Why did slash-and-burn agriculture lead to shifting settlements?

Slash-and-burn agriculture leads to shifting settlements primarily because it is a method of cultivation designed for environments where long-term, continuous farming on the same plot is not sustainable without advanced soil conservation or fertilizers.1

In this system, a plot of land is cleared by burning vegetation, which provides temporary fertilization from the ashes. However, after a few years of cultivation, the soil’s nutrient levels decline and the field often becomes overrun by weeds. To maintain productivity and allow the land to regenerate its natural vegetation, the cultivators abandon the exhausted plot and move their operations to a new area. This cycle of plot rotation necessitates the movement of settlements, as the farmers must relocate to remain near their active fields.12

While this practice is sometimes criticized for its impact on forest fertility, it serves as a traditional adaptation to specific tropical soil conditions, allowing small clearings to recover as forest over time.12