Calculates Lorey's Height — silv_lorey

Tree's mean height weighted by basal area

Usage

silv_lorey_height(height, g, ntrees = NULL)

Arguments

height: Numeric vector of heights
g: Numeric vector of basal areas
ntrees: Optional. Numeric vector of number of trees per hectare. Use this argument when you have aggregated data by diametric classes (see details).

Value

A numeric vector

Details

The function calculates Lorey's mean height according to:

$$h_L = \frac{\sum n_i g_i h_i}{\sum n_i g_i}$$

When ntrees is not provided (i.e. ntrees = NULL) the formula is simply the weighted mean of the provided heights and basal areas:

$$h_L = \frac{\sum g_i h_i}{\sum g_i}$$

Examples

## Calculate Lorey's Height by plot and species
library(dplyr)
inventory_samples |>
  mutate(g = silv_basal_area(diameter)) |>
  summarise(
    lh  = silv_lorey_height(height, g),
    .by = c(plot_id, species)
  )
#> # A tibble: 14 × 3
#>    plot_id species    lh
#>      <int>   <int> <dbl>
#>  1       7      27 18.5 
#>  2       8      83  5.46
#>  3       8      28 17.7 
#>  4       8     294  6.95
#>  5       8      81  6.14
#>  6      10      81  7.51
#>  7      10      72 14.2 
#>  8      10      83  6.37
#>  9      10      27 28.6 
#> 10      53      27 23.5 
#> 11     189      81 12.6 
#> 12     189      84 12.9 
#> 13     189      82 10.9 
#> 14     189      83  9.49