近51a来额济纳旗绿洲胡杨年生长期对气候变化的响应

Response of Populus Euphratica′s Annual Growth Period to Climate Change in Ejina Banner′s Oasis over the Last 51 Years

利用额济纳旗绿洲胡杨林分布区内的气象站点1960—2010年的日平均气温和日平均最低、最高气温的数据,采用气候倾向率和相关分析等方法,研究了胡杨年生长期开始日、终止日、生长期天数、展叶始期、叶黄始日的变化特征及其对气候变化的响应。结果表明,近51a来研究区胡杨年生长期有开始日提早,终止日推后,年生长期延长,展叶始期提前,叶黄始日微推后的变化趋势。相关分析结果显示,胡杨年生长期开始日受3月平均气温影响最大,终止日受10月平均气温影响最大,胡杨生长期与3—11月平均气温呈显著正相关关系。4月平均气温对胡杨展叶始期的影响最大,且展叶始期与4月平均温度的负相关关系最显著,相关系数达0.678 2(α=0.001)。胡杨叶黄始日受9月平均气温的影响最大,且平均气温越高,胡杨叶黄始日越推迟。可见,研究区内胡杨对气候变化的响应比较明显。

Based on the average daily temperature, average daily maximum and minimum temperature data from the weather stations of Ejina Banner in the oasis of Ejina Banner in the 1960-2010s, the methods like s climate trending rate and correlation analysis were used to analyze the varying characteristics of beginning and ending dates of annual growth period, day number of growth period, and beginning dates of leaf expansion and yellow leaf stage for the Populus euphratica, as well as its response to climate change. Results showed that in the recent 51 years, the beginning date of annual growth was becoming earlier, but the ending date was becoming later; the annual growth period was prolonged; and the beginning date of leaf unfolding was becoming earlier and the beginning date of yellow leaf stage, slightly later. Correlation analysis shows that the beginning date of annual growth was greatly influenced by the average temperature in March and the ending date, by the average temperature in October. There was a significantly positive correlation between the growth period and the average temperature from March to November. The average temperature in April had a significant influence on the beginning date of leaf unfolding, and the correlation between them was negative with a correlation coefficient as high as 0. 678 2（a=0. 001）. The average temperature in September had a maximum influence on the beginning date of yellow leaf stage. The higher average temperature in September, the later the beginning date of yellow leaf stage was. Therefore, there was an obvious response of the Populus euphratica to climate change in the study area.