Down to Earth – Planting trees: Climate cure-all?
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It sounds like an effortless solution to one of humanity’s greatest challenges: using trees as a tool to capture carbon dioxide. As the climate crisis deepens, countries and companies have embarked on a global tree-planting spree. But could they end up doing more harm than good?
France’s southwestern Périgord department is probably home to the country’s densest forests. The region’s hilly terrain is hardly ideal for planting trees. And yet, this is where more than 12,000 trees have been planted over 8 hectares of land. It’s all part of France’s Low Carbon Label, which provides a stamp of approval to carbon offset forestry projects. The principle is simple: companies pay to plant trees that capture and store carbon dioxide, providing a legal framework for them to offset their emissions by subsidising tree-planting schemes.
“Forests are like extraordinary factories that transform carbon dioxide into a material that we all know: wood,” says Jérôme Chanel of Alliance Forêts Bois, the forestry cooperative in charge of the project.
According to the cooperative’s estimates, this plot of land will help compensate approximately 1300 tonnes of C02, equivalent to driving 9 million km.
Can trees really get us out of the climate crisis?
To be sure, they can be of great help, as trees are the world’s largest terrestrial carbon sink. Here in France, they absorb 20 percent of emissions. The problem is that we are pouring out so much CO2 that trees simply won’t keep up. Even if vegetation covered the planet, we could store 40 to 100 gigatonnes of CO2. Our annual emissions, though, stand at 10 gigatonnes.
Planting trees can only be part of the solution, as long as we plant the right tree in the right place and for the right reason. And before companies even begin to consider offsetting their emissions, they should think about reducing them first.
That’s not what happens in practice, says Myrto Tilianaki, climate justice advocacy officer at CCDF-Terre Solidaire, a non-profit based in Paris. Tilianaki combed through the climate strategies of three major corporations that have made tree-planting schemes a pillar of their CO2 reduction plans: Nespresso, Total Energies and Air France.
“They’re relying mostly on carbon offset projects, and it’s just an excuse not to act,” she says.
Soil: The hidden side of nature
Trees do have a role to play in reducing CO2 but France’s National Research Institute is also interested in what’s happening down below. Laurent Augusto, who leads a research project in an experimental forest in the Gironde region, says there is as much CO2 captured in the soil as there is in the leaves. As the trees grow, leaves containing CO2 will fall off, transferring that same CO2 onto the soil.
The objective for Laurent and his team is to understand which species store more carbon dioxide in the soil. They already have promising results.
“Softwoods such as fir, spruce or pine store a little more carbon in the soil than hardwoods,” he says. “Hardwoods, on the other hand, store carbon in the soil for a longer period of time, so that’s also something to look out for.”
