age_h_gnfi3: Inverse Tree Height Growth Model of the 3rd German National...

In ForestElementsR: Data Structures and Functions for Working with Forest Data

Inverse Tree Height Growth Model of the 3rd German National Forest Inventory (2012)

Description

Inverse tree height growth model of the third German National Forest Inventory of 2012 \insertCitebwi3_methods_2017ForestElementsR. Allows to estimate a tree's age at any height if its height is known at a given age.

Usage

age_h_gnfi3(species_id, h_m, h_m_known, age_yr_known)

Arguments

species_id	Vector of species id's preferably following the ger_nfi_2012 species coding. Ideally, these species_id's are provided as a fe_species_ger_nfi_2012 object. See Details for how other species codings are handled.
h_m	Single numeric value or vector of tree heights (m) for which the age is to be estimated
h_m_known	Vector of known height (m) values at age age_yr_known
age_yr_known	Vector of ages (years) for which the height h_m_known is known

Details

Originally, the function was parameterized for species and species groups corresponding to the national forest inventory's species coding (fe_species_ger_nfi_2012). We have attributed in addition these the original parameters also to the species codings fe_species_tum_wwk_short, and fe_species_bavrn_state_short. When called with a given species coding, the function will try to use the "nearest" of these three alternatives. Fallback option is the attempt to use fe_species_tum_wwk_short.

Value

A single age value or vector of age values corresponding to h_m

References

\insertAllCited

See Also

Other growth functions: age_d_gnfi3(), d_age_gnfi3(), h_age_gnfi3()

Examples

  # A European beech has a height of 25.2 m at age 75. Estimate
  # its age at height 26.8 m
  age_h_gnfi3(100, 26.8, 25.2, 75) # 100 is ger_nfi_2012 code for E. beech

  # Do the same backward in time, age at height 21.7 m
  age_h_gnfi3(100, 21.7, 25.2, 75)

  # Apply for more than one tree, different species, same age
  h_known   <- c(23.1, 16.2, 35.2, 19.3, 21.8)
  h_age     <- c(25.5, 18.2, 38.0, 21.6, 24.2)
  species   <- as_fe_species_tum_wwk_short(c(3, 3, 3, 6, 6))
  age_h_gnfi3(
    species, h_m = h_age, h_m_known = h_known, age_yr_known = 60
  )

ForestElementsR documentation built on April 3, 2025, 7:47 p.m.