Climate Signals from Tree Ring Chronologies of the Upper and Lower Treelines in the Dulan Region of the Northeastern Qinghai-Tibetan Plateau Analysis of stable carbon isotopes in different components of tree rings of Pinus sylvestris var. mongolica Research advances in dendrochronology. RESPONSE OF RADIAL GROWTH TO NEIGHBORING COMPETITION AND CLIMATE FACTORS IN TAXUS CUSPIDATA A Dendroclimatic Study of Relic Picea meyeri in Inner Mongolian Steppe