West Africa: How We Mapped Billions of Trees Using Satellites, Supercomputers and AI

[The Conversation Africa] The possibility that vegetation cover in semi-arid and arid areas was retreating has long been an issue of international concern. In the 1930s it was first theorized that the Sahara was expanding and woody vegetation was on the retreat. In the 1970s, spurred by the "Sahel drought", focus was on the threat of "desertification", caused by human overuse and/or climate change.