Aim There is increasing interest in the role that biological traits, and historical and biogeographic processes, play in the formation of phylogeographic patterns. An arid belt that once existed in northern China might have affected many plants, but this has yet to be tested in an arid‐tolerant, wind‐dispersed species. Here, we tested how intrinsic and extrinsic factors have affected the phylogeography of Populus davidiana . L...