West Africa's transition zone is one of the world's most ecologically fragile areas and is widely assumed to be experiencing a deforestation crisis. For a century experts have held villagers responsible. But recent research in Guinea shows the exact oppposite. Instead of disappearing, forest cover has in fact been increasing - due to farmers's skill in transforming savanna into forest. This video explains how the research team's anthropological research combined with oral histories, archives and aerial and satellite images to produce these findings. It gives voice to villagers and shows how easily experts can reach wrong conclusions if they ignore local knowledge and history.