Individual and Temporal Variation in the Sensitivity of Pinus densata Growth to Climate in the Shergyla Mountains
In order to recognize the differences among different individuals of Pinus densata on the Xizang Plateau and the problem of sensitivity to climate response.In this study,we collected sample cores of P.densata,a dominant tree species in the Shergyla Mountain region of Xizang,and de-trended them with the ARSTAN program to obtain the growth indices of each tree-round sequence.The correlation of tree growth with temperature and precipitation and the similarities and differences among its tree individuals were analyzed by comparing the consistency between tree individuals at the two sites.The results showed that(1)At the upper elevation limit,17(61% )of the 28 individual trees were not significantly correlated with any month's temperature,while the remaining 11 trees were significantly correlated with temperature.From October of the previous year to September of the current year,only 11% of the 28 tree-round sequences were significantly positively correlated with 12-month temperatures,whereas at the lower elevation limit 10 of the 32 trees(31% )did not have significant correlations with temperatures in any month,whereas there were significant correlations between the remaining 22 trees and temperatures;and 24% of the 32 tree-round sequences were significantly positively correlated with 12-month mean temperatures.(2)Relative to temperature,the tree-whorl sequences of 25 out of 28 trees(90% )at the upper elevation limit were significantly correlated with precipitation,whereas at the lower elevation limit,the tree-whorl sequences of 19 out of 32 trees(60% )were significantly correlated with precipitation;the tree-whorl sequences were significantly correlated with 12-month precipitation in only 13% of the 12-month average;(3)The tree-whorl sequences at the upper elevation limit were categorized into 7 and 5 groups according to climatic factors,and the tree-whorl sequences at the lower elevation limit were all categorized into 6 groups.The lower limit was divided into 6 groups.This led to the conclusion that there was high growth variability among individual trees,low consistency of tree-rotation sequences with temperature and precipitation,and that temperature and precipitation at the upper elevation limit were weakly limiting alpine pine growth,while the lower elevation limit was mainly constrained by temperature.In addition,in the context of global warming,the occurrence of microhabitats,disturbance events,and internal tree characteristics may reduce the sensitivity of tree growth to climate change.
万方数据
维普
