 Some authors restrict the phrase "directed forest" to the case where the edges of each connected component are all directed towards a particular vertex, or all directed away from a particular vertex (see branching).A "rooted tree" is a tree in which one vertex has been designated the "root".The edges of a rooted tree can be assigned a natural orientation, either "away from" or "towards" the root, in which case the structure becomes a "directed rooted tree".