rForest (version 0.1.4)

poly5Model: Fitting a fifth-degree polynomial taper model

Description

poly5Model is used to fit a fifth-degree polynomial taper model

Usage

poly5Model(dbh,ht,di,hi, plotxy)

Arguments

dbh,

vector of diameter at breast height

ht,

vector of measured tree heights

di,

vector of measured tree diameters at i heights

hi,

vector of measured tree i heights

plotxy,

plot the fitted model

Value

Returns a fifth-degree polynomial taper model as an object of class "lm"

References

Schoepfer (1966) model :fifth-degree polynomial taper model

• $di/dbh=(hi/ht)+(hi/ht{)}^2+(hi/ht{)}^3+(hi/ht{)}^4+(hi/ht{)}^5$

Examples

# NOT RUN {
# Importing forest inventory data
data(ForestInv01) 

# setting model parametersdbh and ht
hi<-ForestInv01[,2]
di<-ForestInv01[,3]
ht<-ForestInv01[,4]
dbh<-ForestInv01[,5]

# fitting the fifth-degree polynomial taper model
fit <- poly5Model(dbh,ht,di,hi, plotxy=TRUE)
#grid()
# }