GCubeR (version 0.1.3)

dagnelie_br: Single-entry Dagnelie branch volume (tarif "br")

Description

Computes the branch volume \(v_{br}\) (in cubic metres per tree) using Dagnelie's single-entry "br" equations. The branch volume is derived from the stem circumference at 1.30 m (c130, in cm) and the tree species, using species-specific polynomial coefficients stored in the reference table danbr.

Usage

dagnelie_br(data, output = NULL)

Value

A data.frame identical to the input data but augmented with:

• species-specific coefficients and validity ranges,

• dagnelie_br: the computed Dagnelie tarif-"br" branch volume (m\(^3\) per tree).

Arguments

data

A data.frame containing at least:

• c130: stem circumference at 1.30 m (cm),

• species_code: tree species code.

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.

Supported species

The following species codes are supported by dagnelie_br:

• "QUERCUS_SP",

• "QUERCUS_ROBUR",

• "QUERCUS_PETRAEA",

• "QUERCUS_PUBESCENS",

• "QUERCUS_RUBRA"

• "FAGUS_SYLVATICA",

• "ACER_PSEUDOPLATANUS",

• "FRAXINUS_EXCELSIOR",

• "ULMUS_SP",

• "PRUNUS_AVIUM"

• "BETULA_SP",

• "ALNUS_GLUTINOSA",

• "LARIX_SP",

• "PINUS_SYLVESTRIS",

• "CRATAEGUS_SP"

• "PRUNUS_SP",

• "CARPINUS_SP",

• "CASTANEA_SATIVA",

• "CORYLUS_AVELLANA",

• "MALUS_SP"

• "PYRUS_SP",

• "SORBUS_ARIA",

• "SAMBUCUS_SP",

• "RHAMNUS_FRANGULA",

• "PRUNUS_CERASUS"

• "ALNUS_INCANA",

• "POPULUSxCANADENSIS",

• "POPULUS_TREMULA",

• "PINUS_NIGRA",

• "PINUS_LARICIO"

• "TAXUS_BACCATA",

• "ACER_PLATANOIDES",

• "ACER_CAMPESTRE",

• "SORBUS_AUCUPARIA",

• "JUNGLANS_SP"

• "TILLIA_SP",

• "AESCULUS_HIPPOCASTANUM",

• "ROBINIA_PSEUDOACACIA",

• "SALIX_SP"

Details

The "br" tarif branch volume is calculated as: $$ v_{br} = a + b\,c130 + c\,c130^2 + d\,c130^3 $$ where \(a\), \(b\), \(c\), and \(d\) are species-specific coefficients.

The function performs the following steps:

• checks that the input data frame contains the required variables c130 and species_code,

• validates that c130 is numeric,

• verifies that all species are available in the danbr reference table and issues a warning otherwise,

• merges the input with danbr to retrieve coefficients and species-specific validity ranges (min_c130, max_c130),

• warns when c130 values fall outside the recommended range,

• computes tarif-"br" branch volume and returns the augmented data frame.

If one or more species codes are not found in danbr, the function issues a warning and returns NA-values for missing coefficients and volumes. Trees with c130 values outside the recommended species-specific range produce a warning but still receive a computed branch volume.

See Also

danbr for species-specific coefficients.

Examples

df <- data.frame(
  c130         = c(145, 156, 234, 233),
  species_code = c("PINUS_SYLVESTRIS", "QUERCUS_RUBRA",
                   "QUERCUS_SP", "FAGUS_SYLVATICA")
)
dagnelie_br(df)