ForestElementsR (version 2.0.1)

h_standard_bv: Calculate Tree Heights with the Bavarian Standard Height Curve System

Description

Implementation of the standard height curve system used by the Bavarian State Forest Service kennel_r_beech_bavaria_1972ForestElementsR. The structure of the approach was developed by R. Kennel together with a parameterisation for European beech (Fagus sylvatica). Later, anonymous scientists have extended the parameters for all species (groups) covered by the tum_wwk_short species coding. The standard height curve system allows to estimate a tree's height when its dbh is given together with the quadratic mean diameter, the corresponding quadratic mean height, and the age of the stand it belongs to.

Usage

h_standard_bv(species_id, dbh_cm, age_yr, d_q_cm, h_q_m)

Value

A vector of the estimated heights

Arguments

species_id

Vector of species id's following the tum_wwk_short or the bavrn_state_short species coding. If another coding is provided, an attempt will be made to convert it into the "nearest" of the two codings mentioned above. The default is a conversion attempt to tum_wwk_short. The species id's can also be provided as numeric values (double or integer) or character. These will be interpreted as and converted to fe_species_tum_wwk_short. If all conversion attempts fail, the function will terminate with an error.

dbh_cm

Vector of tree dbh values in cm (dbh = stem diameter at breast height, i.e. 1.3 m)

age_yr

Vector of stand age values in years (will be recycled following the rules for tibbles)

d_q_cm

Vector of quadratic mean stand diameters (will be recycled following the rules for tibbles)

h_q_m

Vector of quadratic mean stand heights (will be recycled following the rules for tibbles)

Details

In order to provide maximum flexibility in applying the function h_standard_bv, the stand values (age, mean height, mean diameter) can be provided with each tree diameter individually. This allows estimating heights for trees from different stands at the same time. In the same way, the provided species codes are not required to be the same for each tree.

References

See Also

Other standard height curve systems: h_standard_gnfi3()

Examples

  species_id <- fe_species_tum_wwk_short(rep(3, 7))  # Seven Scots pines
  dbh <- c(10.1, 27.4, 31.4, 35.5, 39.8, 45.2, 47.2) # and their diameters
  # Estimate the heights of these trees assuming they are from a 100 year old
  # stand with a mean diameter of 35.5 cm, and a corresponding mean height
  # of 28 m.
  h_standard_bv(species_id, dbh, age_yr = 100, d_q_cm = 35.5, h_q_m = 28.0)

  # Compare with sister function h_standard_gnfi3 which does not require
  # stand age
  h_standard_gnfi3(species_id, dbh, d_q_cm = 35.5, h_q_m = 28.0)