stratvol: Stratified wood volume by DBH classes

In PhytoIn: Vegetation Analysis and Forest Inventory

Stratified wood volume by DBH classes

Description

stratvol computes wood volume (m^3 ha^{-1}) stratified by diameter at breast height (DBH, in centimeters) classes for each taxon in a forest inventory. Individual tree volume is calculated as V_i = ABi \times h \times shape.factor, where ABi is the individual basal area at breast height and h is tree height. Volumes are then summed within DBH classes and standardized per hectare using the inventoried area stored in obj.

Usage

stratvol(obj, classes = 20, shape.factor = 1, rm.dead = FALSE)

Arguments

obj	An object of class "param" produced by phytoparam, containing the inventory data, variable names, and global area statistics used for standardization.
classes	Numeric vector of breakpoints (in centimeters) defining the DBH classes. If a single value is supplied, two classes are formed (\leq value; > value). Defaults to 20.
shape.factor	Stem form correction factor used in the individual volume calculation (V_i = ABi \times h \times shape.factor). Default 1 (cylindrical shape).
rm.dead	Logical. If TRUE, individuals labeled as dead (rows whose taxon string equals the dead code stored in obj$vars) are excluded from all calculations. Default FALSE.

Details

- DBH classes are defined from the numeric breakpoints provided in classes, using closed–open intervals internally and labeled for readability as: <=a, ]a-b], …, >z (all in centimeters). - Individual volume is computed as V_i = ABi \times h \times shape.factor. Summed volumes per class are divided by the inventoried area (in hectares) retrieved from obj$global, yielding m^3 ha^{-1}.

Value

A data.frame with one row per taxon and the following columns:

• Taxon: Taxon label.

• One column per DBH class (labeled in centimeters), containing the summed wood volume per hectare (m^3 ha^{-1}) for that taxon within the class. Missing combinations are returned as 0.

Note

• Units: Supply size classes in centimeters. The function assumes ABi and h yield volume in cubic meters before per-hectare standardization.

• Class limits: Class breakpoints should not exceed the maximum observed DBH; otherwise the function stops with an error.

Author(s)

Rodrigo Augusto Santinelo Pereira ([e-mail])

References

FAO (1981). Manual of forest inventory—With special reference to mixed tropical forests. Food and Agriculture Organization of the United Nations.

See Also

phytoparam

Examples

# Creating the 'param' object with phytosociological parameters
point.param <- phytoparam(x = point.df, measure.label = "CBH",
                          taxon = "Species", dead = "Morta", family = "Family",
                          circumference = TRUE, su = "Point", height = TRUE,
                          quadrat = FALSE, d = "Distance", rm.dead = FALSE)

# Stratified volumes with a single breakpoint (<= 20 cm; > 20 cm)
stratvol(point.param, classes = 20)

# Stratified volumes with multiple classes (<= 5], ]5–10], > 10 cm)
stratvol(point.param, classes = c(5, 10))

# Using a taper/form correction factor and excluding dead trees
stratvol(point.param, classes = c(10, 20, 30), shape.factor = 0.7, rm.dead = TRUE)

PhytoIn documentation built on Nov. 5, 2025, 5:47 p.m.