Street Science: Burn, Bernal, Burn

Image courtesy of Ben Golder.

Image courtesy of Ben Golder.

The question started with a picture. It showed Bernal Hill on fire. As your eyes moved to the right, the flames dissolved into thick gray smoke and then into green grass and blue, cloudless sky. It was part of series of maps of actual and potential wildlife corridors in San Francisco, plotted out by Ben Golder, part of a team that mapped all of San Francisco’s streets that aren’t technically streets. Golder is headed to Barcelona to plot out similar corridors there as part of a Fulbright fellowship.

In this case, the imaginary burning was all to benefit a delicate kind of wild. Early accounts of San Francisco describe the city’s hills as covered in wildflowers, says Amber Hasselbring of the Mission Greenbelt Project. Bernal still has a few wildflowers, but most of the hill is covered with invasive annual grasses – wild radishItalian ryegrass and yellow oxalis, all hand-weeded by a dedicated group of volunteers every third Sunday. Wouldn’t fire be more fun?

Golder makes the point that a significant percentage of the city’s population leaves every summer to attend a fire festival in a desert six hours away. A fire festival in the city could mean less gasoline burnt in transit. More adequate toilet facilities. Though an end to the cleared-out city that many have come to look forward to during the last week of August.

I pushed the image of endless rows of porta-potties and fake fur out of my mind, and thought of the highway. I was driving back from Los Angeles during one of those long, hot summers when all of central California seems to be made of tinder. A hill on the side of the highway had erupted into orange flame against the purple horizon. A narrow line of firemen marched up toward it, as tiny as figures in a diorama. It was one of the most beautiful things I have ever seen. I would go to that.

“With enough participation from the city and community owners, it would be totally possible to set Bernal Hill on fire,” says Hasselbring. A few decades ago, the fire department set fire to Bernal Hill and Glen Canyon every year before July 4. The burns weren’t part of any ecological agenda; they served double duty as a training operation and a way to make both locations less flammable on what is still the busiest night for wildfires in San Francisco.

Pat Gardner, deputy chief at the SFFD,  remembers working the fires, but not with unalloyed fondness. “It was fun because it was a good thing to learn about the job,” but starting them, he says, was stressful. “You don’t just walk through the grass with a flare. You have to take the wind conditions into account, and the slope of the hill. There are experts that do this.”

The burning stopped on Bernal after pressure from the EPA and the State Fire Marshal, combined with a controlled fire in another city that got out of control and took out several homes. There was also a distinct lack of fondness for dragging hoses up Bernal in the hot sun (“That was before we all had wildland firefighting uniforms,” says Gardner. “Being up there in all our heavy black gear: Not fun.”) The burns ended by mutual agreement.

Now the SFFD does its wildfire training in other, more tolerant municipalities, and only puts out urban wildfires that are set by other means: cigarette butts, stray chimney sparks, sun shining through broken glass and onto dried vegetation, kids (and adults) with firecrackers. The Presidio continued controlled burning until roughly a year ago, when the park decided to pay the SFFD to manage fire safety instead of maintaining its own force, and SFFD decided the burns were too risky.

If the invasives were burned away, would the wildflowers return? “When there’s a fire, it flushes the seed bank,” says Josiah Clark, an ecological consultant who has worked with the Golden Gate National Recreation Area and the SF Recreation and Park Department to preserve the native plants left in the city.

The native plants that have persisted in this area have a nose for opportunity — fire can get them going, shooting up out of the ground and into a world they have been persuaded is cleared of any plants that might get in their way. Clark has seen the sprouting rate of the wildflower seeds he collects go from 5 percent to 90 percent just by dumping them into a saucepan filled with gravel and boiling water and shaking them before planting.

McLaren Park is the most fire-prone park in the city. It’s large, not heavily used, and popular with firecracker enthusiasts. It also has some of the city’s healthiest populations of native plants. Clark is convinced that the two are connected. “Ecology is made of stochastic events,” he says. (By which he means: Random.)  “Fireworks are stochastic.”

It’s known that the native people who lived in San Francisco did controlled burning. But, says Hasselbring, “with Bernal’s ecology today, I don’t know which plants would benefit.”

The wrong plants, according to Jake Sigg, one of the city’s earliest native plant advocates. “Fire by itself would be useless. The weeds here are from Mediterranean climates like ours. They do just fine.” Wildflowers didn’t rebound when the fire department used to burn the hill, he says, because fire alone won’t do it. A burn, or series of burns, would need to be followed by years of spreading wildflower seed, and then mowing and hand-weeding to help wildflowers re-establish themselves.

Maybe, says Clark, if the fire was timed differently, to the months of August and September, when the hill is most likely to burn on its own.

Setting fire to Bernal would be exciting, they all say, but when asked by a reporter about the practicality of setting Bernal on fire, all say there are more critical things to local ecology.

If only, says Hasselbring, people would stop buying plants from commercial nurseries, which soak their wares in pesticides before selling them. No, says Sigg, what would be nice is if everyone who had the room for a native oak tree or a willow planted one, since they provide critical habitat for migratory birds. Clark? He’d prefer it if people planted more trees on the street, and fewer in public parks, since San Francisco’s native ecology didn’t have many trees to begin with. “I get it,” he says. “A lot of people want to adopt a tree. Who wants to adopt a sunny meadow?”

Sigg was once a city gardener. He spent 31 years doing it — 16 of them at Strybing Arboretum, supervising and coaxing non-native plants into not dying here. A reassignment/exile to maintain the playgrounds and tennis courts at Crocker Amazon and McLaren Park was a conversion experience. In the face of the functioning ecosystems still existing in both places, gardening became boring. “Native plants are a much richer experience,” he says. “Gardening — once you stop, it reverts to weeds. But with natives it’s this whole complex web. I thought that was where it’s at.”

Sigg is also of the opinion that the idea of nature in the city, as much as he’s dedicated himself to it, is at this point largely an exercise that does more to build human community than to secure spaces for the plants and animals that have managed to persist within city limits. “I came here in 1946,” he says. “I remember when Diamond Heights was just wildflower fields, before the San Francisco Redevelopment Agency declared it a blighted area and wiped it out. Every vacant lot in this city is slowly being filled in. You have to understand that what we are doing is commensurate to what needs to be done. But until the Messiah comes, we do what we can.”

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2 Comments

  1. Man, that’s just sad :(

  2. George

    Strange that Jake Sigg was a huge supporter of the fees implemented by the San Francisco Botanical Garden Society!

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