poly5Model: Fitting a fifth-degree polynomial taper model

In rForest: Forest Inventory and Analysis

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"

Author(s)

Carlos A. Silva, Samuel P. C. Carvalho, Carine Klauberg Silva and Manoela de O. Rosa

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

# 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()

Example output

Warning messages:
1: In rgl.init(initValue, onlyNULL) : RGL: unable to open X11 display
2: 'rgl_init' failed, running with rgl.useNULL = TRUE 
3: .onUnload failed in unloadNamespace() for 'rgl', details:
  call: fun(...)
  error: object 'rgl_quit' not found 

rForest documentation built on Oct. 4, 2021, 9:06 a.m.