河道断流对胡杨(Populus euphratica)径向生长量的影响

Comparison of Tree-ring Growth of Populus euphratica under Long-term Zero Flow Condition in the Lower Reaches of the Tarim River

以塔里木河下游胡杨(Populus euphratica)为研究对象,基于树木年轮学的方法,借助小波分析法与Mann-Kendall、Mann-Whitney检验方法,将不断流条件下的树木年轮径向生长量作为对照,分析了塔里木河下游河道长期断流条件下胡杨径向生长量的变化特征,并进行了趋势检验及突变检验。结果表明:(1)塔里木河下游生态输水使树木年轮生长发生了良性转变;(2)1972年塔里木河下游断流以来,1970—1999年期间,英苏、喀尔达依、阿拉干、依干不及麻断面的胡杨径向生长量的变化呈缓慢变化的趋势,整个变化是长期的、缓慢的过程,而不是迅速的、突变性的;(3)生态输水对树木年轮生长的影响是人为作用下的短期的突变过程;(4)与长期断流相比,在不断流条件下,从1970年到2009年,胡杨径向生长量呈有规律的升降交替的变化趋势;在长时期序列(1962—2008年)下,胡杨径向生长量以25年周期变化,大周期(25年)内又包含着小周期(11年与5年)。

We analyzed the variation trend in radial increment of Populus euphratica under conditions of long-term zero flow in the lower reaches of the Tarim River through methods of wavelet analysis and Mann- Kendall, Mann-Whitney trend test. The results are as follow： （1） Benign changing of tree-ring width in the lower reaches of the Tarim River occurs because of the ecological water conveyance. （2） There is a slowly decreased trend in radial increment of Populus euphratica in Yinsu, Kardayi, Alagan and Yiganbjm transects, because of the zero flow in the lower reaches of the Tarim River in 1970--1999, the whole variation is a long-term and slow process, rather than rapid changes, nor has the mutation. （3） There is a short-term and mutation influence in human factors on radial increment, such as the ecological water conveyance. （4） Compared with the zero flow condition, under the condition of non-zero flow, the regular alternate trend of rise and fall presented in tree-ring width in 1970-- 2009 ; Under long series （ 1962-- 2009）, tree-ring width variation takes on 25-year cycle, large cycle （25-year） include small cycle （11-year and 5-year）.