Driving through California, one passes by hundreds – if not thousands – of eucalyptus groves. They are almost more common to see than oak trees, which are native to California, unlike eucalyptus. So one may ask: where did they come from, and why are they still here?

Eucalyptus trees, specifically the Blue Gum eucalyptus, were introduced to California in 1853 from Southern Australia and planted in Bolinas in the early 1900s. Since then, the trees have destroyed the native plants, including oak trees and coyote bushes. Eucalyptus trees were thought to be perfect for the quickly expanding state as they are fast-growing, tall trees that provide quick and easy resources and windbreak. The wood was intended for buildings and, most importantly, railroads. What wasn’t considered back then was the quality of the wood itself. 

“Eucalyptus was particularly unsuitable, as the ties made from eucalyptus had a tendency to twist while drying, and the dried ties were so tough that it was nearly impossible to hammer rail spikes into them,” Firesafe Marin, a nonprofit dedicated to keeping the country safe from fires, wrote in an article titled “Eucalyptus Trees and Wildfire.” 

Although planted to support the growing railroad industry, the trees weren’t suitable to be railroad ties. They were also intended to be used as a sponge for valleys, sucking the water out of the natural lakes to create farmland to feed the quick-growing Californian population. The trees were planted across California and can be found almost anywhere in Marin County.

Eucalyptus trees make up a significant portion of the trees in Bolinas, Calif. They spread across the town, between the two roads leading up to the most inhabited part of town, and what locals call “the Mesa.” 

The Mesa’s roads are essential for the residents to leave Bolinas. Along with that, the sole fire station is on the Mesa, the second closest being over a 15-minute drive away in Stinson Beach. Both of the roads are surrounded by eucalyptus trees, which are likely to fall during windy storms. These roads are essential for fire personnel to be able to do their jobs, and when the huge trees fall over, residents and firefighters are trapped on the Mesa.

There are five main problems with eucalyptus trees: habitat loss, bird deaths, water consumption, fire danger, and road blockage. 

In Australia, their native home, the bacteria in the soil are capable of breaking up fallen trees, but in California, the tree’s leaves and bark create an impermeable layer that the soil can’t break down, and therefore other plants then can’t grow through, according to Keith Hansen, a birder in Bolinas. The lack of biodiversity in eucalyptus forests is harmful to the animals who would have been living there. 

 Many native Californian birds, such as crows or cormorants, roost in the tall eucalyptus trees. This creates two problems. First, the bark of the trees is smooth and slippery, unlike the native oak tree, and when strong winds come, the nests just “slide right off their posts,” Hansen said. 

Second, the eucalyptus flower, though filled with pollen that birds can’t resist, creates a danger for specifically Californian birds. Unlike those in Australia, the birds in California have their nostrils closer to the end of their beak. 

“Birds stick their face into the flower, get honey over their nose, and over the weeks and months of mixing dirt and sap, the big black tarry thing of honey and dirt and bugs and feathers on their noses closes their nostrils and they can’t breathe,” Hanson said.

Eucalyptus trees, also known as “water guzzlers,” work as sponges for water. Once the tree is three years old, its water consumption grows exponentially, reaching 200 liters per day, or around 50 gallons, according to the World Rainforest Movement, a program that works to preserve rainforests across the globe. California, known for its near-constant state of drought, cannot afford to lose the huge amount of water the trees drink daily.

In drought-ridden California, during the dry, hot, months of August, September, and October, the state is especially susceptible to wildfires. The bark and oils within eucalyptus trees make them especially flammable. 

“Fire creates its own wind, and these tall trees can send sparks a hundred feet away,” Chuck Oakander, a renowned arborist, known around Bolinas as “The Tree Guy,” explained. Once the trees catch fire, it spreads incredibly fast. 

On Oct. 20, 1991, the combination of unseasonably high temperatures and dense, uncontrolled vegetation created a huge fire that rampaged Oakland, Calif.

“During the 10 hours the fire swept through the Oakland and Berkeley Hills, one building was ignited every 11 seconds,” reported the National Park Service in an article titled “A Complex Challenge, estimating that over 70% of the energy released through vegetation  combustion was due to eucalyptus trees.

The trees are tall, growing to around 150 feet. The water table in Bolinas is very high, meaning the water is close to the top of the soil. This means that the tree roots grow out instead of down because the trees can get all the nutrients they need from the ground’s surface. This results in very unstable trees. When the wind picks up, many fall down. 

“I’ll show up and there will be this huge tree on its side and this disc of dirt with roots in it, and you’ll look at it from its side and be like ‘how did this much dirt and root hold up this hundred-foot tree?’” Oakander recalled.

“I think that every time a eucalyptus tree has fallen there’s some type of trouble – a power outage or road blockage that inconveniences me and other people in Bolinas,” Tamalpais High School senior and Bolinas resident Jacob Alfaro-Hands said.

There have been countless occasions just this year when Bolinas students were late for school, many of them due to a eucalyptus tree in the road, Alfaro-Hands said.

The Bolinas Eucalyptus Project (BEP) has been working to remove the eucalyptus trees in a large part of Bolinas, approximately 700 trees in total, with the goal to restore the native plants and keep roads open for medical personnel during times of need. 

“We can reopen the door to the coevolutionary history of our plants and their associated insect and bird species here in Bolinas, a door that has been closed for way too long,” the BEP mission statement states. 

Visit The Eucalyptus Project website to learn more about the project.

One hiccup in the plan of removing Eucalyptus trees is their inhabitants. Though the trees have very few birds, Monarch butterflies have chosen them as their ideal winter roosting place. They require tall trees, dense forests, and enough moisture in the air for them to be hydrated, but not too much to soak their wings. 

Oak trees, a native plant to the region, are too short and have too dense of a canopy for them to appeal to the butterflies. The eucalyptus groves, on the other hand, are perfect.

“The variability of growth forms within and between species and their rapid growth makes for a more resilient grove. For example, eucalyptus will respond to canopy openings by pushing out epicormic branches, sealing up the edges of groves against the wind,” according to a study done through the University of California Los Angeles Institute of Environment and Sustainability.

Monarch butterflies seem to prefer the non-native trees, and for many, the decision is between removing an invasive species or allowing the monarchs to return to their previous population. 

“This year’s 2020 Thanksgiving and New Year’s annual count observed less than 2,000 overwintering monarchs in coastal California. This is a 99.9% decline since the 1980s,” The Marin Audubon Society reported, who work to preserve and restore natural ecosystems and donate the land to the California Department of Fish and Game and the Marin County Open Space District. 

Monarch butterflies, though their official standing on the endangered list is debated, are still near the “red zone” for critically endangered species. 

On the BEP website, there is a page dedicated to answering the many concerned questions about the Monarch population after their habitat is destroyed. They explain that the land will be planted with “early spring, late fall, and winter blooming nectar plants to create food supplies for monarchs during clustering and their southward migration.”

Creekside Science, a group that does research to provide solutions to environments in need, conducted an in-depth study of the monarch habitat on the Mesa.

Eucalyptus trees are abundant across Marin and with every tree that falls, more damage is being done to the environment. Despite resistance from monarch advocates, BEP hopes to follow through with their removal plan for the eucalyptus surrounding the two Mesa roads. Marin County has even approved a measure to remove many young eucalyptus trees, in hopes of reducing the fire danger that the forests create. 

Any projects that may take place will require years to complete and possibly decades to determine their success in preserving the wildlife that depended on the trees, such as the monarchs.

Just this past winter, countless eucalyptus trees fell, resulting in bus delays, and students being tardy to school.

“Every time there’s a storm I know a eucalyptus is going to fall. I’ve been late to school because of road closures from trees falling so many times. It’s absurd,” Alfaro-Hands recalled.