Refuting Jake Sigg: No, 90% of Insects Do Not Eat Only Native Plants

Jake Sigg, considered the doyen of San Francisco’s native plant activists, has an influential newsletter. Recently, it said: “Did you know that 90 percent of insects can only eat the native plant species with which they’ve co-evolved?” It included a link to a video from the California Native Plant Society (CNPS) … which provided no evidence for the statement at all. Nor was there any data to substantiate the claim – which is false. In fact, as Professor Art Shapiro points out, insects easily adapt to using other plants than the ones  they “co-evolved” with. He notes, “… the urban-suburban California butterfly fauna is now overwhelmingly dependent on non-native plants.

FIRST, THE NATIVE PLANT SOCIETY VIDEO

Here’s the link to the video:  Plants are the Foundation. https://www.facebook.com/YerbaBuenaCNPS/videos/459268941549309/

Not only did the video from not contain any reference to 90% of insects, it was in itself an interesting piece of sleight-of-hand. It made the fair point that plants were the foundation of the web of life.

Then, I suppose because it was from CNPS, it said: “None of us can live without them, especially native plants” and “Native plants support local wildlife”… the video shows a Western Tiger Swallowtail butterfly fluttering in. They’re native butterflies, but they don’t need native plants. In San Francisco, they breed on (non-native) London Plane Trees that are found on Market Street and other urban streets, which means their caterpillars readily eat those non-native leaves.

The video continues...”and ecosystems. The web of life depends on them For habitat

And it illustrates this with a photograph of a great horned owl, which nests on large tall trees, usually non-native eucalyptus, as in this photograph below.

Bumblebee on oxalis flower

Bumble bee on wild radish flower

 

“for food”

Then it shows a bumblebee on a Western thistle (native)… except that bumblebees happily nectar on a vast number of non-native plants, including wild radish and the yellow oxalis that Jake Sigg loves to hate.

Then it adds a picture of a Monarch butterfly… which does indeed depend on milkweed as its nursery plant (though it nectars on non-native ivy flowers as well as eucalyptus blossoms). But it readily breeds on non-native milkweed as well as native milkweed (and contrary to some native species activists, non-native milkweed does not spread disease or reduce breeding success). More to the point, the western migration of the Monarch butterfly relies heavily on (non-native) eucalyptus trees to over-winter in. Without the eucalyptus, the western migration will probably die out.

It argues that habitat is shrinking (with a picture of a highway in LA), which is perhaps reasonable (though farming is more likely the culprit than urban sprawl). And goes on to suggest planting native plant gardens. That’s not objectionable in itself, of course, but it’s planting a mix of various kinds of plants that will benefit the most species.

So though the video certainly shows the need for plants as the basis of an ecosystem, it emphatically does not make the case for native plants.

NO, 90% OF INSECTS DO NOT DEPEND ON NATIVE PLANTS

We reprint, with permission and minor changes, a thorough refutation of the statement from Professor Art Shapiro, published on the Million Trees blog. In sum, Professor Shapiro challenges the statement, and points out that “ecological fitting” – which allows species that didn’t “co-evolve” to interact – is very common. He cites examples from all over the world.

ERADICATING NON-NATIVE PLANTS DOES NOT BENEFIT INSECTS

We briefly reactivate the Million Trees blog to publish an interesting and important debate between Jake Sigg and Professor Art Shapiro about the relationship between insects and native plants.  Their debate was initiated by this statement published in Jake Sigg’s Nature News on April 26, 2019:

“Did you know that 90 percent of insects can only eat the native plant species with which they’ve co-evolved?”

Jake Sigg has been the acknowledged leader of the native plant movement in the San Francisco Bay Area for 30 years.  He is a retired gardener for the Recreation and Parks Department in San Francisco. Art Shapiro is Distinguished Professor of Ecology and Evolution at UC Davis.  He has studied the butterflies of Central California for 50 years.

Jake and Art are both passionately committed to the preservation of nature, but their divergent viewpoints reflect their different experiences.  Jake’s viewpoint is based on his personal interpretation of his observations.  As a gardener, his top priority is the preservation of plants rather than the animals that need plants.  As a scientist, Art’s viewpoint is based on empirical data, in particular, his records of plant and butterfly interactions over a period of 47 years as he walked his research transects about 250 days per year. The survival of butterflies is Art’s top priority.

Although their discussion is informative, it does not resolve the questions it raises because Jake and Art “agree to disagree.”  Therefore, Million Trees will step into the vacuum their discussion creates to state definitively that it is patently false to say that “90% of insects can only eat native plants.” That statement grossly exaggerates the degree of specialization of insects and underestimates the speed of adaptation and evolution.

There are several reasons why insects do not benefit from the eradication of non-native plants:

  • Insects use both native and non-native plants.
  • Pesticides used to eradicate non-native plants are harmful to both plants and insects as well as the entire environment.
  • There is no evidence that insects are being harmed by the existence of non-native plants.

INSECTS USE BOTH NATIVE AND NON-NATIVE PLANTS

This statement was recently made in an article published by Bay Nature magazine about Jake Sigg:  “More than 90 percent of all insects sampled associate with just one or two plant families.”  (7,500 insect species were sampled by the cited study.  There are millions of insect species and their food preferences are largely unknown.)  This exaggerated description of specialization of insects seems the likely origin of the subsequent, inappropriate extrapolation to the statement that specialized insects require native plants.

Anise Swallowtail butterfly in non-native fennel. Courtesy urbanwildness.org

There are over 600 plant families and thousands of plant species within those families.  Most plant families include both native and non-native plant species.  An insect that uses one or two plant families, is therefore capable of using both native and non-native plant species.

We will use the Oxalidaceae plant family to illustrate that insects can and do use both native and non-native plants.  Oxalidaceae is a small family of about 5 genera and 600 plant species.  We choose that family as an example because Jake Sigg’s highest priority for eradication is a member of that plant family, Oxalis pes-caprae (Bermuda buttercup is the usual common name)In a recent Nature News (April 9, 2019), Jake explained why:  Oxalis is not just another weed; this bugger has a great impact on the present and it will determine the future of the landscapes it invades.”

Five members of the Oxalis genus in the Oxalidaceae family are California natives. An insect that uses native oxalis can probably also use the hated Bermuda buttercup oxalis because they are chemically similar. 

Honeybee on oxalis flower, another non-native plant being eradicated with herbicide

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THE CONSEQUENCES OF ERADICATING NON-NATIVE PLANTS

Partly because of Jake’s commitment to eradicating non-native oxalis, San Francisco’s Recreation and Parks Department has been spraying it with herbicide for 20 years Garlon (triclopyr) is the herbicide that is used for that purpose because it is a selective herbicide that does not kill grasses in which oxalis usually grows.  Garlon is one of the most toxic herbicides available on the market.  More is known about Round Up (glyphosate) because it is the most widely used of all herbicides.  However, according to a survey of land managers conducted by California Invasive Plant Council in 2014, Garlon is the second-most commonly used herbicide to eradicate non-native plants.

Garlon is toxic to bees, birds, and fish.  It is an endocrine-disrupter that poses reproductive and developmental risks to female applicators.  It damages the soil by killing mycorrhizal fungi that are essential to plant health by facilitating the transfer of nutrients and moisture from the soil to plant roots. 

A recent article in the quarterly newsletter of Beyond Pesticides explains that insecticides are not the only killers of insects: “Insecticides kill insects, often indiscriminately and with devastating consequences for biodiversity, ecosystem stability, and critical ecosystem services. Herbicides and chemical fertilizers extinguish invaluable habitat and forage critical to insect survival. Taken together, insecticides, fungicides, herbicides and chemical fertilizers make large and growing swaths of land unlivable for vast numbers of insect species and the plants and animals they sustain.” The loss of insects where herbicides are used to kill non-native plants are undoubtedly contributing to the failure of attempts to “restore” native plants which require pollinators and insect predator control as much as non-native plants.

In other words, eradicating non-native oxalis is damaging the environment and the animals that live in the environment.  Furthermore, after twenty years of trying to eradicate it, Jake Sigg admits that there is more of it now than there was when this crusade began:  “Maybe you’ve noticed that there’s more and more of it every year, and fewer and fewer other plants.  That is unlikely to reverse.”  (Nature News, April 9, 2019).

Coyote in oxalis field. Copyright Janet Kessler

In fact, local failure of eradication efforts mirrors global failures of similar attempts:  “…despite international policies aimed at mitigating biological invasions, the implementation of national- and regional-scale measures to prevent or control alien species has done little to slow the increase in extent of invasions and the magnitude of impacts.” 

[Ref: “A four-component classification of uncertainties in biological invasions: implications for management,” G. LATOMBE , S. CANAVAN, H. HIRSCH,1 C. HUI, S. KUMSCHICK,1,3 M. M. NSIKANI, L. J. POTGIETER, T. B. ROBINSON, W.-C. SAUL, S. C. TURNER, J. R. U. WILSON, F. A. YANNELLI, AND D. M. RICHARDSON, Ecosphere, April 2019.]

DO INSECTS BENEFIT FROM ERADICATING NON-NATIVE PLANTS?

There is no question that insects are essential members of every ecosystem.  They are the primary food of birds and other members of wildland communities.  They perform many vital functions in the environment, such as consuming much of our waste that would otherwise accumulate.

The Economist magazine has reported the considerable evidence of declining populations of insects in many places all over the world.  (However, the Economist points out that the evidence does not include large regions where insect populations have not been studied. The Economist is therefore unwilling to conclude that the “insect apocalypse” is a global phenomenon.) The report includes the meta-analysis of 73 individual studies that describe declines of 50% and more over decades. The meta-analysis concluded that there are four primary reasons for those declines, in order of their importance:  habitat loss, intensive farming, pesticide use, and spread of diseases and parasites.  The existence of non-native plants is conspicuously absent from this list of threats to insect populations.

In other words, although the preservation of insects is extremely important, there is no evidence that the eradication of non-native plants would benefit insects.  In fact, eradication efforts are detrimental to insects because of the toxic chemicals that are used and the loss of the food the plants are providing to insects.

JAKE SIGG AND PROFESSOR SHAPIRO DISCUSS INSECTS AND NATIVE PLANTS

The discussion begins on April 26, 2019, with this statement published in Jake’s Nature News:

“Did you know that 90 percent of insects can only eat the native plant species with which they’ve co-evolved?”

On April 26, 2019, Arthur Shapiro wrote:

“No, I didn’t know 90% of insects can only eat the native plants with which they’ve co-evolved. I’ve only been studying insect-plant relationships and teaching about them for 50 years and that’s news to me, especially since on a global basis we don’t know what the vast majority of insects species eat, period! That’s even true for butterflies and moths, which are probably the best-studied group. And it’s even true here in California, one of the best-studied places on the planet (though way behind the U.K. and Japan). Where on earth did that bit of non-information come from?”

Jake Sigg responds:

“Art, I did my best to run down source for that statement.  As I suspected, it may lack academic precision.  That kind of precision is hard come by, and what exists is not entirely relevant.  Most of the information comes from Doug Tallamy.  But the statement is not accurate; it should have read “…90 percent of plant-eating insects eat only the native plants they evolved with”.  Whether that is true or not I don’t know, but it accords with my understanding and I am willing to go along with it, even if proof is lacking.  If you wait for scientific proof on everything you may wait a long time and lose a lot of biodiversity.  I have had too much field experience to think that exotic plants can provide the sustenance that natives do.

I expect you will be unhappy with this response.”

On May 2, 2019, Art Shapiro replies:

“If Tallamy said “90% of the plant-eating insects that I have studied…”  or “90% of the plant-eating insects that have been studied in Delaware…” or some such formulation I might take him more seriously. The phenomenon of “ecological fitting,” as described by Dan Janzen, is widespread if not ubiquitous. “Ecological fitting” occurs when two species with no history of coevolution or even sympatry (co-occurrence) are thrown together and “click.”  A.J.Thorsteinson summed up some 60 years ago what is needed for an insect to switch onto a new host plant: the new plant must be nutritionally adequate, possess the requisite chemical signals to trigger egg-laying and feeding, not possess any repellents or antifeedants and not be toxic.

That set of circumstances is met very frequently. To those of us who study it, it seems to happen every other Tuesday.  As we showed, the urban-suburban California butterfly fauna is now overwhelmingly dependent on non-native plants. The weedy mallows (Malva) and annual vetches (Vicia) are fed upon by multiple native butterfly species and are overall the most important butterfly hosts in urban lowland California. . Within the past decade, our Variable Checkerspot has begun breeding spontaneously and successfully on Butterfly Bush (Buddleia davidii). The chemical bridge allowing this is iridoid glycosides. When I was still back East I published that the Wild Indigo Dusky Wing skipper, Erynnis baptisiae, had switched onto the naturalized European crown vetch (Coronilla varia) which had converted it from a scarce and local pine-barrens endemic to a widespread and common species breeding on freeway embankments. And the hitherto obscure skipper Poanes viator, the Broad-Winged Skipper, went from being a rare and local wetland species best collected from a boat to becoming the most abundant early-summer butterfly in the New York metropolitan area by switching from emergent aquatic grasses and sedges to the naturalized Mesopotamian strain of Common Reed, Phragmites australis. I can go on, and on, and on. If you find a sponsor for me to give a lecture about this in the Bay Area, I’ll gladly do it. If you promise to come!

I won’t snow you under with pdfs. Here’s just one, a serendipitous one that resulted from my walking near Ohlone Park in Berkeley. And one from the high Andes in Argentina. That paper cites one of mine in Spanish demonstrating that the southernmost butterfly fauna in the world, in Tierra del Fuego and on the mainland shore of the Straits of Magellan, is breeding successfully on exotic weeds.-! Copy on request.”

On May 2, 2019, Jake Sigg published his last reply:

“I believe many of your statements, Art, and many of these cases I am familiar with.  A conspicuous local example is the native Anise Swallowtail butterfly that still lays eggs on native members of the Umbelliferae, the parsley family, but which also breeds on the exotic fennel, which is an extremely aggressive weed that in only a few years can transform a healthy and diverse grassland supporting much wildlife into a plant monoculture—that, btw, won’t even support the butterfly, which shuns laying eggs where its larval food plant is too numerous and easy target for a predator, like yellow jackets.

What puzzles me is why you can keep your equanimity at the prospect of losing acres of very diverse habitat to a monoculture of fennel.  You live in the heart of the world’s breadbasket where for hundreds of miles both north and south there are almost no native plants except those planted by humans.  That would tend to distort one’s view.  I don’t mean to be flip, but it is not normal for even an academic to be indifferent about a loss of this magnitude.  I have worked hands-on on the land (I was raised on a ranch) all my life and still work every Wednesday maintaining our natural habitat in San Francisco—a task that hundreds of citizens pitch in on because they value the quality and diversity of the areas.  And why do you remain indifferent, are you just a contrarian?  You cite examples to bolster your view, but the examples are too small a percentage to be meaningful and wouldn’t stand up against a representative presentation.

I got my view from life.  I type this in my second-floor sunroom, which looks into a coast live oak growing from an acorn I planted in the late 1960s, about 50 years ago and which is immediately on the other side of the window.  It is alive with birds of many different species—flocks of bushtits, chickadees, juncos every day (plus individuals of other species), which species-number balloons in the migratory season.  What I can’t figure out is how the tree can be so productive as to stand up to this constant raiding.  I will take instances of this sort as my guide rather than the product of academic lucubrations.  And I will throw in Doug Tallamy; the world he portrays is one I recognize and love.

I think our battle lines are drawn.  This discussion could go on, as we have not even scratched the surface of a deep and complex subject.  But will either of us change our minds?  No.”

“Jake Sigg:  N.B.  Art responded with another long epistle, not for posting.  It clarified some of the points that were contentious and seemed to divide us.  We differ, but not as much as would appear from the above discussion.”


On a personal note, we’d like to point out that one of the writers of this article has a (non-native) red wattle tree outside their window – which also attracts bushtits, juncos, and chickadees, not to mention hummingbirds (both Anna’s and Allens), house finches, white-crowned sparrows, and a bunch of other species. Oak trees are certainly good habitat – but so are a lot of other plant and tree species, where ever they originate.

 

Drought-Adapted Eucalyptus NOT Dying by the Thousand

This is a recent post from SutroForest.com, republished with permission and minor edits. We think it is important because the allegation that tens of thousands of eucalyptus trees are dying can be used as an excuse for forest destruction.

Jake Sigg, retired San Francisco Recreation and Parks Department (SFRPD) gardener who is considered the doyen of the Native Plant movement in San Francisco, has a widely circulated email newsletter. In it, he has been pushing the argument that thousands of eucalyptus trees in San Francisco are dying of drought, as evidenced by epicormic growth on these trees: “2015 is the year of decision, forced upon us by 20,000 to 30,000 dead trees.” He is suggesting they will be a fire hazard and that SFRPD act, presumably by cutting down the trees. In a recent post, he published a picture of a tree covered in young blue-green leaves, and predicted it would be dead within a year.

But he’s mistaken.

Eucalyptus trees are drought-adapted, and the shedding of mature leaves followed by sprouting of juvenile leaves (epicormic sprouting) is one of their defense mechanisms. These trees survive in areas far drier than San Francisco, where fog-drip provides an important source of summer moisture.

2015-05-27 ab eucalyptus with epicormic growth wordEUCALYPTUS RESPONSE TO DROUGHT

Eucalyptus trees are adapted to drought. They shed mature leaves and twigs so they don’t lose water through transpiration (the tree version of breathing, which takes place mainly in the leaves.) Later, they can replace the lost branches and leaves through “epicormic sprouting.”

Blue gum eucalyptus trees have buds buried deep under their bark. When the tree is stressed, they may shed adult leaves and later sprout new leaves along their branches. When you see a eucalyptus tree that seems to have shaggy light bluish-green new leaves along its branches or trunk – that’s epicormic sprouting.

Here’s what Jake Sigg said in a recent newsletter: “According to arborists, the trees produce these abnormal shoots from epicormic buds when their lives are seriously threatened. In this case, the tree is expected to be dead by the end of 2015. On Bayview Hill, barring heavy unseasonal rain, hundreds of the trees will be dead this year. Yet the City continues to not see a problem.”

We asked UC Berkeley Professor Emeritus Joe McBride and California’s leading expert on eucalyptus for his opinion. He’s observed this condition in trees along the edge of the Presidio forest and explains, “This response is common in blue gum as a mechanism to reduce transpiration rates in order to survive drought years.”

He continues: “I am not convinced that the trees will die in large numbers.

bayview-hill-2010 smTwo girdled trees

THE GIRDLED TREES OF BAYVIEW HILL

As an aside, we find it ironic that Mr Sigg should be so concerned with dead trees on Bayview Hill, given that’s where nativists girdled hundreds of healthy eucalyptus trees to kill them.

(This is done by cutting around the tree, thus starving it of nutrients that are carried only in the outer layers of the tree-trunk.) It’s clearly visible in the two photographs here, both taken on Bayview Hill.

EUCALYPTUS ADAPTS

Eucalyptus globulus thrives in Southern California, Spain, Portugal, India – all places hotter and drier than San Francisco. In fact, one of the reasons eucalyptus is so widely planted – including in climates both hotter and drier than in San Francisco – is that it adapts to a wide range of conditions. Here’s a quote from R.G. Florence’s textbook, Ecology and Silviculture of Eucalyptus Forests:

florence quote

From p.121 of the same book: “… they regulate their water usage in hot dry summers by closing their stomata [breathing pores in the leaves] during the day and lowering their rates of gaseous exchange. They adapt by their elastic cell structure to water stress.”

EPICORMIC SPROUTING IS IMPORTANT IN EUCALYPTUS

Mr Sigg describes “how to identify a dying blue gum” as follows: “Look for trees with thinning foliage and copious juvenile leaves (called coppice shoots) hugging the main stems. These coppice shoots are easy to see because of their blue color and tight clustering, as opposed to the adult leaves, which are 6-8 inches-long, dull-olive-colored and sickle-shaped and which hang from the ends of long branches. These coppice shoots are the give-away that the tree is in trouble and is destined to die soon…” (He later corrected “coppice shoots” to epicormic growth.)

But again, this is not actually true.

In fact, epicormic sprouting allows eucalyptus to survive not only drought, as described above, but even fire. The epicormic sprouting grows into new branches to replace the ones that have been damaged in the fire. This is from Wikipedia: “As one of their responses to frequent bushfires which would destroy most other plants, many Eucalypt trees found widely throughout Australia have extensive epicormic buds which sprout following a fire, allowing the vegetative regeneration of branches from their trunks.[4][5] These epicormic buds are highly protected, set deeper beneath the thick bark than in other tree species, allowing both the buds and vascular cambium to be insulated from the intense heat.[4]”

(The references are: [4] “Effects of fire on plants and animals: individual level”. Fire ecology and management in northern Australia. Tropical Savannas CRC & Bushfire CRC. 2010. Retrieved 27 December 2010. [5] “Learn about eucalypts”. EUCLID – Eucalypts of Australia. Centre for Plant Biodiversity Research. Retrieved 27 December 2010.)

And sometimes, dead branches and leaves and epicormic growth don’t even indicate stress – it’s part of the normal growth cycle. R.G. Florence’s book on eucalyptus says: the “mature crown of a eucalypt maintains itself by the continual production of new crown units, which die in turn. There will always be some dead branches in a healthy mature crown.” He goes on to say an “undue proportion of dead branches is an unhealthy sign” but a “reasonable proportion of death of crown units should be accepted as normal.” He also discusses the “epicormic shoots from dormant buds on the top and sides of the branch develop into leaf-bearing units of the mature crown.” (p.13) Eucalypts go through stages of development that include extensive self-thinning, particularly in younger trees. (p. 194)

Another reason for epicormic sprouts on eucalyptus is increased light. From Wikipedia, with references: “Epicormic buds lie beneath the bark, their growth suppressed by hormones from active shoots higher up the plant. Under certain conditions, they develop into active shoots, such as when damage occurs to higher parts of the plant or light levels are increased following removal of nearby plant. Epicormic buds and shoots occur in many woody species, but are absent from many others, such as most conifers.” [The Wikipedia article references the Encyclopedia Britannica.]

We have seen these epicormic sprouts in eucalyptus trees around the clubhouse in Glen Canyon after many trees were removed.

epicormic sprouts on eucalyptus when nearby trees removed

We also saw them on Mount Sutro near where 1,200 trees were removed for “fire safety.”

MISTAKING DEFENSES FOR DEATH THROES

In summary, then, epicormic sprouting does not indicate that the tree is near death. It may indicate that the tree is responding to drought (or even to other stresses like pesticide use or damage to its root systems) with defensive measures. It’s like declaring that everyone who has a fever is bound to die of it. The trees below are the same ones featured in the picture at the start of this article – one year later, they’re surviving, not dying.

Epicormic sprouting on eucapyptus 2014In some cases, epicormic sprouting may indicate nothing at all, except that the tree is going through a normal growth phase, or changed light conditions following removal of nearby trees.

LIVING WITH A FEW DEAD TREES

We asked Dr McBride if it made sense to cut down these trees. “I do not think the city would be justified in cutting trees down as a fire prevention action,” he says. “Cutting down drought-stressed trees at this point would be much more costly, sprouting would be difficult to control without herbicides, and the litter on the ground would have to be removed to decrease the fire hazard.”

“The problem as I see it is the accumulation of leaves, bark, and small branches on the ground. This material presents a serious fuel problem when it dries out sufficiently.” However, he points out that “In many eucalyptus stands in San Francisco the eucalyptus ground fuel (leaves, bark, and small branches) seldom dries to a point that it can be ignited because of summer fog and fog drip.” In dry areas, the best course is to “launch a program of ground fuel reduction by removing the litter from beneath eucalyptus stands.”

The eucalyptus-tree nest hole of the red-shafted flicker - San Francisco. Janet Kessler

Eucalyptus-tree nest hole of red-shafted flicker – San Francisco. Copyright Janet Kessler

A few trees may indeed die, with the drought or without it. If you think of a forest as a normal population, you expect to find some trees that are in thriving and some that are hanging on, and some that are dying – just like in any population. And dead and dying trees are very valuable to wildlife: They’re more likely to have cavities that are suitable for nesting (and are easier to excavate for woodpeckers and other cavity-building species). They also have bugs that come to feast on the decaying wood, and that’s bird-food.

Land Grab by NAP – Expanding Mazanita “Designated” Area

Recently, the television station KPIX ran a story about the Franciscan manzanita. US Fish and Wildlife, threatened by a lawsuit, designated this plant as an endangered species.  It’s now in the process of designating critical habitat for it. This critical habitat includes part of Mt Davidson – and some private land in people’s back yards.

Here’s the video:

franciscan manzanita at Golden Gate Park

Click on the picture to see the KPIX video

Even supporters of Native Plants – such as Jake Sigg, interviewed for this TV clip – are saying this effort is expensive and futile. Meanwhile, plants grown from cuttings of the Doyle Drive specimen now grow in many botanic gardens (including Golden Gate Park),  as school yards, back yards and who knows where else, since the plants are commercially available for under $20.

So why did San Francisco Recreation and Parks’  Natural Areas Program add more land to the designated areas?

(See our story about that HERE, and an article about the neighbors’ reaction HERE. )

Open Letter to Jake Sigg: Transparency

[Note: This article is slightly modified from one that originally appeared at SutroForest.com.]

This is an open letter to Jake Sigg who has wrongly criticized the San Francisco Forest Alliance and Save Sutro Forest. We invite Mr. Sigg – doyen of San Francisco’s native plant activists and publisher of an email newsletter – to talk directly with us any time. We believe that talking to people with a different point of view is important.

However, let’s set the record straight with facts, shall we?

JAKE SIGG’S ALLEGATION

Dear Mr. Sigg,

Yesterday, your newsletter published a post regarding CalFire’s assessment of risk in San Francisco. It  included an astonishing allegation:

SF Forest Alliance/sutroforest.com has been known for selective quotations that alter or reverse what writers intended. We have all learned to question authority and to insist on transparency. SFFA/sutroforest.com needs to become transparent in its messages. Its withholding of the complete opinion of Cal-Fire deprives the public of the information it needs to protect itself.”

SETTING THE RECORD STRAIGHT

We object. We never “alter or reverse” what writers intended. We stand for transparency, and try as far as we can to include references so people can go back and look at sources if they wish. (In this post, relevant links are at the end of this article.)

Nor have we (or SutroForest.com) withheld “the complete opinion of CalFire.” In fact, what we have quoted of CalFire is taken from two sources that you or other readers may verify: The CalFire website; and the FEMA letter about Mount Sutro Forest.

(1) The CalFire website.

That is where we obtained this map, which shows that CalFire gives its lowest hazard rating to Sutro Forest (and most of San Francisco). We provide that link again here: CalFire Hazard Map.

CAL FIRE map shows Mt Sutro Forest has the lowest level of fire hazard (gray color indicates areas not rated - mainly built areas)

CAL FIRE map shows Mt Sutro Forest has the lowest level of fire hazard (gray color indicates areas not rated – mainly built areas). The blue and pink pointer lines added by us.

We also referred to the page on the CalFire website, where in an update it said:  “Update, 11/2008:
CAL FIRE has determined that this county has no Very High Fire Hazard Severity Zones (VHFHSZ) in LRA [Local Responsibility Area]…”

(2) A letter from FEMA to Cal EMA regarding UCSF’s application for funding to cut down trees on Mount Sutro.

Here is an excerpt from that letter, originally posted at SutroForest.com. It includes a conversation that FEMA had with a Wildland Fire Scientist in CalFire:

fire hazard FEMA critWe do not think that “alters or reverses” the intent of the letter. But if you wish to verify this, the full letter is linked at the end of this article.

SO IS WHAT CALFIRE SAID DIFFERENT?

Now for the substantive objection. We think that what we’re seeing is different conclusions reached by our opponents and ourselves.

What CalFire explained is that fire has two factors: Fuel Rank, and Rotation Rank (or the risk of ignition). Fuel rank is only density of vegetation, and all agree that the vegetation density in Mount Sutro Forest is high.

The second factor is the risk of ignition, and that is low in most of San Francisco. (The CalFire map above shows a little orange spot on the edge of San Mateo County that has High – but not Very High – risk.) San Francisco’s climate is cool and not extreme. Right now, while the rest of the country has a heat wave, the fog blows through our city.

forest 6Ignition risk is particularly low in Mount Sutro Forest, which lies directly in the city’s fog belt (as also in Mount Davidson, for the same reason). The Cloud Forest effect increases moisture levels considerably as the trees harvest moisture from the fog, and store it in the dense understory. It’s obvious that the best way to keep ignition risk low is to trap that moisture and reduce evaporation.

The post included in your newsletter describes an anonymous conversation with an unnamed person within CalFire.   It is unclear what recommendations discussed there come from the interviewer, or from an individual within CalFire. (Though you apparently consider it the “complete opinion of Cal-Fire,” it does not appear on the CalFire website.)

We hope to make our own contact with CalFire, and report on it.

WHY THE UCSF PLAN IS COUNTERPRODUCTIVE

Even if the UCSF Plan for Sutro Forest reduced the Fuel Rank (and we don’t see how it would, given that the Plan would be to fell the trees and leave them there as logs and chips), it would raise the ignition risk by drying out the forest, reducing both harvested and retained moisture, and by increasing wind velocities in this very windy part of San Francisco.

FEMA had similar questions for UCSF. This is again a quote from the same letter cited above.

FEMA Letter - drying the forestThis doesn’t look like a good trade-off, especially since this is not a distant wild-land, but in the midst of the city with access to water sources and fire-fighting capability.

map usgs ed paved roads in Sutro ForestThere is actually a fire-station on the Stanyan side of the forest, a fact that was cited during the hearing about opening the trail from Stanyan into the forest through SF RPD’s Interior Greenbelt. At that meeting, Ray Moritz (who was also hired by UCSF separately) allayed neighbors’ concerns about increased ignition risk from such a trail by saying that overall risk was low. The report of that meeting, written from contemporaneous notes, is HERE.

We don’t think a model based on increasing ignition risk while reducing fuel is workable for this site. And aside from the environmental damage this “solution” would cause, in reduced carbon sequestration, poorer pollution control, potential hillside destabilization, increased water run-off, lost habitat, and use of substantial amounts of toxic pesticides – this is not reversible in the short or medium term. If we discover it’s all a horrible mistake, it cannot be undone once the trees lie on the ground as logs and chips.

REFERENCES

1.  CalFire references:

  • Map is linked HERE
  • Update noting no “Very Severe Fire Hazard” HERE

2.  FEMA Letter (in two parts):

Mt Sutro PDM – Letter from FEMA – Environmental-Pt 1

Mt Sutro PDM – Letter from FEMA – Environmental-Pt 2

And if anyone wishes to further verify that this indeed is the letter – it is available to anyone who requests it under the Freedom of Information Act from FEMA, and as Public Records Information from UCSF.