At Mad Max: Fury Road, Charlize Therons Furiosa seeks to return to Green Square, a tree-lined oasis in the otherwise lifeless wasteland to which Earth has become. However, when Furiosa arrives at the holy place, she finds only skeletal tribes and extensive dunes. She screams in fear. Without trees, every hope seems lost.
Furiosa's feelings were justified. "Forests are the lifeblood of our world," says Meg Lowman, director of the Tree Foundation, a nonprofit organization in Florida dedicated to tree research, exploration, and education. "Without them we lose extraordinary and essential functions for life on earth."
The services of the trees for this planet range from the storage of carbon and the protection of the soil to the regulation of the water cycle. They support the natural and human food systems and provide home to countless species ̵
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Much of the deforestation has taken place in recent years. Since the beginning of the industrial age, forests have declined by 32%. Especially in the tropics, many of the world's remaining three trillion trees fall quickly, and each year, according to the Nature Study, about 15 billion trees are felled. In many places the tree loss accelerates. In August, the National Institute for Space Research reported an increase in fires in Brazil's Amazon rainforest of 84% compared to the same period in 2018. Slash-and-burn is also particularly evident in Indonesia and Madagascar.
Subject to an unimaginable catastrophe, however, there is no scenario in which we would fell every tree on the planet. But if we imagine a dystopian Mad Max-style world where all the trees on earth have died suddenly, we can gauge how lost we would be without them.
There would be a massive extinction of all groups of organisms, both locally and globally – Jayme Prevedello
"Let me just start with how awful a world without trees would be – they are irreplaceable," says Isabel Rosa a lecturer in environmental data and analysis at Bangor University in Wales. "If we get rid of all the trees, we will live a planet [on] that may not feed us anymore."
If trees disappeared overnight, much of the planet's biodiversity would disappear. Loss of habitats is the main cause of extinction worldwide. The destruction of all remaining forests would be "catastrophic" for plants, animals, fungi and more, says Jayme Prevedello, an ecologist at Rio de Janeiro State University in Brazil. "There would be a massive extinction of all groups of organisms, both locally and globally."
The wave of extinction would extend beyond forests and destroy wildlife, which depends on individual trees and small tree populations. For example, in 2018, Prevedello and his colleagues found that biodiversity in areas with scattered trees was 50 to 100% higher than in open areas. "Even a single, isolated tree in an open area can act as a magnet for biodiversity and attract many animals and plants and provide them with resources," says Prevedello. "Therefore, the loss of individual trees can significantly affect local biodiversity."
The planet's climate would also change drastically in the short and long term. Trees convey the water cycle as biological pumps: they suck water from the soil and store it in the atmosphere, turning it from liquid to vapor. In this way, forests contribute to cloud formation and precipitation. Trees also prevent flooding by capturing water rather than letting it flow into lakes and rivers and protecting coastal communities from storm surges. They hold soil in place that would otherwise wash away in the rain, and their root structures contribute to the flourishing of microbial communities.
Without trees, previously forested areas would become drier and prone to extreme drought. If it rained, the flood would be catastrophic. Massive erosion would affect the oceans and stifle coral reefs and other marine habitats. Teared islands would lose their barriers to the ocean and many would be washed away. "Removing trees means that large amounts of land are lost to the ocean," says Thomas Crowther, global systems ecologist at ETH Zurich and lead author of the 2015 Nature Study.
In addition to mediating the water cycle, trees have a localizing cooling effect. They provide shade that maintains the soil temperature and, as the darkest thing in the landscape, they absorb heat instead of reflecting it. In evapotranspiration, they also conduct energy from solar radiation into the transformation of liquid water into vapor. With the loss of all these cooling benefits, most of the places where trees once stood would be instantly warmer. In another study, Prevedello and his colleagues found that the complete removal of a 25 km² piece of woodland caused local annual temperatures to rise by at least 2 ° C in tropical areas and by 1 ° C in temperate areas. Similar temperature differences have been found by researchers when comparing forest and open spaces.
On a global scale, trees fight the climate-induced warming by storing carbon in their trunks and removing carbon dioxide from the atmosphere. According to an IPCC report published in August, deforestation already accounts for 13% of total global carbon emissions, while land-use change generally accounts for 23% of emissions. Once all the trees on the planet have been eradicated, previously forested ecosystems are "more likely to be a source of carbon dioxide emissions into the atmosphere than a sink," says Paolo D & # 039; Odorico, a professor of environmental science at the University of California. Berkeley.
Large amounts of carbon would enter the oceans, leading to extreme acidification and possibly killing everything but jellyfish.
Over time, Crowther predicts that 450 gigatons of carbon would be released into the atmosphere – more than double the amount people have already contributed. This effect would be temporarily offset by smaller plants and grasses. While smaller plants bind carbon faster than trees, they also release it faster. At some point – perhaps over a few decades – these plants could no longer withstand the coming warming. "The timeline depends on where you are, as the decomposition in the tropics is much faster than in the Arctic," says D'Odorico. "But as soon as carbon dioxide is in the atmosphere, it does not matter if it comes from here or from there."
As the decomposition slowly detonated this ticking carbon bomb, the Earth would transform into a "vastly warmer planet, Crowther says – the varieties we've never seen existed have evolved. Large amounts of carbon would also enter the oceans, leading to extreme acidification and possibly killing anything but jellyfish.
However, human suffering would begin well before catastrophic global warming. The increasing heat, the disruption of the water cycle and the loss of shade would cost billions of people and animals death. Poverty and death would also affect many of the 1.6 billion people who currently depend directly on forests for their livelihoods, including the harvest of food and medicines. Due to the lack of firewood, more and more people would not be able to cook or heat their homes. All over the world, those whose work revolves around trees – whether as lumberjacks or paper makers, fruit growers or carpenters – would suddenly be unemployed and destroy the global economy. The wood sector alone employs 13.2 million people and, according to the World Bank, generates $ 600 billion annually.
Agrarian systems would also get out of hand. Shadow crops like coffee would drop drastically, as would those that rely on pollinators in trees. Due to temperature and precipitation fluctuations, places where crops were formerly grown could suddenly fail, while others that were previously unsuitable could become desirable. Over time, however, soils would be depleted everywhere, requiring significant amounts of fertilizer to survive the plants. Further heating would make most places ultimately uncultivable and uninhabitable.
In addition to these devastating changes, health effects would be expected. Trees purify the air by absorbing pollutants and holding particles on their leaves, twigs and trunks. Researchers at the US Forest Service have calculated that 17.4 million tonnes of tree-only air pollution are being eliminated each year in the US alone. This corresponds to a value of 6.8 billion USD (5.6 billion GBP). At least 850 lives will be saved and at least 670,000 cases of acute respiratory problems avoided.
D & # 039; Odorico adds that outbreaks of rare or novel diseases may also occur, transmitted by species with which we do not normally come in contact. He and his colleagues found that the transmission of Ebola to humans occurs at focal points of forest fragmentation. A sudden loss of forests could lead to temporary exposure to more frequent zoonotic infections such as Ebola, the Nipah virus and the West Nile virus as well as mosquito-borne diseases such as malaria and dengue fever.
A growing body of research also indicates that trees and nature are good for our spiritual wellbeing. For example, the New York State Department of Environmental Conservation recommends that you go through forests to improve overall health, including reducing stress, increasing energy levels, and improving sleep. Trees also seem to help the body recover: a famous 1984 study found that patients who had recovered from surgery had shorter hospital stays if they had a green view and not a brick wall. Recent research has shown that staying near grass and trees alleviates symptoms in children with attention-deficit hyperactivity disorder. Numerous studies also show a positive correlation between green areas and school performance of the children. Trees can even help combat crime: a study found that 10% growth in tree cover was accompanied by a 12% reduction in crime in Baltimore.
"Forest bathing" is now a doctor's prescription in Japan – Kathy Willis  "So many things that cause problems with physical and mental well-being can be significantly reduced by staying in a wooded environment," says Kathy Willis, professor of biodiversity at Oxford University. "That's why" forest bathing "in Japan is now a doctor's prescription."
The loss of trees would also be lamented at a deep, cultural level. Trees are a staple food for countless childhoods and play an important role in art, literature, poetry, music and much more. They have dealt with animist religions since prehistory and play a prominent role in other major religions that are practiced today. Buddha attained enlightenment after sitting under the bodhi tree for 49 days, while Hindus worship peepal trees symbolizing Vishnu. In the Torah and the Old Testament, God makes trees on the third day of creation – before any animals or humans – and in the Bible Jesus dies at a wooden cross made of trees.
"Many people look at forests with dollar signs," says Lowman. "But we never thought of a financial figure for the spiritual significance of the forests."
Even if we could live in a world without trees, who would want that? – Thomas Crowther
All in all, man would struggle for survival in a world without trees. Urbanized Western lifestyles would soon be a thing of the past and many of us would die of hunger, heat, drought and floods. Lowman believes that the surviving communities are likely to be those who have preserved traditional knowledge of how to live in treeless environments, such as the Australian Aborigines. Crowther, on the other hand, surmises that life would exist only in a Mars-like colony made possible by technology and completely separate from the existence we have always known.
"Even if we could live in a world without trees, who would like to? "Crowther says. "This planet is unique to everything else we know in the universe right now, because this inexplicable thing is called life, without trees almost everything would just be screwed."
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