hydraulics_defoliation: Hydraulic-related defoliation

In medfate: Mediterranean Forest Simulation

Hydraulic-related defoliation

Description

Functions to calculate the proportion of crown defoliation due to hydraulic disconnection.

Usage

hydraulics_proportionDefoliationSigmoid(
  psiLeaf,
  P50,
  slope,
  criticalLeafPLC = 0.88,
  cvLeafP50 = 10
)

hydraulics_proportionDefoliationWeibull(
  psiLeaf,
  c,
  d,
  criticalLeafPLC = 0.88,
  cvLeafP50 = 10
)

Arguments

psiLeaf	Leaf water potential (in MPa).
P50, slope	Parameters of the Sigmoid function.
criticalLeafPLC	Critical leaf PLC corresponding to defoliation
cvLeafP50	Coefficient of variation (in percent) of leaf P50, to describe the variability in hydraulic vulnerability across crown leaves.
c, d	Parameters of the Weibull function.

Details

The functions assume that crowns are made of a population of leaves whose hydraulic vulnerability (i.e. the water potential corresponding to 50% loss of conductance) follows a Gaussian distribution centered on the input P50 and with a known coefficient of variation (cvLeafP50). The slope parameter (or the c exponent in the case of a Weibull function) is considered constant. Leaves are hydraulically disconnected, and shedded, when their embolism rate exceeds a critical value (criticalLeafPLC).

Value

The proportion of crown defoliation.

Author(s)

Hervé Cochard, INRAE

Miquel De Cáceres Ainsa, CREAF

See Also

hydraulics_conductancefunctions

medfate documentation built on Sept. 3, 2026, 9:06 a.m.