Response of Radial Increment of Populus euphratica to Ecological Water Conveyance in Lower Reaches of the Tarim River

The Tarim River Basin,located in Xinjiang Uygur Autonomous Region in northwest China,is the largest inland river basin in China.The ecological process here has undergone great changes due to human disturbance over the past 50 years.In order to rescue the strategic green corridor in lower reaches of the Tarim River,ecological water conveyance has been bring into effect from May 14th,2000.By using dendrohydtology for reference and taking single factor analysis of variance,the authors researched how Populus euphratica's growth rings responded to the ecological water conveyance.The results showed that within the distance of 300 m to the river,the radial increment of Populus euphratica is highly different at significant level 0.001;on the contrary,beyond 300 m to the river,the difference of radial increment of Populus euphratica isn't significant at level 0.05.That means Populus euphratica within 300 m range to the river would respond more positively to the water conveyance than those beyond 300 m.By this token,although the linear conveyance can alleviate vegetation decline near watercourses,and partly improve the entironment,it is unable to hold back the whole deteriorated ecosystem along the Tarim River.