The Ents are creature species in The Lord of the Rings. They live within the forests of Fangorn, which border the civilization of Sauron and the Orcs and Uruk-Hai bred there. During the war of the Ring, the Ents moved in on Isengard after Peregrin Took had Treebeard go towards Isengard and see what Saruman had done to all of his friends who were trees.
They continued to thrive in Isengard but Saruman had escaped from their watch.