Planting trees will not save the climate
Not the CO2 traps as you think, but the operation usually ends up doing more harm than good.
Human beings have long believed that planting trees, any tree, anywhere, would be beneficial, something Mother Nature would cry out for, and that could even solve our climate crisis. Tree planting initiatives continue to multiply, to the point where it would be impossible to list them all.
This passion is partly explained by the fact that, in certain places, they sequester carbon. A reality widely regarded as synonymous with "line the earth with trees, and the problem of climate change will be resolved" - a reason why tree planting programs are so popular with carbon polluters looking to save costs depollution.
President Donald Trump, for example, immediately joined the billion-dollar trees initiative launched in January 2020 by the World Economic Forum. He promised the participation of the United States and even exalted it during his State of the Union address: "To protect the environment, a few days ago, I announced that the United States would join the One Billion Trees initiative, an ambitious effort to bring government and the private sector together to plant new trees in America and around the world. "
Threat to ecosystems
Planting trees can be a good thing, especially in countries where predatory logging and other land uses have destroyed soil stability and deprived local people of shade, clean water, fish, and fruit.
But such initiatives are the exception. In reality, mass plantings are likely to do more harm than good. And it is almost impossible to distinguish good projects from the bad.
More important problem is the ecological disaster that tree planting can cause if not done carefully. Few projects disclose the planted species. Even fewer commit to planting only native species. And when they do, they are inclined to plant monocultures, which have almost no value in terms of wildlife and are vulnerable to disease, insects, and wind.
Forests are complex machinery with millions of cogs training each other. It is impossible to plant a forest; you can only plant one plantation.
Trees planted in the wrong places, especially where they are naturally scarce, destroy native ecosystems. Grasslands, to name a few, are important habitat for a wide range of wildlife. But since European colonization, the American population has destroyed them by planting trees there.
When Julius Sterling Morton left Michigan to settle in Nebraska in 1854, he decided that Mother Nature had it all wrong. In due time, he urged "a large army of ploughmen [...] to come and fight against the woodless meadows" and on April 10, 1872, he instituted the first Day of the tree or Arbor Day. Twenty-four hours later, a good million trees had degraded the prairies of Nebraska.
Planting trees, especially on the consecrated day, has become a national obsession. To celebrate the hundredth anniversary of Arbor Day, an eponymous foundation, based in Nebraska, was created.
Morton's mentality is still very much at work there. Join and you'll be given ten Colorado blue spruce seeds, along with instructions on how to plant them. It will be perfect if you live in the center or south of the Rockies. But everywhere else, these trees are aliens.
"Desolation" of eucalyptus
The recent placing on the market of biodegradable cups containing tree seedlings illustrates the extent of our enthusiasm for planting trees. Not only do these cups encourage the illegal dumping of garbage, but they also guarantee that bad trees will be planted in the wrong places.
These informal plantations are, however, an American tradition. In 1876, no doubt inspired by Arbor Day, a man named Ellwood Cooper, living in Santa Barbara, California, wanted to amend his 800-hectare ranch, mostly treeless, by planting 50,000 feet of eucalyptus trees. In three years, the trees had exceeded 12 meters, an incredible growth rate which will earn them the nickname of "miracle trees". The eucalyptus is not native to California.
Sometime later, the University of California and the United States Department of Forests distributed eucalyptus on the fly. The meadows, the chaparral, and the cut forests were crammed with these foreign plants. A century after the first Arbor Day, 110,000 hectares of eucalyptus trees had been planted in the United States, including 80,000 hectares in California.
When I put my arm in a pile of eucalyptus leaves and bark in Bolinas, California, I can't touch the bottom. Why? Because the microbes and the insects that eat them are in Australia, not California.
Native plant communities cannot survive on these plantations because the eucalyptus trees kill the competition with their own herbicide, prompting botanists to call these monocultures "desolate".
Eucalyptus has evolved with fire and draws its resistance from it. Its peaks don't just burn, they explode. Living near a eucalyptus forest is like being near a refinery where the staff would have the right to smoke cigarettes.
But eucalyptus trees remain popular in California. We continue to plant them, and the authorities who seek to protect populations and restore native ecosystems by shaving the eucalyptus trees inevitably run into the fury of their fans who, among other things, accuse them of being "plant Nazis" ".
Carbon sink chimera
According to a mantra heard for more than three decades, trees are beneficial, even if they disturb native ecosystems because they can serve as carbon sinks.
In 1988, the American Forestry Association (now American Forests ), which celebrated its 113th anniversary, launched its international ReLeaf campaign with the slogan " Plant a tree, refresh the planet ". Too bad it's not that simple.
A study by the Lawrence Livermore National Laboratory concludes that any benefit from carbon sequestration from trees planted above a line along the northern Florida border is largely lost since the solar heat absorbed and retained by the trees warms the climate.
The idea that a significant proportion of the carbon spewed by humanity can be absorbed by planted trees is a pipe dream. But that dream got back on its feet in July 2019, when the Crowther Lab in Zurich published an article in the journal Science proclaiming that by planting a trillion trees, it was possible to store "25% of the reservoir of current atmospheric carbon ”.
The claim is ridiculous because you can't plant that many trees - the number is a third of all those on Earth today. Even if we stay well below the target, we would have to destroy grassy surfaces (meadows, pastures, and savannas) that reflect rather than absorb solar heat and which, under current climatic conditions, are of better carbon sinks than natural forests, not to mention planting. In addition, unlike trees, meadows store most of their carbon underground, which means that it is not released in the event of a fire.
Crowther's study horrified climatologists and environmentalists. Forty-six specialists have reported their complaints in another article, explaining that planting trees in the wrong places can exacerbate global warming, increase the risk of fire and devastate wildlife.
Scientists at the Crowther Lab were particularly criticized for "making people believe that the meadows and savannas would eventually be sites for restoration thanks to the trees" and for overestimating by a factor of 5 "the potential for carbon capture by new trees".
Drying of wetlands
Tree crops are already destroying much more efficient natural areas for storing carbon - such as wetlands. When organic litter is trapped underwater, it cannot release carbon since there is no oxygen to decompose it.
The efficiency of carbon sequestration in coastal wetlands (marshes, mangroves, and seagrass beds) increases in fact with global warming because, as the sea level rises, there is more and more space storage for this trash.
Poorly designed tree plantations can dry up wetlands. See the living initiative to plant 2.4 billion trees in the Cauvery river basin in India, launched by the Isha Foundation, based in Coimbatore.
Leonardo DiCaprio, whose foundation is one of its main financiers, was given a letter signed in September 2019 by ninety-five Indian public interest groups and environmental protection groups opposing this plan.
It says: “The biodiversity, the forests, the meadows, and the immense delta region that this river feeds would be devastated. [...] It seems that this program considers, in a rather simplistic way, that the river could be saved by planting trees on its banks and those of its streams, its tributaries and on its flood plains [...], a method promoting a monoculturalist paradigm of landscape restoration that the Indians have rejected for a long time. ” According to the Isha Foundation, this letter would only reflect a base desire to "advertise itself".
Also last September, Ireland committed to planting 440 million trees as part of its climate action plan. Many of them will be commercially prized Sitka spruces from the Pacific Northwest in North America. Once cut, the sequestered carbon will be released into the atmosphere.
At the same time, these extraterrestrials will dry up wetlands, worsen global warming by absorbing and retaining solar heat, and, as the Irish Wildlife Trust warns, will accelerate the disappearance of fish and wildlife (started after the planting of other trees foreigners).
Useless carbon offset
The idea that planting trees would be a panacea for Earth's ills is as popular with polluters as it is among nations, a reality that has given birth to the lucrative carbon offsetting sector. Polluters use third parties - often invisible, uncontrolled, and in other countries - to plant any tree, anywhere.
In November 2019, EasyJet announced it would spend 30 million euros on tree planting and other carbon reduction programs, becoming the first airline to offset all of its CO 2 emissions.
In February 2020, Delta Air Lines also committed to neutralizing its emissions by investing $ 1 billion over the next decade. The company remained vague on the details of this strategy, but the planting of trees would hold a good place there.
Carbon compensation has been assimilated to indulgences, these absolution tickets bargained for by the Catholic Church before the Reformation - go and sin no more, unless of course you again put your hand in your pocket to be forgiven your future sins.
Also, companies responsible for planting so-called climate trees often charge for trees they would have planted in all cases, or even pocket the money without planting anything at all.
According to Kevin Anderson, a professor at the University of Manchester (UK) specializing in energy and climate change, the entire carbon offset sector is a "scam". In 2019, after two decades of carbon offsetting, CO 2 levels reached their historic highs.
Restoration in progress
Carbon offsetting could be effective if polluters paid to protect existing forests, and perhaps also to restore wetlands and grasslands by cutting down planted and invasive species.
In Montana, the American Prairie Reserve restores the native prairie on 162,000 hectares, shaving Bohemian olive trees and Chinese honey locusts and sowing old agricultural land with native plants.
The same restoration is carried out by the US Fish and Wildlife Service ( USFWS ) in national wildlife refuges like Bowdoin and Medicine Lake, also located in Montana.
"I have old photos of settlers on the prairie, and there isn't a single tree on the horizon," says Neil Shook, who runs these two shelters. Today, we have trees everywhere. By cutting them, there is an increase in the vegetation of the prairies and the songbird populations. But people continue to plant olive trees. You just have to cross the refuge border to see what happens when you don't cut. Private land is simply crammed with trees. ”
In Iowa, thanks to an aggressive slaughter campaign led by the USFWS in the Union Slough National Wildlife Refuge, plants, birds, and mammals dependent on the prairies are coming back in force. For years, tree enthusiasts have rebelled against the managers of Union Slough, accusing them in particular of "arboricide". But as the refuge expands, the scandal fades.
The reform seems to take two steps back and three forward. "We are pushing for San Francisco to plant native trees that will bring wildlife to the city and connect it to our parks," said Jacob Sigg of the California Native Plant Society. But the network of elders plants non-native species and is deaf to our arguments. Planting trees anywhere makes me shiver with terror. I see progress, then I hear a big vegetable saying that it will plant “a trillion trees”. ”
Sigg was exhilarated when I questioned him on Angel Island. The island was ravaged by the famous "desolation" of the eucalyptus trees the last time I went there. Today, he assures me, practically all eucalyptus trees have been cut and chipped, and native meadows and holm oaks are recovering. The California Department of Parks and Recreation has heard the company's arguments. Whatever the sometimes violent campaigns of pro-Eucalyptus groups, he held out.
I don't think you could find a better formula than that of the great landscape photographer Ansel Adams when he had attended the tree plantations organized by the scouts in the prairie of the Golden Gate National Recreation Area: “I cannot imagine d he enterprise is more insipid than planting trees in an area which is naturally devoid of it and to impose an interpretation of natural beauty on a large landscape full of beauty and wonder, and the excellence of eternity. " In many cases, treeless landscapes are not the only natural, but they are also better for the Earth.