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Default forest management actions

Source: R/defaultManagementFunction.R
defaultManagementFunction.Rd

Function defaultManagementFunction implements actions for 'regular' and 'irregular' management models of monospecific or mixed stands, whereas function defaultManagementArguments returns a list with default values for the parameters regulating management. Both functions are meant to be used in simulations with fordyn.

Usage

defaultManagementFunction(x, args, verbose = FALSE)

defaultManagementArguments()

Arguments

x

An object of class forest

args

A list of arguments regulating management actions, e.g. the list returned by defaultManagementArguments

verbose

A logical flag enabling console printing

Value

Function defaultManagementFunction returns a list with the following items:

  • "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.

Function defaultManagementArguments returns a list with default arguments:

  • "type": Management model, either 'regular' or 'irregular'.

  • "targetTreeSpecies": Either "all" for unspecific cuttings or a numeric vector of target tree species to be selected for cutting operations.

  • "thinning": Kind of thinning to be applied in irregular models or in regular models before the final cuts. Options are 'below', 'above', 'systematic', 'below-systematic', 'above-systematic' or a string with the proportion of cuts to be applied to different diameter sizes (see details).

  • "thinningMetric": The stand-level metric used to decide whether thinning is applied, either 'BA' (basal area), 'N' (density) or 'HB' (Hart-Becking index).

  • "thinningThreshold": The threshold value of the stand-level metric causing the thinning decision.

  • "thinningPerc": Percentage of stand's basal area to be removed in thinning operations.

  • "minThinningInterval": Minimum number of years between thinning operations.

  • "yearsSinceThinning": State variable to count the years since the last thinning ocurred.

  • "finalMeanDBH": Mean DBH threshold to start final cuts.

  • "finalPerc": String with percentages of basal area to be removed in final cuts, separated by '-' (e.g. "40-60-100").

  • "finalPreviousStage": Integer state variable to store the stage of final cuts ('0' before starting final cuts).

  • "finalYearsBetweenCuts": Number of years separating final cuts.

  • "finalYearsToCut": State variable to count the years to be passed before new final cut is applied.

  • "plantingSpecies": Species code to be planted. If missing, planting does not occur and only natural regeneration is allowed.

  • "plantingDBH": Initial DBH (cm) of planted species.

  • "plantingHeight": Initial height (cm) of planted species.

  • "plantingDensity": Initial density (ind./ha) of the planted species.

  • "understoryMaximumCover": Percentage of overall shrub cover to be left after any silvicultural intervention. If missing, shrub cover will not be left unmodified.

Details

This function implements silvicultural actions following either 'regular' or 'irregular' management models. Irregular models are implemented by executing thinning operations only, whereas regular models include both thinning and a set of final cuts. Thinning occurs anytime a stand-level metric (e.g. basal area) crosses a given threshold, and different kinds of thinning operations are allowed. Unrealistic high frequency thinning can be avoided by setting a minimum number of years to happen between thinning operations. Final cuts start whenever mean DBH exceeds a given threshold, and may include different cuts separated a number of years. The function can be applied to target management of specific taxa (instead of assuming a monospecific stand), but the thresholds that determine thinning operations apply to stand-level metrics. Mean DBH will be calculated for the target species only. Planting is only allowed under regular management models, and is applied after the last final cut. Understory clearings are assumed to occur anytime there is an intervention on trees, an only a residual shrub cover is left.

Thinning types:

  • above: Extract largest trees (according to DBH) until thinning objective is met.

  • below: Extract smallest trees (according to DBH) until thinning objective is met.

  • systematic: Extract equally from all size classes until thinning objective is met.

  • above-systematic: Extract half the objective as systematic thinning and the other hald as above thinning.

  • below-systematic: Extract half the objective as systematic thinning and the other hald as below thinning.

  • free string: A string specifying the proportion of tree cuts from size classes, with size classes separated by "/" and each one composed of a number specifying the upper limit and a number indicating its proportion, separated by "-" (e.g. "10-50/40-30/60-20").

See also

fordyn

Author

Miquel De Cáceres Ainsa, CREAF

Aitor Améztegui, UdL

Jose-Ramon Gonzalez Olabarria, CTFC

Examples

# Load example forest object
data(exampleforest)
  
# Define arguments
args = defaultManagementArguments()
  
# Call management function
f = defaultManagementFunction(exampleforest, args)
  
#list names
names(f)
#> [1] "action"          "N_tree_cut"      "Cover_shrub_cut" "planted_forest" 
#> [5] "management_args"
  
# Action performed
f$action
#> [1] "thinning"
  
# Number of trees cut for each cohort
f$N_tree_cut
#> [1]   9.76362 384.00000
  
# Percent cover of shrubs removed
f$Cover_shrub_cut
#> [1] 0.75