Responses of radial growth of Pinus yunnanensis to climatic and hydrological factors at different altitudes in Western Yunnan, China

Abstract

A tree-ring width chronology (STD) was established using tree-ring cores of Pinus yunnanensis from two sites with different altitudes in Western Yunnan, to study the responses of radial growth to climatic and hydrological factors. The results showed that the radial growth of P. yunnanensis in Western Yunnan was mainly affected by precipitation, temperature and runoff. The radial growth of P. yunnanensis at high altitude (2413.3 m) was controlled primarily by high temperature in summer and runoff in the monsoon season. In contrast, the radial growth of P. yunnanensis at low altitude (1062.6 m) was mainly controlled by precipitation in the growing season and annual runoff. The responses of radial growth of P. yunnanensis at high altitude to temperature change was unstable due to the existence of the temperature threshold. Due to the weakening of the East Asian summer monsoon in the 1980s, the temporal stability of tree growth response at low altitude to precipitation and runoff fluctuated. The radial growth of P. yunnanensis at different altitudes in Western Yunnan was related to the Asian summer monsoon and El Nio-Southern Oscillation.