A term used by the old Ent Treebeard to describe the role and purpose of his people in the world. The Ents protected the trees in their charge in just the same way as a shepherd protects sheep, and indeed they were able to literally herd their trees. In the form of Huorns, some of those trees could move and even speak, at least to the Ents. A forest of these Huorns was herded by the Ents into the valley of Helm's Deep at the time of the Battle of the Hornburg, and helped secure a final victory for the Rohirrim over Saruman's forces.