GCubeR (version 0.1.3)

vallet_vc22: Calculate Commercial Volume (vc22) up to 7cm Diameter at Breast Height (dbh)

Description

Computes the commercial wood volume (vc22, over bark, up to a 7 cm top-diameter) using the Vallet polynomial model, based on dbh (cm) and htot (m).

Usage

vallet_vc22(data, na_action = c("error", "omit"), output = NULL)

Value

The resulting data frame with the new column vallet_vc22

(Commercial Volume in m3).

Arguments

data

A data frame containing tree measurements. Must include the columns: species_code, dbh (diameter at 1.30m, in cm), and htot (total height, in m).

na_action

How to handle missing input values. "error" (default) stops if core required values are explicitly NA. "omit" removes rows with missing core data.

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 model is valid only for trees with a diameter at 1.30m (dbh) greater than or equal to 7 cm.

The polynomial formula used is: $$VC22_{dm^3} = a \cdot \frac{h_{tot}}{dbh} + (b + c \cdot dbh) \cdot \frac{\pi \cdot dbh^2 \cdot h_{tot}}{40}$$

Coefficients a, b, c are species-specific and loaded from the vallet_vc22.csv file.

Examples

data_test_vc22 <- data.frame(
  species_code = c("PICEA_ABIES", "FAGUS_SYLVATICA", "UNKNOWN_SPECIES", "QUERCUS_ROBUR"),
  dbh = c(19.1, 25.5, 15.9, 6.4), 
  htot = c(25, 18, 20, 22)
)

results_console <- vallet_vc22(data_test_vc22)
print(results_console)