dbhMetric {basifoR}

DBH metrics

Description

This function can format tree diameters at breast height and tree heights according to the sampling design of the Spanish National Forest Inventory (SNFI). The function is used by other routines of basifoR to derive tree metrics, see Details section. Implementation of this function using data sets of the SNFI can be burdensome. Use dendroMetrics instead to recursively derive tree metrics.

Usage

dbhMetric(dbh, met = "d")

Arguments

dbh

numeric. Either diameters at breast height (mm) or tree heights (m). Vectors are averaged. Zero values are formatted to NA.

met

character. Any of five metrics: mean diameter at breast height ('d'), basal area ('ba'), number of trees ('n'), or tree height ('h'). Default 'd'.

Details

Replicates of tree diameter 'd' are averaged. The tree heights 'h' are formatted from mm to dm for further evaluation of volume equations. The basal areas are computed transforming the diameters from mm to cm and using the formula: ba (m2 tree-1 ha-1) = pi * d(cm)^2 * (4 * 1E4)^-1. The number of trees per hectare 'n' are calculated considering the sample design of the NFI: each plot consists of four concentric subplots with radii 5, 10, 15, and 25 m. The minimum diameters recorded in the subplots are 7.5, 12.5, 22.5, and 42.5 cm respectively. Considering these, any of four estimates is printed: 127.32, 31.83, 14.15, or 5.09.

Value

numeric. A tree metric: mean diameter (mm), tree basal area (m2 tree-1), number of trees (dimensionless), or tree height (dm).

Author(s)

Wilson Lara <[e-mail]>, Cristobal Ordonez <[e-mail]>, Felipe Bravo <[e-mail]>

Examples

dbh <- dbhMetric(c(10.7, 11.5), 'h')# average tree height (dm)