‘Terrible’ and ‘wonderful’: the saga of the Australian tree that found the perfect habitat in Brazil
On 01 July, BBC Brazil published an interesting article on eucalyptus plantations and the risk of fires. What attracted us most was the publicity about the discoveries of Prof. Bill Gammage about how the Aborigines use fire to their benefit. Many other researches around the world advocate the same application of fire used by Aborigines. Working on Fire has extensive know-how in controlled burning and is available to the national and international market to discuss potential solutions related to integrated fire management.
For some, it is dangerous and should be treated as an invader. For others, an example of versatility and resilience.
Accused of facilitating the spread of the fire that has caused 64 deaths in Portugal this month, eucalyptus has awakened passions since leaving Australia to become one of the most (im)popular trees in the world.
Criticised by environmentalists and feared by rangers, the plant is at the same time exalted by its growing commercial applications, ranging from folk medicine to fabric production.
In Brazil, where it found habitat even more favourable than that of its native land, the tree already occupies an area equivalent to almost three states of Alagoas – and continues to expand.
The Portuguese were the first Western people to know the eucalyptus since Portuguese explorers arrived in the 16th century to East Timor in Southeast Asia. The territory is home to three native species of this genus of plants.
But the trees only became popular in the West some centuries later, during the colonisation of Australia, the origin of about 700 types of eucalyptus trees.
Over the course of several million years, the tree has adapted so much to Australia that it has become dominant in almost every biome in the country – and fires have played a central role in this process.
Several species of eucalyptus produce flammable oils and exchange bark, branches and leaves frequently. The accumulation of this material at the foot of the trees facilitates the propagation of fires.
When the flames reach the trunk, they ascend to the highest branches, forming large balls of fire. The heat can cause the tree to explode, throwing flames in multiple directions.
That is why fires in areas with many eucalyptus – like those in Portugal this month – are so destructive and difficult to contain. And that’s why in Australia, one of the most common species of the genus is also called “tree-gasoline.”
Fire in a eucalyptus can destroy everything, including eucalyptus, but not the seeds of these trees, which are the first to germinate when the flame goes out.
The seedlings quickly replace the dead eucalyptus and also occupy the space of other species burned.
Travel by the Pacific
The adaptability and rapid growth of eucalyptus caught the attention of California settlers, who planted it on a large scale beginning in the 19th century to supply timber for expanding cities.
Until, in the 1980s, an Australian beetle crossed the Pacific and parasitized the Californian eucalyptus. Without natural predators on the other side of the ocean, the beetle’s larvae quickly devoured the tree trunks.
One of the chances is that the insect has come to the US on imported logs.
American researchers then fetched a tiny wasp in Australia that parasitized the beetle’s eggs. The plague was controlled, although Californian eucalyptus remains vulnerable to attack – now led by humans.
Villainized by occupying the space of native plants and being hostile to the local fauna, the tree has been eradicated from parts of the State by public agencies.
“Eucalyptus trees are terrible,” a resident told the Santa Cruz Sentinel newspaper in a report on the upheaval caused by the fall of trees in 1996.
“They are a danger in fires, they are a danger when it rains, and they drive out local trees.”
The decision to extirpate them from the state, however, did not please everyone, and some accused the detractors of the eucalyptus of “plant xenophobia.”
Despite the offensives, eucalyptus survived in California, where it also staged major fires. In 1991, 25 people died and 3,000 houses were destroyed when the flames spread through eucalyptus trees in the Oakland suburb
In Australia, one of the greatest tragedies of its kind in history, a series of fires in Victoria left 173 dead in 2009.
But these phenomena have not always been so deadly in the eucalyptus motherland, according to historian Bill Gammage of the National University of Australia.
In 2012, Gammage was awarded by the Australian government for a book in which he analysed paintings from the time of the arrival of the Europeans to the country. The historian noted that the images rarely showed very extensive areas of continuous forest – there used to be empty spaces, with undergrowth, between stretches of dense forest.
Aboriginal peoples, who at the time were still scattered over much of Australia, had shaped those territories. In creating clearings in the woods, they sought to attract animals that ate ground plants to hunt them.
Gammage also realized that the forests of that time interspersed stretches of young plants and others of older trees. The difference was due to the fire: new trees sprouted in areas that had burned not too long before.
Aborigines, Gammage says, used controlled fires to open clearings and manage forest development. When they noticed that the carpet of dry branches and leaves began to thicken, they set the forest on fire.
Thus, says the historian, they forced the animals to flee, going against the hunters. And so they controlled the amount of fuel accumulated anywhere in the forest, preventing the formation of fires that were out of control.
For the Aborigines, the greatest weapon against fire was fire itself.
The historian concluded that, before the arrival of the Europeans, Australia was an immense Aboriginal garden – not a territory free of human interference, as many believe.
Today, in several of the places portrayed by early European explorers, Gammage says there are closed, uniform, planted or natural forests. Several clearings were gone, and the fires became more dangerous.
From railroads to pharmacy
In Brazil, there are no records of such deadly fires in eucalyptus, although the country has one of the largest areas occupied by the tree in the world. In 2015, according to IBGE, these plantations reached 7.4 million hectares.
According to Humberto Angelo, professor of forestry at the University of Brasilia (UnB), fires are less frequent here for three reasons.
First, the most common eucalyptus trees in Brazil have fewer leaves and branches than the predominant species in other parts of the world. Second, because the humidity of Brazilian soils ensures that microorganisms consume much of the plant waste, reducing the stock of flammable material. Third, because plantation owners often take precautions to avoid fires and preserve their assets.
Angelo states that the commercial use of eucalyptus in Brazil began in 1904 in Rio Claro, in the interior of São Paulo. As native forests thinned out, the plant was used for the manufacture of sleepers, pieces that support the trains of the trains.
From the 1960s, with tax incentives granted by the military dictatorship, eucalyptus plantations spread throughout much of the South, Southeast and Midwest of the country.
According to Angelo, today the main destination of the tree in Brazil is the paper and pulp industry. “If you go to a furniture store and come over any piece of MDF (wood fibre), there will certainly be eucalyptus there.
Milk cartons and many other grocery packs, “he says.
In recent years transgenic eucalyptus with ultraflexible fibres has been used even in the production of medicine capsules and tactel tissues.
The professor says that the second largest destination of the tree is like charcoal in the steel industry.
Angelo says that while a Brazilian eucalyptus tree is ready for cutting from the age of seven, in the Northern Hemisphere, the trees that produce pulp take up to 100 years to reach maturity.
According to him, not even in Australia, the eucalyptus grow so fast, because there they face natural enemies that do not exist here.
Angelo rebuts one of the main criticisms of the tree. “The idea that eucalyptus dries the soil has been widely propagated, but studies show that it consumes as much water as corn, for example.”
He says that while supplying the furniture industry, eucalyptus reduces pressure on native forests and that the tree has proved useful even for food production.
Much of the honey sold in Brazil today, says Angelo, comes from the eucalyptus flower. And in recent years, many ranchers have been planting the tree to have another source of income and to provide more comfort to livestock.
“Before the ranchers would clear everything to plant grass, and the ox would be there under the sun, without any parasol,” says Angelo. “Now he can rest under the eucalyptus.”
He says trees can also serve as a windbreak for more sensitive crops.
Even small farmers recognise the qualities of eucalyptus – although many criticise the release of transgenic plant species, which happened in 2015 (Brazil was the first country to authorise them).
“It’s a wonderful tree, the problem is the monoculture,” says Jaime Carvalho, a small farmer in the Rubira settlement in Piratini (RS).
He says that eucalyptus planted in the settlement are sold as anchors for construction or as firewood for potteries.
In agroforestry systems, which combine fruit trees and undergrowth, the use of eucalyptus is often used to fertilise other plants.
Poison X Medicine
Eucalyptus has played a role even in traditional Brazilian medicine.
For 23 years he has owned a natural remedy stall in the centre of Brasília, the Valdemar da Costa Piauí Raizeiro says to work with more than 500 plants.
He says that the eucalyptus leaf, used in the preparation of teas, is among the two or three most sought after.
The same tree whose burning can kill by asphyxiation is used in Brazil to treat respiratory problems.
“For those with a cough, sinusitis or bronchitis, there is no better remedy,” says the salesman.
Article originally published here.
Rua Luis Spiandorelli Neto
30, Sala 301
Valinhos-SP, BraZil, CEP 13271-570
Tel: +55 19 3246 1534