In The Lord of the Rings: The Two Towers, Treebeard leads the Ents’ attack on Isengard.
Treebeard is an ancient Ent who lives in Fangorn Forest. Merry and Pippin meet him after escaping from the Uruk-hai, and they tell him how Saruman’s forces are destroying trees. At first, Treebeard is reluctant to become involved because Ents are slow to reach decisions and do not easily accept the concerns of other peoples.
The Entmoot eventually decides that Saruman’s actions require a response. Treebeard leads the Ents to Isengard, where they break the defenses, flood the industrial complex, and trap Saruman’s forces. Treebeard is not a wizard or an ordinary talking tree; Ents are a separate ancient people created to protect living trees. He should also be distinguished from Quickbeam, another Ent who joins the attack.