Burning question: Why can’t the East Bay agree on the future of eucalyptus trees?

The Berkeley Hills have a smell to them, all-encompassing but never overwhelming. You grow accustomed to it, and then maybe you leave the city for a while, for a trip or school elsewhere, but when you return, it’s there to welcome you back. Clean, minty, almost medicinal: The smell says you’re home. 

It can be funny, then, to learn that the source of the scent is one of the most contentiously debated plants in the Bay Area: the blue gum eucalyptus tree, whose origins, despite all the intimate associations with California, are an ocean away. In recent decades, the eucalyptus has become the subject of a rancorous argument pitting environmentalists, scientists and neighbors against one another. 

Brought to California in the 19th century via seed envelopes from Australia, the eucalyptus has since made itself comfortable. It thrived in the Bay Area climate and quickly spread throughout the area. But the trees didn’t appear in droves by chance. They were purposely planted by early settlers to provide timber, block wind, and beautify the area. It didn’t take long to figure out they weren’t great for lumber, but by then it was too late — the gums were here to stay. 

Eucalyptus trees are simultaneously dry and filled with flammable oil. They shed long, shaggy debris, covering the ground with dry fuel for wildfires, and when they catch fire the oil in them burns hot and fast. Their seed pods can explode in a wildfire, shooting embers across the landscape. Apart from the wildfire risk, they grow rapidly and have died in massive numbers over the last couple of years, causing a nuisance for some homeowners and land managers and sparking calls to have the invasive species felled en masse. 

On the other hand, they provide vital shade and habitat for native and endangered species. Their tall crowns and long limbs collect dew that rains down on the forest floor after foggy East Bay nights. Since the day they were rooted in California soil, there has been a vocal constituency fighting for them to stay, with many claiming that their years-long presence has now established them as part of the California ecosystem. Even the author, Theodor Geisel, better known as Dr. Seuss, was inspired by these tall trees, writing The Lorax around the same time he was trying  to stop the eucalyptuses by his home from being cut down for a suburban development. The book inspired generations of children to fight for the environment. Some of them no doubt grew up to become the very environmentalists who now see the trees as a hazard. 

Such are the complications of the fight over the eucalyptus. The usual environmental battle lines — tree huggers vs. industrial growth at any cost — don’t apply. And the questions that are raised go to the heart of California’s political life: What do you think about when you hear the word “invasive”? What does “native” mean, particularly in a state whose ecoregions exceed its political boundaries? What is and isn’t authentically Californian? 

The stakes are high, and so is the temperature of the rhetoric, which has a way of taking on the intensities of other political debates. Activists accuse groups that want to clear eucalyptus trees of racism and nativism, drawing spurious analogies to human social categories. Those against eucalyptuses warn of falling tree limbs, burning homes, and choking native ecosystems.

The conversation is once again heating up. On Oct. 18, the Keller Fire sparked to life in the Oakland Hills, temporarily displacing 500 residents, and the Berkeley Fire Department urged hills residents to pre-emptively evacuate their homes in case a separate fire started nearby. This happened while thousands of eucalyptus trees in both Berkeley and the East Bay Regional Park District were being thinned to reduce fire risk. 

Khari Helae, assistant fire chief for the East Bay Regional Park District, took a diplomatic approach in describing the polarized field of debate. “For us, at the East Bay Regional Park District, we have lots of different constituents and members of the community who have different opinions,” he said. “We have people who love the eucalyptus trees and see them as forested areas and they like them. And then we have people who want all the eucalyptus trees removed.”

Twisted timber

Let’s take it back to right before the start of this debacle: the Gold Rush. Gold in California hills brought an estimated 90,000 people to the state to seek their fortune in 1849. With the influx of people, early settlers began to worry about an impending lumber shortage. As a solution, they started planting vast amounts of eucalyptus trees. Not only did the eucalyptus grow quickly, but they also provided shade, blocked wind, and looked and smelled nice. At one point, they were even recruited to the fight against malaria through what was known as the miasma theory of disease. The science was dubious, but there was some truth to the notion that the eucalyptus prevented malaria. Because the trees drank up so much water, there were fewer standing pools for disease-carrying mosquitoes to breed in. 

Eucalyptus trees easily adapt to the area where they are planted and can flourish in drier conditions. And flourish they did. But to the chagrin of many settlers, the eucalyptus turned out to be a lousy source of lumber, certainly not the hardwood of the future that many speculators in the early 20th century had banked on. The wood tends to twist when it dries, rendering it largely unusable for things like railroad construction. The boom soon went bust. Eucalyptus plantations were quickly abandoned, left to grow and grow on their own. 

For a long time, few were bothered by the extra greenery, but things started to change in the 1970s. An early major precipitant, according to Jared Farmer’s Trees in Paradise: A California History, was an unlikely frost that swept across the East Bay in December 1972. Millions of trees died, and eucalyptus trees across the area were dropping limbs everywhere, sparking fears that kids could be crushed under their heavy branches. 

Around this time, environmentalists started to bristle about the eucalyptus tree’s status as a nonnative species. This conversation was enveloped in a growing consciousness of the importance of native plant life. Eucalyptuses were soon given a disparaging, albeit scientifically accurate, epithet: invasive.

The moniker stuck, and soon people were discussing whether or not they belonged in California at all. Within a decade, the casual conversations around eucalyptus trees would turn into a heated battle over safety, environmentalism, and what qualifies a plant as “native.” 

What’s in a name? A lot

In the 1980s, a federal effort to remove the nonnative blue gums from the Marin County portion of the Golden Gate National Recreation Area (GOGA) to mitigate fire risk had to be dialed back after a furious public outcry, as Farmer recounts in Trees in Paradise. He writes: “Hundreds submitted comments to the [the California Department of Parks and Recreation]. Their message: Don’t nuke the eucs! A Marin County opposition group, Preserve Our Eucalyptus Trees (POET), accused the DPR of prejudice, phobia, ‘speciesism,’ and ‘plant racism.’ The group’s cofounder noted that ‘eucalyptus has been in California for 100 or more years, and many of us regard them as a natural part of the state’s landscape.’” 

Farmer quotes from a letter to the DPR submitted by a concerned resident: “I’m sure the people who came up with this idea are not native, either. America is a melting pot of many races, as well as species of flora and fauna. Stop the Marin Chainsaw Massacre!”

Botanists may cringe at the casual conflation of socially constructed hierarchies with plant species. It goes without saying these terms are not interchangeable. 

But how we talk about things matters. The language we use, the context we give, and the biases we bring to conversations change how things are perceived. This has been well-known in the environmental community for some time, and scientists and advocates have worked carefully over the years to create clear definitions around how they categorize plants that do not originate in a certain area but have ended up there.  

A nonnative species is any species that has been placed in an environment in which it would not have naturally grown. Some scientists prefer the term “introduced” to “nonnative” as it can carry less stigma. 

An invasive species is also something that has been introduced to an area. The important distinction is that it also harms the environment in which it is placed. For example, tomatoes are not native to the United States, but they are not considered invasive. 

The California Invasive Plant Council, an organization dedicated to protecting California ecosystems from invasive species, classifies the eucalyptus, specifically the Tasmanian blue gum eucalyptus, as a “limited” invasive species — downgraded in recent years from “moderate” — meaning either that its impacts are minor or that there wasn’t enough information to give it a higher score. Some of the problems the eucalyptus presents, as listed by the council, are impacts on biodiversity due to displacement, loss of understory due to debris and chemicals from the tree, and flammability. It was that last one that forever changed the eucalyptus’ reputation. 

A fire fight

On Oct. 19, 1991, nearly 33 years to the day before the Keller Fire, a devastating wildfire consumed the Oakland and Berkeley Hills — residential areas right on the edge of the wilderness. At the height of the fire, over 1,500 firefighters were working to tame the blaze. In a historical irony, they made their last stand near the Claremont Hotel, built in 1915 by the real estate developer Frank Havens, whose company planted some 3 million eucalyptus seedlings in the East Bay. By the end of the firestorm, nearly 3,500 residences had been destroyed, 1,500 acres had burned, and 25 people had been killed. 

Many factors fed the fire’s destructiveness: the Diablo high winds and dry weather; poor coordination between neighboring fire agencies; windy, narrow roads with dense vegetation. But the eucalyptus trees also got their fair share of the blame. 

According to a fire management newsletter released by the National Park Service, “dense vegetation was identified as a major contributor,” to the 1991 fire. “And in particular, dense eucalyptus forests. It was estimated that over 70% of the energy released through the combustion of vegetation was due to eucalyptus. In many cases, eucalyptus trees were adjacent to houses, with their canopy spreading over the roofs. The density of fuels immediately surrounding homes resulted in a continuous chain that spread the fire from structure to structure.”

Suddenly the rumblings about eucalyptus trees turned into cries of rage, with people demanding they be removed. In response, other residents started to demand for these trees to be protected. 

Two main organizations of Oakland Hills’ residents emerged: the Hills Conservation Network and the Claremont Canyon Conservancy, each with its own views on wildlife mitigation, vegetation management, and most notably the role of eucalyptus trees. They also had different ideas about how to stop a disaster like the 1991 Hills fire from happening again. 

In 2004, UC Berkeley implemented a project to clear large swaths of eucalyptuses near Claremont Canyon. At this time, it cut down thousands of eucalyptus trees. In 2015, the university, along with the city of Oakland and East Bay Regional Park District, received money from the Federal Emergency Management Agency to continue this work. FEMA was subsequently sued by both the Hills Conservation Network and later the Claremont Canyon Conservancy. The first group was against cutting down numerous eucalyptus trees; the second group felt the cutting wouldn’t go far enough. 

Berkeley residents outside of these two groups showed up on July 18, 2015, to protest the clearing of these trees. Some stripped down naked, hugging the trees. 

FEMA eventually pulled the funding, and it wasn’t until 2023 that the university was granted permission to cut down the trees. In between these events, there were fights over vegetation plans, tax measures and more, all of which seemed to center around two main opposing views. The first is that eucalyptuses have been unfairly scapegoated, and they shouldn’t be cut down in the name of fire safety. The second is that eucalyptuses present increased fire risks that need to be mitigated to keep people safe.  

Neighbor against neighbor

Elizabeth Stage is president of the Oakland Firesafe Council, board member for the Claremont Conservancy, and supporter of Measure MM, a special tax just passed by Oakland voters designed to fund vegetation management to combat wildfire risk and includes addressing eucalyptus trees throughout the hills.

She was walking down the street of her Claremont neighborhood in the runup to the election when she approached a man she didn’t recognize to give him a Measure MM door hanger. She handed it to him and asked if he knew about the legislation. Oh did he. Not only had he heard of the legislation; he in fact hated it. Stage had unknowingly run into Dan Grassetti, founder of the Hills Conservation Network. 

Grassetti started HCN about a decade after the 1991 fire when he saw “an increase in activity around cutting down really two species of trees: eucalyptus and Monterey pines.” For him, part of the appeal of living in the hills is the ecology that has been in place for the last couple of centuries. He claims that the people in the community who have been calling for eucalyptus and other nonnatives to be cut are using fire risk as a way of pushing a “native plant agenda.” It’s an agenda that does not align with his group’s values, he said.

“We’ve been very adamant all along that we’re nonpartisan with regards to the ethnicities of plants and that where we are concerned is around fire risk,” Grassetti said.  

He feels that cutting the eucalyptus will only make fires worse by taking away shade that stops certain flammable grasses and other brush from growing. He also noted that eucalyptus trees provide critical habitat and moisture for the area. On top of this, he says that it’s not people’s place to decide at what point in time certain plants joined the ecosystem. 

“Well, at what date in the past are things the way they were supposed to be?” said Grassetti. “This idea that you woke up one day and you decided that it should be different, therefore the public at large should pay to transform this 200-year-old ecosystem into something more to your liking, is just the height of arrogance.”

In response to comments like these, Stage said that while certain people want all the eucalyptuses gone, she is not one of them. 

“I like the smell of eucalyptus just as much as the next person,” said Stage. “But I don’t like highly flammable species whether they’re American or Australian.”

Stage said she is not “picking on” eucalyptus trees but is highly concerned about them living in close proximity to residential areas. She said that the same compounds that make them smell nice are the ones that make them highly flammable. Eucalyptuses are not the only trees that are quick to burn, Stage said. She isn’t in the camp of taking them all out, because she said there needs to be more ecological research on what other trees are flammable. 

“I like them as a species,” Stage said. “I just don’t like them in my backyard.”

The trouble with restoration

While there are two main schools of thought, the issue is far from a binary one. While eucalyptus trees are technically invasive, they have been here for nearly two centuries. Things in nature have an amazing ability to adapt, and that remains true for how the California ecosystem responded to the eucalyptus. 

“They have challenges, and they have benefits,” said Helae of eucalyptus trees. 

Helae and the fire crews and fuels management team for the park district are tasked with the maintenance of eucalyptus and other vegetation in the park.

The park district is neutral about eucalyptus trees. According to Helae, they are neither all good nor all bad, and the park district manages them accordingly. It is true that eucalyptus trees present a greater “fuel load,” meaning they create more debris on the ground, and that they also burn hotter and faster and are expensive to treat and manage. But Helae also pointed out that they provide habitat for bird life and certain reptiles, and create necessary shade for certain ecological resources. Monarch butterflies also rely on eucalyptus trees for overwintering locations. 

In order to balance these challenges, the park district staffers thin the eucalyptus trees and plant native plants in their place. In doing so, they stop the excess growth of brush by keeping the canopy coverage intact. The park district does not clear-cut eucalyptus groves. 

A couple of years ago, the park district experienced a major die-off of eucalyptus trees caused by disease and drought, which contributed to wildfire risk in the park. The fuels management team has been working to address the dead eucalyptus, mainly in Anthony Chabot Regional Park. At the end of its latest project, the district will have thinned trees in 666 acres of parkland. 

“By thinning trees, what we’re really aiming to do is not to remove all hazardous fuels, but to treat the area,” said Helae. He said that, if a fire does burn through, it doesn’t have the ladder fuels to set the tops of the trees on fire. This helps keep the flames at manageable heights for firefighters. 

To reduce wildfire risk, Berkeley Fire launched a eucalyptus understory cleanup program in September, allowing residents to apply for a one-time trimming of lower limbs and removal of dead and dried leaf and bark litter to help them meet the city’s defensible space requirements. Meanwhile, the Berkeley FireSafe Council, a group devoted to “effective mitigation” of hazardous fuels, has cleared out 250 eucalyptus trees in Hillside Canyon with funding from UC Berkeley and others.

No one alive today has ever known a California without eucalyptus trees. When environmentalists talk about restoring native ecosystems, they often raise the question of when in history things were “right” — a tricky thing, as Grassetti pointed out. Species have adapted to the environment that humans have impacted — and such is the case with eucalyptus groves.

If you make changes to the modern landscape with the goal of restoring it to a past one, you inevitably will incur both positive and negative impacts. This helps explain why, for instance, two neighbors who live just a few houses down from each other disagree so vehemently on what to do with the trees around their neighborhood. At the places where wildland and humans have become enmeshed, all questions of preservation and restoration go begging. Preserve what? Restore to when? They become debates about nothing short of what it means to be Californian.   

Berkeleyside environment reporter Iris Kwok contributed reporting to this story.