cladeSizes is a vector giving the size of the clade descending at each node:tips all have the value 1, internal nodes have their number of tip descendants.
numClades is a vector where numClades[[i]] is the number of clades of size i in the tree.
All clade sizes are calculated, but the output can be restricted using maxClade to just those of size up to 'maxClade'.
Arguments
tree
a tree of class phylo or phylo4. The tree should be binary and rooted; if not it will be coerced into a binary rooted tree using multi2di, if possible.
maxClade
an integer between 1 and the number of tips (the default), specifying the maximum clade size of interest.