In San Francisco, A Dying Forest Waits for Action

by on July 23, 2014

 
Sutro Forest is facing complications from invasive ivy that is choking its trees and interrupting its ecosystem. Photo by Becca Andrews.
 

 

Walk a few feet into the jungle on the west side of San Francisco’s Mount Sutro Open Space Reserve, and you’ll come to an unusual three-headed eucalyptus tree. Its single trunk is firmly rooted, and three trees sprout tenuously from the base, limbs stretching out away from the prevailing west wind and into the tangle of brown-and-green that dominates this 61-acre open space area.

We’re standing to the left of the trunk as a group of four cyclists pauses to study the Cerberus and debate their route. The apparent quirk of nature is an unexpected gift during their workout—they glance at the tree, they glance at their phones, they glance at the tree, they glance at each other, they glance at the tree.

Craig Dawson, meanwhile, just gazes at the tree. He stands at its base and surveys it and its surrounding plant life, gently probing the bark like a doctor searching for a diagnosis. To Dawson, who knows this place as well as anyone, the tree isn’t some kind of poetic, natural rebellion — it’s a sign that the forest is sick. The extra stress of multiple “heads” drains the tree’s main trunk of its water supply, turning what is referred to by Dawson as a “moisture sweet spot” into a stilled heart that will eventually give way to deep splits. Splits lead to breakage; breakage leads to limbs that crash to the ground with a sound Dawson likens to a clap of thunder. Sutro Forest is quickly becoming a hazardous place for hikers and bikers who want to escape the city without leaving it.

“If you hear something crack above you, just move quick,” Dawson says. “They call these falling branches widow-makers for a reason.”

Craig Dawson, executive director at Sutro Stewards, says that the forest cannot remain in limbo much longer without posing a real threat to its visitors. Photo by Becca Andrews.

Craig Dawson, the executive director of Sutro Stewards, says that the forest cannot remain in limbo much longer without posing a real threat to its visitors. (Photo by Becca Andrews)

Sutro’s once-thriving blue gum eucalyptus trees are dying for a variety of reasons, including age and drought, both of which make the trees more susceptible to disease, pests, and fire. And there are likely other causes yet to be identified by the master arborists and biologists studying the forest. But the foresters generally agree that time is running out for this urban forest, which is owned and managed by the University of California, San Francisco. At the moment, though, the university does not have an approved environmental impact report for maintenance, and in the absence of major work conditions are deteriorating fast. Dawson’s eight-year-old nonprofit, Sutro Stewards, has built and maintained trails through the forest, and performs some small-scale tasks, but the Stewards’ resources are limited. Attempts to come up with an updated management plan have stalled, so for now the Sutro Forest remains in limbo.

Until the late 1800s, the centrally located prominence that would soon be named Mount Sutro was covered in native coastal shrubs, grasses and wildflowers. It was most definitely not a forest. But Adolf Sutro, at the time the mayor of San Francisco, owned the hill, and a forest was what he wanted on his hill. So in 1886 he planted imported blue-gum eucalyptus and other fast-growing non-native trees  in honor of Arbor Day. Sutro’s efforts 130 years ago birthed the modern forest, which is problem number one: The typical life span of a blue gum eucalyptus in California is about a century, Dawson says. But that’s not Sutro’s problem any more. In 1895, Sutro donated 13 of Mount Sutro’s acres to UCSF, and the university bought another 90 acres that included the rest of the hill in 1953. Since then, UCSF’s relationship with the area, and its attempts to come up with a plan for it, have been complicated by the passionate voices of community members who have become invested in their local open space but who don’t necessarily agree on how it should be cared for.

The Sutro Stewards, along with a handful of master arborists, thought they had a workable plan in January 2013, when UCSF released a draft EIR that announced intentions to reduce the fire risk by thinning the forest and removing the dying eucalyptus trees. That plan, however, was met with fierce opposition from people who considered the removal of trees—any trees—as destruction of their beloved forest. The draft document received more than 300 comments, many of which argued that nature should be allowed to take its course in Sutro Forest. The uproar effectively stymied further action: In November 2013, the university announced that it was planning for a new EIR taking an entirely different approach and managing the forest solely for fire danger (mainly by bulldozing particularly dangerous areas); in February 2014, a university spokesperson said that that EIR had been withdrawn, and that work on the original draft EIR was continuing. UCSF’s website states that the delay is due to an “unforeseen workload.”

Damon Lew, UCSF’s assistant director of community relations, says master arborist Kent Julin is helping the university draft a new EIR, tentatively slated for release this fall, that will address all 300 comments. Julin says he can’t discuss the new report’s progress, but says that the state of Sutro Forest is grim. Invasive species like blackberry and English ivy are overwhelming the ecosystem and choking the previous inhabitants—and, more importantly, creating a severe fire hazard by collecting “fine fuel” like twigs and leaves. Typically, in a forest like this, a disturbance of some sort—like a fire—would clear the thick understory and allow new trees to grow. But fire isn’t an acceptable management option in a densely populated city where local firefighters have more experience with burning buildings than  forest fires,

But some now argue that never mind an intentional, controlled burn: the entire area could go up in an uncontrolled blaze. Longtime San Francisco city gardener, native plant advocate, and Sutro Steward volunteer Jake Sigg sees fire as a distinct possibility in the city’s drought-stressed, sick eucalyptus groves.

“People find it hard to credit the possibility of a fire in these areas,” Sigg wrote in his Nature News email newsletter on June 10. But he describes stumbling into a chest-high pit of dry fuel five years ago and having an “epiphany” about the alarming level of fuel accumulation in the forest. “The long strips of annually-shedding blue gum bark have been known to carry fire 12 miles, enough to carry glowing embers from San Francisco to the East Bay hills,” he wrote. “At the risk of sounding alarmist, it is not unrealistic to portray a scenario of a rare General Alarm fire.”

Julin says he agrees, especially given this year’s drought. “On any given day in the summertime, if there’s no fog, there’s a potential for a fire.”

Although UCSF does basic fire prevention maintenance—last summer, workers cleared vegetation away from the roads through the grove and this year cut back growth from campus housing and other UCSF structures— Dawson and Julin say they worry it’s not enough. “The issue that we have been talking about for 16 years has suddenly come to a boil,” Dawson said. “There’s no question these trees are sick, there’s no question whether these trees are going to survive—they are not—and this [current state of the forest] is a game changer.”

As he walks through the forest Dawson gestures at thick ivy and blackberry vines that  snake their way up pale tree trunks. Among other impacts, the brambly mess makes it difficult for birds of prey, such as the great horned owl, to hunt rodents, forcing the birds to  the forest’s outer edges. A dead tree catches Dawson’s eye. The trunk, barely visible through the thick green net of ivy, is huge, but as it stretches into the sky, the branches are smaller and bare. The only green is the emerald of the ivy, and the only sign of the former canopy is the skeletal remains of dead eucalyptus.

“Look at that, that’s all ivy, the tree is being supported just by ivy,” Dawson says.

The problems have become so great, the tangle in the forest so dense, that there is no easy solution. Bulldozers can temporarily clear away blackberry and ivy, but that also spreads  the seeds, ensuring the invasive plants will come back just as strong. Eucalyptus themselves are notoriously difficult to remove: cut the trunk off and they will resprout if not treated. Bag the trunk to prevent regrowth and the tree can resprout in multiple places, all along its roots. Poison the tree and it will suck up the poison and send it out into its roots, killing everything around it. To remove a single tree can cost thousands of dollars; multiply that by the 45,000 (or so) trees in the reserve.

Back at the foot of the three-headed tree, the cyclists decide to take a trail that veers off in the opposite direction of the unnatural phenomenon. They zip off through the trees, calling back and forth to each other. A few joggers also pass by, earbuds in, enjoying the breeze filtering through the forest. Dawson and I pick our way back through the dense understory, listening carefully for the slightest hint of a cracking branch.

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12 comments:

Jeff Miller on July 23rd, 2014 at 3:21 pm

Why should action be taken to save invasive species that harm our native plants and wildlife? Blue-gum eucalyptus is a nasty invasive species that prevents undergrowth of many native plants, gums up the bills of native birds not adapted to them, and poses a severe fire risk. The eucalyptus should be removed. Does the author even see the irony in the statement that “invasive species like blackberry and English ivy are overwhelming” the invasive eucalyptus?

prc food on July 23rd, 2014 at 4:53 pm

Do you believe everything someone tells you?

The eucs do not gum up birds beaks – that is an odd and interesting fallacy.

The eucs are LESS flammable than grasses and bushes (native or not). There has not been a fire on Mt Sutro or Mt Davidson since the Great Depresseion when “hoboes” were living there and making fires.

The eucs CAPTURE water from the fog and channel it into the forests, where the ground in the untouched unthinned areas is moist year-round.

Understory plants are inhibited by most tree species; oak inhibits more plant growth than do eucalypts.

Incidentally, the eucs are not “invasive” – their population has not increased or moved into areas not originally planted.

And – not sure how you like the Mission’s warm climate, but it’s those trees that stop the wind and fog from covering the entire city and bay – which is what SF life included BEFORE they were planted.

There is much to learn about our city biome. Links to Commonwealth Club talks::

Dr. Joe R. McBride http:
//sfforest.net/2014/07/10/understanding-eucalyptus-in-the-bay-area-dr-joe-r-mcbride/

Dr. Scott Carroll http:
//www.commonwealthclub.org/events/archive/podcast/scott-carroll-conciliation-biology-13014

Dr. Arthur M. Shapiro http:
//www.commonwealthclub.org/events/archive/podcast/arthur-m-shapiro-ecological-communities-and-march-time-32414

Dig into the info, and think some more…

Camp Mothers on July 23rd, 2014 at 8:11 pm

“Look at that, that’s all ivy, the tree is being supported just by ivy,”

Right, defying the laws of physics. Pretty unlikely.

About the owls – please don’t cut down any more trees! Glen Canyon lost so many of its owl trees, and owls ended up trying to find homes on Diamond Heights condo balconies…

And, though against the law during the nesting season, there has already been extensive tree trimming.

About bugs or diseases – they are ever present in any species population, but do we exterminate species because a few individuals have health problems? Not humans. Not humane.

The dryest parts of Sutro Forest are the parts that have been thinned or cut back. The deep green is still just fine.

Someone ask Dawson to stop his extreme domination of our lovely SF treasure.

Mille Trees on July 24th, 2014 at 5:35 am

As usual, Bay Nature asked the opinion of those who are demanding the destruction of the urban forest and they get the answers they want. No one who is opposed to the destruction of the forest is asked their opinion, including the certified arborists who say the forest is healthy or the academic ecologists who have said that Mr. Dawson’s amateur opinion of the health of the forest is “pure twaddle.” After all, Mr. Dawson is just trying to earn a living and his chosen profession is destroying trees and replacing them with little colored flags, so why shouldn’t we take his word for it?

For starters, Mr. Dawson is mistaken that eucalyptus trees typically live one hundred years. Tasmanian blue gum lives in Australian from 200-500 years, towards the longer end of that range in milder climates such as ours. The library is full of reference books that would provide such basic information, but why read a book when you can ask Mr. Dawson’s opinion?

Blue gum is drought tolerant and lives successfully in drier and hotter climates. Claims that the trees are dying of drought are ridiculous. The tall trees condense the fog and double the amount of precipitation in the forest. Where the trees are left alone the trail is wet with puddles. Where the trees have been destroyed in the past year, the trail is dry. The limbs of the trees that are destroyed are left lying around in brush piles, bonfires waiting to happen.

There is no economic interest in saving trees. All the economic interest is in destroying them. Therefore, they will be destroyed. That’s the American Way! And Bay Nature will actively participate in that destruction.

Mille Trees on July 24th, 2014 at 8:44 am

As usual, Bay Nature asked the opinion of those who are demanding the destruction of the urban forest and they get the answers they want. No one who is opposed to the destruction of the forest is asked their opinion, including the certified arborists who say the forest is healthy or the academic ecologists who have said that the amateur opinion of the health of the forest is “pure twaddle.” After all, why not take the word of those who are just trying to earn a living and whose chosen profession is destroying trees and replacing them with little colored flags?

Mr. Dawson is mistaken that eucalyptus trees typically live one hundred years. Tasmanian blue gum lives in Australia from 200-500 years, towards the longer end of that range in milder climates such as ours. The library is full of reference books that would provide such basic information, but why read a book when you can ask Mr. Dawson’s opinion?

Blue gum is drought tolerant and lives successfully in drier and hotter climates. Claims that the trees are dying of drought are ridiculous. The tall trees condense the fog and double the amount of precipitation in the forest (empirically proven). Where the trees are left alone the trail is wet with puddles. Where the trees have been destroyed in the past year, the trail is dry. The limbs of the trees that were destroyed a year ago are left lying around in brush piles, bonfires waiting to happen.

There is no economic interest in saving trees. All the economic interest is in destroying them. Therefore, they will be destroyed. That’s the American Way!

Keith McAllister on July 24th, 2014 at 9:52 am

The ivy is holding up the dead eucalyptus? Well, that’s the kind of silly statement you get when self-styled “experts” talk to like minded ideologues. You can say anything you like if it puts eucalyptus in a bad light; no one in that hermetic community asks for evidence.

The “diseased forest” attack is relatively new. The expected public enthusiasm for pointless native plant restoration didn’t materialize. FEMA asked UCSF for evidence that Mt Sutro was a fire hazard; UCSF didn’t have evidence and withdrew their application for FEMA funding for the project. Scientific studies have shown a diverse biological community in eucalyptus forests, not the claimed “biological desert.” Thus the original foundations of the assault on our urban forests have collapsed, making a new rationalization necessary.

Sutro Stewards presented a list of tree diseases and pests, with no evidence that they actually exist on Mt Sutro, and, for the ones that do exist, no evidence that they are present at levels unusual in a normal 100 year old forest. I could also compile a list of serious human diseases that could be present in San Francisco. But if I then claimed the population faces imminent doom, you would probably ask for some evidence that the diseases were actually here, and at alarming levels.

Lu on July 24th, 2014 at 11:48 am

This incredible forest has been under attack for years now. And yet it still thrives, and looks best in areas where there are the most trees. The trees work together synergistically to support each other from wind and draw in the moisture from fog. In areas where the forest is thinned out, it’s dry and dusty and not nearly as pretty.

People need to realize that some of these “nativist” folks are dupes in the big chemical business plan. Somewhere in Australia, someone who has swallowed the nativist kool-aide is frantically pouring Monsanto or Dow toxics over a redwood tree (invasive!!) or a group of California poppies (exotic!!) and the end result is that we are all being poisoned.

We have finite water, especially here in CA. How much of this killing of healthy trees and pouring on of toxics “to prevent resprouting!!” (and now forest disease!!”) can we handle? People seem to miss the connection between shrinking forests/urban sprawl and human sickness.

The toxic application of pesticides that nativism requires is causing human sickness and robbing wildlife of habitat.

from Earth Island Institute: “Denial: To be found everywhere we look: in the corporations that place profit over people, communities, and nature; in the politicians who make decisions that will help the financial picture for their short tenure, but harm the environment for all who come after; and in the logging and fishing companies that use unsustainable practices.

As long as certain assumptions go unchallenged, denial can maintain itself (the Titanic can’t really be sinking, it must just be making a banked turn). It is the illusion that if it is not in my backyard yet, then it is not really a problem–at least not for me.”

We are the only species systematically destroying our habitat. And the habitat of other beings. Stop killing trees and wildlife for your own gain, and stop trying to turn back the clock to when the landscape was different. The earth is trying to evolve and without these pesticides. Wake up, please.

Jeff Miller on July 25th, 2014 at 3:12 pm

The usual vitriol, hyperbole and insults from the “save the invasive trees” crowd.

Lu jumps to the assumption that anyone who wants to restore native habitats wants to use pesticides or is a dupe of the chemical industry. In response: http://www.biologicaldiversity.org/campaigns/pesticides_reduction/index.html

prcfood: I believe what I see with my own eyes and I’ve seen several native birds with gummed up beaks from foraging on eucalyptus, and I regularly talk with ornithologists and experienced birders who have seen the same thing. Thanks for the patronizing comments though.

Keith McAllister on July 26th, 2014 at 2:18 pm

“a nasty invasive species?” Sounds like Jeff is the one reacting with vitriol and hyperbole. And the emotion is based on being factually incorrect. Blue gum eucalyptus does not invade. That’s the simple fact. There are rare circumstances where blue gums can spread when streams carry their seeds, or seeds fall down hill. But basically the blue gums just sit where they were planted. The land covered by blue gums in the Bay Area is shrinking, not expanding. Even the euc-hating California Invasive Plant Council says blue gum has “low invasive potential” with a “stable population in California.” It is simply an abuse of the English language to call them “invasive.”

The beak gumming myth should be retired. The story has been passed around in the hermetic native plant community for 15 years without any evidence surfacing. Try it Jeff. Spend some time on Google Scholar trying to find a single piece of scientific evidence that eucalyptus kills birds by gumming beaks. If it really happened, it should be pretty easy to come up with some evidence. Someone could present some dead birds, together with an analysis of any substance found on their beaks. Get it published in a refereed scientific journal. But so far, nothing, absolutely nothing. A few people claiming to see dirty faces on some birds just doesn’t cut it. Dirty faces don’t kill birds (or toddlers).

Lu makes no *assumption* that native plant fanatics want to use pesticides. They do, in fact, use them now. San Francisco’s Natural Areas Program uses lots, more than all the rest of the Recreation and Park Department combined. (With the exception of Harding Golf Course, where there are contractual obligations to the PGA to keep that artificial landscape free of all weeds.) UC Berkeley and East Bay Regional Parks are now using, and plan to continue to use, pesticides in their futile attempts to “restore” native plants. And your link to Center for Biological Diversity is most telling. CBC is proud to oppose pesticide use by agriculture, golf courses, town house managers, etc. But they always carve out an exception in their settlement agreements: pesticides can be used to kill non-native plants if the claim is made that so doing will benefit native species. Simple hypocrisy. Oh, but that may be insulting.

Jeff Miller on July 28th, 2014 at 7:15 am

Keith McAlister your comments about eucalyptus are delusional. It turns out, eucalypts are trees. They have seeds. That fall off the tree…and sprout. I used to live off Tunnel Road, where the East Bay hills fire was. I’ve seen eucalypts expand their range and invade an area, both pre- and post-fire.

Regarding pesticides – how many lawsuits have you won that resulted in sweeping restrictions on pesticide use on hundreds of thousands of acres in CA? None, I suspect. We’re proud of our accomplishments protecting endangered and native CA species from pesticides. Try to find another organization that has done more to protect wildlife and people in CA from pesticides. Difference between you and me is I actually do the rerstoration work, while you seem to dwell in the comments section trying to prove you are purer and holier than all the rest.

Keith McAllister on July 28th, 2014 at 8:13 am

My comments on eucalyptus are based on scientific studies done by scientists who actually examine what happens in eucalyptus forests. Not based on stories passed around within an ideological community of euc haters. Yes, eucs have seeds. But they are not seeds eaten by wildlife and transported elsewhere. They are tiny and dense–not carried by wind. So the sprouts occur right under the parent tree. As I said above, they can sometimes fall down hill or be carried downstream by water. But that is rare in California. Read some science; it is not controversial that E. globulus is not spreading in California. Unfortunately CBD is made up primarily of lawyers, not scientists.

Nothing you have said about CBD and pesticides contradicts what I said. You object to pesticide use EXCEPT when used in your crusade against native plants.

Really, “purer and holier?” That’s CBD in a nutshell.

Mille Trees on July 28th, 2014 at 11:36 am

Mr. Miller is another example of my original comment: those who advocate for the destruction of the forest are earning their living on these destructive projects. He is employed by the Center for Biological Diversity. His job description is “writes press and outreach materials…does community organizing and media work.” In other words, he is just doing his job by trying to discredit our defense of the forest.
There is no money in saving trees. All the money is in destroying them. Therefore they will be destroyed. It’s the American Way!
Although we are not paid to defend our urban forest, here is a brief list of what we are doing for the environment in contrast to those who are paid to destroy it: We are not killing useful animal habitat with herbicides. We are not destroying trees that are storing millions of tons of carbon that is released into the atmosphere as carbon dioxide when they are destroyed.
First, do no harm. It is a principle that is lost on the people who are earning their living destroying our urban forest.

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