Eucalyptus trees california fires

Eucalyptus in California

History of Eucalyptus in California

With over 700 species, Eucalyptus is a diverse genus of flowering trees and shrubs part of the Myrtaceae family. Members of the genus dominate the tree flora of Australia, yet they have been planted extensively world-wide for the past 150 years and have been successful as exotics due to their fast growth, capability to adapt and thrive in degraded, acidic and dry soils, prolific seed dispersal abilities, and relatively good resistance to pests (Rockwood et al., 2008; Ritter, 2014). Worldwide among the most commonly grown species are bluegum (Eucalyptus globulus), flooded gum or rose gum (E. grandis), and red gum (E. camaldulensis) (Ritter, 2014).

Historical Overview

From the first planting of eucalyptus seeds in 1853, to the eucalyptus “boom” of the 1870s, to the hundreds of thousands of trees decorating the city’s landscape today, eucalyptus trees are an integral, iconic part of San Francisco’s history (Nance, 2014). As the San Francisco-based writer Harold Gilliam stated: “the Eucalyptus seems an indispensable element of this State’s landscapes, as indigenously Californian as the redwoods, the poppy fields, the long white coastal beaches, and the gleaming granite of the High Sierra” (McBride, 2014).

The history of Eucalyptus planting in California is a spectacular story of introduction, naturalization and decline. Once seen as an indispensable component of the landscape, eucalyptus trees quickly became seen as invasive species threatening the native flora and biodiversity of the state (Crawford, 2008; McBride, 2014).

Non-native to California, the main species planted are the blue gum, red gum, sugar gum (Eucalyptus cladocalyx), red ironbark (Eucalyptus tricarpa), silver dollar gum (Eucalyptus polyanthemos), and lemon scented gum (Corymbia citriodora) (McBride, 2014). Initially introduced during the gold rush, the first recorded eucalyptus planting in California was in 1853, in the Golden Gate Nursery (Crawford, 2008; Nance, 2014). Plantings peaked during the “eucalyptus craze” of the 1870’s and the “eucalyptus boom” of 1907 to 1913 in both the Bay Area and in southern California (Farmer, 2014; McBride, 2014).

In the latter half of the 20th century, social engineers and planners promoted widespread eucalyptus planting to achieve a number of different management objectives (Ritter, 2014). Eucalyptus species were preferred since they can adapt and grow in severely dry regions that have been historically unable to maintain vegetation, and therefore, provide shade and shelter in areas that otherwise would have been dominated by dried grasses (Nance, 2014). Eucalyptus trees were used to improve the quality of the farmland, they used as windbreaks, they were used as a source of hardwood timber and firewood supply for coastal communities, and due to their extensive root system they were even used to drain the swamps in the fight against malaria (McBride, 2014; California Invasive Plant Council, 2014). Pioneer planters and state authorities promoted the planting of eucalyptus as a producer of railroad ties, as a preserver of soil and climate, and as a solution to meet future timber needs, supplying lumber for houses, piers, railways and fences, while also providing a source of tannin, fiber and fuel. (Nash, 2013; McBride, 2014; Farmer, 2014). During the early 1900s, planting of eucalyptus was seen as a way of coping with the lack of forest timber. However, after it was discovered that eucalyptus wood is not only unsuitable for rail road ties (since the wood had a tendency to twist while drying), but also is a poor source of timber, these plantation became largely abandoned and left un-managed (Farmer, 2014).

The long history of widespread eucalyptus planting has resulted in several species becoming controversial during the 1980s. During that time, the positive attitude towards eucalyptus shifted swayed by concerns regarding “non-native” and “invasive” species and their impacts on native ecosystems (Nash, 2013; Ritter, 2014). A native species was defined as plants that existed in California prior to 1769, the year when Father Junipero Serra settled the first mission in San Diego (Nash, 2013). Eucalyptus started to be perceived as a “nuisance” due to its ability to quickly spread, its encroachment on habitat deemed critical to native plants, its significant ground water consumptions and high flammability potential (peeling bark and falling eucalyptus leaves that litter the forest floor also represented a significant fire hazard) (Nance, 2014). Shortly after the Oakland hills fire of 1991, numerous parks in the coastal region began removing significant numbers of blue gums, as did other public, and private institutions (Nash, 2013).

Today, eucalyptus groves have become a predominant features of the landscape. They are an integral part of the ecosystem, providing habitat for many native species, such as nesting sites for migratory bird species, and critical habitat for migratory monarch butterflies (Stock et al, 2004; McBride, 2014). Eucalyptus trees grow well at high densities (8 ft average spacing between tress), and subject to few diseases or pests (McBride, 2014).

Eucalyptus trees throughout California are admired for their valuable characteristics (paper pulp, honey production, shade, windbreak functions, aesthetics, and ornamentals functions), while at the same time, they are seen as foreign invaders (California Invasive Plant Council, 2014; Ritter, 2014). Eucalyptus groves have a documented impact on the microclimate (on temperature, relative humidity, wind velocity, precipitation, and fog drip), and trigger changes to light availability by increasing shading, and inhibiting the growth of understory vegetation, (McBride, 2014). Changes in soil characteristics (pH, carbon content, nitrogen, phosphorus, calcium), and stream conditions (increased stream litter), impacts on erosion and sedimentation, and changes in nutrient dynamics have also been recorded.

The next section will further explore the ways in which eucalyptus influences abiotic ecosystem processes and briefly discuss the effects of eucalyptus plantations on the natural ecosystems, biodiversity, wildlife, and ecosystem services.

Modification of site conditions by eucalyptus

Eucalyptus triggers changes to the microclimate, fire regime, and to the hydrologic characteristics of the area, and can potentially have allelopathic effects on other plant species.

Changes to the microclimate: From the edge to the interior of an eucalyptus grove, microclimate conditions change due to shading and leaf litter. This in turn, impacts the species assemblages found in different parts of the forest (McBride, 2014).

Changes to the fire regime: The oily resins characteristic of eucalyptus, are much more ignitable compared to other tree species, and burn at higher fire intensities. Eucalyptus leaves have intermediate flammability in comparison to other species, however, dead leaves are the most energy-rich components with high flammability potential (Dickinson and Kirkpatrick 1985; California Invasive Plant Council, 2014). Drifting burning material has a great potential to ignite spot fires (Boyd, 1997), since ignited leaves and bark can be lofted into the air and distribute embers over long distances (Bossard et al. 2000). However, cool and damp dense eucalyptus forests also have the potential to reduce fire risk (McBride, 2014).

Changes to the hydrology of the area: Eucalyptus species such as eucalyptus globulus, or blue gum, also cause changes to the hydrology of the region. Eucalyptus globulus, for example, is able to withstand prolonged dry summers by tapping into the deep water reservoirs with its far-reaching root systems (California Invasive Plant Council, 2014). It can extract water from the soil at even higher soil moisture tensions than most mesophytic plants (California Invasive Plant Council, 2014). (Soil moisture tension is a negative pressure representing the energy needed for the plant to extract water from the soil. The higher the soil moisture tension, the more energy is needed to extract water from the soil.)

Allelopathic effects: Eucalyptus groves can potentially have allelopatric effects since the aromatic compounds from decaying eucalyptus leaves have been found to interfere with the germination of another native plants (California Invasive Plant Council, 2014; McBride, 2014). Allelopathy is a phenomenon through which a plant releases a chemical compound that interferes with the germination and growth of other plants. If released into the environment, allelopathic materials inside a tree can produce a positive or negative change in the survival, growth, reproduction and behavior of other organisms (Ghnaya et al., 2016).

For more information on Eucalyptus trees please refer to Wolf and DiTomasso, 2016.

How Eucalyptus Trees Stoke Wildfires

News reports about wildfires in California—currently battling its largest fire ever—and Portugal, which has also been battling huge fires in recent years, highlight the dangers posed by eucalyptus trees. But why, when nearly all eucalypts are native to Australia and neighboring islands?

Fire certainly wasn’t on the minds of those who spread eucalypts around the world. As geographer Robin Doughty details it, eucalypts were taken from Australia after Europeans first arrived in the late eighteenth century. He describes a combination of “push” and “pull” factors. The pull was the appeal of exotic, ornamental plants by botanists, royals, and other estate owners. The push factor was originally a single individual. The German-born botanist Ferdinand Jacob Heinrich von Mueller migrated to Australia in 1847. Within a decade, he was the world’s leading evangelist for eucalypts. Through books, correspondence, and, rather more to the point, the mailing of seeds, this Johnny Eucalyptus helped spread the tree around the world.

The best place to see eucalypts in the United States is in the southern half of California. One of von Mueller’s correspondents was the president of Santa Barbara College, who joined the eucalyptus cult in the 1870s. The region between San Diego and the Bay Area was the locus of a veritable boom in Australian trees. The re-forestation was sold as a get-rich-quick scheme, harvested as lumber for fuel and furniture, with a sideline in miraculous eucalyptus oil. By the early 1900s, Berkeley had fourteen species growing within its boundary; another one hundred and fifty species were being tested in the state. But the speculative boom, as so many others, went bust. For one thing, petroleum was the up-and-coming fuel. And it turned out that the best lumber was from mature trees, not the quickly harvested plantation types. A glut of eucalyptus oil meant that if often went rancid before marketing.

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Brett M. Bennett, a historian of forest management, discusses the “globalization of eucalypts” from 1850 through the end of the twentieth century. In his case studies (India, South Africa, and Thailand), the trees “changed local ecologies and encouraged a movement towards market-based capitalism…at the expense of indigenous groups living in or near forests.” Traditional land use systems and habitats were replaced with monoculture for the benefit of local and/or international elites.

The flip side of this industrial expansion of eucalypts is that these trees burn really well. Also known as gum trees, they produce gummy resin and oily leaves. The oil is what makes eucalypts toxic to most herbivores, excepting koalas, who can munch away because of their gut bacteria, unique intestines, and twenty-two hours of sleep a day. Long used for medicinal purposes, this remarkable oil has been tested in ethanol and petroleum mixtures and as a fuel in its own right. So when it comes to eucalyptus canopies, wildfires burn through them furiously; the thin, burning bark can be blown over a mile in the wind.

So now, more than a century later, eucalypts grow tall throughout a lot of California, waiting for the next fire. These once exotic trees have become a potent fuel in this new era of megafires.

Why are there so many eucalyptus trees in California? What caused their widespread existence in this state?

Why are there so many eucalyptus trees in California? What caused their widespread existence in this state?

Parts of Australia have a similar Mediterranean climate to the Bay Area in particular. Eucalyptus were introduced by Australians during the gold rush. Later, plantations were planted in the hopes of providing timber for railroad building. But they proved unsuitable.

I have heard, but am not able to find reference to the fact, that during WWII they were planted as windbreaks because they are hardy and fast growing.

They are now considered a hazard because they are oily and a problem in fire. The park across the street from me (Buena Vista Park) has been gradually removing them for a couple of decades. There are places in San Francisco where they remain and should be removed. One such example is Sutro Forest an 80 acre plot mostly owned by the state. It once held the remains of 1100 eucalyptus trees that grew in the Western part of the city. The state (UCSF) is in process of removing these trees. They face opposition from some residents who presumably are unaware of the fire danger.

Another such area is Glen Canyon Park in San Francisco. The natural canyon has a number of eucalyptus trees. I walk my dogs there (near the canyon but not in it because of coyotes) and the wind frequently whips up out of the canyon. There are a number of wooden condo buildings near the rim. A fire would be catastrophic. The Cities current plan is to ignore the overgrown canyon and develop an evacuation plan for the residents. Good luck with that.

Importing non native species should only be done after very carefully studying the impact on the environment.

Eucalyptus

Eucalyptus

Eucalyptus globulus, blue gum eucalyptus, is a tree that is not native to California. It is an invasive plant that was introduced from Australia and naturalized in the wild. The California Invasive Plant Council (CAL-IPC) classifies the most common blue gum eucalyptus as a moderate invasive because the trees need certain conditions to thrive.

All eucalyptus species are prone to fire, and should be removed or require significant maintenance within 100′ of structures to reduce wildfire hazards.

California. In the 1850s, Eucalyptus trees were introduced to California by Australians during the California Gold Rush. Much of California has a similar climate to parts of Australia. By the early 1900s, thousands of acres of eucalypts were planted with the encouragement of the state government. It was hoped that they would provide a renewable source of timber for construction, furniture making and railroad ties. It was soon found that for the latter purpose 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.

One way in which the eucalyptus, mainly the blue gum E. globulus, proved valuable in California was in providing windbreaks for highways, orange groves, and other farms in the mostly treeless central part of the state. They are also admired as shade and ornamental trees in many cities and gardens.

Eucalyptus plantations in California have been criticised because they compete with native plants and do not support native animals. Fire is also a problem. The 1991 Oakland Hills firestorm which destroyed almost 3,000 homes and killed 25 people was partly fuelled by large numbers of eucalypts close to the houses.

Care & Maintenance:

Eucalyptus trees are not recommended due to their fire prone nature. Consider removing fir trees within 100′ of structures or 15′ of roadways. If a tree must be maintained in the defensible space zone (within 100′ of structures), extreme care should be taken to reduce the associated wildfire hazard.

Remove all limbs within 10′ of the ground, or 1/3 the height of the tree if less than 30′ tall

Remove all dead wood, peeling bark, and twiggy growth regularly

Provide canopy separation so that no limbs touch nearby trees or plants

Remove all “ladder fuels,” shrubs, and immature trees growing below

Remove fallen leaves, bark, and detritus regularly

Remove any leaves or limbs which fall on the roofs of nearby buildings, and repeat regularly during fire-season

Learn more about Eucalyptus

Reeling from its deadliest forest fire, Portugal finds a villain: eucalyptus trees

Once shaded in canopies of leaves, the N-236-1 is a rural road that cuts through central Portugal, hugging hillsides pungent with eucalyptus and pine.

Now it is littered with husks of burned cars. Along the shoulder, ashen wisps of tree trunks stand sentinel like totem poles. A headline in Portugal’s Expresso newspaper calls it “The Saddest Street in Portugal.”

It’s where many of the 64 victims of Portugal’s deadliest wildfire were burned alive last weekend, trapped in their cars.

Smoke rises from fire in the Leiria District of Portugal, on June 17, 2017. (Paulo Cunha / European Pressphoto Agency) Advertisement

Even as thousands of firefighters still battle the flames, and coroners identify the charred remains of those who were unable to escape, investigators are probing the cause of the fire. Portugal’s prime minister says dry lightning was likely to blame.

But as its accomplice, environmentalists finger a newcomer, which has populated these hills as quickly as Portuguese have abandoned them for jobs in the city: eucalyptus trees.

Non-native eucalyptus and gum trees, with their medicinal fragrance and frosty blue-green leaves, now cover a quarter of all forested land in Portugal. First imported from Australia in the 18th century, they are among the world’s fastest-growing trees, and have become Portugal’s most common one — a profitable cash crop for paper and pulp. Portugal is Europe’s largest producer of eucalyptus pulp. It’s one of the country’s biggest exports.

But eucalyptus trees can exacerbate deadly fires. Their sap is flammable, and so is their bark, which flies off when burned, igniting new fires up to 100 yards away.

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California has had a similar history with eucalyptus trees, which bore at least some of the blame for the second-deadliest fire in the state’s history — the 1991 Oakland hills fire that claimed 25 lives.

“Our climate is like California. It’s normal to have fires here. But with the introduction of eucalyptus, they have lots of material to burn,” said João Branco, with the Portuguese environmental group Quercus. Its name is Latin for “oak,” a native tree the group is lobbying to have planted instead of eucalyptus.

Firefighters try to extinguish a wildfire on June 19, 2017, near Pedrogao Grande, Portugal. (Pablo Blazquez Dominguez / Getty Images)

Native oaks and laurels are more resistant to fires, but eucalyptus trees burn faster and hotter, making wildfires harder to control. The Portuguese government has pledged to ban new eucalyptus plantations, but the law has not yet been finalized.

“The government was negligent. This was a predictable fire, because it’s very well known in Portugal, the problem of eucalyptus and its connection to fires,” Branco said. “Everybody knew this could happen. It was a matter of time.”

Tiny Portugal is one of the most heavily forested countries in Europe, and suffers more wildfires than its larger neighbors. Last summer, Portugal was home to half of the total acreage lost to wildfires across the European Union. Most of the land is privately owned, not managed by the government.

The World Wildlife Fund’s Portugal branch in a statement said “human negligence” and “a lack of adequate forest management” led to the deadly fire. A one-word front-page headline on Portugal’s Público newspaper asked: “Why?”

The local paper industry is fighting any eucalyptus ban, warning that it would cost thousands of jobs and hurt Portugal’s trade balance. It points out that more fires erupt on abandoned land than on managed plantations.

Advertisement This was a predictable fire, because it’s very well known in Portugal, the problem of eucalyptus and its connection to fires. João Branco, with the Portuguese environmental group Quercus

Visiting the fire lines 95 miles northeast of Lisbon, President Marcelo Rebelo de Sousa told reporters Sunday “it was not possible to do more than what has been done” to prevent and respond to the blaze. Firefighters are among the dead and injured.

In the past half-century, parts of Portugal’s countryside, especially in the central hills where this fire broke out, have been largely abandoned, and vegetation is overgrown. There are fewer farmers plowing fields, and fewer farm animals to graze on otherwise flammable underbrush.

“What drew us to our land was the history: the grapes, olives and cork oaks — the heritage trees of the area,” said Nicole Hayes, 27, who moved 18 months ago to the town of Pedrógão Grande, now at the epicenter of the fire. “Unfortunately, now these farming communities have broken down and the land has been sold off to eucalyptus plantation companies.”

When the fire broke out Saturday, Hayes happened to be in her native Wales for her grandmother’s funeral. Otherwise, she said, she, her partner and their 7-month-old baby might have been caught on route N-236-1, along with their neighbors.

Roses were placed on the burned-out remains of a car in which a woman died after it ran off the N-326-1 highway near Pedrogao Grande in central Portugal on June 19, 2017. (Armando Franca / Associated Press)

“The road we usually use as our main exit was the road that the fatalities happened on. It’s overwhelming,” she said. “There’s a very high possibility that we would have been one of those families that was taken by the fire.”

Hayes has since returned to Portugal from the U.K. She can’t reach her house yet, but heard from a neighbor that it is still standing. Staying with relatives 40 minutes away, she said smoke from Pedrógão Grande is visible. “You can smell it. The sky is aglow. The swimming pool was filled with ash and debris. And we’re 40 minutes away. That’s how far it’s traveled.”

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Locals inside the fire zone recount phoning emergency services more than 20 times on Saturday night, when the flames erupted. No one came. One group of elderly residents survived by jumping into a water storage tank. Officials say telephone lines, cellphone towers and electricity pylons were felled by the fire. Police couldn’t close roads quickly enough.

“There are sirens, but these sirens go off so frequently that we’ve become complacent to them,” Hayes said. “It was so easy for so many people to leave it to the last minute to escape.”

About 40 miles away in Mata Da Rainha, Portuguese officials held a fire prevention seminar for farmers this past spring, said Laurence Manchee, who attended after recently buying a plot of land that had burned almost completely in a forest fire five years ago.

Like Hayes, he’s part of a small community of foreigners repopulating abandoned areas of central Portugal, attracted by affordable fertile land and an off-the-grid, sustainable lifestyle.

“A lot of our trees are still there, but they’re like charcoal, and they’ve regrown from the shoots. The issue with eucalyptus is that when you chop one down, five grow back. It’s great for someone who wants to sell eucalyptus, but it’s not good for us,” said Manchee, 35.

Although eucalyptus trees burn quickly, they also regenerate fast, from buds buried deep in their inner bark. They have adapted to dry, fire-prone climes. Fires actually help spread eucalyptus, by clearing out native trees.

Manchee is trying to thin out eucalyptus regrowth on his land, and cultivate native cork and holm oaks. But invasive eucalyptus spread fast and suck water from the soil, depriving other plants and drying out the ecosystem — making it more vulnerable to wildfires.

At least six fires are burning across Portugal, but all of the fatalities so far have been in the Pedrógão Grande area.

“It’s a lot of work. We need to chop down trees to create fire breaks,” Manchee said. “Every day, you see smoke from a different place on the horizon.”

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Frayer is a special correspondent.

ARTICLE. California hillsides were ablaze last year and it looks like a similar disaster may occur again this season. Eucalyptus trees are common in California and the warmer states of the United States. They are also found in Australia, of which many are native. The blue gum variety were introduced around the 1850s as ornamental plants and as timber and fuel. So are eucalyptus trees flammable? In a nutshell, yes. These beautiful stately trees are filled with aromatic oil, which makes them highly combustible. The picture this paints is of California and other areas experiencing serious eucalyptus fire damage.

Eucalyptus trees are widespread in California and have been introduced to many other warm states. In California, the trees have spread so prolifically that there are entire woodlands almost completely made up of gum trees. Efforts are underway to eradicate the introduced species and return woodlands to the native species. This is because the eucalyptus has displaced natives and it changes soil composition where it grows, altering other life forms as it does so. Eucalyptus fire hazards are also cited in efforts to remove the trees.

There are some native eucalyptus but the majority have been introduced. These hardy plants have delightfully scented, volatile oil in all parts of the plant. The tree sheds bark and dead leaves, which make a perfect pile of tinder under the tree too. When the oils in the tree heat up, the plant releases flammable gas, which ignites into a fireball. This accelerates the eucalyptus fire hazards in a region and discourages firefighting efforts. Removal of the trees has been recommended largely due to eucalyptus fire damage but also because they are taking the place of native species. The plants are considered dangerous in fire prone areas because of their habit of shooting sparks if they catch fire. Eucalyptus oil and fire are a match made in heaven from the fire’s perspective but a nightmare for those of us in its path.

On hot days in Tasmania and blue gum’s other native regions, eucalyptus oil vaporizes in the heat. The oil leaves a smoggy miasma hanging over the eucalyptus groves. This gas is extremely flammable and the cause of many wild fires. The natural detritus under the tree is resistant to microbial or fungal break down due to the oils. This makes the tree’s oil a wonderful antibacterial, antimicrobial, and anti-inflammatory, but the unbroken down material is like using kindling to start a fire. It is tinder dry and contains the flammable oil. One bolt of lightning or a careless cigarette and the forest can easily become an inferno.

Scientists speculate that flammable eucalyptus trees evolved to be “fire friendly.” Rapidly catching fire until there is no obvious tinder allows the plant to retain most of its trunk when fire moves on to find more to burn. The trunk can sprout new limbs and regenerate the plant unlike other types of trees, which have to re-sprout from the roots. The ability to retain the trunk gives the eucalyptus species a jump start on regrowing from the ashes. The plant is already head and shoulders above the native species when fire recovery begins. The eucalyptus trees easy recovery added with its volatile oily gasses, make it a potentially threatening species for California woodlands and similar areas known to house these trees. ~ From GardeningKnowHow.com

READ MORE at Gardening Know How: Eucalyptus Fire Hazards: Are Eucalyptus Trees Flammable https://www.gardeningknowhow.com/ornamental/trees/eucalyptus/eucalyptus-fire-hazards.htm

HOW DO WE ELIMINATE DANGEROUS EUCALYPTUS TREES?

JAN 03 2019 02:40 PM

By Denise S. Adams

How do we mobilize to get the City and County to remove dangerous, combustible Eucalyptus trees? The founding estate Barrons imported from Australia these foreign weed trees that spread quickly, and are cost-prohibitive to maintain. Each tree costs property owners thousands which results in neglect: pay the water bill or pay for tree care.

The County only wants to maintain certain trees every 5-10 years by pruning a few branches. Occasionally Edison will trim a few branches, only if branches engage with high power wires, and multiple customers complain. EDISON does agree it would be wonderful for the Barker Pass Rd trees to be removed that are in the extreme high wind tunnel. EDISON acknowledges that nothing has changed since the 1925 earthquake and fire due to exposed high voltage wires, and old transformers.

With Sacramento planning to take over PG&E, and possibly Edison due to fires, we can expect less or no maintenance in Calzuela. City Council has yet to focus on fire and disaster prevention.

As part of the endangered species of property owners, what’s the plan to remove these horrible trees? We’ve had enough drama and trauma in Montecito and SB.

Do you have an opinion on something local? Share it with us at [email protected] The views and opinions expressed in Op-Ed articles are those of the authors and do not necessarily reflect those of edhat.

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December 29, 2018 – Eucalyptus Tree Falls on Home

California Eucalyptus. Everywhere.

The late tobacco heir became state forester from 1886 to 1888 and promoted the hell out of eucalyptus, handing out free seeds and everything. He also wrote a book about the tree in 1895. As you can imagine, he, like Cooper, felt this cash crop was going to be a massive boon for the California economy. And at the time, California, especially southern California, was a largely treeless landscape, so having eucalyptus grow so well easily changed the look of the state almost instantly. As Kinney continued to promote and plant the tree, eventually the prods woke the sleeping giant, the California public.

In 1909, over twenty thousand acres of eucalyptus were planted. Farmers turned over seasonal crops into large stands of Blue Gum.

Thanks to deforestation and depletion of Appalachian hardwood resources, investors and farmers looked to eucalyptus for a solution to bridging the shortage. It was the makings of a speculative bubble, because, keep in mind, although there were some benefits the tree brought, no one really knew how well the trees would work for use as building materials, railroad ties, furniture construction, etc. all the many, many uses touted by the euc-enthusiasts over the years.

BUBBLE BURST

Turns out eucalyptus wood sucks for construction and furniture building, unless the tree is hundreds of years old as used in Australia. The US Dept. of Agriculture promoted this fact and unceremoniously popped the Blue Gum bubble, confirming what many people had discovered: the wood warped, fissured and twisted as it dried. Other materials had to step up to fill the opportunity-deficit: synthetic materials, concrete and steel.

These days, you’ll usually find Blue Gum lining farms or ornamentally in gardens/arboretums. Some eucalyptus groves are truly beautiful. I have fond memories of being a child and running for miles in acres of Blue Gum in the Nipomo Mesa forest. The one great practical use for these giant weeds turns out to be their windbreak quality. Today, you’ll find the trees functionally lining the US-101, adjacent to farms, breaking the wind and halting migrating dust.

Though Eucalyptus oil is still commonly used in cough syrup, it’s also used for its antiseptic properties, the trees are described by Kinney in his book as having an anti-malarial property–as the trees drink mosquito breeding cesspools. Obviously, cesspools are no longer an issue for modern day waste-water management. And furthermore, though Kinney hypothesized the oil had antimalarial attributes, the vexing issue held: Australia has massive eucalyptus forests and malaria within those forests. So the issue is more complex than simply a snake oil cure-all solution. Another great thing about eucalyptus oil? Highly flammable. Explosive even. The trees actually like fire, as it helps spread their seedpods and kill off competitors.

Eucalyptus tereticornis’ buds, capsules, flowers and foliage, Rockhampton, Queensland. Photo by Ethel Aardvark.

Wildland firefighters in Australia and in some areas of California are very familiar with eucalyptus trees. They are native and very common in Australia and are planted as ornamentals in the United States. The leaves produce a volatile highly combustible oil, and the ground beneath the trees is covered with large amounts of litter which is high in phenolics, preventing its breakdown by fungi. Wildfires burn rapidly under them and through the tree crowns. It has been estimated that other than the 3,000+ homes that burned in the 1991 Oakland Hills Fire in California, about 70 percent of the energy released was through the combustion of eucalyptus.

Eucalyptus is one of three similar genera that are commonly referred to as “eucalypts”.

Jon Henley, a reporter who covered the numerous large bushfires a year ago in Australia, has written a book about fire down under, titled “Firestorm: Surviving the Tasmanian bushfire”. Below is an excerpt:

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“…Gum trees, as eucalypts are known, ‘are like weeds that come up on bombed-out blocks’, adds Jamie Kirkpatrick, professor of geography and environmental studies at the university. ‘They’re fantastically fast growers and great colonisers, but not great competitors.’

Eucalypts typically let through a lot of light, allowing other vegetation types such as scrub and grass to grow beneath them. They can live for maybe 700 years. But they won’t regenerate, Kirkpatrick explains, if what is growing beneath them over the years becomes too dense. Most eucalypt species, therefore — there are more than 600 in Australia, between 30 and 40 in Tasmania — have evolved traits that allow them to survive and prosper in the fires that will clear that undergrowth.

Some, like the mighty, 100-metre-tall Eucalyptus regnans — also known as the mountain ash, stringy gum or Tasmanian oak — hold their seeds inside small, hard capsules; a fire will instantly trigger a massive drop of seeds to the newly fertilised ground.

The myriad bright green buds that sprout spectacularly from the trunks of other eucalypts in the aftermath of a big fire are another kind of regeneration mechanism, bursting through the scorched and blackened bark within weeks of a blaze.

Within five or six years, ‘a burned forest will be looking pretty good’, Kirkpatrick says. ‘And a large proportion of Tasmania’s flora fits into this fire ecology. Pea plants, wattles — their germination is stimulated by heat and smoke. Fire is really, really important in Tasmania.’

At the centre of it all, though, is the eucalypt. Because these trees do not just resist fire, they actively encourage it. ‘They withstand fire, they need fire; to some extent, they create fire,’ Bowman says. ‘The leaves, the bark, don’t decompose. They’re highly, highly flammable. And on a hot day, you can smell their oils.’

The bark and leaves of eucalypts seem almost made to promote fire. Some are known as stringyor candle-barks: long, easily lit strips hang loosely off their trunks and, once alight, whirl blazing up into the flammable canopy above, or are carried by the wind many kilometres ahead of a fire to speed its advance.”

This is an edited extract from Firestorm: Surviving the Tasmanian bushfire by Jon Henley (Guardian Shorts £1.99 / $2.99)

Get it from Amazon Kindle or directly from Guardian Shorts.

Eucalyptus Fire Hazards: Are Eucalyptus Trees Flammable

California hillsides were ablaze last year and it looks like a similar disaster may occur again this season. Eucalyptus trees are common in California and the warmer states of the United States. They are also found in Australia, of which many are native. The blue gum variety were introduced around the 1850s as ornamental plants and as timber and fuel. So are eucalyptus trees flammable? In a nutshell, yes. These beautiful stately trees are filled with aromatic oil, which makes them highly combustible. The picture this paints is of California and other areas experiencing serious eucalyptus fire damage.

Are Eucalyptus Trees Flammable?

Eucalyptus trees are widespread in California and have been introduced to many other warm states. In California, the trees have spread so prolifically that there are entire woodlands almost completely made up of gum trees. Efforts are underway to eradicate the introduced species and return woodlands to the native species. This is because the eucalyptus has displaced natives and it changes soil composition where it grows, altering other life forms as it does so. Eucalyptus fire hazards are also cited in efforts to remove the trees.

There are some native eucalyptus but the majority

have been introduced. These hardy plants have delightfully scented, volatile oil in all parts of the plant. The tree sheds bark and dead leaves, which make a perfect pile of tinder under the tree too. When the oils in the tree heat up, the plant releases flammable gas, which ignites into a fireball. This accelerates the eucalyptus fire hazards in a region and discourages firefighting efforts.

Removal of the trees has been recommended largely due to eucalyptus fire damage but also because they are taking the place of native species. The plants are considered dangerous in fire prone areas because of their habit of shooting sparks if they catch fire. Eucalyptus oil and fire are a match made in heaven from the fire’s perspective but a nightmare for those of us in its path.

Eucalyptus Oil and Fire

On hot days in Tasmania and blue gum’s other native regions, eucalyptus oil vaporizes in the heat. The oil leaves a smoggy miasma hanging over the eucalyptus groves. This gas is extremely flammable and the cause of many wild fires.

The natural detritus under the tree is resistant to microbial or fungal break down due to the oils. This makes the tree’s oil a wonderful antibacterial, antimicrobial, and anti-inflammatory, but the unbroken down material is like using kindling to start a fire. It is tinder dry and contains the flammable oil. One bolt of lightning or a careless cigarette and the forest can easily become an inferno.

Fire Friendly Flammable Eucalyptus Trees

Scientists speculate that flammable eucalyptus trees evolved to be “fire friendly.” Rapidly catching fire until there is no obvious tinder allows the plant to retain most of its trunk when fire moves on to find more to burn. The trunk can sprout new limbs and regenerate the plant unlike other types of trees, which have to re-sprout from the roots.

The ability to retain the trunk gives the eucalyptus species a jump start on regrowing from the ashes. The plant is already head and shoulders above the native species when fire recovery begins. The eucalyptus trees easy recovery added with its volatile oily gasses, make it a potentially threatening species for California woodlands and similar areas known to house these trees.

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