Can We All Get Along? Part 2 - The Great Eucalyptus Debate

Sutro Forest - understory of nasturtiums and ivy

I had thought that my interest in propagating our local native plants would be a nice, noncontroversial way to make a modest contribution to the world, avoiding all contention and discord. Uh...

When someone told me about hiking on Mount Sutro Open Space Reserve (which I wrote about in Can We All Get Along? Part 1), I of course Googled it to learn more. I soon found a web site called Save Mount Sutro Forest. I confess reading this site caused my hackles to rise and my fangs to show. To see why, sample this page: "Nativism versus the Environment."

The very name, Save Mount Sutro Forest is polemical. This is a site with an axe to grind. I wandered the internet investigating this topic of eucalyptus for quite a few days before coming across the person behind SMSF. It is, or anyway was in 2009, Dan Grassetti -- here's a New York Times Bay Area Blog article about him and his other arena of concern, also about removal of eucalyptus trees, hill conservation network.

Mostly ivy
Yes, he and others I've encountered (look at Death of a Million Trees for example) say we nativists have an agenda - to replace all non native plants with natives [insert maniacal laughter here]. Using toxic chemicals! and clear cutting! Gutting majestic and harmless trees! [Insert graphic pictures of recently cleared sites  - as examples of how horrible the results are.] It's true that it can take a lot of work to restore native habitat. Where that work is not done, results vary.

As another example of the challenging polemic, the Save Mount Sutro writer accuses the Sutro Stewards volunteer group of "destroying habitat" and "taming the wildness of this naturalized forest." They were removing Himalayan blackberry thickets, it seems. Yes, it does create habitat areas for birds. It also creates a lot of dry dead brushy stuff that is a fire hazard.

Dry brushy understory of Himalayan blackberry

Himalayan blackberry is an invasive spreader. We have a perfectly good native blackberry - I know because I chop it back regularly on my property near our home to reduce fuel load. It grows back green. I like it fine.

We nativists, it is said on the SMSF site, don't like "novel ecosystems" like the Mount Sutro forest because we want everything to remain static, and we hate change. But that seems to be more true of the SMSF outlook -- They want the forest to stay pretty much just the way it is.

Ironically a recent post expresses solidarity with the efforts of a eucalyptus tree sitter in Tasmania who is protesting the logging of an old growth Eucalyptus forest. The logic there kind of baffles me.  After all - she's a "nativist!" To be consistent SMSF should reserve their praise for a Tasmanian sitting in a redwood tree to protect a stand of introduced redwoods!  Oh well - it makes sense in that they both like eucalypts I suppose, but I imagine they wouldn't get on very well with each other past that one fact.

The SMSF site makes a number of factual claims. They call the area a "cloud forest" and state that if left unthinned, the blue gum eucalyptus is less of a fire hazard than if thinned (and than the native coastal scrub and prairie vegetation that would have grown there originally) because the trees cause fog drip that keeps everything moist.

Most of the forest is owned and managed by the University of California, San Francisco (UCSF). Their well-researched plans and ongoing care of the reserve belie, it seems to me, any need to "save" the forest. (For a summary, you can see a presentation used for community meetings here.) Their Q and A web page debunks the cloud forest descriptor and the claimed fire-preventive effect of fog drip -- the UCSF writer states:

Reduction of fog drip does not increase fire hazard because fog drip only moistens surface soil and does not replenish the internal moisture content of the living trees or understory very well. Dampness and green appearance disguise the internal conditions of the plants. The Mount Sutro undergrowth has a dense, dead sub-canopy under the leafy green surface.
He or she does not cite evidence for that statement, though.

It seems likely that that lots of wildlife uses the forest trees, as the SMSF site states. I found reference to this same feature on a page about the eucalyptus trees on the Jepson Prairie Preserve too - a "nativist" site no less!

Farther along the trail

But the SMSF claim that the trees are not allelopathic? There is plenty of evidence that they are. Ironically, it turns out that the fog drip contributes to the allelopathic effect (see Fog drip: a mechanism of toxin transport from Eucalyptus globulus). In fact some people have tested the effectiveness of these eucalyptus chemicals as a herbicide (Abstract of results: it is effective on some weeds, and actually encourages others). I don't know if people on "my side" exaggerate the allopathic point ("desertification" didn't turn up any relevant results on Google) to emphasize the undesirability of eucalyptus trees in California, as SMSF claims.

On the SMSF site you can see photos of some of the understory plants that are shown to disprove the supposed claim about desertification: calla lilies, and forget-me-nots. I have a feeling that they are shown as a tweak to us "nativists" since both are known to be invasive in my neck of the woods.

(The SMSF folk call this a naturalized and wild old growth forest with a novel ecosystem. I'll maybe write about this topic in another post but it opens up to a very large discussion that may just take me too long to research and adequately cover.)

In Sutro Forest, I also saw a lot of nice ferns and some other natives (see my last post, Can We All Get Along? Part 1, for photos) as well as the dominant non-native ivy. I'd say our eucalypts along the coast have much less of an understory - I'll have to check that out.

Higher again in the eucalyptus forest - less understory here.

However, one of the main reasons people like don't like to have eucalyptus trees on their properties -- and I've got three very large ones -- is the fear of them exploding like fire bombs in a wild fire. I live in dread of them bursting a medium fire into a conflagration. I haven't removed them only because it'll cost thousands of dollars.

But according to the SMSF folk, I may not have to feel so bad about them after all! In fact - I can feel good - They have a fire protective effect! Wow, can it really be so?

SMSF states that these trees evolved in a similar way to our own Mediterranean climate plants, and if we treat the trees like other trees, as far as fire safety -- limbing up to avoid fire ladders, clearing flammable litter from below -- then there is no greater problem from these than from any other tree. In fact their bark is fire retardant.

I know that there are similar myths and misconceptions about chaparral habitat's flammability -- yes, it's flammable, but not more so than the plants people tend to put in its place. What Rick Halsey says on the Chaparral Institute web site about chaparral reminds me of what Dan Grassetti says about eucalyptus. Has it been vilified as a water-sucking oily and allelopathic firebrand?

According to a 1972 UC Davis study, Eucalyptus: fuel dynamics and fire hazard in the Oakland Hills, fuel buildup occurs very rapidly in unmanaged stands. In a frost, eucalyptus trees can shed a lot of litter. Fuel reduction programs are required. Eucalyptus oil in the leaves is very flammable, but the duff seems to be a lot less so - the oils decompose in about six months. I know ours shed huge strips of bark. The study doesn't mention the crown exploding though.

The SMSF site even has a post Why Eucalyptus Trees can Actually Fight Fire. It bases this claim on a white paper, Computational Fluid Dynamics and Combustion Engineering by David Porreca, about use of eucalyptus to deflect flying embers and stop the spread of fire! How counter intuitive is that? Is Mr. Porreca a maverick like Dan Grassetti seems to be? Can we take this seriously? On what does he base his statements?

At the end of the day, I do feel somewhat more reconciled to my three giant eucs. My general philosophy is that if a major fire comes through, we are out of here. This place is toast, eucs or not. Probably. Only good luck and a wayward wind would save it. I would certainly come back to see the fire followers and the natural succession of natives that occurs after a fire, and probably rebuild. But a minor fire - I'd like to feel the place is defensible against that. And if I am to believe Mr Grassetti and ignore our local fire department advisors, clearing the fuel load around the eucs might well be enough to provide that result. Hm. What do you think?


Jason said…
Thanks for this post. I don't know anything about eucalyptus, but if I had to choose between the fire department and UCSF on the one hand and activists who reach their conclusion first and then search for data to back it up - it would be no contest. Yup, I would definitely go with the fire department and UCSF. Maybe there are folks you could call up and speak to directly?

I appreciate your take on the "anti-nativist" folks. I was dumbfounded to read a related guest post in Garden Rant. The author, who is from the Bay Area, denounced the removal of eucalyptus. I was skeptical, but admitted to myself I didn't know much about her topic.

Then she went on to claim that in the Midwest, native plant fanatics are trying to cut down ALL trees in order to restore the prairie. What's more, the prairie is itself no more than an artificial ecosystem caused by fires set by Native Americans.

Now this was something I did have direct knowledge of, and it was absurd on all counts. Yet when I posted a response, she stuck to her claims, citing as evidence photographs she had seen of piles of dead trees killed by the dreaded conservationists.

We have people who think this way here in Chicago. They cause real problems for people who are serious about protecting natural areas. Not much we can do about it except try to educate the broader public as well as public officials.
Country Mouse said…
I read your comment with great interest, Jason, thanks. We have similar experiences. It took me a long time to write this post and I wasn't sure if I was wise to even attempt. On the one hand - you put it very well about folks who reach conclusions first and then attempt to back them up. That is a good way to put how I felt. At the same time, I have to examine my own thinking to be sure I'm not guilty of the same thing, and I have to examine what they say - regardless of their motives - to see what I can learn from their claims. I did find myself believing without foundation because I trust the sources rather than because I examined the supporting evidence. I'll be continuing to seek education and to disseminate information in the future to be sure. I agree education and discussion is key - but we all know how hard it is to talk across such idealogical divides. I just read the garden rant post you refer to. It took so long that now the rain has started and I missed my gardening window of opportunity for the day - oh well maybe I'll get out anyway! Here's a link to the really excellent discussion - the comments are more interesting than the post, really a lively discussion.
Interesting post. Except for their nectar value for bees during the winter months, I've always rather loathed Eucalyptus. They are inordinately messy, and I remember an awful lot of finger pointing after the Oakland Hills fire being directed toward the overabundance of these trees in that area.

Regardless, litter aside, I don't know if they're more or less flammable. I'm not sure it really matters. I've seen how fast our native Bay Laurels burn, even after a recent rain, and with our overall lack of woodland habitat management, especially here in the Santa Cruz Mountains, I think it's fair to say that all our fuel loads are greater than they should be. The fires are bigger, and they burn hotter. I'm with you, between terrain and fuel load, if there's a fire here, we're gone, and I presume everything here will be too. But you provide a lot of food for thought.
Keith McAllister said…
You were right to point out that the UCSF writer offered no evidence to support his/her description of the cloud forest on Mt Sutro. On your next visit you will undoubtedly see that the description is simply not accurate. Why would UCSF make such claims?

UCSF applied to FEMA for funding of a project to destroy eucalyptus on Mt Sutro and replace the trees with native plants. FEMA funds hazard mitigation projects, and specifically does not fund landscape alteration projects. That is to say: FEMA does not fund “native plant restorations.” UCSF's application was for “wildfire hazard reduction.” For a period of several years UCSF spokespersons made many public statements claiming the eucalyptus posed a high fire hazard which their project would alleviate. The quote from UCSF that you present is typical.

In a letter dated Oct 1, 2009, FEMA asked UCSF to provide evidence that there was a "very high" wildfire hazard on Mt Sutro and to provide evidence that the UCSF project would reduce that wildfire hazard. FEMA’s letter suggested that some UCSF claims regarding wildfire hazard on Mt Sutro were not accurate, and were contradicted by the California Department of Forestry and Fire Protection, which rates the risk as moderate, its lowest risk rating. UCSF didn’t (or couldn't) provide the requested evidence, but instead announced in February, 2010 that they were withdrawing their grant application.

There is simply no evidence that eucalyptus are more flammable than other trees, and certainly not more flammable than brush and dry grass. You shouldn’t worry that your three eucalyptus trees are eucalyptus. It is important to clear defensible space around your home, free of dead vegetation, regardless of the species.
Country Mouse said…
Thanks for your inputs all - I feel like what we need is a Fact Checker like they ran during the elections! I may not be done with all this yet!
I think I remember reading that the houses that burnt in that great Australian fire, were built amongst Eucalyptus trees, where they had been told not to!

From personal experience I am much more afraid of the pine trees I saw blazing like torches when we were in a mountain fire in Camps Bay. I remember another evening looking up at the end of Table Mountain, watching the blazing trees, flame up and fall, step by step down the mountain, as we watched in silent horror.
Country Mouse said…
Yes, around here there are quite a lot of monterey pine. Though they are local not too far off, they don't do so well out of their natural niches. The ones here were provided by the forest service 50 years go or more, because they are fast growing. They were no doubt of the stock they bred for the commercial plantations besides. They tend to get old and sick quite rapidly and are a big fire risk too as they rot and dry out and fall over. Yup, we shouldn't really be here, and yet - here we are.