Fangorn ForestFangorn - Perhaps the oldest forest in Middle Earth and home to Treebeard (after whom the forest is named).

 

"Treebeard carried the hobbits in his arms as on the previous day.  At the entrance to the court he turned to the right, stepped over the stream, and strode away southwards along the feet of great tumbled slopes where trees were scanty.  Above these the hobbits saw thickets of birch and rowan, and beyond them dark climbing pinewoods.  Soon Treebeard turned a little away from the hills and plunged into deep groves, where the trees were larger, taller and thicker than any that the hobbits had ever seen before.  For a while they felt faintly the sense of stifling which they noticed when they first ventured into Fangorn..." ~The Two Towers, Book III, chap. 4 (Treebeard)