"Choice after a long life that suddenly got even longer in the span of a few years." He invited people into it after going solo, got wrapped up in a world filled with people, and then killed the woman he loved when she-- well, it wasn't really Jean anymore. "Lived in the forest," Logan says as he slides on a pair of pants, and by forest, he literally lived in a cave.

But those are details that seem unnecessary and hard to explain without understanding that he's not completely human. He's a mutant, and the forest has a certain meaning to him that is hard to put into words.