Eucalyptus: How California’s Most Hated Tree Took Root
By Daniel Potter
KQED News, Bay Curious
1 February 2018
Photo couresty of Berkeleyside
In addition to picturesque coastlines and world-renowned wineries, California is known for its high density of eucalyptus trees. Despite being one of California’s most iconic trees, the eucalyptus tree actually originated more than 8,000 miles away.
The main species of eucalyptus trees found in California are Tasmanian blue gum, or eucalyptus globulus. They are known for sickle-shaped leaves, deciduous bark that is shed each year, and for reaching more than 100 feet.
So how did eucalyptus trees end up in California? During the Gold Rush of 1850, Australians brought envelopes of seeds to California, where wood was in short supply. In this “era of wood power,” wood was essential for energy creation, construction and transportation.
Even in the poor soil, the eucalyptus trees flourished. Joe McBride, Professor Emeritus of Landscape Architecture & Environmental Planning at UC Berkeley, states, “In an average rainfall year here in California, these trees probably put on 4 to 6 feet in height and maybe, in their early growth years, a half-inch to an inch in diameter”.
In addition to altering the Californian landscape and providing firewood, eucalyptus trees also served as windbreakers.
In fact, that was the original purpose of what is now the largest, densest grove of blue gum eucalyptus in the world, on campus at Berkeley, says McBride. It was planted around 140 years ago to provide a windbreak for an old cinder running track — to keep its fine ashen gravel from blowing into athletes’ faces.
Eucalyptus, however, proved a problematic tree. The blue gum was terrible for woodworking, and would often split and crack. Further, the trees began draining local wells.
Still, the tree would play an important role in protecting and maintaining California’s parks and forests. In the early 20th century, the U.S. Forest Service began to fear that much of the country’s forests had been overexploited and would not grow back. Officials warned of a looming timber famine.
The fast-growing and resilient eucalyptus tree was planted widely to buffer the blow of the anticipated number famine. In just a few years, millions of blue gums were planted from Southern California up to Mendocino.
Despite the preparation, the timber famine never arrived, as forests further east proved to be more resilient than originally expected. Landowners did not even see the value in felling the hastily planted eucalyptus trees. As such, much of the California landscape if composed of this long-abandoned crop.
Today, the eucalyptus tree is hotly contested for its fire-fueling potential. Due to the frequent shedding of the bark, critics argue that high-density eucalyptus areas are more prone to fast-spreading fires. Defenders of the trees assert that many of California's native greenery also have a tendency to burn.
The blue gum species is classified as a moderately invasive species. “Although there’s been marginal expansion of some eucalyptus stands, it’s really not well adapted for long-distance dispersal. It hasn’t really spread very much on its own,” McBride said.
With an estimated 40,000 eucalyptus planted across California, the trees will not be easy to uproot. It can be costly to remove just one eucalyptus if it lieds near a building, and keeping the tree from resprouting can be challenging and tedious.
However, as the state’s climate continues to warm, and the possibility of future large-scale drought looms, arborists are of two minds: some speculate that water shortages will leave the aging eucalyptus groves unable to reproduce,and some believe that the trees may ultimately prefer a hotter and drier climate.