medfate (version 2.8.0)

fordyn: Forest dynamics

Description

Function fordyn implements a forest dynamics model that simulates growth, mortality, recruitment and (optionally) management actions in a given forest stand during a period specified in the input climatic data.

Usage

fordyn(forest, soil, SpParams, meteo, control,
       latitude , elevation = NA, slope = NA, aspect = NA,
       CO2ByYear = numeric(0),
       management_function = NULL, management_args = NULL)

Value

A list of class 'fordyn' with the following elements:

• "StandSummary": A data frame with stand-level summaries (tree basal area, tree density, shrub cover, etc.) at the beginning of the simulation and after each simulated year.

• "SpeciesSummary": A data frame with species-level summaries (tree basal area, tree density, shrub cover, etc.) at the beginning of the simulation and after each simulated year.

• "CohortSummary": A data frame with cohort-level summaries (tree basal area, tree density, shrub cover, etc.) at the beginning of the simulation and after each simulated year.

• "TreeTable": A data frame with tree-cohort data (species, density, diameter, height, etc.) at the beginning of the simulation (if any) and after each simulated year.

• "DeadTreeTable": A data frame with dead tree-cohort data (species, density, diameter, height, etc.) at the beginning of the simulation and after each simulated year.

• "CutTreeTable": A data frame with cut tree data (species, density, diameter, height, etc.) after each simulated year.

• "ShrubTable": A data frame with shrub-cohort data (species, density, cover, height, etc.) at the beginning of the simulation and after each simulated year.

• "DeadShrubTable": A data frame with dead shrub-cohort data (species, density, cover, height, etc.) at the beginning of the simulation (if any) and after each simulated year.

• "CutShrubTable": A data frame with cut shrub data (species, density, cover, height, etc.) after each simulated year.

• "ForestStructures": A list with the forest object of the stand at the beginning of the simulation and after each simulated year.

• "GrowthResults": A list with the results of calling function growth for each simulated year.

• "ManagementArgs": A list of management arguments to be used in another call to fordyn.

• "NextInputObject": An object of class growthInput to be used in a subsequent simulation.

• "NextForestObject": An object of class forest to be used in a subsequent simulation.

Arguments

forest

An object of class forest. Alternatively, the output of a previous run, if continuing a previous simulation.

soil

An object of class soil.

SpParams

A data frame with species parameters (see SpParamsMED and SpParamsDefinition).

meteo

A data frame with daily meteorological data series. Row names of the data frame should correspond to date strings with format "yyyy-mm-dd" (see Date).

control

A list with default control parameters (see defaultControl).

latitude

Latitude (in degrees). Required when x$TranspirationMode = "Sperry".

elevation, slope, aspect

Elevation above sea level (in m), slope (in degrees) and aspect (in degrees from North). Required when x$TranspirationMode = "Sperry". Elevation is also required for 'Granier' if snowpack dynamics are simulated.

CO2ByYear

A named numeric vector with years as names and atmospheric CO2 concentration (in ppm) as values. Used to specify annual changes in CO2 concentration along the simulation (as an alternative to specifying daily values in meteo).

management_function

A function that implements forest management actions (see details).

management_args

A list of additional arguments to be passed to the management_function.

Author

Miquel De Cáceres Ainsa, CREAF

Details

Function fordyn simulates forest dynamics for annual time steps, building on other simulation functions. For each simulated year, the function performs the following steps:

1. Calls function growth to simulate daily water/carbon balance, growth and mortality processes and update the forest object.

2. If required, calls function management_function, using as parameters the forest object and management_args, which may result in a density reduction for existing plant cohorts and/or a set of new planted cohorts.

3. Simulate natural recruitment (for species present in the stand or given in a seed rain input).

4. Prepares the input of function growth for the next annual time step.

5. Store forest status, management arguments, and summaries.

To enable forest management, the user needs to provide a function that implements it, which is passed to fordyn via its argument management_function. Such function should have the following arguments:

• "x": the forest object representing the stand to be managed.

• "args": a list of parameters regulating the behavior of the management function.

• "verbose": a logical flag to enable console output during the execution of the management function.

and return a list with the following elements:

• "action": A string identifying the action performed (e.g. "thinning").

• "N_tree_cut": A vector with the density of trees removed.

• "Cover_shrub_cut": A vector with the cover of shrubs removed.

• "planted_forest": An object of class forest with the new plant cohorts resulting from tree/shrub planting.

• "management_args": A list of management arguments to be used in the next call to the management function.

An example of management function is provided in defaultManagementFunction.

See Also

growth, recruitment, plot.growth, defaultManagementFunction

Examples

if (FALSE) {
#Load example daily meteorological data
data(examplemeteo)
#Prepare a two-year meteorological data with half precipitation during 
#the second year
meteo2001 = examplemeteo
meteo2002 = examplemeteo
meteo2002$Precipitation = meteo2002$Precipitation/2
row.names(meteo2002) = seq(as.Date("2002-01-01"), 
                           as.Date("2002-12-31"), by="day")
meteo_01_02 = rbind(meteo2001, meteo2002)

#Load example plot plant data
data(exampleforestMED)

#Default species parameterization
data(SpParamsMED)

#Initialize control parameters
control = defaultControl("Granier")

#Initialize soil with default soil params (4 layers)
examplesoil = soil(defaultSoilParams(4))

#Call simulation function
fd<-fordyn(exampleforestMED, examplesoil, 
           SpParamsMED, meteo_01_02, control,
           latitude = 41.82592, elevation = 100)

#Stand-level summaries
fd$StandSummary

#Tree table by annual steps
fd$TreeTable

#Dead tree table by annual steps
fd$DeadTreeTable
}