Societal and climatic controls on swidden cultivation in the Eastern European Plain.

Slash-and-burn cultivation was among the earliest systems of land use that allowed agriculture to expand into forested and less naturally fertile zones beyond the regions where it first developed, but the chronology of this agricultural system is debated. The development and history of slash-and-burn cultivation on the Eastern European Plain was established for the first time using a novel approach. A dataset of 120 radiocarbon dates was obtained on charcoal from swidden soil horizons in major river basins. The earliest swiddens appeared in the Bronze Age in the Dnieper basin, becoming widespread in the beginning of the Early Iron Age. Radiocarbon dates reflect four major waves of expansion of groups practicing swidden agriculture into new territories between 4000 and 500 years ago, and more numerous and asynchronous basin-scale migrations. The expansions alternated with centennial-scale breaks when swiddens became sporadic or disappeared. After the last prolonged break, 200 BCE to 100 CE, slash-and-burn cultivation rapidly expanded and persisted in the forest zone of Eastern Europe. The onset of swidden cultivation and peaks in swidden occurrence coincided either with climate cooling or with climatic transitions.