Video and Data for 'Branch Orientation: A Potential Indicator of Stem Rehydration and Water Stress'

Stem rehydration and water stress are critical ecohydrological processes in temperate and boreal forests, shaping seasonal water balance and productivity. In snow‑dominated systems, the timing of rehydration signals the transition from winter dormancy to spring growth, yet low‑cost field indicators remain scarce. This dataset documents synchronous stem radius changes and branch posture dynamics in balsam fir (Abies balsamea) during early and late spring (March–May 2022) in the Harp‑4 catchment, Muskoka River Watershed, Ontario, Canada (45°22′N, 79°6′W). High‑frequency dendrometer data were combined with time‑lapse imagery to capture freeze–thaw cycles, snowmelt recharge, and rainfall events, with supporting meteorological data from the Dorset Environmental Science Centre. The repository includes the final compiled video (integrating imagery, dendrometer, and environmental data), processed dendrometer time series, and the code used for visualization. These data provide evidence that branch posture can serve as a qualitative, low‑cost indicator of stem rehydration and subsurface water availability, with further research encouraged across species and forest types. Specifically, this repository contains: README.txt (metadata and processing details) Nehemy_Hackmann_McDonnell_VideoTimelapse_Harp4_Waving_Trees.MP4 (time-lapse video documentation) Harp4_Dendrometer-radius_2022.csv (stem radius time series) RScript-Dendrometer_animation-Nehemy_Hackmann_McDonnell_2025 (.RScript) This dataset was used in the following publication:Nehemy, M. F., Hackmann, C., McDonnell, J.J. Branch Orientation: A Potential Indicator of Stem Rehydration and Water Stress. Hydrological Processes. Article DOI:10.1002/hyp.70389 Magali F. Nehemy and Christina A. Hackmann contributed equally to this study. For inquiries regarding data use, please contact Magali Nehemy ([e-mail]). This work was conducted on the traditional territory of the Anishinaabeg, including the Ojibway, Chippewa, and Algonquin peoples, whose care for this land continues to guide us. We thank Dr. Barbara (Moktthewenkwe) Wall for sharing her knowledge of the trees and waters, Huaxia Yao (Dorset Environmental Science Centre) for meteorological data, and Jim Buttle for early conversations on Harp‑4. Support was provided by the NSERC Discovery Grant Program (MFN, JJM) and the Dorothea Schlözer Program, University of Göttingen (CAH).