taper_kozak {timbeR}

Kozak (2004) Taper Function.

Description

Kozak (2004) Taper Function.

Usage

taper_kozak(dbh, h, hih, b0, b1, b2, b3, b4, b5, b6, b7, b8, p)

Arguments

dbh

tree diameter at breast height, in centimeters.

h

total tree height, in meters.

hih

ratio between the height of the section (hi) and the total height (h) .

b0, b1, b2, b3, b4, b5, b6, b7, b8

model parameters.

p

numerical value representing the first inflection point calculated in the segmented model of Max and Burkhart (1976).

Value

a numeric value indicating the diameter at the section.

References

Kozak, A. (2004). My last words on taper equations. The Forestry Chronicle, 80(4), 507-515.

Examples

library(dplyr)
library(minpack.lm)
library(timbeR)

tree_scaling <- tree_scaling %>%
mutate(did = di/dbh,
       hih = hi/h)

kozak <-  nlsLM(di ~ taper_kozak(dbh, h, hih, b0, b1, b2, b3, b4, b5, b6, b7, b8, p),
data=tree_scaling,
start=list(b0=1.00,b1=.97,b2=.03,b3=.49,b4=-0.87,b5=0.50,b6=3.88,b7=0.03,b8=-0.19,p =.1))