Estimates stand age from BD Forêt TFV (Type de Formation Végétale) field using area-weighted spatial intersection, following tuto 04 methodology. Falls back to direct age field, establishment year, or NDVI proxy.
Usage
indicator_temporal_age(
units,
layers = NULL,
bdforet = NULL,
age_field = "age",
establishment_year_field = NULL,
current_year = NULL
)Arguments
- units
An sf object with forest parcels.
- layers
A nemeton_layers object (optional). Used to resolve bdforet.
- bdforet
An sf object with BD Forêt V2 polygons. If NULL and layers provided, resolved from layers.
- age_field
Character. Column name with stand age (years). Default "age". Used as fallback if BD Forêt not available.
- establishment_year_field
Character. Column name with establishment year. Used as fallback if age_field not found.
- current_year
Integer. Current year for age calculation from establishment year. Default uses current system year.
Value
Numeric vector of estimated age in years (one per parcel). Default value is 50 when no data available.
Details
**Primary method** (BD Forêt TFV):
Spatial intersection of parcels with BD Forêt polygons
Age estimated from vegetation type (TFV field): - Forêt fermée feuillus / Futaie feuillus: 100 years - Forêt fermée conifères / Futaie conifères: 80 years - Forêt ouverte / Taillis: 45 years - Peupleraie: 20 years - Jeune peuplement / Lande boisée: 15 years - Other: 50 years (default)
Area-weighted average across overlapping polygons
**Fallback methods** (in order):
Direct age column in units
Establishment year column
NDVI-based maturity estimate
See also
Other temporal-indicators:
indicator_temporal_change()
Examples
if (FALSE) { # \dontrun{
library(nemeton)
data(massif_demo_units)
layers <- massif_demo_layers()
# Primary method: BD Forêt
result <- indicator_temporal_age(massif_demo_units, layers = layers)
summary(result)
# Direct age field
units <- massif_demo_units
units$age <- runif(nrow(units), 20, 250)
result <- indicator_temporal_age(units, age_field = "age")
} # }