We'll Just Plant Trees! It's Not That Simple; Past Projects Boosted Deforestation, Missed Targets
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Tree-planting programs have run into problems from the start. In 1987, an executive at the energy company AES Corporation had the idea of trying to cancel out 40 years of CO2 emissions from its coal plant in Connecticut by planting trees in the mountains of Guatemala. It was the first “carbon offset” project — and while it sounded fine in theory, it didn’t go exactly as planned. As farmers in the region started planting trees, they weren’t growing as many crops as they used to and started running low on food. Then, before the 40-year project was over, the locals began cutting down the trees for fuel and lumber. In 2009, one study calculated that the program had only offset about 10 percent of the coal plant’s emissions.
Such problems have continued to plague tree-planting projects. The vast amount of land required to plant trees to suck up carbon, the U.N. Intergovernmental Panel on Climate Change warned in a report last month, will take up land needed to grow food and also make it harder for some plant and animal species to survive.
Plus, the trees that are planted don’t always get the care and attention they need to survive, and they sometimes end up displacing native forests. In Turkey, volunteers planted 11 million trees around the country on one day in 2019; a couple of months later, as many as 90 percent of the saplings were dead, a result of being planted at the wrong time and not getting enough water. That same year, a tree-planting program in Mexico may have actually caused deforestation: Farmers were cutting down the jungle to get money to plant new seeds, leading to the loss of an estimated 280 square miles of forest, roughly the size of New York City.
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On top of all that, when forests are lost, the trees that replace them don’t provide the same benefits. In a recent study, Hua and researchers around the world looked at the differences between native forests and tree plantations — forests planted to produce a lot of wood, often with just one or two types of fast-growing trees, like eucalyptus or acacia. Looking at more than 260 studies from 53 countries, they found that native forests blew plantations out of the water on almost all the ecological benefits they studied, in terms of storing carbon, preventing soil erosion, managing water supplies, and providing habitat for plants and animals.
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https://grist.org/science/does-planting-trees-actually-help-climate-change/