Is there a link between the rise and fall of the Tuyuhun tribe (northwestern China) and climatic variations in the 4th–7th centuries AD?

• Tree-ring data provide clues for understanding society dynamics in Tuyuhun Tribe.
• Climate fluctuated in dry and wet conditions in the history of Tuyuhun society.
• The thriving of the Tuyuhun society generally corresponded to wet climate.
• Relationship between climate and warfare and envoy activities are complex.

It has long been recognized that the dynamics of human societies are influenced by climate change, but the degree to which climatic variation affects the rise and fall of an independent society is still debated. We tackle this issue by examining the history of the semi-nomadic Tuyuhun tribe from northwestern China that existed from the early 4th century to the middle of the 7th century AD, and its relationship to regional climatic variation. The climatic data used are proxy spring precipitation reconstructed from tree rings of Sabina przewalskii Kom. from the core region previously inhabited by the Tuyuhun. Our results show that climatic conditions during the period covered by Tuyuhun can be divided into three dry periods, three wet periods and one period of intense dry–wet fluctuation. By comparing the societal development with climate, we found that there was an association between the rise and fall of the tribe and the fluctuations of dry–wet climate conditions. However, the relationship between climate and warfare and the tribe's policy of sending envoys and offering tributes to neighboring powers was complex. Such activities took place in both dry and wet periods making it difficult to draw a clear conclusion about the role of climate in regulating the dynamics of the Tuyuhun tribe.