Temporal And Spatial Responses Of Radial Growth Of Larix Chinensis To Climate Change In The Qinling Mountains

The Qinling Mountains is an important geographical boundary between the north and the south in China,and it is an ideal area to study the response of forest ecosystems to climate change.In recent years,with the intensification of global warming,the response of tree growth to climate change has attracted more and more attention.In the Qinling Mountains,At present,most studies have focused on the relationship between radial growth and climate response of trees,but little is known about temporal changes in tree growth in response to climate.Therefore,further research on the spatial and temporal characteristics of the response of tree growth to climate change in this region is of great significance for the protection and management of mountain forests.Larix chinensis is a deciduous conifer species endemic to the Qinling Mountains.It constitutes the highest alpine treeline in the Qinling Mountains,and it is extremely sensitive to climate change.Therefore,this paper collects tree ring samples of Larix chinensis from14 different altitudes(the altitude ranges from 3110 m to 3400 m)on the northern slope of Taibai Mountain and establishes a standard width chronology to analyze the response relationship of its radial growth to climate,and then explore the radial growth Variation characteristics of the relationship between growth and climate response over space and time.The results show:(1)Correlation analysis and principal component analysis show that there is obvious regional consistency between the chronologies,which means that the Qinling Larix chinensis chronology contains strong common climate signals,low temperature is the main climatic factor limiting the radial growth of Larix chinensis at different altitudes,especially the temperature in the early and growing seasons;on the other hand,The sensitivity of radial growth to climate is higher at high and low altitudes,but lower at middle altitudes where climate is suitable.(2)In the past ten years,the radial growth of Larix chinensis showed a gradual upward trend,and the growth rate increased with the increase of altitude.In the future,climate warming may further accelerate the radial growth of Larix chinensis.(3)As time goes on,Radial growth of Larix chinensis in Qinling mountains is unstable in response to climate change.From 1960 to 1979,due to the abnormally abundant spring precipitation,the negative correlation between radial growth and precipitation was strong;meanwhile,the summer precipitation was beneficial to the growth of Larix chinensis,especially in July and August;after 1980,especially since the climate warming in the late1990 s,the response of Larix chinensis to atmospheric temperature throughout the growing season has been significantly enhanced,and the limiting effect of precipitation has become weaker.In addition,there were also differences in the months with the strongest positive response to atmospheric temperature for the radial growth of Larix chinensis at different altitudes since 2000.