California Eucalyptus: A Biological Treasure

Someone posted an intriguing note on the A Historic Forest page of this website. It suggested something we hadn’t thought of before: that the eucalyptus here may be a repository of genetic material not found even back in Australia.

Here’s what he posted:

“Considering the timespan of its planting, the trees at Mt. Sutro may be something more than historic. San Francisco Bay in California is one of the very few areas of the world where some of the oldest Eucalyptus globulus grown out of Australia during the 19th century still stand.GiantGlobulus small

“In Europe, where these trees arrived more or less at once, the oldest standing E. globulus are in the range of 100 to 125 years old, and are normally protected as heritage trees.

“The total number of eucalypt trees in these circumstances around the world is very small over the total, ranging optimistically some few thousands only.

“For the case of Mount Sutro, their historic value may be complemented with a “hidden” genetic value. Indeed, they could be considered “genetic repositories” that could allow to “trace back” the Californian E. globulus landrace to its original race or races in Australia, be it mainland Australia or Tasmania.

“In other words, they are living pieces of biological archaeology. Their original parent trees might no longer be standing due to clearing as Australia was built. Mount Sutro trees could be … a lost tribe and the last of their kind.

“Each old eucalypt cleared down for concrete in California is a vanishing footprint of history. And, maybe, a vanishing nowadays-unique gene pool.”

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11 Responses to California Eucalyptus: A Biological Treasure

  1. The Garden Coach says:

    Yes indeed. We have never been here in San Francisco at this point in history with the Eucalyptus. They have”naturalized”reproducing at an exponential rate and dangerous size for our westerly winds.
    We have inherited a huge amount of biomass to figure out how to live safely with today. There has been a lot of rather alarmist fear about managing the E. globulus (Giant Blue Gum species) because they are stately and beuatiful.
    However, the fact is they are naturalizing far quicker than any local management agencies can evaluate, yet alone manage for basic safety.
    This website has been set up through an extreme point of view out of fear that all these trees are going to be eradicated versus managed. We can have historic groves of eucalyptus that don’t even need to be reforested!
    Here, without true summer drought due to fog and associated drip, they are growing and regenerating into dense and unhealthy stands with many broken branches.
    We cannot fall pray to fear and say “don’t touch the eucalyptus!” We must for their very health and ours. These are human-created, artificial conditions, especially for a dense urban city. Call UCSF and support SOME management!

  2. savesutro says:

    Garden Coach,

    You sound like someone who cares about the forest, but it also sounds like you’re talking about a different forest than the one we walk in regularly. There’s nothing unhealthy about these stands.

  3. The Garden Coach says:

    I am curious where exactly you walk.
    There are “healthy” tree stands. Others are clearly headed for an early death. I cannot ignore critical, learning trees. We need help. We should keep the windbreak intact, the fore-stands of eucs. that block the westerlies and manage problem tres. These is also nothing wrong wih diversifying the interior forests with the other forest which has suffered, such as the oks and toyon complex around “Ishi’s Cave” for example.
    We need help. We need the UCSF plan or something that is responsible energy going forward.
    Eucs. are tough. Diversity is god.
    We will lose our opportunities to get some money for management.
    We cannot stalemate peoples’ interests even if they do not match our exact visions.
    Let’s try to move forward together with the current energy our communities have now.

  4. Jimbo says:

    You are against diversifying the Sutro understory with local native plants, yet you wholeheartedly support keeping a “genetic repository” of eucalyptus here in SF at the expense of everything else. So what would you plan to do with that, create some kind of Australian native plant restoration project? That’s a rich double standard. Lambast UCSF and local groups of hundreds of volunteers for wanting to support our own community of plants that are on the verge of winking out, because you have an invaluable historic repository to perform other fantasy restorations in far off lands. Wow. Good luck spinning that twisted logic.

    • savesutro says:

      The pressure on native plants is coming from climate change and habitat loss where they already exist. Destroying Sutro Cloud Forest isn’t going to stop any species from “winking out.” Global warming might; and cutting down trees gives that a push in the wrong direction.

      Converting a few acres in the middle of a city surrounded by gardens and other biota isn’t achieving anything – at best, you get tiny Native Plant Museums that require a great deal of gardening to manage. Without the valiant and continued efforts of the volunteers in weeding and mulching, without the irrigation system running through the garden, this garden would revert to weeds very quickly.

      It’s only a few acres now. As you expand it, the gardening part of it requires more manpower than all the volunteers can provide, and worse, toxic chemical spraying. This is not Natural, even though it’s “Native.” Look at Twin Peaks, eroded, trashy, sprayed with Roundup and worse… Mission Blue Butterfly habitat without any Mission Blue Butterflies.

      I consider myself an environmentalist. But I do not consider what the nativists are doing to be environmentally friendly. I admire the volunteering spirit. I feel like we should be on the same side. But we’re not, on account of trees and chemicals.

      Instead, I ask you, just for a moment, to think of this forest as something rare and wonderful – a temperate cloud forest, man-made but natural, requiring no chemicals and very little “gardening.” It’s a special place. It’s rarer than Grindelia Hirsutula, the Hairy Gumweed.

      If you were a defender of that Cloud Forest, it would be amazing.

  5. NatureLover says:

    Dear Jimbo, You accuse us of “keeping a “genetic repository” of eucalyptus here in SF at the expense of everything else.” This is the fallacious assumption at the core of the nativist agenda, that it is only the presence of non-natives that are threatening the existence of native plants.

    This is quite simply not true and it has been demonstrated repeatedly in the so-called “natural areas.” Trees and plants have been destroyed repeatedly simply because they aren’t native. Natives are planted repeatedly but they don’t survive.

    The native plant garden on the Sutro summit survives only because it is irrigated and sheltered from the wind by the non-native trees. These are the observable facts.

    They are supported by scientific research which reports that the ranges of native plants have changed and will continue to change as a result of climate change. Heightened CO2 levels in the urban setting are a contributing factor. Many natives are dependent upon frequent fires for seed germination and suppression of natives that will dominate w/o fire, such as coyote brush (heaven forbid that we say coyote brush is invasive!).

    It’s long past time for environmentalism to put global warming at the top its agenda. If and when they do so in San Francisco, the nativist agenda will take a back seat because deforestation is one the primary causes of global warming. Since there were virtually no trees in San Francisco, destroying non-native trees means NO TREES. Ironically, nativists are contributing to the demise of their preferred plants by promoting an agenda that contributes to global warming and global warming will result in the end of native plants in their historic ranges.

  6. Jimbo says:

    The plan isn’t to “destroy” the forest or remove all the trees and you know it. The plan is to remove some of the trees in some parts of the forest (only 23% of total acreage of UCSF land), so that the understory can be diversified with a larger variety of plants. No one other than you is claiming that all the trees will be removed. No one other that you is claiming tht the goal is to remake the original grasslands a la Twin Peaks. The dense “cloud forest” consists mainly of about 5 different plants (eucs, acacia, himalyan blackberry, ivy, erharta rice grass) with a smattering of other non-native plants and natives. A true forest consists of a largeer variety of plants that support a larger variety of birds, animals and insects. A monoculture of trees on a hill that happens to get fog does not make a cloud forest. You use the term “cloud forest” as hyperbole to build emotion so that people make an equation between it and a true temporate old growth cloud forest as found in, say, the Olympic Peninsula. Sutro forest is no more a cloud forest than is a Christmas tree farm in the Marin hills. I ask you, for a moment, to think of what the forest could be if you enhance it by increasing the diversity of plant life contained in it. The eucalyptus will never be removed from Sutro, it would require more money than all the FEMA grants in the world can provide and that’s not the goal here. I don’t want the forest removed either, I want it improved.

    • savesutro says:

      For some definitions of “improved.”

      The plan calls for the removal of 90% of all trees under 3 feet in girth, and almost all the bushes/ shrubs. UCSF estimated a removal of 3000 trees on 14 acres. That isn’t grassland, but it certainly would gut the forest on those 14 acres. And UCSF describes them as “demonstration plots” which suggests that they would – as they can find funding – replicate the same thing all over the forest.

      A true forest consists of trees: Muir Woods is mainly redwood with an understory of Bay Laurel. No one says it’s a monoculture of sequoia on a hill that resembles an overgrown Christmas tree farm (even though it’s in the Marin Hills, and redwoods look more like Christmas trees). Because it’s Native.

      Sutro Forest is a Cloud Forest because it traps moisture from the fog, which is then soaked up by the duff and protected by the understory plants. It gets around 30% of its water from the fog. It’s the reality. It’s the way this forest fuctions.

      You look at it and see non-native planted trees that get in the way of some Native species you want to plant there. I look at it and see a magnificent eco-system that has settled into a particular place over 120 years, and exists there as it could nowhere else.

      In fact, Sutro Forest as it is has as much bio-diversity as Muir Woods does. Only it’s “non-native.” What’s the big fuss? All of Golden Gate Park is non-native. Not every patch of green in the city has to be Nativised.

      There are a lot of “native areas” in the city and just outside it. I don’t see the need to gut 23% of the Sutro Cloud Forest for the purpose, and interfere with the way it retains water and holds up the mountainside now.

      Stop, look, see it for the unique ecosystem it is. I’m guessing from the context of your posts that you’re a Steward. It would be awesome if you treasured it for what it is, rather than just another place to make into just another Nativist experiment.

  7. Jimbo says:

    Naturelover, this blog post is calling it a genetic repository, not I. I’m just marveling at the train wreck of logic.
    By the way, the summit garden was irrigated during the first couple of years to establish the garden. The irrigation system is no longer used.

    If you’re certain that the restoration work already underway is so destructive, you should check out the rock outcrop along the historic trail. It was cleared of blackberry (by the Boy Scouts – those evil do-gooders) and replanted. With minimal “gardening” and no irrigation, the hillside is flourishing with hundreds of plants, consisting of over 30 different plant varieties that were seeded from existing populations in San Francisco. It is amazing the success that a little volunteer work can bring.

  8. savesutro says:

    I’m a bit disturbed to hear that the Native Garden is no longer irrigated. I hope it’s checked to make sure the water still works. That’s where it’s dry.

    If you identify exactly where the Rock Outcrop by the Historic Trail is, we will gladly publish photographs on this website.

  9. NatureLover says:


    It is your mistaken belief that the eucalypts are killing native plants that I was commenting on. Just the usual footwork to change the subject to suit your agenda.

    As for pointing to successes….perhaps there are some, especially in the short run. That doesn’t alter the fact that there are many failures.

    As for the irrigation…if as you claim the irrigation system is no longer used, we will try to verify that. I find it hard to believe that the irrigation system is fully intact several years after it is no longer used.

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