Growth of Loblolly pine trees
Loblolly data frame has 84 rows and 3 columns of records of
the growth of Loblolly pine trees.
An object of class
c("nfnGroupedData", "nfGroupedData", "groupedData", "data.frame")
containing the following columns:
a numeric vector of tree heights (ft).
a numeric vector of tree ages (yr).
an ordered factor indicating the seed source for the tree.
The ordering is according to increasing maximum height.
This dataset was originally part of package
nlme, and that has
methods (including for
print) for its grouped-data classes.
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)
Mixed-effects Models in S and S-PLUS, Springer.
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)))