Towards Transparency in Sampling for Plant Xylem Water Isotope Studies: Current Practices and New Perspectives

Authors

• Magali F. Nehemy, The University of British Columbia-Okanagan
• Hannes P.T. De Deurwaerder, Virginia Tech
• Ginevra Fabiani, Swiss Federal Research Institute WSL
• Gregory R. Goldsmith, Chapman UniversityFollow
• W. Jesse Hahm, Simon Fraser University
• Danielle Hudson, The University of British Columbia-Okanagan
• Suzanne Jacobs, Justus Liebig University
• Huai Jianjun, Northwest A&F University
• James Knighton, University of Connecticut - Storrs
• Marco M. Lehmann, Swiss Federal Institute for Forest, Snow and Landscape Research WSL
• Pedro A. M. Leite, Stephen F. Austin State University
• Kevin Li, University of Connecticut - Storrs
• Min Li, Northwest A&F University
• Xiuqiang Liu, Umeå University
• Aline Meyer Oliveira, University of Glasgow
• Yunpeng Nie, Chinese Academy of Sciences
• Natalie Orlowski, Dresden University of Technology
• Daniele Penna, University of Florence
• María Poca, Universidad Nacional de San Luis
• Ricardo Sánchez-Murillo, The University of Texas at Arlington
• Hongxiu Wang, University of Saskatchewan
• Mingyi Wen, Northwest A&F University
• Lixin Wang, Indiana University Indianapolis
• Seth E. Younger, University of Georgia
• Giulia Zuecco, University of Padova
• Scott T. Allen, University of Nevada, Reno

Document Type

Article

Publication Date

10-19-2026

Abstract

Xylem water isotope values are widely used to trace plant water sources. However, the sampling decisions that precede extraction are rarely fully reported in isotope studies, limiting reproducibility and cross comparisons. A survey of 42 researchers across five continents, complemented by a virtual community workshop, revealed substantial methodological diversity: only 51% maintain standard operating procedures, with variation in organ selection among respondents (branches 73.8%, stems 64.3%, roots 35.7%), sapwood-heartwood separation (63.2% separate), bark removal (59% always) and transport conditions (56% ice packs vs. 39% ambient). From the surveyed researchers, 77.5% adapt sampling strategies to their extraction system, but these adaptations are rarely documented. This means that reported methods systematically underrepresent the process chain influencing isotopic outcomes. Given that varying circumstances and research objectives might preclude universal standardization, we introduce a Xylem Sampling Form: a structured metadata tool that makes sampling details explicit and comparable across studies without prescribing specific protocols, laying groundwork for future data-driven evaluation of how upstream sampling choices propagate into isotopic uncertainty.

Comments

This article was originally published in Hydrological Processes, volume 40, issue 10, in 2026. https://doi.org/10.1002/hyp.70748

Recommended Citation

Nehemy, M. F., H. P. T. De Deurwaerder, G. Fabiani, et al. 2026. “ Towards Transparency in Sampling for Plant Xylem Water Isotope Studies: Current Practices and New Perspectives.” Hydrological Processes 40, no. 10: e70748. https://doi.org/10.1002/hyp.70748.

Copyright

The authors

Creative Commons License

This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License