Interspecific variation in the timing and magnitude of hydraulic redistribution in a forest with distinct water sources

Journal Article · 18 February 2022 · Plant and Soil

DOI: https://doi.org/10.1007/s11104-021-05253-9 · OSTI ID:1900222

Belovitch, Michael  ^[1]; Brantley, Steven ^[2]; Aubrey, Doug P. ^[3]

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1. Univ. of Georgia, Athens, GA (United States); Univ. of Georgia, Aiken, SC (United States); The Jones Center at Ichauway, Newton, GA (United States); Odum School of Ecology, Athens, GA (United States); University of Georgia Savannah River Ecology Laboratory
2. The Jones Center at Ichauway, Newton, GA (United States)
3. Univ. of Georgia, Athens, GA (United States); Univ. of Georgia, Aiken, SC (United States)

Trees regulate water availability among their rooting strata through a nocturnal, passive transference of water known as hydraulic redistribution (HR). This study investigates differences in HR and groundwater use among common canopy species in longleaf pine (Pinus palustris Mill., Pinaceae) woodlands and explores environmental factors influencing HR. HR was estimated by sap flux of lateral roots and main stems of three mature canopy species (P. palustris, Quercus laevis Walter., Fagaceae and Quercus margarettae Ashe., Fagaceae). We used δ18O and δD of xylem water, soil water, and groundwater to determine water source. Finally, we related HR to environmental factors (Temperature, VWC, VPD) to better understand controls of HR dynamics. Pinus palustris had higher water use than either Quercus species, and also redistributed significantly more water as a nocturnal subsidy. HR fluxes were inversely related with mean nightly temperature and independent of shallow soil moisture. Stable isotope mixing models, based on δ¹⁸O and δD, indicated that all species have access to groundwater, but utilized shallow soil water in differing amounts when available. In systems with strong water potential gradients among soil strata, any species with access to a groundwater source is likely capable of HR; however, the magnitude of HR varies significantly by species, even among closely related taxa.

• Research Organization: Savannah River Ecology Laboratory (SREL), Aiken, SC (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: EM0005228
• OSTI ID: 1900222
• Journal Information: Plant and Soil, Journal Name: Plant and Soil Journal Issue: 1-2 Vol. 472; ISSN 0032-079X
• Publisher: Springer NatureCopyright Statement
• Country of Publication: United States
• Language: English