hydraulics_scalingconductance: Scaling from conductivity to conductance

In medfate: Mediterranean Forest Simulation

Scaling from conductivity to conductance

Description

Functions used to scale from tissue conductivity to conductance of different elements of the continuum.

Usage

hydraulics_maximumSoilPlantConductance(krhizomax, krootmax, kstemmax, kleafmax)

hydraulics_soilPlantResistances(
  psiSoil,
  psiRhizo,
  psiStem,
  PLCstem,
  psiLeaf,
  krhizomax,
  n,
  alpha,
  krootmax,
  rootc,
  rootd,
  kstemmax,
  stemc,
  stemd,
  kleafmax,
  leafc,
  leafd
)

hydraulics_averageRhizosphereResistancePercent(
  krhizomax,
  n,
  alpha,
  krootmax,
  rootc,
  rootd,
  kstemmax,
  stemc,
  stemd,
  kleafmax,
  leafc,
  leafd,
  psiStep = -0.01
)

hydraulics_findRhizosphereMaximumConductance(
  averageResistancePercent,
  n,
  alpha,
  krootmax,
  rootc,
  rootd,
  kstemmax,
  stemc,
  stemd,
  kleafmax,
  leafc,
  leafd,
  initialValue = 0
)

hydraulics_taperFactorSavage(height)

hydraulics_terminalConduitRadius(height)

hydraulics_referenceConductivityHeightFactor(refheight, height)

hydraulics_maximumStemHydraulicConductance(
  xylemConductivity,
  refheight,
  Al2As,
  height,
  taper = FALSE
)

hydraulics_rootxylemConductanceProportions(L, V)

Arguments

krhizomax	Maximum rhizosphere hydraulic conductance (defined as flow per leaf surface unit and per pressure drop).
krootmax	Maximum root xylem hydraulic conductance (defined as flow per leaf surface unit and per pressure drop).
kstemmax	Maximum stem xylem hydraulic conductance (defined as flow per leaf surface unit and per pressure drop).
kleafmax	Maximum leaf hydraulic conductance (defined as flow per leaf surface unit and per pressure drop).
psiSoil	Soil water potential (in MPa). A scalar or a vector depending on the function.
psiRhizo	Water potential (in MPa) in the rhizosphere (root surface).
psiStem	Water potential (in MPa) in the stem.
PLCstem	Percent loss of conductance (in %) in the stem.
psiLeaf	Water potential (in MPa) in the leaf.
n, alpha	Parameters of the Van Genuchten function (rhizosphere vulnerability curve).
rootc, rootd	Parameters of the Weibull function for roots (root xylem vulnerability curve).
stemc, stemd	Parameters of the Weibull function for stems (stem xylem vulnerability curve).
leafc, leafd	Parameters of the Weibull function for leaves (leaf vulnerability curve).
psiStep	Water potential precision (in MPa).
averageResistancePercent	Average (across water potential values) resistance percent of the rhizosphere, with respect to total resistance (rhizosphere + root xylem + stem xylem).
initialValue	Initial value of rhizosphere conductance.
height	Plant height (in cm).
refheight	Reference plant height of measurement of xylem conductivity (in cm).
xylemConductivity	Xylem conductivity as flow per length of conduit and pressure drop (in kg·m-1·s-1·MPa-1).
Al2As	Leaf area to sapwood area (in m2·m-2).
taper	A boolean flag to indicate correction by taper of xylem conduits (Christoffersen et al. 2017).
L	Vector with the length of coarse roots (mm) for each soil layer.
V	Vector with the proportion [0-1] of fine roots within each soil layer.

Details

Details of the hydraulic model are given in the medfate book

Value

Values returned for each function are:

• hydraulics_maximumSoilPlantConductance: The maximum soil-plant conductance, in the same units as the input segment conductances.

• hydraulics_averageRhizosphereResistancePercent: The average percentage of resistance due to the rhizosphere, calculated across water potential values.

• hydraulics_findRhizosphereMaximumConductance: The maximum rhizosphere conductance value given an average rhizosphere resistance and the vulnerability curves of rhizosphere, root and stem elements.

• hydraulics_taperFactorSavage: Taper factor according to Savage et al. (2010).

Author(s)

Miquel De Cáceres Ainsa, CREAF

References

Christoffersen, B. O., M. Gloor, S. Fauset, N. M. Fyllas, D. R. Galbraith, T. R. Baker, L. Rowland, R. A. Fisher, O. J. Binks, S. A. Sevanto, C. Xu, S. Jansen, B. Choat, M. Mencuccini, N. G. McDowell, and P. Meir. 2016. Linking hydraulic traits to tropical forest function in a size-structured and trait-driven model (TFS v.1-Hydro). Geoscientific Model Development Discussions 9: 4227–4255.

Savage, V. M., L. P. Bentley, B. J. Enquist, J. S. Sperry, D. D. Smith, P. B. Reich, and E. I. von Allmen. 2010. Hydraulic trade-offs and space filling enable better predictions of vascular structure and function in plants. Proceedings of the National Academy of Sciences of the United States of America 107:22722–7.

Olson, M.E., Anfodillo, T., Rosell, J.A., Petit, G., Crivellaro, A., Isnard, S., León-Gómez, C., Alvarado-Cárdenas, L.O., and Castorena, M. 2014. Universal hydraulics of the flowering plants: Vessel diameter scales with stem length across angiosperm lineages, habits and climates. Ecology Letters 17: 988–997.

See Also

hydraulics_psi2K, hydraulics_supplyFunctionPlot, spwb, soil

medfate documentation built on Aug. 29, 2023, 5:07 p.m.