silviculture (version 0.2.0)

silv_density_sdi: Calculates the Stand Density Index

Description

The Stand Density Index (SDI) is relationship between the average tree size and density of trees per hectare.

Usage

silv_density_sdi(ntrees, dg, classify = FALSE, max_sdi = NULL)

Value

A numeric vector

Arguments

ntrees

A numeric vector representing the number of trees per hectare

dg

A numeric vector of quadratic mean diameters

classify

whether to classify the values using USDA thresholds

max_sdi

used when classify = TRUE. The maximum SDi, which depends on the species, stand type, and site

Details

The SDI has different interpretation depending on the species, location, and also the management type (even-aged, uneven-aged...). The value of maximum SDI must be determined from the literature and used carefully. The option classify = TRUE will use this value to classify the SDI in low density (<24%), moderate density (24-35%), high density (34-55%), and extremely high density (>55%).

Examples

## calculate SDI for a Pinus sulvestris stand (max 990)
silv_density_sdi(ntrees = 800, dg = 23.4, max_sdi = 990)

## check base classification (other can be used)
silv_density_sdi(ntrees = 800, dg = 23.4, classify = TRUE, max_sdi = 990)