In J.R.R. Tolkien’s legendarium, the shepherds of the trees are called Ents.
Ents are ancient tree-like beings who protect forests and care for the trees. The best-known Ent is Treebeard, whose name in Sindarin is Fangorn. Ents play a major role in The Lord of the Rings when they attack Isengard after learning about Saruman’s destruction of the surrounding forests.
Tolkien drew on older traditions about animated trees and forest beings, but the Ents are distinctively his creation within Middle-earth. Their slow speech and deliberative behavior are recurring features of their portrayal. The word “ent” also has an Old English connection: in the poem Beowulf, the phrase eormengrund refers to the world of the “giants,” and Tolkien used related Old English vocabulary in his world-building.