Abstract:

The growth dynamics of trees under the background of climate change have been a hot topic of ecological concern,therefore exploring the relationship between tree growth and climate is of great significance.In order to study the climate response laws of tree growth in northwest Yunnan Plateau,we selected Yulong Snow Mountain and Laojun Mountain as two typical areas,and studied the relationship between radial growth and climatic factors of Tsuga dumosa,by using the method of tree ring chronology.Two residual chronologies of T.dumosa were established by using data from tree ring widths and the spatiotemporal correlation between the annual ring index and climate factors was further analyzed.The results showed that T.dumosa growth was influenced by both precipitation and temperature.The radial growth of T.dumosa in Yulong Snow Mountain was significantly and positively correlated with the temperature in previous November and current June,and its growth was negatively and positively correlated with the precipitation in June and October of the current year,respectively.T.dumosa growth in Laojun Mountain was mainly affected by the water and heat conditions in May,showing a significantly negative correlation with temperature and a significantly positive correlation with precipitation,while showing a significantly positive correlation with temperature and precipitation in October.In the sliding analysis,the dynamic response of precipitation is more stable than temperature,confirming the decisive role of moisture conditions on an interannual scale.The growth of T.dumosa in Laojun Mountain presented the most significant correlations with precipitation of previous October and current May,while in Yulong Snow Mountain,significant correlations with precipitation of current June appeared in most years.The research results reveal the climate "memory effect" of the radial growth of T.dumosa on the late growing-season of the previous year,and the "immediate response" effect on the water and heat combination at the end of spring and beginning of summer in current year.

Key words: dendrochronology, climate response, radial growth, hengduan mountains