silv_stand_dominant_diameter: Calculates the dominant diameter

In silviculture: Utility Functions for Forest Inventory and Silviculture

Calculates the dominant diameter

Description

Calculates the dominant diameter using Assman and Friedrich method, or Weise method

Usage

silv_stand_dominant_diameter(
  diameter,
  ntrees = NULL,
  which = "assman",
  quiet = FALSE
)

Arguments

diameter	Numeric vector with diameter classes
ntrees	Optional. Numeric vector with number of trees per hectare. Use this argument when you have aggregated data by diametric classes (see details).
which	The method to calculate the dominant diameter (see details)
quiet	if TRUE, messages will be supressed

Details

The dominant diameter D_0 is the mean diameter of the 100 thickest trees per hectare. Therefore, diameter and ntrees should be vectors of the same length.

• Assman: calculates the D_0 as the mean diameter of the 100 thickest trees per hectare

• Weise: calculates the D_0 as the quadratic mean diameter of the 20% thickest trees per hectare

Value

A numeric vector

Examples

## calculate d0 for inventory data grouped by plot_id and species
library(dplyr)
inventory_samples |>
mutate(dclass = silv_tree_dclass(diameter)) |>
  summarise(
    height = mean(height, na.rm = TRUE),
    ntrees = n(),
    .by    = c(plot_id, species, dclass)
  ) |>
  mutate(
    ntrees_ha = silv_density_ntrees_ha(ntrees, plot_size = 10),
    d0        = silv_stand_dominant_diameter(dclass, ntrees_ha),
    .by       = c(plot_id, species)
  )

silviculture documentation built on Nov. 5, 2025, 7:13 p.m.