Eucalyptus Myths

As a result of a concerted anti-eucalyptus campaign, a number of myths exist. Owing to these myths, felling of eucalyptus seldom considers negative environmental effects on insects, birds and animals – and people. In the case of Sutro Forest, we are not aware of any analysis of the impact on the resident wildlife.

1. Eucalyptus only lives about 100 years, so they’re reaching the end of their lives. (FALSE)

This is often used to justify tree-felling. Here’s an example of a news item in the Chronicle, based on interviews with [Sutro Stewards Executive Director] Craig Dawson and with UCSF. But it’s a myth. Eucalyptus in the tropical and arid areas of Northern Australia tend to get killed by termites and fire before they’re 200 years old. In temperate, rainy Southern Australia they live 400-500 years. San Francisco’s Sutro Forest is much closer to Southern Australia in climate, since it lacks wildfires and cyclones and receives rain as well as summer fog drip.

Eucalypt ecology” by Jann Elizabeth Williams, John Woinarski (Cambridge University Press, 1997): “… it appears that individual stems of eucalypts can reach between 400-500 years in Southern Australia , whereas it has been suggested that individual stems in semi-arid and tropical Northern Australia only reach around 100-200 years.” It goes on to say, “The combination of frequent fires, extensive piping by termites, and cyclonic activity in Northern Australia may contribute to the apparent difference in longevity between eucalypts in Southern and Northern Australia.

2. Nothing grows under eucalyptus trees because they poison other plants. (FALSE)

Calla lilies in eucalyptus forest, Presidio SF (NPS picture)

Undergrowth in a stand of eucalyptus

A ramble through Sutro Forest will disprove that as effectively as possible. The undergrowth is dense enough to impassible in most places, and trails have to be hacked into the forest.

Thanks to commenter Gus for a scientific explanation on his blog in a post called: Seven Key Issues on Eucalyptus and Alelopathy.

(See comments at the end of this page.)


3. Eucalyptus doesn’t attract bees . (FALSE)

Eucalypt flowers are mainly pollinated by insects, but birds and small mammals may also act as pollinating agents.

http://wiki.bugwood.org/Eucalyptus_globulus#POLLINATION

From photo by Susan Walter

Photo credit: Janet Kessler

In fact, eucalyptus is particularly valuable as bee pasture, because it blooms year-round. It gives the honey a distinctive peppermint taste. (Oh, and Honey Bees aren’t native either.)

The hollows in older eucalyptus trees also provide homes to animals, birds — and wild bees as in this bee tree picture. (If you click on the picture, a larger version will come up with the bees circled in red.)

4. Eucalyptus pollen causes allergies. (MOSTLY FALSE)

Unlike wind-pollinated plants such as mountain cedar, oak, and a number of grasses, eucalyptus relies on insects and birds for pollination. Wind-pollinated plants have light pollen, which is more allergenic. Insect-pollinated plants have heavy pollen which isn’t broadcast on the wind, and doesn’t cause as much allergy. In San Francisco, juniper and grasses are major allergen-producers.

[Edited to Add: However, this is not saying that eucalyptus is not allergenic: some people are sensitive to eucalyptus pollen, and they will get allergic reactions to it. It's just not as allergenic as the lighter pollens of oak and grasses and mountains cedar.]

5. Eucalyptus groves don’t support birds. (FALSE)

Source: 123rf.com

Birders have identified over 40 species of birds in Sutro Forest.  This article has a list and pictures. This is not unique to Sutro Cloud Forest.  From a Nature Conservancy assessment:

The wildlife in a Eucalyptus forest varies depending upon the geographic location of the grove. At Jepson Prairie Preserve, CA, Swainson’s hawk and yellow warblers, both of which are “Blue Listed” species of concern, nest in the trees. At Pescadero Creek County Park, south of San Francisco along the coast of California, great blue herons and egrets use the trees to build their rookeries.

Pygmy Nutchatch in eucalyptus, San Francisco. Photograph by Harry Fuller

“Over 100 species of birds use the trees either briefly or as a permanent habitat. The heavy-use birds feed on seeds by pecking the mature pods on trees or fallen pods; so they must wait for the pods to disintegrate or be crushed by cars. .Among the birds that feed on seeds in the trees are: the chestnutback chickadee and the Oregon junco. Examples of birds that feed on ground seeds are the song sparrow, the fox sparrow, the brown towhee, and the mourning dove. Birds that take advantage of the nectar from blossoms either by drinking the nectar or by feeding on the insects that are attracted to the nectar include Allen’s hummingbird, Bullock’s oriole, redwinged blackbird, and blackheaded grosbeak.

photo credit: Janet Kessler

“Birds that use the trees as nest sites include the brown creeper, which makes its nest under peeling shags of bark and feeds on trunk insects and spiders, the robin, the chickadee, the downy woodpecker, and the red shafted flicker. The downy woodpecker and the red shafted flicker peck into the trunk of dead or dying trees to form their nests. When these nests are abandoned, chickadees, Bewick wrens, house wrens and starlings move in. Downy woodpeckers use dead stubs to hammer out a rhythmic pattern to declare their territories.

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

http://wiki.bugwood.org/Eucalyptus_globulus#WILDLIFE

6. Eucalyptus trees kill birds through ‘beak-gumming.’ (FALSE)

Misleading illustration

This myth is traceable to a conjecture that was presented as a theory, and repeated as a fact – a 1997 article that has benefited from a “signal-boost” from the anti-eucalyptus campaign. It argues that unlike the long-beaked Australian birds, which co-evolved with the eucalyptus flower, short-beaked Californian birds get their faces gummed while foraging in eucalyptus flowers and suffocate.

Australian Rose Robin, photo credit “Aviceda” (Creative Commons)

This ignores the facts:

(1)  Australia has numerous short-beaked bird species foraging in eucalyptus and has no evidence of beak-gumming.

(2) The eucalyptus flower is not especially deep.

(3) Other birders have not seen evidence of high mortality under eucalyptus trees.

Here’s a detailed article, with pictures.

7. Eucalyptus groves have no wildlife. (FALSE)

Monarchs in eucalyptus, California. Source: 123rf.com

Migrating monarch butterflies depend on eucalyptus groves as a wintering spot. This is true not just in Pacific Grove, but even as close by as Fort Baker (below the Golden Gate Bridge). [ETA 2011: And also in San Francisco.]

And that’s just the start.

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

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

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

“A Eucalyptus grove is not a sterile environment. The population density of the animals mentioned can be partially attributed to the presence of eucalypts. With a program of cutting trees and burning debris, some animal residents will disappear because they have restricted home ranges or are sedentary. If an animal’s living area (leaf litter, logs, bark) and food supply are destroyed, the animal will either die or attempt to move to another area which is already fully occupied.”

http://wiki.bugwood.org/Eucalyptus_globulus#WILDLIFE

8. It’s invasive. (FALSE in practice)

Eucalyptus isn’t invasive in dry areas; it’s actually best-suited to damp coastal climates. Where water is not an issue, it’s true that eucalyptus globulus can be invasive, gradually taking over adjacent native areas. That is, when there are adjacent native areas. In Sutro Forest, there are no adjacent native areas – the forest is bounded by roads and housing. The eucalyptus is not invading our homes and gardens.

In fact, in the San Francisco Bay  Area, eucalyptus forest cover actually declines, not invades, based on sixty years of research by William Russell (USGS) and Joe Mc Bride (UC Berkeley). There’s a good article about it at Death of a Million Trees, a blog against unnecessary tree-felling.

9. It’s not native. (TRUE)

It comes from Australia, and was brought here around 150 years ago. (We’re not native either. Are you? Where were you 150 years ago?) Nothing we eat is native either: Corn, peaches, avocado, broccoli, strawberry, artichoke, chicken, beef. In fact, the only “native” product in most people’s diet is fish.

10. It easily drops branches and poses a threat to people beneath. (MOSTLY FALSE)

All trees drop branches – or even fall over – under certain circumstances.

Tree-fall fatalities are very rare.  [ETA Aug 2011: We found a 2008 study from Kent State University; in the 12 years from 1995-2007, there were 407 tree-related fatalities in the US - an average of about 34 deaths per year. These are concentrated on the East Coast owing to a combination of trees and tornadoes. By comparison, lightning kills an average of 62 people annually in the US.]

Three tragic deaths in the Bay Area were caused by an oak tree (a 2010 winter storm knocked it into tent cabin in Santa Rosa); American elm (a San Jose toddler was killed by a falling tree in 2010); and a redwood (a San Francisco woman in 2008).  Another serious non-fatal injury was caused by an oak tree during the 2009 Vineman triathlon in Sonoma. And in 2003,  a dead Monterey Pine fell on a car on Brotherhood Way, killing a woman.

[ETA Aug 2011: An oak tree fell on an SUV in Napa Valley in March 2011, killing a Vallejo man. And an oak branch fell and seriously injured a 16-year-old girl on a Russian River camping trip in 2000. ETA July 2013: A black oak tree broke and killed a counselor at Camp Tawonga near Yosemite.]

11. Eucalyptus is extremely flammable and is involved in most California wildfires. (MOSTLY FALSE)

In fact, native plant areas – the scrub and wild-flowers known as chaparral – are more flammable than any tree. Eucalyptus is actually fire-resistant. In fact, it may actually fight fires by acting as a windbreak and blocking flying embers. It will burn in forest fires, but so do all trees. Many people think of the devastating Oakland Hills fires; but a inquiry there noted that trees were not the primary hazard – not even eucalyptus trees. (Click here for a post on that subject.) Grass fires are actually more dangerous (click here for more on the subject). There’s also an excellent post on the Death of a MillionTrees website on the subject.

And here’s a detailed article: Why Native Plants are more Fire-Prone than Eucalyptus

46 Responses to Eucalyptus Myths

  1. NatureLover says:

    Yes, the UCSF grant application makes this claim: “..the oils in the [eucalyptus] foliage and bark suppress the growth of native and other plants.” (page 10)

    This tired old allegation is truly ironic, given that the native plant garden on the summit of Mount Sutro was planted in eucalyptus chips! “The summit, which was cleared of much of its topsoil by the Department of Defense in the mid-1960s and was recently covered with approximately six inches of eucalyptus chips.” (page 46, “Mt Sutro Open Space Reserve Management Plan” 2001)

    This was written before the installation of the native plant garden in 2003. I am happy to report that the garden is thriving in the eucalyptus chips, which are still visible on the ground. [Yes. It continues to be mulched with eucalyptus chips - see photo above.]

    However, in evaluating the success of the garden, please keep in mind that the garden has been extensively irrigated for over 5 years. So much for the claim that native plants are drought tolerant. Yet another myth that doesn’t stand up to reality.

    • Brian says:

      Are you sure about that? perhaps that irrigation was installed to help establish the plants not so much to maintain them. So it’s silly to try and use that to advocate your obsession with this one tree.

  2. George Wertheim says:

    We live very close to Mt. Sutro. Our 22-year-old eucalyptus has recently. How do we ascertain if we’re dealing with drought, insect infestation or other threats to its health? Can you suggest websites where there are pictures? Might you suggest a eucalyptus-specialist arborist? Thanks very much. Yours truly, George Wertheim

  3. Balasubramanian Aiyar says:

    Since last one year I am working on Genetic transformation in Eucalyptus. Really its very informative for person like me who are starting their research career in Eucalyptus.
    Thank you very much for the valuable information

  4. Considering the topics raised in this article, I think your readers might like to read further on the “Nothing Grows Under Eucalyptus Myth” at our Eucalyptologics blog:

    Seven key issues on Eucalyptus and alelopathy
    Or seven reasons why stating eucalypts poison soils is mostly… bullshit.

    Best wishes to Mount Sutro Forest, may it be left standing.

  5. The Garden Coach says:

    How quickly we have forgotten the Oakland Fire Tragedy and the gardeners and Kathleen Bolton killed in Stern Grove from falling eucalyptus and redwood branches. You can’t rely on fog drip to repress fire and there is staff sorely lacking to manage for priority hazard trees, eucs. or not. The duff is getting thicker and it’s plenty dry. Blackberry is masking homeless camps and there are plenty of hangers in those trees. So, much for the precautionary principle!
    Help get money to manage Sutro, get FEMA money and help! This is an emergency !

    • webmaster says:

      Garden Coach,

      I really appreciate your starting a discussion here.

      In fact, we have a post on the Oakland fire from a fire-fighter who was on the panel to investigate it afterward – and they concluded that eucalyptus was not responsible for the fire. In fact, no trees were. There are no homeless people or hazardous conditions in the two zones where the trees are to be felled: We walk those around those areas frequently. In fact, we haven’t seen any homeless camps in the UCSF forest.

      And as someone noted further down, Ms Bolton was killed by a falling redwood branch. Not eucalyptus.

      Nativists who despise eucalytus and blackberry will despise it. But it’s an ideology, not a matter of fact or science.

  6. The Garden Coach says:

    Let go of the “native” vs. “non-native” thing. It’s polarizing. Ecology 101: biodiversity exemplifies stronger, more resilient (and interesting) park lands. It’s more about promoting biodiversity and diversity in general. Sure there are purists native plant folk. But, certainly you must realize no one is calling for clear-cutting and scraping Sutro into a sand dune. There will always be historic eucalyptus forests in San Francisco.
    Sutro and all Eucalyptus forests are however homogenizing (not sterilizing) our natural heritage and landscapes. Look past the European dominance of nature and their relatively recent introduction and remember the coast live oaks, California Christmas Berries (toyon), madrones, elderberries, box elders, canyon oaks, Islais Creek Cherries and on and on. We can have them and eucalyptus!
    SUPPORT UCSF DOING SOMETHING ABOUT THIS MESS! Manage the dam place for aging, clearly threatened eucalyptus! These things are falling!
    Furthermore, if you are really walking up on Sutro you will indeed find som homeless camps/activity amidst the otherwise impenetrable blackberry. Thanks to recent efforts there are actually some usable trails opening up. I believe it was the Mt. Sutro Stwards and the Natural Areas Program, among others that is actually doing something to make this place usable and enjoyable.
    Thank you too for getting these important issues on=line.

  7. savesutro says:

    Garden Coach,

    It is not a mess. It’s a beautiful, healthy, forest. The trees are young compared to their potential lifespan – eucalyptus can live for 400-500 years, and moreover, they regenerate from the same source, like redwoods do. They’re not failing, and they’re not falling down. The forest has a few dead trees – fewer than I saw in Muir Woods recently. They’re part of the ecosystem. The woodpeckers need them, and so do some other species.

    Also: It’s a bounded forest. Sutro Forest isn’t homogenizing other landscapes any more than Golden Gate Park is, or my backyard. It’s a natural area, bounded by streets and buildings on all sides. If you can support a historic eucalyptus forest, support this one.

    There are a number of other native species areas in the City – many of which could use some extra help. Why not plant those species there? This forest is special. Knocking it down to make it look like Twin Peaks certainly won’t make it more interesting.

    And frankly, I personally find it difficult to be enthusiastic about native plant restoration that relies heavily on pesticide use, disruption of existing biota, and that looks and acts dead 6-9 months of the year. The Himalayan blackberry provides more food and cover to birds and other wildlife than any chaparral.

    By the way: Where are these “homeless camps”? I read about some near the Laguna Honda lake, but I heard those had been cleared out. If you know where they are, let us know.

    • Brian says:

      Not all native plant restoration relies on pesticide use so rest assured SaveSutro you can be enthusiastic about it. What could be a good idea to Both the “Nativists” and the advocates to save Adolph Sutro’s planted forest would be to gradually cut down and replace the Eucalyptus forest tract by tract with the Native Monterey Pine (from the closest wild stand to preserve the genetic integrity of the species) in order to maintain some sort of canopy AND please the residents of the neighborhood AND help support and honor California’s native natural heritage and OUR legacy all at the same time!

      • webmaster says:

        It seems the native plant advocates don’t consider Monterey Pine to be native either. (It’s native to the Monterey Peninsula, and this is not the Monterey Peninsula…) It has another downside, actually two: It’s vulnerable to canker, and it’s naturally a relatively short-lived tree (about 50-60 years) while the eucalyptus is long-lived at 200-400 years. Redwoods would be nice, but there are only a few wind-sheltered areas that are suitable for those in this forest.

        I don’t know about all other native plant restorations; here in Sutro Forest, herbicides are certainly in the plan. And herbicides are being widely used in “Natural Areas” all over the city.

  8. NatureLover says:

    Oh geez…..Kathleen Bolton was killed by a REDWOOD BRANCH!!!! More specifically, she was killed by the negligence of the Recreation and Park Dept. which paid a certified arborist big bucks to evaluate all the trees in Stern Grove and then ignored what the arborist said. HortScience identified hundreds of hazardous trees in Stern Grove. Several hundreds of those trees remain to this day, over one year after Kathleen was needlessly killed.

    The City just approved a settlement of $650,000 for Kathleen’s family. It should have been much more since it was basically negligence that caused her death. What is the point of evaluating all the trees if you don’t plan to do anything about it?

    UCSF paid HortScience to evaluate all of the trees on Sutro in 1999. All the trees that HortScience considered hazardous (and were in locations where people walk or drive) have been removed years ago. The claim that the trees now need to be removed because they are hazardous is BOGUS, just like this entire project.

    I can’t imagine that anyone would object to an updated evaluation of hazardous trees. That has nothing to do with fire mitigation. If they are hazardous, by all means remove or prune them. But that wouldn’t qualify for a FEMA grant, hence the fiction that this project is for the purpose of fire mitigation.

  9. Thank you for your efforts to help clear up misconceptions regarding Eucalyptus. As with many things, conventional wisdom regarding ecology is often incorrect, but unfortunately has a life of its own.

    Chaparral, California’s most characteristic native ecosystem, suffers its own list of misconceptions, two of which were repeated in “The Natural History of California” cited above. We’ve learned quite a bit since the book was published in 1992.

    First, we now know that in the current environment, chaparral does NOT require, “fire for proper health and vigor.” Due to human-caused ignitions the real problem is too much fire rather than not enough. High fire frequencies are threatening to eliminate what is left of California’s shrubland ecosystems.

    Secondly, mature chaparral does NOT become, “senile, in which case growth and reproduction are reduced” during long fire-free periods. Old-growth chaparral is incredibly vibrant with an ecological richness not found in younger stands. Again, with increased fire frequencies, we are losing most of our old-growth chaparral stands which include huge manzanitas with trunks the size of a person’s waist. Old-growth stands were also the preferred habitat of the now extinct California grizzly bear.

    To find out more, please visit our website at http://www.californiachaparral.org.

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  14. JJ tha Jet Playne says:

    why didn’t Adolph Sutro mandate that Koalas were to be imported along with the Eucalyptus trees. Without the maintenance of the Koala, the trees look really messy.
    The primary plants on Sutro… ivy, eucalyptus, and blackberry are kind of greedy, ecologically speaking. They may be good for some kinds of animals, but it’s a limited range of pollen and fruit to choose from.
    I say we should keep a few groves of “old-growth” eucalyptus as historic artifacts, but quite a few should be replaced with a wider variety of plant life.

    • webmaster says:

      Hmm. Didn’t realize that forest trees were supposed to look neat, or that koalas were supposed to be arborists… still, they’re cute. It would have been interesting to have them wandering through our forest. :-)

      Considering that Sutro Forest has 93 species of plants, that’s not a bad range. And it’s in the broader Twin Peaks area, which also has grasslands, flowers both native and non, and even chaparral above Laguna Honda lake. This part of San Francisco also has a lot of backyard gardens with flowers, shrubs and even trees (and bird feeders). Birds aren’t confined to the forest, and neither are the insects or other animals.

      With this diverse habitat, birds and insects actually have a lot to choose from, and the dense forest is part of that diversity. Eucs, blackberry and ivy are good at producing a lot of food and cover in a relatively small space. Destroying the forest would reduce habitat diversity and biodiversity.

      It’s kind of neat for the critters right now… they get the taqueria and Outback and pizza to choose from. And probably Chez Panisse as well.

      • Jonathan says:

        Considering that I haven’t seen any notable endangered species listed as currently living in the eucalyptus, whereas a good number of our most endangered local species could have lived in the habitat the eucalyptus replaced, I don’t see how destroyed the forest would reduce biodiversity. Providing habitat for a bunch of common, widespread species doesn’t increase biodiversity. Replanting extremely rare habitats that support species that may otherwise be on the verge of extinction does. If Mt. Sutro was supporting our most endangered butterflies, amphibians, reptiles, and other creatures (which are only found in a handful of sites), instead of the same stuff you can find in every city park in the U.S., then we’d be seeing actually corporate biodiversity.

      • Brian says:

        Well. the forest is not really “natural”, Mt. Sutro is more like a naturalized area. I think what a few other people feel and I could definately speak for myself is that alot of californias native habitat is threatened or endangered why not cherish what we have left and even help to propagate some of the wildlife that has evolved here in this beautiful land for over many a millenia and make Sutro Forest a treasure in the truest sense of the word my making it a showcase of our natural heritage for city folk and others who come to visit our great city to be truly educated about our rich natural history. As it stands right now it’s none of those things just a nice stand of what some may call a lot of weeds thats not representative of California’s nature.

        • webmaster says:

          To my mind, an artificially planted and carefully gardened native plant area is not “natural” either. If it were, it would not need the use of Garlon, Roundup, or monthly attention. That makes it a garden. I am completely with you on cherishing what we have left. There are areas of coastal scrub above Laguna Honda Reservoir, and on the side of Mt Davidson, and on Twin Peaks. I think they’re worth protecting. But Sutro Forest is, as you say, naturalized, and it’s an amazingly beautiful cloud forest and a viable habitat for native animals and birds. Before the Stewards started to mow down the understory, it was wild and untamed except for the trails. Destroying it would be easy, restoring something more valuable almost impossible.

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  19. clegyrboia says:

    Thank you for this very useful article. The myth about the bird beaks gumming close really made me laugh they surely have not been to Australia and did not do any research to backup their claims.
    Good luck with saving Mount Sutro Forest.

  20. Gwynn O'Neill says:

    After a fire on the hills of Miller Knox park at Point Richmond in Richmond CA, I looked carefully to see how the trees had survived. It was clear to me that the grass and fallen tree debris had burned of course, but the trees that showed the least damage were the eucalyptus. The oaks and others were more scorched.
    As for the other objections to eucalyptus, can we lump all eucalypti together? Maybe some of the myths are true for some of them. We should care about this possible distinction, especially when we need all the trees we can get in global warming, even though that takes more thought and trouble.
    I don’t blame anyone for caring enough about an issue to bring up difficult facts, for or against. I looked into this because I simply think that most types of eucalypti are beautiful; I was biased. I love most native plants, especially in a mass, which gives a breath of the wild outdoors that used to be and still is to some extent. Eucalyptus is not a part of that, but their sheer size is so dramatic, they are lovely.
    They are part of the early history of California, being planted as windbreaks by farmers in the central valley and in southern California, when most of it was farmed, largely for oranges. I grew up there, and artists there were inspired by their beauty.
    We need all the trees we can get, especially the big ones, since they are what usually is cut down when any new “development” goes in.

    • webmaster says:

      Thanks for stopping by to comment. These myths are mainly about eucalyptus globulus, the Tasmanian blue gum. It’s the eucalypt most often seen in California.

  21. As a (hobby) beekeeper from Down Under, I was amused to see that there is a myth – rightly refuted above – that eucalypts don’t attract bees. Beekeepers in Australia get more honey from various kinds of eucalypt than from any other type of plant. Go to any market and you’ll see stalls selling at least half a dozen varieties of eucalypt honey. The wonderful thing about eucalypts is that different species flower at different times of the year, including many which flower in winter or early spring when not much else is available, so honey production can continue year round.

  22. Imported eucalyptus chips well placed around the base of plants is much different from leaves and large strips of bark falling on top of small plants and smothering them. Well maintained, thinned and pruned groves of eucalyptus have to be looked at differently from 90 year old unmaintained stands. If you’ve ever hiked around in the East Bay hills and walked through groves that have 3-4 feet of dried bark and leaves piled up and a huge number of stunted understory trees you would see that only poison oak and bay trees grow in the understory. Eucalyptus has it’s place in the agricultural landscape but not in cities or over houses or in high fire danger areas.

    Eucalyptus may provide cover but it doesn’t provide food. If you compare an eighty year old stand of eucalyptus to an eighty year old stand of carefully planted and pruned pines and oaks the pine oak forest would have significantly more habitat value.

    • webmaster says:

      Hi Matthew,

      Thanks for stopping by to comment!

      Sutro Forest, at least, has a very dense understory left to itself, and a lot of habitat value. Nothing seems to have been smothered. And yes, eucs do provide food — flowering year round, they provide nectar, and attract insects that also become part of the food chain. The vines and the understory also provide cover and food. It’s a pretty lush ecosystem when it’s allowed to function as one. We have a bunch of articles about it on this website; here’s one example (Sutro Forest ecosystem and wildlife habitat).

      Even in the East Bay, the eucalyptus woodland provides as much biodiversity as oak forest (which incidentally also typically has a bay tree understory). The research has actually been done. There’s a good article about it here:

    • webmaster says:

      Also – on the matter of fire danger – it’s a myth. Eucalyptus doesn’t constitute more of a fire danger than any tree, and a eucalyptus woodland is less flammable than native grass and shrublands. Sutro Forest is an even more obvious case — it’s a cloud forest, and pretty wet all year. This summer, even without rain, some of the trails were so slushy they were nearly impassable.

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  24. Irpsit says:

    Well, I live in Portugal, and the facts are these (even though I like the Eucalyptus scent):

    - Portugal is a country with a Mediterranean climate, and poor soils. Generally oak forest tend to create high biodiversity because they provide plenty of food and humus for other plants to grow underneath. It also increases the humidity because oaks transpire plenty of the water they absorb through roots.

    - Our Eucalyptus globulus forests are replacing our native forests. Actually, since the introduction of the Eucalyptus 100 years ago (and pines many centuries before), we nearly don’t have native forests. Eucalyptus now covers near 90% of forests in a significant part of the country. It is the 2nd most common tree in Portugal following the introduced pine.

    [Webmaster: I think you must consider that these are working forests, and planting is done for economic reasons. Oaks are mainly cork oaks and used to harvest cork every ten years or so. Pine and eucalyptus are used for wood and wood-pulp. Cork oaks are apparently the dominant species in Portugal, followed by pine and eucalyptus.]

    - If not so much grows under a pine, then under a Eucalyptus only a handful of species will grow underneath. Here if you walk in most Eucalyptus forests, you only find ferns, calluna vulgaris and pines, and little else. In dense forests, not even those grow. Also no birds, bees and butterflies. PS: I am a Biologist.

    [Webmaster: I cannot say why there is so little diversity in your eucalyptus forest. Perhaps it is the way they are managed, since they are intended for harvesting?]

    - Eucalyptus sucks water from water table; this is a well known fact here. So people remove Eucalyptus if they want to preserve water tables. They even lower the level of water in big dams. They can soak as much water as a oak (that’s a fact) but they do not transpire it like the oak, and their humus take long to decompose (and oils are antibacterial), so it’s a kind of dead, hard and dry humus, which does not favour most plants growing under the canopy. Also, try to grow a vegetable garden under a oak forest clearing, and under a eucalyptus one: the difference is obvious. The soil is kept so poor under the eucalytus stand (and likewise for the pine forest).

    - One thing is however true: Eucalyptus globulus is not invasive, it is mostly planted by greedy people wanting to profit from paper or wood industry. Its seedlings might spread but just like a normal tree, and this is a tree adapted to very poor, dry soils. But it grows much faster than oaks, that’s why it outcompetes it. Also eucalyptus takes control whenever a fire takes place.

    - Fire-wise: there is also a small different. Both oaks, eucalyptus and pines burn easily, but oaks perhaps burn less easily than Eucalyptus and pines; and we know that by observing how fires propagate in Portuguese forests.

    Finally, I am not attacking this tree but speaking from the facts on Portugal. I am a lover of Biology and Nature. Eucalyptus is just a very adapted species to our climate, but it’s not good for biodiversity, and although to have some Eucalyptus forests is nice, to have your almost whole country covered with Eucalyptus (like we have) is a disaster.

    [Webmaster: From what I read, 38% of Portugal is forest (including farmed plantations), and of that, about 20% is eucalyptus, mainly for the wood and wood-pulp industry. What would the land-owners grow instead if they did not grow eucalyptus?]

    We lost a lot, due to the Eucalyptus. That is a fact we cannot escape from. But it’s also mostly because Eucalyptus was aggressively planted by humans.

    [Webmaster: Really it seems the issue is not the eucalyptus, but what would be the other economic uses of the land.]

    • Irpsit says:

      But perhaps you can let me know what species can you grow naturally under a Eucalyptus forest, without having to change the soil or irrigate.

      Webmaster: It depends very much on the conditions in the forest. Here we in San Francisco have a Cloud Forest, which is very wet through the summer because the eucalyptus trees harvest the fog. We have blackwood acacia, blackberry, ivies, ferns, plum trees, pacific reed grass, holly, pine, grasses, and a number of other shade-loving plants and trees. You would need plants that are okay with shade and with whatever water situation you have there.

    • webmaster says:

      Hi Irpsit, and thanks for commenting!

      I’m a bit puzzled. If the eucalyptus uses as much water as an oak but doesn’t transpire it, what happens to the water? Some small part of it is likely retained in the tree, but the remainder?

      I don’t know why there seems to be so few birds in the eucalyptus forests in Portugal. In California, eucs attract a lot of birds because unlike oaks, they flower and thus attract insects and also birds. If the eucalyptus is being planted for lumber, then perhaps it is being managed in a way makes it less useful to wildlife? This will happen if all dead branches and trees are removed, if the understory is cleared or severely trimmed, if the trees are widely spaced so they provide less cover.

      The bees in Portugal do make eucalyptus honey. (I found this link that suggests it’s abundant enough to be sold commercially.

      In California, oak forests and eucalyptus forests have equivalent biodiversity. See this article: “Biodiversity – Another Eucalyptus Myth Busted.

      Let me say, though, that we are definitely *not* advocating for existing oak forests to be chopped down and replaced with eucalyptus. If that is what’s happening in Portugal, it’s a shame.

  25. if we respected life in general – trees,animals – it would be easier to graduate to respecting each other, having first learned from the trees and animals, (being learning to crawl, before we can walk).

  26. Pingback: Fact Check: Nothing Grows Under Eucalyptus? (Allelopathy) | Save Mount Sutro Forest

  27. Michael O'Rourke says:

    Webmaster,

    Who are you? Who are the people behind ‘Save Mount Sutro Forest’? I cannot find a ‘contact’ link on your site (but I am old and sight ain’t so good anymore.) I want to do my bit to save the forest, but I want to know know who I am dealing with. Yes I signed the petition.

    [Webmaster: Hi Michael, Good point! We'll put the contact email on the front page. You can email us at fk94131@yahoo.com and we'll definitely respond.]

  28. Garrett Smith says:

    Hayes Valley Farm (now plowed over) distributed mulch. much of it smelling of Eucalyptus. It was used by many people at HVF and other gardens. I can confirm this Eucalyptus mulch to be excellent for growing food in, even when it is not mixed with anything else.

  29. Ray Baura says:

    Interesting comments. I have a job wherein I have been given the task to plant native plants in and around a multi acre euc forest. I can tell you this: it is very difficult to do so, even in the vicinity due to the chemicals thrown out by the trees leaf and bark litter to say nothing of the roots and shoots which basically poison the soil which is the intention of the tree to inhibit the growth of other plants in its vicinity. Certain chaparral plants throw off similar chemicals. It’s part of their brilliant design.

    [Webmaster: Thanks for stopping by to comment, Ray.

    Perhaps it depends on the specific plants? On Mt Sutro, there's a Native Plant garden on the summit, growing in the vicinity of eucalyptus, and mulched with eucalyptus chips.]

    Indeed, while some things grow underneath (though in our forest very little–and I have been in Sutro Forest) I even have a very hard time with growing California Bay Laurel, yet out of the chemical shadow of the grove it thrives after being planted.

    [Webmaster: You don't say where you are, but water could make a big difference. In Sutro Forest, there's a lot of moisture and so there's lush growth of shade-tolerant plants like ivy and blackberry and acacia. We don't know whether Bay laurel would grow under eucalyptus or not.]

    I would argue the case for Sutro Forest from a historical standpoint which is valid enough (and I am no friend of the euc) not from a biological one because it is an argument ultimately lost (except in Australia where in its native habitat it is in balance with the plants and animals there having evolved in the place over millenia). For sure, the biological proponent of the euc in the non-native (to it) landscape can argue that “birds use it” I have seen some birds on the battlefield and once nesting on an artillery piece at an army base. In my own grove out of thousands of trees I have been only able to identify TWO trees that birds nest in or really involve themselves in and so those are designated and valued for what they are.

    [Webmaster: Again, it's not clear where you are, but perhaps there are other factors? In Sutro Forest there are a lot of birds. There were even more before the understory was mowed down and removed in many areas.]

    Yet, in the oak grove nearby the species count is palpably way larger. You go with what succeeds best where you are. Fight for Sutro as an historic grove; it’s a battle you can more easily win.

    [Webmaster: We tell it like it is... it's historic, which is important; it's also a treasure of a forest. Thanks again for your comments, Ray.]

  30. dale says:

    Guys….really… I live in the bush in Australia…. surrounded by 1,000′s of acres of gum trees….
    I frequently plant within my forest (40 acres) European/american/asian trees (maples, willows, pines, etc etc etc)…. they all thrive,

    Gum trees… highly fire resistant in terms of re-growing after a fire (I’m an x wild-fire man)…. they support bees, wildlife… what’s the problem here?

    Diversity dude, diversity I say…. have u ever had honey from gums? that’s where all Australian honey comes from.

    Someone said cant grow veggie garden underneath…. absolute rubbish

    Most gums don’t suck the water.. a few do… particularly blue gums… there’s 100′s of types of gums… so don’t generalise.

    Want evidence… contact me… I currently work for the state government’s environmental dept… information and education the key…. heard a lot of rubbish above.

    cheers guys from Aus.. Victoria… Bullengarook…. googlemap it hey

  31. Ganeshram says:

    Eucalyptus absorbs lots of water from the soil, and the soil is too dry for other plants to grow. As a farmer, I notice that plants growing near the adjoining eucalyptus plantation do not fair as well as the plants away from it. Also, their leaves change the pH of the soil, making it acidic. Eucalyptus is planted because of its minimal need of care and attention. The wood gets a good price, and the leaves are sold to extract oil. Farmers are convinced to plant eucalytus on their fields, which get ruined in a couple of years. Even if wisdom dawns upon them at this stage, it is extremely hard to get the land to be productive. The love of money is destroying forest converted agricultural fields into barren waste lands.

    [Webmaster: Ganeshram, you seem to refer to areas where eucalyptus has been introduced as a cash crop in India and substituted for other annual crops. That is not the case on Mt Sutro, where the forest was planted for beauty and recreation, and it actually captures water from the fog and not only waters itself but all the other plants in the understory. Eucalyptus is grown for wood crop in many places. Sometimes it's a good thing; other times it's a problem. It depends on a lot of local factors both practical and sociological.]

  32. Pingback: Sutro Forest: Cut Trees, Add Landslide Risk | Save Mount Sutro Forest

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