TY - JOUR
T1 - Forest system hydraulic conductance
T2 - partitioning tree and soil components
AU - Binks, Oliver
AU - Cernusak, Lucas A.
AU - Liddell, Michael
AU - Bradford, Matt
AU - Coughlin, Ingrid
AU - Carle, Hannah
AU - Bryant, Callum
AU - Dunn, Elliot
AU - Oliveira, Rafael
AU - Mencuccini, Maurizio
AU - Meir, Patrick
N1 - Publisher Copyright:
© 2021 The Authors. New Phytologist © 2021 New Phytologist Foundation
PY - 2022/2
Y1 - 2022/2
N2 - Soil–leaf hydraulic conductance determines canopy–atmosphere coupling in vegetation models, but it is typically derived from ex-situ measurements of stem segments and soil samples. Using a novel approach, we derive robust in-situ estimates for whole-tree conductance (ktree), ‘functional’ soil conductance (ksoil), and ‘system’ conductance (ksystem, water table to canopy), at two climatically different tropical rainforest sites. Hydraulic ‘functional rooting depth’, determined for each tree using profiles of soil water potential (Ψsoil) and sap flux data, enabled a robust determination of ktree and ksoil. ktree was compared across species, size classes, seasons, height above nearest drainage (HAND), two field sites, and to alternative representations of ktree; ksoil was analysed with respect to variations in site, season and HAND. ktree was lower and changed seasonally at the site with higher vapour pressure deficit (VPD) and rainfall; ktree differed little across species but scaled with tree circumference; rsoil (1/ksoil) ranged from 0 in the wet season to 10× less than rtree (1/ktree) in the dry season. VPD and not rainfall may influence plot-level k; leaf water potentials and sap flux can be used to determine ktree, ksoil and ksystem; Ψsoil profiles can provide mechanistic insights into ecosystem-level water fluxes.
AB - Soil–leaf hydraulic conductance determines canopy–atmosphere coupling in vegetation models, but it is typically derived from ex-situ measurements of stem segments and soil samples. Using a novel approach, we derive robust in-situ estimates for whole-tree conductance (ktree), ‘functional’ soil conductance (ksoil), and ‘system’ conductance (ksystem, water table to canopy), at two climatically different tropical rainforest sites. Hydraulic ‘functional rooting depth’, determined for each tree using profiles of soil water potential (Ψsoil) and sap flux data, enabled a robust determination of ktree and ksoil. ktree was compared across species, size classes, seasons, height above nearest drainage (HAND), two field sites, and to alternative representations of ktree; ksoil was analysed with respect to variations in site, season and HAND. ktree was lower and changed seasonally at the site with higher vapour pressure deficit (VPD) and rainfall; ktree differed little across species but scaled with tree circumference; rsoil (1/ksoil) ranged from 0 in the wet season to 10× less than rtree (1/ktree) in the dry season. VPD and not rainfall may influence plot-level k; leaf water potentials and sap flux can be used to determine ktree, ksoil and ksystem; Ψsoil profiles can provide mechanistic insights into ecosystem-level water fluxes.
UR - http://www.scopus.com/inward/record.url?scp=85121439736&partnerID=8YFLogxK
U2 - 10.1111/nph.17895
DO - 10.1111/nph.17895
M3 - Article
SN - 0028-646X
VL - 233
SP - 1667
EP - 1681
JO - New Phytologist
JF - New Phytologist
IS - 4
ER -