Huge swathes of land in Chile, Brazil and Argentina are covered with millions of Araucaria, or monkey puzzle trees, thanks to people planting or cultivating them more than a thousand years ago, a new study shows. Recent logging means the landscape is now one of the world’s most at-risk environments.

It had been thought the forests expanded due to wetter and warmer weather. But the research shows the rapidly expanding pre-Columbian population of South America, Southern Jê communities, were really responsible.

New excavations and soil analysis shows the forests, still hugely culturally and economically important to people living in South America, expanded between 1,410 and 900 years ago because of population growth and cultural changes.

Dr Mark Robinson, from the University of Exeter, who led the British Academy and AHRC-FAPESP-funded research, said: “Our research shows these landscapes were man-made. Communities settled on grassland, and then – perhaps because they modified the soil, protected seedlings or even planted trees – established these forests in places where geographically they shouldn’t have flourished.”

Source: Critically endangered South American forests were man made