Loblolly {datasets}  R Documentation 
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
Loblolly
Format
An object of class
c("nfnGroupedData", "nfGroupedData", "groupedData", "data.frame")
containing 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.
Details
This dataset was originally part of package nlme
, and that has
methods (including for [
, as.data.frame
, plot
and
print
) for its groupeddata classes.
Source
Kung, F. H. (1986), Fitting logistic growth curve with predetermined carrying capacity, in Proceedings of the Statistical Computing Section, American Statistical Association, 340–343.
Pinheiro, J. C. and Bates, D. M. (2000) Mixedeffects Models in S and SPLUS, Springer.
Examples
require(stats); require(graphics)
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)
age < seq(0, 30, length.out = 101)
lines(age, predict(fm1, list(age = age)))