In the past decade, planting trees has come to represent many things: a virtuous act, a practical solution and a symbol of hope in the face of climate change. But can planting a trillion trees really save the world?

Visiting the Eden Reforestation Projects in Goiás, Brazil, and interviewing numerous international scientists and activists, the journalist Zach St. George offers a vivid insight into the root of the tree-planting movement — from the Green Belt Movement of the 1970s to the Trillion Tree Campaign of the 2010s — and considers the concept’s environmental potential, as well as the movement’s shortcomings.

This story was written by Zach St. George and recorded by Audm. To hear more audio stories from publications like The New York Times, download Audm for iPhone or Android.