Yaning Chen Yapeng Chen Jonathan M. Friedman Gonghuan Fan Jarre Heng A. Hati Shubao Liu 2015 <p class="p1"><span class="s1">Investigation of the water sources used by trees of different ages is essential to formulate a conservation strategy for the riparian tree, <i>P</i>. <i>euphratica</i>. This study addressed the contributions of different potential water sources to <i>P</i>. <i>euphratica</i> based on levels of stable oxygen and hydrogen isotopes (&delta;</span><span class="s2">18</span><span class="s1">O, &delta;</span><span class="s2">2</span><span class="s1">H) in the xylem of different aged <i>P</i>. <i>euphratica</i>, as well as in soil water and groundwater along the lower Heihe River. We found significant differences in &delta;</span>^{<span class="s2">18</span>}<span class="s1">O values in the xylem of different aged <i>P</i>. <i>euphratica</i>. Specifically, the &delta;</span>^{<span class="s2">18</span>}<span class="s1">O values of young, mature and over-mature forests were &minus;5.368(&plusmn;0.252)&nbsp;&permil;, &minus;6.033(&plusmn;&nbsp;0.185)&nbsp;&permil; and &minus;6.924&nbsp;(&plusmn;&nbsp;0.166)&nbsp;&permil;, respectively, reflecting the reliance of older trees on deeper sources of water with a &delta;</span>^{<span class="s2">18</span>}<span class="s1">O value closer to that of groundwater. Different aged <i>P</i>. <i>euphratica</i> used different water sources, with young forests rarely using groundwater (mean &lt;15&nbsp;%) and instead primarily relying on soil water from a depth of 0&ndash;50&nbsp;cm (mean &gt;45&nbsp;%), and mature and over-mature forests using water from deeper than 100&nbsp;cm derived primarily from groundwater.</span></p> application/pdf 10.1007/s11284-015-1270-6 en Springer Japan Use of ²H and ¹⁸O stable isotopes to investigate water sources for different ages of <i>Populus euphratica</i> along the lower Heihe River article