaps the answer is that he doesn’t really want more birds, he is only interested in certain birds: “But If you want migrants to visit your city, if you want rare birds to breed in your local parks, and if you want a county list that exceeds 200 species, then please get involved in local habitat management and restoration, and be ready to speak up for nature in your city.”

The "managed" portion of the Sutro forest: orange flags and weeds — The “managed” portion of the Sutro forest: orange flags and weeds

Here is another contradiction in Mr. Dumbacher’s appeal for your support for destroying most of the Sutro forest: “we should try to manage a more natural forest.” In what sense is a “managed” forest also a “more natural” forest? The Sutro forest is natural now, wild and unmanaged, a delightful mess. We see no benefit in “managing” it. Our experience with the managed summit of Mount Sutro is herbicide use (in the past), irrigation, wood chips, and dry weeds populated with colored flags where someone has apparently planted something that didn’t emerge from the wood chips.

Does Mr. Dumbacher speak for you? Do you share his view of “nature?”

Postscript: Mr. Dumbacher’s viewpoint is particularly troubling because he is Chair of the Department of Ornithology and Mammalogy at California Academy of Sciences, the Bay Area’s leading institution of science education. It seems that there is little science in Mr. Dumbacher’s viewpoint as expressed in his article.

In defense of a dense forest

In the fifteen years that we have debated with native plant advocates about their desire to destroy our non-native urban forest, the arguments they use to justify their plans have changed many times in response to our push-back against their plans. In the latest round of argument about plans for the Sutro Forest in San Francisco, the justification devolved to the claim that “thinning” the forest would improve its health and reduce fuel loads. We will set aside the claim about fuel loads in this post because we have published many articles to address the bogus claim that the existing Sutro Forest is a fire hazard. Although we don’t agree that “thinning” is an accurate description of a project that intends to destroy 90% of the trees on 75% of the Sutro Forest, we will set that issue aside for the moment as well.

The dense and healthy Sutro Forest. Courtesy Save Sutro

In this post we will address the claim that “thinning” a forest to less than 50 trees per acre—with trees a minimum of 30 feet apart–will improve forest health. We have reported that the few trees that remain will be subjected to a great deal of wind which will suppress their growth. The few remaining trees will also be vulnerable to windthrow because they will be subjected to more wind than they are adapted to. Trees develop their defenses against the wind based on the amount of wind they experience during early stages of their growth.

A dense forest is a healthy forest

As we often do on Million Trees, we will challenge the conventional wisdom that a “forest” with few trees is healthier than a dense forest, based on the assumption that the trees are released from competition with their neighbors for available resources. We will report on a new argument for the advantages of dense forest for optimal forest health, i.e., that the forest is essentially a community which functions best when it is densely populated:

“It is the evolutionary nature of a tree to be part of a forest or plant community. Trees do not grow as lone individuals under natural conditions. This principle of cooperation referred to by biologists as mutualism appears to have governed organisms from their beginnings.

“Despite the universal gregarious nature of trees, they are almost always discussed and depicted as solitary specimens. Children’s books, technical publications, and literature on gardening only illustrate and discuss the atypical form of a tree—the symmetrical, low-branched, open grown form. All of our knowledge about trees is colored by this cultural archetype. We celebrate the singular specimen.

“Observe trees growing on a natural woodland site. The tall erect trunks of closely spaced forest trees and branch configurations shaped to admit light are two of the more obvious adaptive responses of trees to forest conditions. Each layer of the forest contains examples of this kind of adaptive geometry. The result is that trees can grow very well in dense forest conditions, and in fact are uniquely suited to what we regard as close spacing. For example, it is not unusual to find northeastern forests growing at densities of 400 trees per acre. This is equivalent to trees ten feet apart in both directions. Much higher and lower densities also occur naturally. It is significant that trees can adapt to such a wide range of conditions. A group of Maple trees growing five feet apart is just as healthy or at least better able to survive than a single tree growing in an open meadow. The slower growth rate of trees growing close together is part of their adaptive response and does not indicate that they are less healthy than faster growing trees.

A lone eucalyptus trees in the Mountain View Cemetery.

“The popularized open grown individual tree has an adapted form that is not as sturdy as the forest shaped tree. The tree needs the lower, more spreading branching as protection for its trunk and roots. Its faster growth rate actually produces less sturdy wood.

“To retain their vitality when growing close together, trees adjust their form and growth rate. In this way, they are able to share the more limited amount of sunlight and root space. Trees of the same species do not kill each other off in a fight for survival. This more dramatic image has greater popular appeal but limited accuracy. In the natural process of forest succession, a certain species will dominate all other trees for a given soil type and climate. This is a long term process that occurs because less tolerant trees tend to grow on a site first and would not occur if the climax species were planted first. It is true that in natural repropagation of a clear area, a superabundance of seedlings is often produced, and later thinned by competitive survival of the stronger individuals. This process is limited for the most part to the seedling and early stages of forest succession, and is a lesser factor to later development of the forest when the adaptive process assumes a more important role than competition…

“Through observation of trees growing in natural habitats, a designer can conclude that there is no biological basis for keeping trees far apart, since they grow at every possible spacing” (1) (emphasis added)

An analogy to human society

The community of trees in a forest reminds us of a civilized human society in which individuals cooperate for the collective benefit of society. Like a healthy forest, a civilized human society is one in which cooperation trumps competition. It doesn’t seem to be a coincidence that native plant advocates consider competition more powerful than cooperation both in a forest of trees and in human society. Many native plant advocates seem to share a dark outlook about both human society and our healthy urban forest.

Update: We are pleased to report that UCSF announced on Thursday, November 21, 2013, a significant revision of their plans. ~~Only~~ ~~trees 6″ in diameter will be destroyed,~~ * which means fewer trees will be destroyed than originally planned. Only the perimeter of the forest will be thinned to reduce perceived fire hazards to the surrounding residential neighborhood. They do not plan to use herbicides. The details of the revised plan and the timeline for its approval and implementation are available on the Save Sutro website.

*Update: UCSF has corrected this information in response to an inquiry from the Save Sutro webmaster: “The correct information is that the proposed Hazard Reduction Measures recommend removing trees with a stem diameter of less than 10” in the North and South project areas, and to remove trees with a stem diameter less than 6” in the West project area.”

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(1) H.F. Arnold, Trees in Urban Design, 1993, pgs 49-50

Comparing the Sutro Forest with Albany Hill

In a recent edition of Jake Sigg’s Nature News, one of his readers compared the Sutro forest unfavorably to the eucalyptus forest on Albany Hill:

“The [Sutro] ‘ forest ‘ is unmanaged, many of the trees are deteriorated and unhealthy, spacing is unusual and given the super invasive ivies and H. blackberry, overall habitat diversity is degraded.

For example , I look at El Cerrito Hill [officially Albany Hill] (near Central Av exit of east bay I-80 at Golden Gate Fields) and see a ‘ eucalyptus’ forest with fewer and larger trees , featuring an adjacent and penetrating coast live oak woodland and a ground cover that features wide species diversity.

Granted El Cerrito does not have the fog intensity of Mt. Sutro, BUT it also shows signs of management…

Anyway, all of this is my un-scientific observation. I think, with some thinning of eucs, control of ivy and blackberry spread, the establishment of habitat corridors and discreet regions and maintenance of trails, that Mt. Sutro could continue to provide a ‘ forest’ aesthetic and include much improved habitat diversity and fire potential reduction.”

We are always trying to understand the perceptions of native plant advocates in the Bay Area, so we went to take a look at Albany Hill. We are happy to report that we found much to like. However, the comparison with the Sutro forest is mistaken in many ways, which we will explain in this post.

Creekside Park

We started our walk at the Creekside Park on the north side of Albany Hill. It is a riparian corridor created by the confluence of two creeks, Cerritos and Middle creeks. The vegetation is almost exclusively native. The Creekside Park is carefully tended by native plant advocates who have planted many of the natives, but the Coast Live Oaks that are the predominant tree species are said to have been here prior to settlement. (1)

The oaks cover the northern slope of Albany Hill, which was typical of native oak woodland in the East Bay . The oaks benefit from the water provided by the creek and they also occupied north-facing slopes where there is more moisture in the soil than on the south facing slopes that are exposed to the sun. The prevailing wind in the Bay Area is usually from the southwest, so there is also some protection from the wind on the north side of the hill. There were never any oaks on Mount Sutro, and the assumption that there will be in the future seems delusional, given their horticultural requirements.

Looking up from the Creekside Park, we can see the eucalyptus forest on the top of Albany Hill which has not “invaded” the oak woodland. The fact that the eucalyptus forest has not encroached on the oak woodland is documented by two planning documents. The first “Albany Hill Master Plan” was written in 1991. It included vegetation maps that can be compared to the second “Albany Hill Creekside Master Plan” which was written in 2011. The second plan states that the eucalyptus forest had not expanded during that 20 year period. It also states that the eucalyptus forest isn’t regenerating. That is, it is not replacing itself, let alone expanding. Yet, it is consistently called an “invasive species” in the master plan approved in 2012. (2) “Invasive” seems to be the pejorative adjective used by native plant advocates to describe all non-native plants and trees, whether actually invasive or not.

During that 20-year period from 1991 to 2011, the eucalyptus forest was not “managed” as Sigg’s correspondent believes, because the plan was not funded. (1) Hence, a second plan was written in 2011. This is a scenario we often see played out on our public lands. Elaborate plans are written. Often they are not implemented. Sometimes we are just as happy they aren’t.

Let’s enjoy a few of the beautiful native plants and trees before we leave Creekside Park to visit the eucalyptus forest on the top of the hill.

This is a lovely little Madrone in full bloom. We recall wanting to plant a Madrone in our backyard over 30 years ago. They weren’t available in nurseries then. We assume they are now, which is great. But we digress.

This is one of the few California lilacs (ceanothus) we saw. Bumble bees were busy in the lilacs. They are nesting close by in the ground beneath an oak. If the bared ground on Mount Sutro is covered in the wood chips of the trees that are destroyed, as planned, native bees will not be able to penetrate that deep wood mulch.

This is one of many lovely oak trees, surrounded by ivy, which doesn’t seem to be doing it any harm. In fact, the master plan for Albany Hill says there are no plans to eradicate ivy in the riparian corridor because it “…would require considerable cost and labor to fully eradicate and whose spread is often limited to areas in the immediate vicinity.”

The Eucalyptus Forest on Albany Hill

The eucalyptus forest on Albany Hill was planted by a dynamite company in the late 19^th century. The trees were planted to muffle the sound from frequent explosions, as well as provide some protection to neighboring residents. (1) There were many reasons why early settlers to the Bay Area planted eucalypts. Some were practical reasons, such as this, and some were aesthetic.

Albany Hill is much drier than Mount Sutro. It is further away from the ocean where fogs form and often hover for weeks on end during the summer. In general, the East Bay is considerably less foggy than San Francisco.

Because it is a much drier environment, the eucalyptus forest on Albany Hill is less dense than the Sutro forest and it has considerably less understory. The understory on Albany Hill is non-native annual grass and native toyon shrubs, which are said to have been planted either by man or by birds “carrying” seeds from other locations. (2) Hmmm….let’s stop to think about that. The toyon is a native shrub that was “introduced” to Albany Hill and is thriving there under the canopy of the eucalyptus forest. The 2012 master plan for Albany Hill says that the toyon understory has expanded since the 1991 master plan.

The future of the eucalyptus forest on Albany Hill

As we have said, the eucalyptus forest on Albany Hill has not been “managed” to date. Since the master plan was approved in 2012, only $50,000 has been allocated for vegetation management on Albany Hill. So, what is planned for the eucalyptus forest in the future? Here are the plans for the future, according to the master plan that was approved in 2012:

The eucalyptus forest will be “phased out” slowly over time by removing hazardous trees as necessary to ensure public safety, removing new seedlings where the forest interfaces with native oak woodland, and not replacing trees that die of old age. Since the predominant species of eucalyptus in the Bay Area (Blue Gum) lives in Australia from 200-500 years, and it has been here for only about 100 years, it is reasonable to assume that this is a very long-term plan.
This plan should require a lot less herbicide than destroying 90% of the trees on 75% of Mt. Sutro, as planned there, because we assume a dead tree will not resprout. A lot of herbicide is often needed to prevent resprouts after healthy eucalypts are cut down.
The forest will be managed for fire safety by mowing the annual grasses, where ignition is most likely to occur; by limbing trees up to separate the understory shrubs from tree limbs to remove “fire ladders” to the tree canopy; and by cleaning woody debris from under the trees on an annual cycle.
The plan acknowledges the benefit of maintaining a closed canopy, both in the eucalyptus forest and the oak woodland. The closed canopy shades the forest floor and suppresses the growth of non-native weeds.

This all sounds eminently reasonable to us: much less destructive than plans for the Sutro forest, yet addressing fire hazard and safety issues in a responsible way.

Neighbors on the leeward side of the hill will eventually lose their windbreak as the tall trees disappear, but that will happen so slowly that they are unlikely to react. On the other hand, plans for Albany Hill could change many times in the next 100 years. We hope the current preoccupation with the nativity of plants and trees will have faded long before the eucalyptus forest dies of old age.

And so, ironically, we agree with Jake Sigg’s correspondent that plans to manage Albany Hill are better than the plans to destroy the Sutro forest. We just don’t agree about why.

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(1) http://en.wikipedia.org/wiki/Albany_Hill

(2) “Albany Hill Creekside Master Plan,” City of Albany, 2012

The Healthy Trees of San Francisco

The San Francisco Natural Areas Program (NAP) plans to destroy thousands of healthy trees in San Francisco’s parks. The Draft Environmental Impact Review (EIR) for NAP’s destructive plan reaches the bizarre conclusion that removing thousands of trees will have no significant impact on the environment. This conclusion is based on several fictional premises. In a previous post we examined the fictional claim that all the trees that will be removed will be replaced within the natural areas by an equal number of trees that are native to San Francisco. In this post we will examine another of the fictional premises: that only dead, dying, hazardous, or unhealthy trees will be removed.

We have many reasons to challenge the truth of the claim that only dead, dying, hazardous or unhealthy trees will be removed:

The management plan for the Natural Areas Program tells us that young non-native trees under 15 feet tall will be removed from the natural areas. By definition these young trees are not dead or unhealthy because they are young and actively growing.
The management plan has not selected only dead, dying, hazardous trees for removal. Trees have been selected for removal only in so far as they support the goal of expanding and enhancing areas of native plants, especially grasslands and scrub.
The predominant non-native tree in San Francisco, Blue Gum eucalyptus lives in Australia from 200-400 years, depending upon the climate.(1) In milder climates, such as San Francisco, the Blue Gum lives toward the longer end of this range.
However, there are many natural predators in Australia that were not imported to California. It is possible that the eucalypts will live longer here: “Once established elsewhere, some species of eucalypts are capable of adjusting to a broader range of soil, water, and slope conditions than in Australia…once released from inter-specific competitions and from native insect fauna…”(2)
The San Francisco Presidio’s Vegetation Management Plan reports that eucalypts in the Presidio are about 100 years old and they are expected to live much longer: “blue gum eucalyptus can continue to live much longer…”(3)
The Natural Areas Program has already destroyed hundreds of non-native trees in the past 15 years. We can see with our own eyes, that these trees were not unhealthy when they were destroyed.

How have mature trees been selected for removal?

The EIR wants us to believe that only dead, dying, hazardous trees will be removed from the natural areas. This claim is contradicted by the management plan that the EIR is claiming to evaluate. Not a single explanation in the management plan for why specific trees over 15 feet tall have been selected for removal is based on the health of the trees. Trees less than 15 feet tall will also be removed, but are not counted by the management plan.

Lake Merced: The explanation for removing 134 trees is “To maintain and enhance native habitats, it is necessary to selectively remove some trees.”
Mt. Davidson: The explanation for removing 1,600 trees is: “In order to enhance the sensitive species habitat that persists in the urban forest understory and at the forest-grassland ecotone, invasive blue gum eucalyptus trees will be removed in select areas. Coastal scrub and reed grass communities require additional light to reach the forest floor in order to persist “
Glen Canyon: The explanations for removing 120 trees are: “to help protect and preserve the native grassland” and “to increase light penetration to the forest floor”
Bayview Hill: The explanation for removing 505 trees is: “In order to enhance the sensitive species habitat that persists in the urban forest understory and at the forest-grassland ecotone, invasive blue gum eucalyptus trees will be removed in select areas.”
McLaren: The explanation for removing 805 trees is: “In order to enhance the sensitive species habitat that persists in the urban forest understory and at the forest-scrub-grassland ecotone, invasive trees will be removed in select areas. Coastal scrub and grassland communities require additional light to reach the forest floor in order to persist.”
Interior Greenbelt: The explanation for removing 140 trees is: “In order to enhance the seasonal creek and sensitive species habitat that persists in the urban forest understory, invasive blue gum eucalyptus trees will be removed in select areas.”
Dorothy Erskine: The explanation for removing 14 trees is: “In order to enhance the grassland and wildflower community, removal of some eucalyptus trees is necessary.”

In not a single case does the management plan for the Natural Areas Program corroborate the claim made in the EIR that only dead, dying, diseased, or hazardous trees will be removed. In every case, the explanation for the removal of eucalypts is that their removal will benefit native plants, specifically grassland and scrub. The author of the EIR has apparently not read the management plan or has willfully misrepresented it.

The track record of tree removals in the natural areas

Although it’s interesting and instructive to turn to the written word in the management plan for the Natural Areas Program to prove that the EIR is based on fictional premises, the strongest evidence is the track record of tree removals in the past 15 years. As always and in every situation, actions speak louder than words.

Hundreds of trees have been removed in the natural areas since the Natural Areas Program began 15 years ago. We’ll visit a few of those areas with photographs of those tree removals to prove that healthy, young non-native trees have been destroyed. This track record predicts the future: more healthy young trees will be destroyed in the future for the same reason that healthy young trees were destroyed in the past, i.e., because their mere existence is perceived as being a barrier to the restoration of native grassland and scrub.

The first tree destruction by the Natural Areas Program and its supporters took the form of girdling about 1,000 healthy trees in the natural areas about 10 to 15 years ago. Girdling a tree prevents water and nutrients from traveling from the roots of the tree to its canopy. The tree dies slowly over time. The larger the tree, the longer it takes to die. None of these trees were dead when they were girdled. There is no point in girdling a dead tree.
One of about 50 girdled trees on Mt. Davidson, 2003

Many smaller trees that were more easily cut down without heavy equipment were simply destroyed, sometimes leaving ugly stumps several feet off the ground.
Bayview Hill, 2002

About 25 young trees were destroyed on Tank Hill about 10 years ago. The neighbors report that they were healthy trees with trunks between 6″ to 24″ in diameter and therefore fairly young trees. The trees that remain don’t look particularly healthy in the picture because they were severely limbed up to bring more light to the native plant garden for which the neighboring trees were destroyed. The neighbors objected to the removal of the trees that remain. The Recreation and Park Department agreed to leave them until they were replaced by native trees. Only 4 of the more than two dozen live oaks that were planted as replacements have survived. They are now about 36″ tall and their trunks are about 1″ in diameter.
Tank Hill, 2002

About 25 young trees were destroyed in 2004 at the west end of Pine Lake to create a native plant garden that is now a barren, weedy mess surrounded by the stumps of the young trees that were destroyed.
Pine Lake "Natural Area" 2011

About 25 trees of medium size were destroyed at the southern end of Islais Creek in Glen Canyon Park about 6 years ago in order to create a native plant garden.
Many young trees were recently destroyed in the natural area called the Interior Greenbelt. These trees were destroyed in connection with the development of a trail, which has recently become the means by which the Natural Areas Program has funded tree removals with capital funding.
Interior Greenbelt Natural Area, 2010. Courtesy SaveSutro

There was nothing wrong with any of these trees before they were destroyed. Their only crime was that they were not native to San Francisco. There are probably many other trees that were destroyed in the natural areas in the past 15 years. We are reporting only those removals of which we have personal knowledge.

If you care about the trees of San Francisco….

If you care about the trees of San Francisco, please keep in mind that the public will have an opportunity to comment on the proposal to remove thousands of trees in the city’s parks. There will be a public hearing on October 6, 2011, and the deadline for submitting a written comment is October 17, 2011*. Details about how to comment are available here.

*[ETA: The deadline for written comments has been extended to October 31, 2011, at the request of the Planning Commission.]

(1) Jacobs, Growth Habits of the Eucalyptus, 1955, page 67

(2) Doughty, The Eucalyptus, 2000, page 6

(3) San Francisco Presidio’s Vegetation Management Plan, page 28