Eucalyptus Exodus

The team at Elkhorn Slough finishes clearing eucalyptus trees by creating biochar, a process that incorporates the burned wood back into the soil to capture all the potential carbon releases.

While clearing thousands of eucalyptus trees around Palo Colorado in Big Sur in 2018, Pat Riparetti’s team discovered in the thick forest a graveyard of sorts – 25 mature redwoods, felled by malnourishment. It was a mass casualty of a native species at the hands of this all-consuming Australian invader.

“We were shocked. Our forester said this was a great example of the effects of this invasive tree and how powerful it could be,” says Riparetti, stewardship director with the Big Sur Land Trust, who was leading the fire prevention effort. “It was just a slow march of eucalyptus transforming the habitat with its sheer dominance.”

All the reasons that make a single eucalyptus tree majestic – lush, skyscraping plants with a trunk that constantly sheds spirals of smooth bark and branches of oblong leaves that emit a scented, medicinal oil – are the same reasons why eucalyptus groves in nonnative habitats have inspired grave concerns and eradication efforts.

“The single tree upon which the hope of the nation is fastened, the only tree which could possibly avert… the inevitable ravages of the hastening timber famine, is the miracle tree – the eucalyptus.” 

Eucalyptus, introduced to California in the 1850s, are the most widely planted trees in the world, according to research out of the Elkhorn Slough National Estuarine Research Reserve. “The single tree upon which the hope of the nation is fastened, the only tree which could possibly avert… the inevitable ravages of the hastening timber famine, is the miracle tree – the eucalyptus,” reads one article from a 1909 edition of Out West magazine.

Eucalyptus grows quickly and bullies other species out of resources. Tall, thick canopies block sunlight; falling bark smothers the ground below while deep roots monopolize soil moisture and leave native plants, such as redwoods, outmatched. The fresh-scented, medicinal oil is toxic to other plants and makes the trees highly flammable.

“If there is a wildfire in one of these groves, it’s going to be horrific,” says Pete Scudder, a director with the North County Fire Prevention District. Groves are scattered throughout the county, from Prunedale to Greenfield, and Garland Park to Big Sur. Clearing them, he says, is pricey and difficult.

Steve Wiley, who lives in Prunedale, has several eucalyptus trees on his property, which he sees as 130-foot matchsticks too expensive to remove.

“Been thinking about cutting them down since I got here. An ounce of prevention is worth a pound of cure but I would have to spend at least $20,000 to get them removed,” Wiley says.

The ability of eucalyptus to dry out soil is especially concerning while the county is under a drought emergency, says Virginia Guhin, education coordinator at the Elkhorn Slough reserve. The team at Elkhorn Slough has cleared 600 eucalyptus trees in recent years in an effort to restore the diverse native habitat. Guhin says they will begin another phase of eucalyptus eradication in the next few weeks.

“The main goal is to manage the land for native plants and animals,” Andrea Woolfolk, the reserve’s stewardship coordinator, said in a statement. “Removing exotic Australian trees where they aren’t providing important habitat for native animals makes sense.”

Christopher Neely covers a mixed beat that includes the environment, water politics, and Monterey County's Board of Supervisors. He began at the Weekly in 2021 after five years on the City Hall beat in Austin, TX.

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