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,
  PLC_crit = 0.88,
  P50_cv = 10
)

hydraulics_proportionDefoliationWeibull(
  psiLeaf,
  c,
  d,
  PLC_crit = 0.88,
  P50_cv = 10
)

Arguments

psiLeaf	Leaf water potential (in MPa).
P50, slope	Parameters of the Sigmoid function.
PLC_crit	Critical leaf PLC corresponding to defoliation
P50_cv	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 follows a Gaussian distribution centered on the input P50 and with a known coefficient of variation (P50_cv). 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 (PLC_crit).

Value

The proportion of crown defoliation.

Author(s)

Hervé Cochard, INRAE

Miquel De Cáceres Ainsa, CREAF

See Also

hydraulics_conductancefunctions

medfate documentation built on April 4, 2025, 2:01 a.m.