Eucalyptus tereticornis’ buds, capsules, flowers and foliage, Rockhampton, Queensland. We pass a man in an excavator stacking eucalyptus logs. Leaves or other components, meanwhile, can tell you only so much about the whole, and individual trees only so much about the forest. “Like, you couldn’t come up with a better way to get that tree to burn.” This tree is surrounded by others just like it; this grove just one of the dozens between here and Lake Chabot, millions of blue gums billowing from the ridgeline like sage-green smoke. But then they catch on fire.” This is one of the areas owned by UC Berkeley, where all of the eucalypts would be removed. Eucalyptus doesn’t constitute more of a fire danger than any tree, and a eucalyptus woodland is less flammable than native grass and shrublands. California eucalyptus tree. But even under the worst conditions, there is the possibility of containing a grass fire, he says. What is ostensibly a debate about fire science is more than that, though—it is really just the latest episode in a decades-old dispute over the Australian trees’ place in the Bay Area. The natural oils of the eucalyptus tree make it extremely flammable. Not just any fire, but the fire, the fire that all this is about. They're poor in biodiversity but contributed to the expansion of forest cover. “The forests are beautiful. There are some native eucalyptus but the majority have been introduced. He is persistently neutral: “Everybody’s right, everybody’s wrong,” he says at one point. But not today. This is another of blue gums’ talents—its bark makes ideal braziers. According to both the FEMA environmental impact statement and a 2016 study of blue gums in California by ecologist Kristina M. Wolf and biologist Joseph M. DiTomaso, blue gum has an ignition rating of 1 out of 10, with one being the most easily ignited. They are also found in Australia, of which many are native. They point me repeatedly to both the 1992 Oakland mayor’s task force report and a 2013 report by the U.S. Forest Service’s Adaptive Management Services Enterprise Team. The East Bay Regional Park District is taking something of a middle approach to fire prevention in the eucalyptus groves it manages, thinning the trees rather than clearing them outright. Leaving the eucalyptus as-is endangers thousands of homes and people and isn’t a viable option, he says. Some 600 members of genus Eucalyptus dominate forests across Australia. “Within a very short time, you have a self-sustaining, low-cost native forest.”. Perhaps as important, Kent says, this side is cheaper. The tree sheds bark and dead leaves, which make a perfect pile of tinder under the tree too. On warm days eucalyptus oil vapour rises above the bush to create the well-known distant blue haze of the Australian landscape. So do all the experts I spoke with, including the ones with no prior knowledge of the FEMA grant. Specialized reproductive structures called "epicormic shoots" sprout from buds on the bushfire damaged trunk of a Eucalyptus tree, about two years after the 2003 Eastern Victorian alpine bushfires. In California, the trees have spread so prolifically that there are entire woodlands almost completely made up of gum trees. Find more gardening information on Gardening Know How: Keep up to date with all that's happening in and around the garden. Eucalyptus cinerea grows 25 to 60 feet tall in warm climates, but it is often grown as an annual shrub in colder climates, where it reaches 6 to 8 feet tall in one season. His most recent article for Bay Nature was on the Resilient by Design contest and the future of the Bay’s shoreline. Oil has a higher energy density and lower ignition point than cellulose (the stuff plant cell walls and Mini Wheats are made of), and in a hot fire, these oils can boil out of the leaf and then ignite, which is why blue gums have a reputation for exploding. “This one I made a promise to, that I was not going to let any harm come to it. -David Bowman, University of Tasmania fire ecologist, In the Bay Area, though, it’s not enough to just say the blue gums are flammable, Dave Maloney points out as we drive from Walnut Creek toward Berkeley. The dead bark and fallen branches are also flammable. Several of the people I spoke with were worried about the use of herbicide as a way to keep the eucalyptus from resprouting. This summer, even without rain, some of the trails were so slushy they were nearly impassable. It’s the same reason that crumpled newspaper will ignite more easily than a log—a fire requires oxygen, heat, and fuel, and grass and balled-up paper are airier and easier to heat to the point of ignition. Quick facts. Efforts are underway to eradicate the introduced species and return woodlands to the native species. The summer fogs have faded, and it’s been unseasonably hot for a week. On warm days eucalyptus oil vapour rises above the bush to create the well-known distant blue haze of the Australian landscape. We walk back down the hill, sliding in the mud. A strong wind begins blowing over the hills from the east. A former assistant general manager for the East Bay Regional Park District, Kent is now on the board of directors at the Claremont Canyon Conservancy, which worked with UC Berkeley to convert the downhill side of the road to native vegetation. To really know with scientific certainty, you’d have to compare fuel moisture content, wind speed, leaf chemistry, caloric content, and ignitability. Although the view didn’t change, I saw something different each time through the eyes of the person I was with. Eucalyptus fire hazards are also cited in efforts to remove the trees. It did not offer an explanation. "— Fabien Hubert Wagner, forest cover study lead author at National Institute for Space Research - INPE Brazil We target grass. The term Eucalypt includes trees which are amongst the closely related genera of Corymbia and Angophora as well as Eucalyptus. The protestors I spoke with disagree with Kent: They tended not to believe that the eucalyptus are more flammable or fire-promoting than native species, and they seemed determined to discount any evidence suggesting otherwise, arguing, as Maloney has, that whichever of the tree’s characteristics might promote fire are outweighed by its services. After a fire, many eucalypt species will sprout epicormic shoots along their entire trunks. In addition, eucalyptus tree care includes annual pruning (in summer) to control top growth and their overall height. By: Bonnie L. Grant, Certified Urban Agriculturist. On hot days in Tasmania and blue gum’s other native regions, eucalyptus oil vaporizes in the heat. When it is harvested, it is cut rather than uprooted, and so grows back, and with speed, making it a renewable materi… I’m going to live up to that promise.” The ground around the tree is littered with its bark and leaves, inches deep in places. Smaller trees lie between, yet to be hauled off or chipped. They provide interesting color to flower arrangements. It wasn’t based on any specific studies, she told me, but was rather an agreement among the experts—as she recalled it, a sort of, “This is what we think. Now it is regrown with native willows, bays, oaks—the species that advocates of the FEMA plan insist will, with some human help, replace the eucalypts—as well as redwoods, nonnative thistle, fennel, and broom. The Sierra Club suit argues that the plan should remove more nonnative trees, that leaving eucalyptus and Monterey pine standing would mean prohibitively expensive maintenance, and that removing the trees would allow native species to flourish. By contrast, the trees would only need to be cleared and the stumps treated with herbicide once, he says. “This is my favorite tree,” Grassetti says, giving it a slap on the trunk. Many eucalyptus species are available as landscaping plants. About a month after my visit to Signpost 29 with Dave Maloney, I return with Dan Grassetti, founder and director of the Hills Conservation Network, the nonprofit that’s filing suit against FEMA. What do you think?’”, “Eucalyptus is flammable. while the eucalyptus is prone to fire. The 1991 Tunnel Fire in the Oakland Hills, which killed 25 people and destroyed more than 3,000 homes, confirmed for many people what they had long suspected: Eucalypts are a hazard. Tucked away inside a rolled-up strip of bark, a fire might live for close to an hour and fly 20 miles. That’s the idea in thinning the eucalyptus—not to prevent fire, but merely to create the possibility of keeping it from growing out of control even in those rare instances when conditions are at their worst. The ability to retain the trunk gives the eucalyptus species a jump start on regrowing from the ashes. Eucalypts are well adapted for periodic fires – in fact most species are dependent on them for spread and regeneration. We stop at a turnout and hike up a path through tall grass that opens into a field. Bay Nature connects the people of the San Francisco Bay Area to our natural  world and motivates people to solve problems with nature in mind. “But the thing that’s most concerning is the volume of material it can produce.” But now, standing by Grassetti’s favorite tree, even this most damning of blue gum statistics seems woefully abstract. Share your love of Bay Area nature with a Bay Nature gift subscription and save over 30%! LSA Associates’ source, in turn, is a 1995 report by Amphion Inc. on the proceedings of a meeting by the Vegetation Management Consortium (which later became the Hills Emergency Forum), a group of local fire management stakeholders and experts. Ross Bradstock, a wildfire expert at the University of Wollongong, says that while being able to empirically compare the flammability of different trees would be useful, it’s not currently possible. “Yes, there is some fuel here,” Grassetti says, then gestures to the head-high brush that surrounds us. 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