%->%                    Add a tree at the bottom of a chain
Nodes                   Nodes Class
Tree                    Tree Class
ancestors               Ancestors of a node
as.list.rtree           Conversion of a tree to a list
as.node                 Conversion to a node
as.rtree                Conversion to an 'rtree' object
chain                   Chain constructor
children                Children of a node
cut_leaves              Cut the leaves of a tree
descendants             Descendants of a node
flatten                 Flatten a tree
height                  Height of a tree
is.binary_tree          Test if a tree is a binary tree
is.chain                Test if a tree is a chain
is.node                 Test if an object is a node
is.root                 Test if a node is a root of a tree
is.rooted               Test if a tree has a root
is.tree                 Test if an object is a tree
label                   Labels of nodes and trees
leaves                  Leaves of a tree
parent                  Parent of a node
print.rtree             Print trees
prune                   Prune a tree
rev.rtree               Reverse a chain
root                    Root(s) of a tree
rtree                   Tree constructor
siblings                Siblings of a node
subtrees                Subtrees of a tree
take_branch             Take a branch of a tree
tree_apply              Apply a function to each node of a tree
update.rtree            Update a tree with new subtrees
