poly5_hi {timbeR}

Estimate the height at which a given diameter occurs in a tree, based on a 5th degree polynomial function.

Description

Estimates the height at which a given diameter occurs in a tree, from the diameter at breast height, total height and coefficients of the 5th degree polynomial function that describes the tree's taper.

Usage

poly5_hi(dbh, h, di, coef)

Arguments

dbh

tree diameter at breast height, in centimeters.

h

total tree height, in meters.

di

diameter whose height of occurrence will be estimated, in centimeters.

coef

numerical vector containing six coefficients of the 5th degree polynomial function that describes the tree's taper.

Value

as numeric value indicating the height at which the given diameter occurs.

Examples

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

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

poli5 <- lm(did~hih+I(hih^2)+I(hih^3)+I(hih^4)+I(hih^5),tree_scaling)

coef_poli <- coef(poli5)

dbh <- 25
h <- 20
hi <- 15

poly5_hi(dbh, h, hi, coef_poli)