We plant a lot of trees to combat global warming, but is this a good idea?

Trees absorb carbon dioxide, so planting trees offsets the emissions we produce. At least that way we can have peace of mind when we fly to the other side of the world. But how effective is planting forests in combating global warming? It dependsAs the English say.

In any case, the matter is more complicated than simply planting large numbers of trees, according to a large study conducted by the United States and other countries. Oregon State University. With a team of eight, the researchers examined thousands of sites in 130 countries where forests had been planted. In about half of the cases, it turned out that it was better to let nature take its course. In the trade magazine nature.

A little nuance
“Trees can certainly play a role in combating climate change,” says researcher Jacob Bukoski. “It’s pretty easy to understand that forests remove and store carbon dioxide from the atmosphere, and planting trees is something that almost everyone agrees on.” But that doesn’t mean it’s always the best plan. “This study provides a nuanced perspective on the whole debate about planting trees to combat climate change.”

Around the world, establishing forests is now seen as an important way to combat climate change. There are two ways to do this, explains Bukoski. “We can let forests regenerate on their own, which is slow but cheap, or we can take a more active approach and plant trees ourselves, which speeds up growth but is more expensive. Our study compares these two approaches to reforestation in low- and middle-income countries and identifies where natural regeneration or planting forests is likely to make more sense.”

Sometimes natural recovery is better.
In 46 percent of the areas studied, restoring natural forests over a 30-year period appears to be the most cost-effective. Planting forests are therefore better in just over half of cases. A combination of both approaches is even more effective. “If your goal is to remove carbon from the air as quickly and cheaply as possible, a combination of naturally regenerated forests and planted forests is the best option,” says Bukoski.

The study shows that natural restoration is best across most of western Mexico, the Andes, southern South America, western and central Africa, India, southern China, Malaysia and Indonesia. Conversely, planted forests are best across most of the Caribbean, Central America, Brazil, northern China, Southeast Asia, the Philippines, and northern, eastern and southern Africa. “Which method is more cost-effective in a given location depends on several factors, including opportunity costs (the yield lost by not choosing the other option, ed.), the amount of carbon stored, the size of the harvest and the costs of implementation,” explains Bukoski.

reduce carbon dioxide emissions
It should be clear that reforestation is always only a complement to climate policy and not a substitute for reducing CO2 emissions through fossil fuel use. By comparison, the total CO2 storage from reforestation over thirty years is less than eight months of global greenhouse gas emissions.

Plus, planting trees is good for more than just capturing carbon dioxide. It can also increase biodiversity and help meet demand for timber. It can also provide much-needed economic activity for local communities. These are all factors that, the researchers say, should be taken into account when planting forests.

But planting a tree in exchange for a plane ride is not a solution at all.