ForestElementsR (version 2.0.1)

species_profile: Species Profile Index After Pretzsch

Description

As an extension of the Shannon Index (shannon_index), the species profile index by pretzsch_forest_2009;textualForestElementsR takes into account the vertical structure of a forest stand. For doing so, the function assmann_layers is called in the background.

Usage

species_profile(
  species_id,
  heights,
  weights = 1,
  n_rep = 1,
  reference_height = NULL
)

Value

The Species Profile Index value resulting from the input data

Arguments

species_id

A vector of species codes, each vector element representing a tree. Preferably, species_id is defined in one of the species codings supported by this package, but technically, this is not even a requirement.

heights

A vector of tree heights, must have the same length as species_id

weights

A vector of weights for each tree, default = 1, i.e. all trees are equally weighted. Must be of length 1 or the same length as species_id. Useful if e.g. trees should be weighted by their basal area.

n_rep

A vector of representation numbers for each tree, typically the number of trees represented per ha by each tree. Does only make a difference if it differs among the trees. Default = 1, i.e. all trees have the same representation number.

reference_height

Reference height for the 100% level of the stand height profile. Internally passed to assmann_layers. If NULL (default), the maximum of heights will be used as the reference height.

Details

Note that this function calculates comparable output only when the same species coding is used for the input parameter species_id.

References

See Also

Other structure and diversity: assmann_layers(), shannon_index()

Examples

  # Monospecific stand
  trees <- norway_spruce_1_fe_stand$trees
  species_profile(trees$species_id, trees$height_m)

  # Two-species mixed stand
  trees <- spruce_beech_1_fe_stand$trees
  species_profile(trees$species_id, trees$height_m)

  # Selection forest
  trees <- selection_forest_1_fe_stand$trees
  species_profile(trees$species_id, trees$height_m)

  # weigh with basal area (i.e. dbh^2)
  species_profile(trees$species_id, trees$height_m, weights = trees$dbh_cm^2)

  # weigh with inverse basal area (i.e. 1 / dbh^2)
  species_profile(
    trees$species_id, trees$height_m, weights = 1 / trees$dbh_cm^2
  )