From time to time, people come by to comment and engage with the information on this website. We appreciate that. ‘Charlie’ commented on several posts, but this comment was long and complex enough that it deserved a separate post.
Charlie: Hmm, well as someone who is not part of your group, the way you are tossing around ‘nativist’ was a big put-off.
‘Nativist’ is a word – like so many in the English language – with multiple meanings: Linguists use it to describe supporters of the position that language acquisition is an inborn aptitude; Politicians use it to describe people who oppose immigration. Over here, we use it to refer to those who support Native Plants and ecosystems at the expense of naturalized ones, and we don’t think we’re confusing the word with its other meanings. We find it less clunky than “Native Plant Advocates” or “Native Plant Supporters.” (Nor were we the first to use it: Michael Pollan used it back in 1994 in a New York Times article, Against Nativism.)
Charlie: I think the idea of people who ‘want to kill every non-native plant’ is a myth. I am very interested in native plants and know a lot of others who are too and I have never met anyone who meets that description. I do think invasive plants should be removed when possible. People who want eucalyptus removed because it is invasive are more anti-invasive than anti-non-native.
Actually, eucalyptus is not invasive except possibly where there’s a lot of moisture. Sutro Forest harvests a lot of moisture, but there’s nowhere for it to invade; it’s a bounded forest. Those Native Plant Advocates who want to remove this eucalyptus refer to it as “California’s largest weed” and to the forest as a “plantation.” Sounds anti-non-native to us.
Charlie: I realize this particular grove of trees is in a very urban area and maybe the best use of the land is leaving it alone. I’m not sure exactly why people are trying to restore it to native plants.
Perhaps because it’s a group that highly values native plants and devalues non-native plants? And also tends to devalue trees?
Charlie: I am worried about what seems like biased/inaccurate science on this web page because people may use this web page to justify ‘protecting’ invasive Eucalyptus stands in places where they are actively displacing natural ecosystems. Our native ecosystems are so threatened, and being crowded out and destroyed in so many ways – do we really need to be promoting the spread of an invasive tree?
We support protecting existing natural ecosystems, whether native or not. “Natural” being what grows naturally without the use of herbicides or massive gardening efforts. This is not to say we don’t support gardens and parks; we do. Golden Gate Park is one of the city’s finest assets. But we don’t support the destruction of a natural (though non-native) ecosystem into a garden of native plants.
We do try not to have inaccurate science here; we mention our sources. We also base a lot of our statements on our own observations, often backed by photographs. If you find inaccuracies, you’re most welcome to say so in comments. But it’s more useful if you’re specific rather than saying ‘ur doing it wrong.’ As to bias – this website was started for a purpose, which is clearly stated.
Charlie: I think most pro-native-plant people want the same thing as you – vibrant, pleasant open space in the community for recreation, wildlife, and performing of ecological function. if you feel that Eucalyptus meets those goals… well maybe you are right. It is the reasoning behind it that I am hung up on.
We too feel that we should be allies rather than opponents. Yet one group that opposes our efforts, Nature in the City, clearly seeks to destroy the existing non-native ecosystem in order to promote the growth of native plants. Their goal is ecological restoration within San Francisco. Since no one is going to destroy buildings for “ecological restoration,” they must address open spaces – many of which already have established ecosystems.
Charlie: I agree that those eucalyptus trees are not likely to spread. But again, a website saying that needs to be very clear that you are only talking about *THOSE* trees. You mention Angel Island where the situation is very different.
Well, on Angel Island the eucalyptus was planted there, it hadn’t invaded the place. It’s all but gone now, and there’s grassland instead. We don’t know much about the prior ecosystem, but in terms of fire-hazard? It’s had several wildland fires since the trees were felled, but none before. The last fire covered half the island.
In fact, there’s no evidence that eucs are actually invasive in any practical way. There’s an article about it on another website, citing research from Berkeley.
Charlie: Is the proposal to remove eucalyptus trees and plant a native plant garden, or to do habitat restoration? These are very different also.
The specific proposal for Sutro Forest is to remove thousands of eucalyptus trees leaving a sparse canopy and a drier environment, mowing down the non-native plants in the understory and encouraging native plants to grow there, and using Roundup and Garlon to prevent resprouting. A Native Plant Garden was in fact put in on the summit and is tended by volunteers from the Mount Sutro Stewards, a part of Nature in the City. It includes
two [ETA: a few] oak trees, now about 10-15 feet tall.
Charlie: I agree also that before the eucalyptus was there, it was cleared/disturbed ranchland. However, before that, it probably had oaks. Every other intact hill along that coast has oaks, why would that one not? I’m not as sure about the redwoods.
Actually, there’s no evidence of oaks there at all. Prior to the non-native grasses, it may have been grassland or chaparral or a mix of the two. On the Western side, sand dunes reportedly came right to the foot of the mountain.
Charlie: Is the understory mainly ruderal plants or are there native plants there as well? I have never seen an eucalyptus grove with any sort of understory at all other than poison oak, thistle, maybe some ivy. If that stand is an exception, that is very interesting since I haven’t come across one like that before.
The understory is mainly blackberry, ivy, and acacia. But there are also a lot of others, including holly, cherry, plum, redwood, toyon, elderberry. A study conducted around 1999 mentions 93 plant species.
Charlie: 125 years is not very long in terms of ecology/natural selection. The genetics of the trees of course have not changed at all since they are the same trees! Has a plant survey been done? If a bunch of non-invasive plants, mosses, and lichens are present under that eucalyptus grove it is indeed an anomalous place and should be studied further. I admittedly have not been in that stand though I have been in other ones in the Bay Area – again the understories in those stands were very sparse.
No, 125 years is not a long time in terms of evolution (though evolution can move very quickly in fast-reproducing species). This is more a matter of adaptation and natural selection – a whole lot of plant species blew in or were bird-carried in from surrounding areas, and those that were adapted to the year-round damp cloud-forest conditions thrived. I’m not sure where you live, but it may be you haven’t seen a eucalyptus cloud forest. It looks very different from the drier inland eucalyptus forests. Possibly – and this is a conjecture – shading and water competition may be causing effects being attributed to phytotoxins. You sometimes see similar effects in redwood forests.
Charlie: I did fly around the area on Google Maps. it is neat to see that this much open space is even still present in the city. I am currently working in a similar open space in Pittsburgh (a forest with native and non-native trees). My first thought when I saw your mountain was ‘wow, what a monoculture of trees’ – if you scroll way north or south and find a place in the coastal mountains and look at one of those forests, you will see a lot more variety. However, I can’t see the understory and perhaps there is a lot more going on there. Certainly the area is better off as an eucalyptus forest than as a development.
The trees are about 80% eucalyptus. But it probably has as many species as say, a redwood forest or an oak/ bay-laurel forest. It’s not rare to have forests with a single dominant species even if they evolved naturally on a site without being planted there.
Fortunately, UCSF has committed to maintaining the 61 acres it owns as an Open Space Reserve, and the remaining 19 acres belongs to the City’s Rec and Parks department.
Charlie: Some constructive criticism: I think the ‘nativist’ stuff will alienate (no pun intended!) a lot of potential allies including scientists and ecologists who care about the area. Why not just say ‘these trees are an important part of the community, they are not harming native ecosystems, and we want them to stay’? That is a solid argument I’d have nothing to say against. After all, it is YOUR forest.
We wish. The Native Plant Advocates say that the “forest” is not a forest, it’s a plantation of California’s largest weed; they want to promote Native Plant biodiversity on the mountain. Unless people recognize it as a valuable ecosystem, they will want to change it, or not care if it’s destroyed. (This isn’t unique to eucalyptus forests. The defenders of old chaparral feel the same way.)
Charlie: I am more concerned, again, with what I see as biased information being used to justify allowing invasive species to ravage through my favorite canyons nearby. I’ve seen people rip the crap out of 100+ year old chaparral for ‘fire clearance’ and leave flammable Eucalyptus trees around their homes – when the fire comes they go up like torches. Chaparral is already a very misunderstood and maligned ecosystem and it breaks my heart to see it villainized again.
We don’t oppose chaparral at all. In fact, there’s an area of chaparral (Number 2 in the picture) below the forest on SF Public Utility Commission land which we would also defend if it were threatened; but so far, thankfully, it’s not. (Incidentally, in the sixty years the forest grew contiguous to that land before the houses were built there, the eucalyptus did not invade the chaparral.)
We would like to promote the diversity of ecosystems in the western part of San Francisco (or for that matter, all of San Francisco). We think preserving the forest (number 1 in the picture) is important in this respect; there are only two patches of dense forest in the area (Mt Davidson, number 4, is the other), and this is both the largest and the densest of them. (Go to the original article for a key to all the numbers.)
On the flammability of eucs: We have a number of articles here suggesting its been overstated. Here’s one. And at Scripps Ranch, San Diego, they certainly didn’t go up like torches when fire came through. They stood when other vegetation – and homes – burned.