Himalayan birch (Betula utilis D.Don) has a wide distribution in the Himalayas.It is also a widespread timberline species.However, we did not know whether this species has dendroclimatic potential.A large-scale of tree-ring network of timberline Himalayan birch (7 forest sites) in the central Himalayas further supported that its growth was primarily controlled by moisture stress rather than by low temperature.In particular, its growth at the timberlines is dominated by moisture availability during the pre-monsoon season, being different with tree growth at other alpine and arctic timberlines.Such a climatic response of timberline tree species is closely related to the worlds largest elevation gradient in association with decreasing precipitation with increasing elevation (above 2000-3000 m a.s.l).On the other hand, it is related to the ecophysiological trait of Himalayan birch preferring to grow in the rain shadow.Given a wide distribution of Himalayan birch forest in the Himalayas, its timberline represents an exceptional case to investigate mechanism driving timberline formation.