Tree-beard is the oldest of the Ents, tree-like beings whose purpose is to protect the forest. After the Ents’ victory over Saruman in Isengard, Tree-beard watches over Orthanc, ensuring it is no longer used to evil purposes. However, Tree-beard proves susceptible to Saruman’s persuasive language, and, believing Saruman to have lost all his power, allows him to escape Orthanc.