How Eucalyptus Fans the CA Wildfire Flames

Hill with trees about to burn in red, orange wildfire
The-Vagabond/iStock via Getty Images

Written by Tad Malone

Published: January 15, 2025

Share on:

Advertisement


At this very moment, fires rage in Los Angeles. It’s the worst in the region’s history. So far, it’s killed more than two dozen people, destroyed 12,000 structures, and left beautiful coastal hamlets like Pacific Palisades in utter ruins. To make matters worse, the wildfires are barely contained.

While firefighters attempt to quell the blazes, people are looking for answers. What caused the fires, and what made them spread so easily? The Santa Ana Winds blowing at an incredible speed south no doubt made the flames grow large and quickly out of control. While arsonists, electrical mishaps, and campfires have taken some of the blame, they do not account for the full story. At least part of the answer may lay with a beautiful, expansive, but pernicious plant: the eucalyptus tree.

What is Eucalyptus?

Rainbow Eucalyptus Trees, Maui, Hawaii, USA

Eucalyptus is a genus that holds over 700 species of flowering plants. With the exception of several shrubs, most eucalyptus species are trees. Characterized by smooth, hard, and fibrous bark and leaves with oil glands, nearly all eucalyptus species are native to Australia and its surrounding islands.

Species like the Tasmanian blue gum (Eucalyptus globulus) grow to heights 200 feet or more and are prized for their durability and quick growth. As such, many Australian plantations produce varieties like the blue gum. Once grown and cut, these varieties provide a valuable (if unwieldy) timber source. Other applications for eucalyptus include pulpwood, honey production, and the creation of essential oils.

Scientists believe the eucalyptus genus originated some 35-50 million years ago. They were a minor plant, so to speak, until about 20 million years ago when a drying of the continent and a depletion of ground nutrients allowed for a more open forest type. Now, the eucalyptus accounts for three-quarters of all Australian forests. Furthermore, every state and territory features at least one kind of eucalyptus species.

Eucalyptus are hearty, mighty plants, characterized by their light-colored bark and unique smell. But they have a superpower, one that likely helped their proliferation: adaptation to wildfire. Most eucalyptus varieties can either resprout after fires or have seeds that can survive harsh blazes. This durability plays an important role in the current Los Angeles wildfires. But how did these native Australian plants even get there?

A Plant’s Migration

eucalyptus diversicolor trees, Claremont Canyon Regional Preserve, Berkeley hiking trail, East Bay Regional Park district, eucalyptus regnans, eucalyptus, redwood trees

Once California was settled and populations grew, its trees suffered. Since they were used in everything from building materials to paper, California’s native trees like the oak became increasingly depleted. The state’s overseers desperately looked for a solution. By the mid-1800s the problem had become national, and states like California started offering incentives for planting trees to combat the depletion of forests. It became a patriotic duty to repopulate forests cut down for lumber.

Simultaneously, European adventurers like Frenchman Prosper Ramel voyaged to Australia and became enchanted with the eucalyptus tree. He was so taken with the tree’s durability and splendor he made it his mission to germinate the genus through the old world. Once he brought it home, French botanists and scientists pioneered the study of the eucalyptus. As such, France became a key distribution point for eucalyptus seeds, which quickly spread and grew in Africa, southern Europe, and the United States.

The California Eucalyptus

Eucalyptus Tree - Trees Native to Australia

The eucalyptus found its way to California during the state’s historical Gold Rush in the 1850s by way of one man: Robert H. Waterman. A ship captain by trade, Waterman had dreams of botany upon his retirement from the high seas. According to his biography, he intended to plant a “heap o’ trees,” and he did.

Upon settling near modern-day Fairfield, California, Waterman immediately tasked friends and colleagues to deliver different trees. His former first-mate, Jim Douglass, reportedly delivered him a bag of blue gum eucalyptus seeds in 1853, the descendants of which still stand in Fairfield. Thanks to the efforts of other Californians in the following years, the eucalyptus rapidly spread through the state. Australia features a similar climate to California, so the plant took to the foreign environment with ease.

While the state had high hopes for the use of eucalyptus in lumber and railroad ties, it quickly found the dried wood to be too twisty and tough to serve much material use. Instead, the trees proved surprisingly useful as windbreaks for highways, orange groves, and other farms. Even today, a drive through California will take you past countless eucalyptus groves dotting either side of the highway. The eucalyptus grew and grew, but not without its consequences.

It’s Role in the Wildfires

Firefighters battle a wildfire because climate change and global warming is a driver of global wildfire trends.

The problem with eucalyptus trees in California is twofold. For one, it’s an invasive species. To survive in its new home, eucalyptus competes with native plants, and it doesn’t support native wildlife. Second, the eucalyptus is not only highly flammable but something of a weapon to surrounding plants. The genus evolved and adapted to wildfires. It survives even the harshest blaze because it can regenerate from epicormic buds buried deep in their bark. The problem is, however, that the plant also produces a highly toxic and flammable oil on its leaves. Once that oil builds up and catches fire, that flame easily spreads through the expansive tree crowns.

Last week, fires sprung up in the Los Angeles area that quickly grew out of control. Though its coastal areas have long been considered high-risk fire areas, no one was prepared for the extent of the damage. Within days, the fires spread through cities like Pacific Palisades, Altadena, and Malibu, destroying 40,000 acres in the process.

Since eucalyptus trees are so ubiquitous in the area that most people think they are native, blame quickly fell on the plant for the fire’s proliferation. It makes sense, considering how easily eucalyptus oil can catch fire and spread through its canopy to surrounding vegetation. Last Wednesday, NBC’s Jacob Soboroff pointed out rows of charred palm and eucalyptus trees during a live broadcast. “When these things go up, it’s like a matchstick,” he told viewers.

Despite insistence from locals that eucalyptus played a significant role in the fires, experts have pushed back. Some suggest it is mostly native plants fueling the fire’s growth. Others point to land-use patterns, illustrating the volatility that sits at the intersection of nature and civilization.

Ultimately, it’s too early to tell just how much eucalyptus factored into the spread of one of California’s most destructive wildfires. While the plant is known as a “widowmaker” for its ability to spread fires that it survives, there may be more substantial factors contributing to the historic blazes.


Share this post on:

Thank you for reading! Have some feedback for us?