h_standard_bv {ForestElementsR} | R Documentation |
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 1972). 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)
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
( |
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.
Value
A vector of the estimated heights
References
Kennel R (1972). Die Buchendurchforstungsversuche in Bayern von 1870 bis 1970. Mit dem Modell einer Strukturertragstafel für die Buche, volume 7 of Forstliche Forschungsberichte München. Forstwissenschaftliche Fakultät der Universität München und Bayerische Forstliche Versuchs- und Forschungsanstalt.
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)