Growth of Loblolly pine trees

Description

The Loblolly data frame has 84 rows and 3 columns of records of the growth of Loblolly pine trees.

Usage

data(Loblolly)

Format

This data frame contains the following columns:

height

a numeric vector of tree heights (ft).

age

a numeric vector of tree ages (yr).

Seed

an ordered factor indicating the seed source for the tree. The ordering is according to increasing maximum height.

Source

Kung, F. H. (1986), “Fitting logistic growth curve with predetermined carrying capacity”, Proceedings of the Statistical Computing Section, American Statistical Association, 340–343.

Pinheiro, J. C. and Bates, D. M. (2000) Mixed-effects Models in S and S-PLUS, Springer.

Examples

data(Loblolly)
plot(height ~ age, data = Loblolly, subset = Seed == 329,
     xlab = "Tree age (yr)", las = 1,
     ylab = "Tree height (ft)",
     main = "Loblolly data and fitted curve (Seed 329 only)")
fm1 <- nls(height ~ SSasymp(age, Asym, R0, lrc),
           data = Loblolly, subset = Seed == 329)
summary(fm1)
age <- seq(0, 30, len = 101)
lines(age, predict(fm1, list(age = age)))