d_dom_weise: Weise's Dominant Diameter

In ForestElementsR: Data Structures and Functions for Working with Forest Data

Weise's Dominant Diameter

Description

The dominant diameter after Weise is the quadratic mean diameter of the 20% biggest trees in a stand. In contrast to the dominant diameter d_100 it is well defined not only in monospecific stands, but also in mixed stands.

Usage

d_dom_weise(d, n_rep = 1)

Arguments

d	vector of diameter values to calculate Weise's dominant diameter of
n_rep	vector of representation numbers (typically the number of trees per ha corresponding to the diameter at the same position), will be used as individual weights for each diameter. If n_rep has length 1, it will be recycled to the length of d. Otherwise, if the length of n_rep does not correspond to the length of d, the function will terminate with an error.

Value

The value of Weise's dominant diameter resulting from the input data

See Also

Other stand diameters: d_100(), d_q()

Examples

# A sample of trees from an angle count sample, where each
# tree represents a basal area of 4 m²/ha
d_cm <- c(12, 13, 25, 27, 28, 26, 26.1, 32, 35, 31, 42)
n_rep_ha <- 4 / ((d_cm / 100)^2 * pi / 4) # representation number of each tree
d_dom_weise(d_cm, n_rep_ha)
d_100(d_cm, n_rep_ha) # dominant diameter d100 for comparison
d_q(d_cm, n_rep_ha) # quadratic mean diameter for comparison

# if 20% of the trees are 100 stems/ha, Weise's dominant diameter and
# d100 are equal
d_cm <- rnorm(n = 500, mean = 35, sd = 7)
d_dom_weise(d_cm, 1)
d_100(d_cm, 1)

# Weise's dominant diameter is greater than d100, if 20% of the trees
# represent less than 100 trees/ha
d_cm <- rnorm(n = 200, mean = 35, sd = 7)
d_dom_weise(d_cm, 1)
d_100(d_cm, 1)

# Weise's dominant diameter is smaller than d100, if 20% of the trees
# represent more than 100 trees/ha
d_cm <- rnorm(n = 800, mean = 35, sd = 7)
d_dom_weise(d_cm, 1)
d_100(d_cm, 1)

ForestElementsR documentation built on April 3, 2025, 7:47 p.m.