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为分析青藏高原东缘半湿润区不同树种树木生长对气候变化的响应规律,于川西米亚罗林区海拔3000 m左右(低海拔)采集铁杉、岷江冷杉、紫果云杉,海拔4000 m左右林线位置(高海拔)采集岷江冷杉、四川红杉,共计182棵树木年轮样芯,建立了不同树种的树轮宽度年表,对不同树种的年轮指数与各月气候因子进行相关分析.结果表明:在低海拔处,树木生长与4、5月气温呈负相关,与4、5月降雨呈正相关,受到春季干旱胁迫的影响;但树种之间存在显著差异:铁杉的生长受春季干旱胁迫影响最严重,岷江冷杉次之,紫果云杉所受影响很小.在高海拔处,树木生长主要受生长季温度的影响,岷江冷杉年轮指数与当年2、7月最低气温呈显著正相关,与上一年10月最高气温亦呈正相关;四川红杉年轮指数与5月最高气温呈显著正相关,但与2月均温、3月最低气温呈显著负相关.近几十年青藏高原东北缘气候有干暖化趋势,如果这种趋势持续发生,低海拔紫果云杉长势将超过铁杉和岷江冷杉;高海拔处的升温更有利于岷江冷杉的生长.
In order to analyze the response of tree species growth to climate change in semi-humid areas on the eastern margin of Qinghai-Tibet Plateau, hemlock, Minjiang fir and purple spruce were collected at about 3000 m altitude A total of 182 tree-ring-like cores were collected from Minjiang River fir and Sichuan Sequoia at the location of the upper and lower reaches of the forest (altitude), and the tree-ring width chronologies of different tree species were established. The annual ring indices of different tree species were correlated with the monthly climatic factors The results showed that at low altitude, the tree growth was negatively correlated with the temperature in April and May, positively correlated with the rainfall in April and May, and was affected by spring drought stress. However, there were significant differences among the species: the growth of hemlock Affected by the spring drought stress, the Minjiang fir was the second, and the purple spruce affected little.At the high altitude, the growth of trees was mainly affected by the temperature of the growing season, and the annual index of Minjiang fir was the lowest in February and July of that year There was a positive correlation between the temperature and the maximum temperature in October of last year. The index of annual rings of the red senescence in Sichuan showed a significant positive correlation with the maximum temperature in May, but negatively correlated with the average temperature in February and the minimum temperature in March. Qinghai-Tibet Plateau in recent decades Northern margin of the dry climate warming trend, if the trend continues, the low altitude purple fruit spruce and hemlock growing more than Minjiang fir; heating at high altitude is more conducive to the growth of the Minjiang fir.