Does planting trees save the Planet? Yes, if they are periurban forests

The study of a group of Italian researchers on Nature Cities

(sustainabilityenvironment.com) – In 2021, the G20 chaired by Italy launched the initiative to plant a thousand billion trees by 2030. The idea stems from a 2019 ETH Zurich study that recalculated the CO2 absorption potential of forests and proposed re- and afforestation as a key solution against climate change. The objective has raised many criticisms, among those who have branded it as a distraction from the imperative of reducing greenhouse gases at the source to those who have questioned the feasibility, to those who have stressed the possible adverse effects. But there is nothing to throw the baby with the dirty water, suggests a study recently published in Nature Cities by a group of Italian researchers: just start from the periurban forests.

The challenge of periurban forests

All over the world, the transition areas between city and country, within 10 km from urban centers, often degraded or impoverished, could alone host between 106 and 241 billion trees. If you count the share of this territory that is cultivated today, you get to 34-101 billion. These periurban forests would benefit in terms of CO2 absorption, but would also promote climate in cities and support biodiversity. And 78% would be achievable in just 20 countries.

“To combat global warming, the solution is theoretically simple: reduce greenhouse gas emissions, in particular CO2, and at the same time absorb the surplus of CO2 from the atmosphere – explains Stefano Mancuso, scientific director of the Foundation for the Future of Cities. – “However, reducing emissions has profound economic impacts and requires time and a global commitment that is currently difficult to ensure. On the other hand, the absorption of CO2 from the atmosphere through reforestation does not present significant technical obstacles and can offer environmental and employment benefits“.

Betting on periurban forests, instead of reforesting remote areas, has lower costs. It also allows to guarantee better thermoregulation both in summer and in winter, reducing the costs of heating and cooling and related energy consumption. A better urban climate directly translates into health benefits. Without forgetting, the authors stress, that periurban forests would also help mitigate the effects of extreme weather events, including heat waves and floods, limiting damage and costs.