P1: Standing Timber Volume Indicator

Calculates standing timber volume (m3/ha) using IFN allometric equations based on species, diameter (DBH), and height data.

Usage

indicator_productive_volume(
  units,
  species_field = "species",
  dbh_field = "dbh",
  height_field = "height",
  density_field = "density",
  method = c("ifn_tarif", "allometric"),
  column_name = "P1",
  lang = "en"
)

Arguments

units

sf object (POLYGON) of spatial units to assess

species_field

Character. Column name containing species codes (IFN format). Default "species".

dbh_field

Character. Column name containing diameter at breast height (cm). Default "dbh".

height_field

Character. Column name containing tree height (m). Optional, can be estimated.

density_field

Character. Column name containing tree density (stems/ha). Default "density".

method

Character. Volume calculation method: "ifn_tarif" (IFN tariff) or "allometric". Default "ifn_tarif".

column_name

Character. Name for output column. Default "P1".

lang

Character. Message language. Default "en".

Value

sf object with added column: P1 (standing volume in m3/ha)

Details

**Calculation** (IFN tarif method):

• Lookup species-specific IFN equation: V = a x DBH^b x H^c

• Calculate individual tree volume

• Scale by tree density: P1 = V_individual x density_stems_ha

**Species Fallback**: If species code not found in IFN tables, uses genus-level equations:

• Broadleaf species -> BROADLEAF_GENUS equation

• Conifer species -> CONIFER_GENUS equation

**Data Requirements**:

• species: IFN species code (e.g., "FASY", "QUPE", "PIAB")

• dbh: Diameter at breast height (1.3m) in cm

• height: Tree height in meters (can be estimated from DBH if missing)

• density: Number of stems per hectare

Examples

if (FALSE) { # \dontrun{
# With species and biometric data
units$species <- c("FASY", "QUPE", "PIAB")
units$dbh <- c(35, 42, 28)
units$height <- c(25, 30, 22)
units$density <- c(250, 180, 320)

result <- indicator_productive_volume(
  units = units,
  species_field = "species",
  dbh_field = "dbh",
  height_field = "height",
  density_field = "density"
)
} # }