utils_rockOptimization: Optimization of rock fragment content

In medfate: Mediterranean Forest Simulation

Optimization of rock fragment content

Description

Function utils_rockOptimization finds optimum rock fragment content in the soil corresponding to given vegetation, weather and target percent loss of conductance (PLC), following a modification of the method proposed by Druel et al. (2023).

Usage

utils_rockOptimization(
  x,
  soil,
  SpParams,
  control,
  meteo,
  PLCquantile = 0.9,
  qPLC_target = 12,
  qPLC_tol = 0.5,
  sew_min = 30,
  max_rocks = 99,
  verbose = FALSE,
  ...
)

Arguments

x	An object of class forest.
soil	An object of class data.frame or soil, containing soil parameters per soil layer.
SpParams	A data frame with species parameters (see SpParamsDefinition and SpParamsMED).
control	A list with default control parameters (see defaultControl).
meteo	A data frame with daily meteorological data series (see spwb).
PLCquantile	Maximum PLC quantile to be calculated across years.
qPLC_target	Target PLC to be achieved (by default 12%).
qPLC_tol	Tolerance of PLC difference to target accepted when finding solution.
sew_min	Minimum soil extractable water (mm) for rock exploration.
max_rocks	Maximum content in coarse fragments allowed for any soil layer.
verbose	A logical value. Print the internal messages of the function?
...	Additional parameters to function spwb.

Details

The function performs a model inversion based on an ecohydrological assumption, consisting in that forest leaf area index is in equilibrium with a low embolism rate under normal conditions. This is translated in that the (by default 90%) interannual quantile of the maximum annual percent loss of conductance (PLC), averaged over plant cohorts, should be close to a target PLC value (by default 12%).

The algorithm first determines the PLC corresponding to the minimum and maximum soil extractable water (SEW). The minimum SEW (SEW_min) is an input parameter, whereas the maximum SEW (SEW_max) corresponds to no rock fragments in the soil.

Then three situations are distinguished:

1. If PLC(SEW_min) < qPLC_target and PLC(SEW_max) < qPLC_target, the function will use uniroot to find the root of the function f(x) = PLC(x) - qPLC_target, where x is SEW, which corresponds to a factor that multiplies the original rock fragment content.

2. If both PLC(SEW_min) < qPLC_target and PLC(SEW_max) < qPLC_target, the function cannot find an optimum, because PLC is always too low, and will return the original rock fragment content

3. Analogously, if both PLC(SEW_min) > qPLC_target and PLC(SEW_max) > qPLC_target, the function cannot find an optimum, because PLC is always too large, and will return the original rock fragment content

Value

Function utils_rockOptimization returns a list containing:

• RFC: A vector with the estimated rock fragment content for each soil layer.

• SEW: Soil extractable water (mm).

• runs: Number of simulations performed.

• message: Text message indicating whether optimization could be done (OK) or not.

Author(s)

Arsène Druel, URFM-INRAE

Nicolas Martin-StPaul, URFM-INRAE

Miquel De Cáceres Ainsa, CREAF

References

Druel, A., Martins, N., Cochard, H., De Caceres, M., Delzon, S., Mencuccini, M., Torres-Ruiz, J., and Ruffault, J.: European forest vulnerability to hydraulic failure: an ecohydrological approach, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-17068, https://doi.org/10.5194/egusphere-egu23-17068, 2023.

See Also

spwb, soil, utils_ldrOptimization

Examples

#Load example daily meteorological data
data(examplemeteo)

#Load example plot plant data
data(exampleforest)

#Default species parameterization
data(SpParamsMED)

#Initialize soil with two layers
examplesoil <- defaultSoilParams(4)

#Rock fragment content optimization (Granier)
utils_rockOptimization(exampleforest, soil = examplesoil,
                       SpParams = SpParamsMED, meteo = examplemeteo,
                       control = defaultControl("Granier"),
                       elevation = 100, latitude = 41.82592)

medfate documentation built on June 8, 2025, 11:43 a.m.