Tree-ring width measurements and isotope data for riparian Populus species, Santa Clara River, 2019

This data set comprises tree-ring data collected from 114 cottonwood trees (Populus trichocarpa and Populus fremontii) within the floodplain of the Santa Clara River, CA. Tree-ring data include annual ring width measurements for all rings of each individual as well as semi-annual (earlywood and latewood) measurements of stable carbon and oxygen isotopes for pure alpha cellulose extracted from annual growth rings corresponding to calendar years 2010-2019 for a subset of 48 individuals. This data set is completed. Carbon and oxygen isotope ratios are reported using “delta” notation (i.e. δ13C and δ18O) calculated by the equation: δ13C (or δ18O) = (Rsample/Rstandard - 1) x1000 where R is the molar ratio of 13C/12C (or 18O/16O), with Rsample being that of tree ring cellulose and Rstandard that of Vienna Pee Dee Belemite (VPDB) for δ13C and Vienna Standard Mean Ocean Water (VSMOW) for δ18O. These data were used for the following publication: Williams, J., J.C. Stella, S.L. Voelker, A.M. Lambert, L. Pelletier, J.E. Drake, J.M. Friedman, D.A. Roberts, M.B. Singer. (2022). Local groundwater decline exacerbates response of dryland riparian woodlands to climatic drought. Global Change Biology.

本数据集包含采自美国加利福尼亚州圣克拉拉河泛滥平原的114株棉白杨（三角叶杨Populus trichocarpa与弗里蒙特杨Populus fremontii）的树木年轮数据。其中，树木年轮数据涵盖每株个体所有年轮的年宽度测量值；此外，针对48株子样本个体2010至2019年对应日历年份的年轮，本数据集还提供了从其年轮中提取的纯α纤维素的半年度（早材与晚材）稳定碳、氧同位素测量值。本数据集已完整收录完毕。碳、氧同位素比值采用δ记法（即δ¹³C与δ¹⁸O）报告，计算公式为：δ¹³C（或δ¹⁸O）=(R样本/R标准品 - 1)×1000，其中R为¹³C/¹²C（或¹⁸O/¹⁶O）的摩尔比，R样本为树木年轮纤维素的同位素比值，R标准品对于δ¹³C为维也纳佩德贝莱迈特（VPDB），对于δ¹⁸O为维也纳标准平均海水（VSMOW）。本数据集相关数据曾用于以下发表成果：Williams, J.、J.C. Stella、S.L. Voelker、A.M. Lambert、L. Pelletier、J.E. Drake、J.M. Friedman、D.A. Roberts、M.B. Singer. (2022). 局地地下水衰减加剧旱地河岸林对气候干旱的响应. 全球变化生物学（Global Change Biology）。