R: Growth of Loblolly pine trees

Loblolly {nls} | 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.

### 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)))

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