GCubeR (version 0.1.3)

rondeux_vc22_vtot: Calculate Total and Commercial Stem Volume (Rondeux, larch)

Description

Computes the total stem volume (rondeux_vtot) and the commercial stem volume at 22 cm (rondeux_vc22) for larch trees according to Rondeux equations, based on the circumference at 1.30 m (c130, in cm) and the total height (htot, in meters).

Usage

rondeux_vc22_vtot(data, na_action = c("error", "omit"), output = NULL)

Value

A data frame identical to data, with two added columns:

• rondeux_vtot: total stem volume (m3)

• rondeux_vc22: commercial stem volume at 22 cm (m3)

Arguments

data

A data frame containing tree measurements. Must include: species_code (uppercase character), c130 (circumference at 1.30 m, in cm), htot (total height, in m).

na_action

How to handle missing essential values (c130, htot). "error" (default) stops if missing values are detected. "omit" removes rows with missing essential fields.

output

Optional file path where the resulting data frame should be exported as a CSV. If NULL (default), no file is written. Export is handled by the utility function export_output() and failures trigger warnings without interrupting execution.

Details

The implemented equations are:

$$v_{\mathrm{tot}} = a_{\mathrm{vtot}} \cdot c_{130}^2 \cdot h_{\mathrm{tot}}$$ where \(a_{\mathrm{vtot}} = 0.406780 \times 10^{-5}\).

$$v_{c22} = a_{\mathrm{vc22}} + b_{\mathrm{vc22}} \cdot c_{130}^2 \cdot h_{\mathrm{tot}}$$ where \(a_{\mathrm{vc22}} = -0.008877\) and \(b_{\mathrm{vc22}} = 0.412411 \times 10^{-5}\).

Expected units:

• c130: cm

• htot: m

• output volumes: m3

These equations are valid only for larch. Rows with other species are returned with NA volumes and a warning is issued.

Examples

df <- data.frame(
  species_code = c("LARIX_DECIDUA", "LARIX_DECIDUA", "LARIX_DECIDUA"),
  c130 = c(60, 65, 55),
  htot = c(15, 18, 20)
)

rondeux_vc22_vtot(df)