ForestElementsR (version 2.0.1)

crown_diameter_silva: Estimate a tree's crown diameter

Description

This function can be used for estimating a tree's crown diameter, given its species, its stem diameter at breast height, and its total height. This is the crown diameter function which is implemented in the forest growth simulator SILVA pretzsch_single_2002ForestElementsR. The crown diameter in this context is defined as the average diameter of the crown at its greatest lateral extension. The crown diameter equations are available for exactly the species (groups) defined in the coding tum_wwk_short. If they are called with another species coding supported by the package ForestElementsR, crown_diameter_silva will attempt to convert them accordingly.

Usage

crown_diameter_silva(species_id, dbh_cm, height_m)

Value

An estimate of the tree's diameter of the crown at its greatest lateral extension in m.

Arguments

species_id

Vector of species id's following the tum_wwk_short species coding. Ideally, these species_id's are provided as a fe_species_tum_wwk_short object. If they are provided as another object, crown_diameter_silva will make an attempt to convert them. If this is not possible, the function will terminate with an error. The species id's can also be provided as numeric values (double or integer) or character. These will be internally converted to fe_species_tum_wwk_short. If this fails (i.e. the user provided species codes not defined in the tum_wwk_short coding), an error is thrown and the function terminates.

dbh_cm

Vector of tree dbh values in cm (dbh = stem diameter at breast height, i.e. 1.3 m)

height_m

Vector of tree height values in m

References

Examples

# Estimate the crown diameter of a Scots pine with a stem diameter
# at breast height of 45.2 cm and a total height of 29.2 m:
crown_diameter_silva(
  species_id = "3",    # will be internally converted to tum_wwk_short
  dbh_cm = 45.2,
  height_m = 29.2
) # 6.1 m (rounded)

# Crown diameter estimate for a European beech with
# the same height and diameter:
crown_diameter_silva(
  species_id = "5",   # will be internally converted to tum_wwk_short
  dbh_cm = 45.2,
  height_m = 29.2
) # 9.6 m (rounded)

# Run vectorized
spec <- mm_forest_1_fe_stand_spatial$trees$species_id
d <- mm_forest_1_fe_stand_spatial$trees$dbh_cm
h <- mm_forest_1_fe_stand_spatial$trees$height_m
crown_diameter_silva(spec, d, h)