An Inconvenient Plant

In a highly unusual move, Michael Chassé, the Presidio's rare-plants coordinator, has agreed to lead a reporter to the site of the very last genetic individual of the once-abundant Raven's manzanita — a location Presidio officials have long kept cloaked in secrecy.

A tall, wiry man with a ready smile, Chassé is outfitted in a brown fleece, thick green cotton pants, and heavy boots, giving him the appearance of a 40-year-old Boy Scout. He mounts a well-used bicycle and pedals expertly up a series of hills, dodging go-karts and choking on the greasy fumes of passing vehicles before veering off the beaten path. Chassé ditches his bike and ascends the side of the bluff, classifying every last bit of vegetation in sight: There's a bee plant! There's a sticky monkey flower — "and it's blooming!" And there's poison oak. In fact, there's a lot of poison oak.

The path to the manzanita soon begins to resemble a game of high-stakes hopscotch: Leap left at the gaping coyote burrow, right at the sun-bleached can of New Coke, and, when possible, avoid the walls of poison oak on all sides (the hopscotch game is fitting; the plant's namesake, Peter Raven, was a boy when he discovered it). Finally, Chassé vaults into a clearing blessedly free of the ubiquitous poison oak and grins — "Well, here we are." And yet there seems to be nothing to see. Apparently, when approaching the Raven's manzanita, you don't look up or even maintain eye level. You look down — way down.

The mythical endangered plant you'd hack through the jungle to behold in a Hollywood adventure film would be a 12-foot tiger-striped behemoth with orchid-like flowers as wide as dinner plates and tureen-sized pitchers capable of digesting large rodents.

Raven's manzanita, however, stands roughly shoulder-high to a Barbie doll. Past battles with a fungal pathogen have left it with several unsightly brown patches. Just inches off the ground, its dime-sized, round leaves ripple in the constant Pacific wind while its delicate, pearl-white flowers dangle like inverted wine glasses. Its gnarled red branches are no thicker than pick-up sticks. It's not what you would call ... majestic. When viewed from afar, it's rather unremarkable — except for the fact that it's the last of its kind.

Two hundred years ago, the manzanita and other low-lying native plants thrived in the Presidio's sandy dunes. Even in the late 19th century, large trees were as difficult to locate in San Francisco as parking spaces are today; it wasn't until 1883 that Major William Jones initiated the planting of the Presidio's 100,000 trees. It wasn't aesthetically motivated: The tall, heavily wooded stands of Monterey pine, Monterey cypress, and blue gum eucalyptus would, Jones declared, "make the contrast from the city seem as great as possible, and indirectly accentuate the idea of the power of the government." They also obscured the base's big guns.

For the sun-loving manzanita and its ilk, however, the trees were essentially a death sentence.

But now scientists and preservationists like Chassé hope to restore the Raven's manzanita and other native plants in the park to their previous glory. How? In large part, by axing thousands of tall, nonnative trees on 75 of the park's 1,480 acres.

And there's the rub. For the Presidio's most vocal neighbors and aficionados, beauty is only bark-deep. The park management's 30-year, $23 million plan calling for the removal of the trees in favor of dune restoration benefiting dozens of small, threatened plants has touched off a war on the former military base. In San Francisco, you can landmark a "historic tree" — but no one has ever thought to designate a historic bush. Maybe that's because city dwellers tend to be more emotionally attached to trees (some scientists, in fact, ponder whether humans' love of trees is hard-wired into our collective memories from the days we swung from them). In any event, local tree lovers opposed to thinning the Presidio's forests have gone so far as to accuse restorationists of carrying on the work of the Nazis.

Meanwhile, even ardent advocates of Raven's manzanita admit its long-term recovery is a long shot: No plant species has yet been revived from its last genetic individual.

So, if the last Raven's manzanita falls in the forest, would San Franciscans make a noise?