ForestElementsR (version 2.2.0)

d_dom_weise: 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)

Value

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

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.

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)