swidden agriculture

Slash-and-burn agriculture, also called fire-fallow cultivation or swidden agriculture, is a farming method that involves the cutting and burning of plants in a forest or woodland to create a field called a swidden. The method begins by cutting down the trees and woody plants in an area. The downed vegetation, or "slash", is then left to dry, usually right before the rainiest part of the year. Then, the biomass is burned, resulting in a nutrient-rich layer of ash which makes the soil fertile https://en.wikipedia.org/wiki/Slash-and-burn