species_profile {ForestElementsR} | R Documentation |
Species Profile Index After Pretzsch
Description
As an extension of the Shannon Index (shannon_index
), the
species profile index by
Pretzsch (2009)
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
)
Arguments
species_id |
A vector of species codes, each vector element representing
a tree. Preferably, |
heights |
A vector of tree heights, must have the same length as
|
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
|
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 |
Details
Note that this function calculates comparable output only when the same
species coding is used for the input parameter species_id
.
Value
The Species Profile Index value resulting from the input data
References
Pretzsch H (2009). Forest Dynamics, Growth and Yield: From Measurement to Model, 2010 edition. Springer, Berlin. ISBN 978-3-540-88306-7.
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
)