After Treebeard ordered the Ents to march to Isengard, the Ents felled Saruman's walls and destroyed every object in and around Isengard; the Tower of Orthanc could not be breached, but Saruman was trapped within.
The Elven-realm Lothlórien was situated near the North of Fangorn Forest and Treebeard had met the Lord and Lady of the Galadhrim of Lothlórien, who refer to him as "Eldest" [REF].