One tree planted for every t-shirt purchased. Or for every bottle of wine. Or each time a credit card is used. Trees planted by national governments to meet global targets and by companies to improve their sustainability record.
As the climate crisis deepens, businesses and consumers are joining nonprofits and governments in a great worldwide wave of tree planting. Last year saw billions of trees planted, in dozens of countries across the planet. These efforts can have triple benefits, creating jobs, absorbing and trapping carbon dioxide, and improving the health of ecosystems.
But when the work is done incorrectly, projects can exacerbate the problems they were supposed to solve. Planting the wrong trees, in the wrong place, can actually reduce biodiversity, accelerate extinctions and make ecosystems much less resilient.
Addressing the loss of biodiversity, which is already as serious a global crisis as climate change, is becoming more and more urgent. The pace of extinctions is accelerating. One million species are at risk of disappearing, some within the next few decades. And the collapse of an ecosystem doesn’t just threaten plants and animals: it endangers the water and food supplies that humanity depends on.
In the midst of the increasingly serious crisis, companies and countries have been investing more and more in planting trees that cover large areas with commercial species that are not native to the region, in the name of combating climate change. These trees absorb carbon but offer little support for the biological networks that once thrived in the areas they come to occupy.
“What’s being created is basically a barren landscape,” said Paul Smith, who heads Botanic Gardens Conservation International, an association of organizations working to prevent plant extinction. “If people want to plant trees, it must also be positive for biodiversity.”
There’s a basic rule of thumb about planting trees: you have to plant “the right tree in the right place.” And there are those who add “for the right reason”.
But in interviews with a range of stakeholders – scientists, public policy experts, reforestation companies and tree-planting organizations – it is clear that people disagree on what is “right”.
For some, large areas of tree cultivation are right, for carbon storage and as a source of wood. For others, they are fruit trees supplied to smallholder farmers. For still others, it is allowing native species to regenerate.
Best efforts try to address these diverse needs, restoration experts say, but it can be difficult to reconcile the conflicting interests.
“It’s a bit like the Wild West,” said Forrest Fleischman, a professor of environmental policy at the University of Minnesota.
Natural Solution
There is not enough land on the planet to be able to combat climate change by planting trees alone, but if this is combined with drastic cuts in the use of fossil fuels, trees can be an important natural solution.
They absorb carbon dioxide and store it in their branches and trunks (although trees also release carbon when they burn or rot). The ability to collect carbon dioxide is why forests are often defined as carbon sinks.
In Central Africa, French oil and natural gas giant TotalEnergies announced plans to plant trees on 40,000 hectares of the Republic of Congo. The project — on the Batéké plateau, an undulating mosaic of grasslands and savannas interspersed with woodlands and patches of denser forest — would absorb more than 10 million tonnes of carbon dioxide over 20 years, according to the company.
“Total is committed to developing natural carbon sinks in Africa,” said Nicolas Terraz, then Total’s senior vice president of production and exploration in Africa, in a company press release about the project in 2021. “These activities extend priority initiatives adopted by the group in order to avoid and reduce emissions, which is in line with its ambition to achieve a zero emissions balance by 2050.”
To achieve zero balance, companies need to remove at least as much carbon from the atmosphere as they emit. Many, like TotalEnergies, are turning to trees to help them deal with this. On the Batéké plateau, a species of acacia native to Australia, intended for selective logging, will cover a large area.
The project, part of a program by the Congolese government to expand forest cover and increase carbon storage, would create jobs, according to the company, and would ultimately increase the diversity of the ecosystem, as local species can develop. with the passage of decades.
But scientists warn that the plan could be an example of one of the worst forms of reforestation: planting trees in an area where they would not naturally occur. Such projects can devastate biodiversity, threaten water supplies and even cause temperatures to rise because, in some cases, trees absorb reflected heat from grass — or, in other parts of the world, snow.
“We don’t want to do evil for the sake of doing good,” said Bethanie Walder, executive director of the Society for Ecological Restoration, an international nonprofit.
The Batéké plateau is one of the least studied ecosystems in Africa, according to Paula Nieto Quintano, an environmental scientist whose studies focus on the region. “Its importance to the work of local populations, its ecology and the functions of its ecosystem are not well understood,” said Nieto.
People who study reforestation emphasize that planting trees is not a panacea.
“I’m afraid many companies and governments see this path as an easy way out,” said Robin Chazdon, a professor of tropical reforestation at the University of the Sunshine Coast in Australia. “They don’t have to work so hard on reducing their emissions because they can say they will offset them by planting trees.”
doing the right thing
All trees store carbon, but their other benefits can vary widely depending on the species and where they are planted.
Eucalyptus, for example, grows fast and its trunk is straight, which makes it a profitable product for lumber companies. Native to Australia and a few islands to the north, its leaves feed koalas, which have evolved to tolerate the potent poison they contain.
But in Africa and South America – where trees are heavily cultivated for timber use, as fuel and, increasingly, for carbon retention – eucalyptus offers far less value to fauna and flora. In addition, they can reduce available water and increase the risk of forest fires.
Experts recognize that reforestation and carbon absorption are complex issues, and that commercial species have a role to play. People need wood, a renewable product whose production and extraction generate less pollutants than the production of concrete or steel. People need paper and fuel for cooking.
Planting fast-growing species for exploitation can sometimes help preserve the native forests that surround them. And by strategically adding a few native species, commercial tree planting areas can help biodiversity by creating corridors for wildlife, linking disconnected habitat areas.
“The restoration movement cannot happen without the private sector,” said Michael Becker, communications director for 1t.org, an organization created by the World Economic Forum to push for the conservation and cultivation of a trillion trees with investment aid. private. “Historically, there have been some bad agents, but we need to draw them to the positive side and convince them to do the right thing.”
One challenge is that helping biodiversity does not offer the same financial returns as carbon storage and the timber market.
Many governments have set standards for reforestation efforts, but often offer broad leeway to the market.
In Wales, one of the most deforested areas in Europe, the government is offering incentives to plant trees. But participants only need to include 25% native species to qualify for government grants.
In Kenya and Brazil, rows of eucalyptus trees grow on lands that were once ecologically rich forests and savannas. In Peru, a company called Reforesta Perú is planting trees in degraded areas of the Amazon rainforest, but is increasingly using cloned eucalyptus and teak to produce wood for the export market.
The balance of biodiversity
When companies promise to plant a tree every time someone buys a product, they typically do so through nonprofit organizations that work with communities across the globe. But globally, only a small fraction of existing tree species are planted frequently, according to scientists and tree-planting organizations.
“They’re planting the same species all over the planet,” said Meredith Martin, an assistant professor of forestry studies at North Carolina State University, who has found that nonprofit tree planting efforts in tropical regions tend to prioritize the needs of employment of local residents, above biodiversity or carbon retention. Over time, she said, these efforts carry the risk of reducing forest biodiversity.
A major obstacle is the lack of supply from local seed banks, which tend to be dominated by popular commercial species. Some organizations overcome this problem by hiring people to collect seeds in neighboring forests.
Another solution, experts say, is to allow forests to recover naturally. If the area has undergone low degradation or is located in the immediate vicinity of an existing forest, the method known as natural regeneration may be cheaper and more effective. Simply isolating certain areas from use as pastures will allow the trees to return, which would bring with it the benefits of carbon uptake and biodiversity.
“Nature knows a lot more than we do,” Chazdon said.
Translation by Paulo Migliacci
