#chamise

mon âme noire

The tiny flowers of chamise (Adenostoma fasciculatum), one of the most common plants in a chaparral ecosystem.

It typically grows in dense clumps and provides food and shelter to mule deer, birds and rabbits, among others. It is very drought tolerant and has a special type of root that allows it to re-sprout even after a devastating wildfire.

This is an excerpt from an article published in Wired on April 15, 2021. It adds to the mounting evidence that there is a high possibility that the 2021 fire year in California will again be highly destructive, starting early and ending late.  Chamise is the dominant plant in the chaparral plant community prominent in the Southern California landscape.

By Matt Simon (photos by Bryant Baker)

If you’re kind of judgmental when it comes to plants, you might describe the chamise plant as “meh.” Technically it’s a shrub, which in the hierarchy of plant types barely outranks a weed. Chamise grows up to a dozen feet tall and sprouts needle-like leaves less than a half-inch long, making it look like overgrown rosemary. Only it doesn’t really smell, even though it’s a  member of the rose family.

When fire scientists want to know how flammable the state’s vegetation might be, they don’t rely on some newfangled gadget. They rely on chamise. “It's a really pretty and kind of understated shrub,” says Bryant Baker, conservation director of the Los Padres ForestWatch, which advocates for the protection of California’s habitats. “And I think because it's so common, it's often taken for granted.”

But Californians ignore it at their peril, because it is an excellent indicator of how dry the whole landscape is getting. Chamise dominates native chaparral ecosystems up and down the state, dense shrublands that are too arid for trees. But the chamise is beautifully adapted to ride out the baking heat: Those tiny, leathery leaves have far less surface area than a broadleaf, so they don’t lose as much moisture. “These plants are adapted to go for many months without a single drop of water, which is pretty amazing,” says Baker. “You don't usually find that outside of desert areas.”

Come summer, the chamise blooms into a mass of small white flowers. These attract insect pollinators, which in turn attract birds—so from the plant a complex ecosystem unfurls. When the flowers start to dry out in the summer heat, they turn a sort of rusty orange. “This can give the appearance that chaparral dominated by chamise is brown and dying, but it's completely normal,” says Baker. “It also makes for some wonderful contrast across the landscape in the late summer and fall.”

Before humans arrived in California, the chaparral only burned periodically, for instance when a thunderstorm rolled through, creating lightning but no rain to drench any ignitions. For this, too, the chamise was well adapted. An intense fire will pretty much obliterate the shrub, leaving only charred stems behind. But the chamise hasn’t given up yet. At its base is a structure known as a burl, which hides growing buds that have been shielded from the fire. Just a few months after a blaze, little bits of green will start growing across the charred earth. “It is remarkable in its ability to resprout after a fire,” Baker says.

But fire scientists aren’t so much interested in the regenerative abilities of the chamise as its powers of prognostication. Because the plant is so abundant, it’s a sort of standardized species—they can sample it all over the state. Fire weather researchers like San Jose State University’s Craig Clements use it to get an idea of how parched vegetation is overall. Clements goes out into the field, randomly samples chamise plants, and takes the material back to the lab. There he measures how much moisture the shrub contains.

And nothing scares a fire weather scientist quite like a year with dehydrated chamise. If it’s dry, then that’s a good indicator that everything is dry. “Right now, these are the lowest April 1 fuel moistures we've ever had,” Clements says. This is supposed to be the time of year when moisture levels are at their highest, thanks to recent autumn and winter rains. But California is withering in a drought. “The shocking thing in 2021 is that we don't have any new growth on chamise in our sample areas,” Clements says. “These plants are stunted by the drought.”

The California landscape appears ready to burn epically this year. “It looks bad, to put not too fine a point on it,” says UC Los Angeles climate scientist Daniel Swain, especially considering that several wildfires have already broken out in heavily forested parts of Northern California.

“I think the forest fire risk this year is going to be about as high as it can be,” Swain adds. “And that's pretty alarming considering what we've seen in the last couple of years.”

With vegetation already so desiccated, accidental ignitions can turn into big blazes. But the worst of the state’s fire season doesn’t typically arrive until autumn, when seasonal winds tear through, driving wildfires at incredible speeds.

There’s a frustrating and often tragic aspect to fire science and predicting the likelihood of ignitions: Researchers like Clements can use chamise and atmospheric modeling to warn when conditions will be ripe for an out-of-control blaze in California, but they can’t say where it’ll break out. In 2018, Clement says, dry fuel and forecasted strong winds told him the fire risk was very high just before the Camp Fire. “I knew the day before there was going to be a bad fire,” he says. “We just didn't know where it was going to be.”

Climate change, of course, is complicating that puzzle, making California’s wildfire crisis all the worse. The rains are arriving later in the year, meaning there’s more time for seasonal winds to drive fires across a landscape that’s been dehydrating since spring. And generally speaking, a hotter, drier atmosphere sucks more water out of plants. Chamise, then, is telling the story of a state struggling with climactic upheaval. “If you think about climate change and wildfire, it's all about fuel moisture,” Clements says. “We're getting drier, so we're pulling more moisture out of these plants and driving lower soil moistures.”