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Variability of tree transpiration across three zones in a southeastern U.S. Piedmont watershed

Publication ,  Journal Article
Boggs, JL; Sun, G; Domec, JC; McNulty, SG
Published in: Hydrological Processes
October 1, 2021

Quantifying the spatial variability of species-specific tree transpiration across hillslopes is important for estimating watershed-scale evapotranspiration (ET) and predicting spatial drought effects on vegetation. The objectives of this study are to (1) assess sap flux density (Js) and tree-level transpiration (Ts) across three contrasting zones a (riparian buffer, mid-hillslope and upland-hillslope, (2) determine how species-specific Js responds to vapour pressure deficit (VPD) and (3) estimate watershed-level transpiration (Tw) using Ts derived from each zone. During 2015 and 2016, we measured Js in eight tree species in the three topographic zones in a small 12-ha forested watershed in the Piedmont region of central North Carolina. In the dry year of 2015, loblolly pine (Pinus taeda), Virginia pine (Pinus virginiana) and sweetgum (Liquidambar styraciflua) Js rates were significantly higher in the riparian buffer when compared to the other two zones. In contrast, Js rates in tulip poplar (Liriodendron tulipifera) and red maple (Acer rubrum) were significantly lower in the buffer than in the mid-hillslope. Daily Ts varied by zone and ranged from 10 to 93 L/day in the dry year and from 9 to 122 L/day in the wet year (2016). Js responded nonlinearly to VPD in all species and zones. Annual Tw was 447, 377 and 340 mm based on scaled-Js data for the buffer, mid-hillslope and upland-hillslope, respectively. We conclude that large spatial variability in Js and scaled Tw was driven by differences in soil moisture at each zone and forest composition. Consequently, spatial heterogeneity of vegetation and soil moisture must be considered when accurately quantifying watershed level ET.

Duke Scholars

Published In

Hydrological Processes

DOI

EISSN

1099-1085

ISSN

0885-6087

Publication Date

October 1, 2021

Volume

35

Issue

10

Related Subject Headings

  • Environmental Engineering
  • 4005 Civil engineering
  • 3709 Physical geography and environmental geoscience
  • 3707 Hydrology
  • 0907 Environmental Engineering
  • 0905 Civil Engineering
  • 0406 Physical Geography and Environmental Geoscience
 

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Boggs, J. L., Sun, G., Domec, J. C., & McNulty, S. G. (2021). Variability of tree transpiration across three zones in a southeastern U.S. Piedmont watershed. Hydrological Processes, 35(10). https://doi.org/10.1002/hyp.14389
Boggs, J. L., G. Sun, J. C. Domec, and S. G. McNulty. “Variability of tree transpiration across three zones in a southeastern U.S. Piedmont watershed.” Hydrological Processes 35, no. 10 (October 1, 2021). https://doi.org/10.1002/hyp.14389.
Boggs JL, Sun G, Domec JC, McNulty SG. Variability of tree transpiration across three zones in a southeastern U.S. Piedmont watershed. Hydrological Processes. 2021 Oct 1;35(10).
Boggs, J. L., et al. “Variability of tree transpiration across three zones in a southeastern U.S. Piedmont watershed.” Hydrological Processes, vol. 35, no. 10, Oct. 2021. Scopus, doi:10.1002/hyp.14389.
Boggs JL, Sun G, Domec JC, McNulty SG. Variability of tree transpiration across three zones in a southeastern U.S. Piedmont watershed. Hydrological Processes. 2021 Oct 1;35(10).
Journal cover image

Published In

Hydrological Processes

DOI

EISSN

1099-1085

ISSN

0885-6087

Publication Date

October 1, 2021

Volume

35

Issue

10

Related Subject Headings

  • Environmental Engineering
  • 4005 Civil engineering
  • 3709 Physical geography and environmental geoscience
  • 3707 Hydrology
  • 0907 Environmental Engineering
  • 0905 Civil Engineering
  • 0406 Physical Geography and Environmental Geoscience