Plot a Tree Sequence
DESCRIPTION:
Allows the user to plot a tree sequence.
USAGE: 
plot.tree.sequence(x, ..., order=c("increasing", "decreasing"))
REQUIRED ARGUMENTS:
x:
object of class "tree.sequence". This is assumed to be the result of some function that produces an object with the same named components (size, deviance, k) as that returned by prune.tree() and shrink.tree().
OPTIONAL ARGUMENTS:
order:
character string describing the order of size on the plot. Use "decreasing" for the natural ordering of k and the amount of pruning. Only the first character is needed.
SIDE EFFECTS:
plots deviance or number of misclassifications versus size for a sequence of trees.
DETAILS:
This function is a method for the generic function plot for class "tree.sequence". It can be invoked by calling plot for an object of the appropriate class, or directly by calling plot.tree.sequence regardless of the class of the object.
SEE ALSO:
plot.tree , prune.tree , shrink.tree , tree .
EXAMPLES: 
z <- tree(Mileage ~ Weight, car.test.frame)
zp <- prune.tree(z)
plot(zp, type = "s") # stairstep plot
zs <- shrink.tree(z)
lines(zs$size, zs$dev)