Stand structure and productivity of Populus euphratica along a gradient of groundwater distances at the tarim River(NW china)

作     者：Frank M.Thomas Michael Jeschke Ximing Zhang Petra Lang 

作者机构：GeobotanyFaculty of Regional and Environmental SciencesUniversity of TrierBehringstraße 2154296 TrierGermany Xinjiang Institute of Ecology and GeographyChinese Academy of Sciences40 South Beijing Road830011 UrumqiChina 

出 版 物：《Journal of Plant Ecology》 (植物生态学报（英文版）)

年 卷 期：2017年第10卷第5期

页      面：753-764页

核心收录：

学科分类：081803[工学-地质工程] 08[工学] 0818[工学-地质资源与地质工程] 

基　　金：German Federal Ministry of Education and Research(BMBF) Funding Measure‘Sustainable Land Management’(project number:01LL0918K) 

主　　题：allometry ground water life history tree-age distribution tugai forest 

摘      要：Aims Along central-Asian rivers in arid regions,lowering of the ground-water level constitutes a major threat to the riparian forests,whose tree layers are dominated by Euphrates poplar(Populus euphratica).Some of these fragile ecosystems are supplied with additional(‘eco-logical’)water for protection and *** investigated interrelationships among groundwater distance,stand structure and above-ground wood production(at the tree and the stand level)in *** stands along a groundwater gradient(distances of 2.0-12.0 m)that also included a plot supplied with‘ecological water’.Methods We measured the height,diameter at breast height and basal area of poplar trees and determined the annual above-ground wood production for the three most recent years on the basis of tree-ring analyses and allometric regressions at three sites at the upper,mid-dle and lower reaches of the tarim River,Xinjiang,NW *** Findingsthe distribution of age classes differed significantly among the plots:in accordance with their life histories,stands growing at a larger distance to the groundwater harboured a larger fraction of old trees(80 years)and,in most cases,a smaller fraction of young trees(≤20 years).the annual above-ground wood production per ha was highest on a plot with a short groundwater distance(2.0 m;maxi-mum of the 3-year investigation period:3.0 t ha−1 a−1)and lowest,at a plot with a large distance to the water table(6.6 m;minimum:0.23 t ha^(−1)a^(−1)).However,the plot located close to the groundwater(and to the river)at the middle reaches exhibited a relatively large interannual variation in above-ground wood production,which can be attributed to interannual variations in the river *** the middle and the lower reaches,these interannual variations on plots with the most favourable water supply were even more obvious at the tree *** the fraction of mature trees(60-99 years old),no significant differences in above-ground wood production were