new_concentric_design: Construct a concentric subplot design

In basifoR: Retrieval and Processing of the Spanish National Forest Inventory

Construct a concentric subplot design

Description

Define a concentric inventory design from subplot radii and minimum diameter thresholds.

The constructor orders subplot tiers by minimum DBH, converts radii to sampled area in square metres, computes trees-per-hectare expansion factors, and returns an object of class "concentric_design" inheriting from "inventory_design".

Usage

new_concentric_design(radii_m, 
    min_dbh_cm, name = "custom", 
    metadata = NULL)

Arguments

radii_m	numeric. Subplot radii in metres, one value per tally tier.
min_dbh_cm	numeric. Minimum diameter at breast height in cm required for a tree to be tallied in each subplot. Must have the same length as radii_m. The function sorts these thresholds in ascending order and reorders the paired radii accordingly.
name	character(1). Human-readable design name stored in the returned object.
metadata	Optional list. Additional design metadata merged with default entries for shape = "circular" and the ordered radii_m.

Details

The function delegates to new_inventory_design

and then appends the ordered radii_m vector plus the

class "concentric_design". The metadata

argument is merged with default entries for circular plot

shape and ordered radii using

utils::modifyList().

Value

An object of class

c("concentric_design", "inventory_design"), returned

as a named list with components name,

min_dbh_cm, sample_area_m2, sf,

metadata, and radii_m. The

sample_area_m2 component stores subplot areas in

square metres, sf stores the corresponding

trees-per-hectare expansion factors, and

metadata contains the merged design metadata.

Author(s)

Wilson Lara [aut, cre] (ORCID: <https://orcid.org/0000-0003-3527-1380>), Cristobal Ordonez [aut] (ORCID: <https://orcid.org/0000-0001-5354-3760>), Aitor Vázquez-Veloso [aut] (ORCID: <https://orcid.org/0000-0003-0227-506X>), Felipe Bravo [aut] (ORCID: <https://orcid.org/0000-0001-7348-6695>)

Examples

dsg <- new_concentric_design(
    radii_m = c(5, 10, 15, 25),
    min_dbh_cm = c(7.5, 12.5, 22.5, 42.5),
    name = "SNFI"
)
dsg

basifoR documentation built on Aug. 26, 2026, 9:06 a.m.