Ithrynluin is certainly correct, Aslan.
The old man that
Aragorn,
Legolas, and
Gimli met at edge of
Fangorn the night they reached the battlefield on the edge of Fangorn was
Saruman.
Gandalf was more aware of Saruman’s movements than is immediately apparent. Speaking with the 3 hunters before Gimli asks if they had seen Gandalf or Saruman the day before, Gandalf says of Saruman:
He was so eager to lay his hands on his prey that he could not wait at home, and he came forth to meet and to spy on his messengers. But he came too late, for once, and the battle was over and beyond his help before he reached these parts. He did not remain here long. I look into his mind and I see his doubt. He has no woodcraft. He believes that the horsemen slew and burned all upon the field of battle; but he does not know whether the
Orcs were bringing any prisoners or not. And he does not know of the quarrel between his servants and the Orcs of
Mordor…
It is possible that Saruman left
Isengard because
Uglúk and his band did not reach Isengard when Saruman expected them, and he went to learn what had happened to them. He could have used the
palantir to observe them, but perhaps that might have exposed too much of his private schemes to
Sauron, to whose palantir the Orthanc-stone was already closely attuned by regular use. That would explain both his late arrival and that “he does not know whether the Orcs were bringing any prisoners or not.” It was fortunate for
Éomer and his
men that Saruman was late!
What I find interesting is that Saruman did not seem to have recognized Aragorn, a Man whom we might suppose had earlier made Saruman’s acquaintance in his travels. That might indicate that Aragorn had never met him, or even avoided him. If he did recognize him, he certainly made no sign, and left as quickly as he could, which was obviously very fast.
It is curious that Saruman would not know that an Heir of
Isildur lived and walked the earth. In “The Passing of
the Grey Company” in his speech with Legolas and Gimli, Aragorn remarks,
Did I not openly proclaim my title before the doors of Edoras? … The eyes in
Orthanc did not see though the armour of
Théoden; but Sauron has not forgotten Isildur and the
sword of
Elendil.
When Aragorn began his travels, Saruman was still a member of
the White Council in good standing, considered an ally of the West. Galdor asked why he was not at the
Council of Elrond: the
Elves knew nothing of his treachery. Neither Gandalf nor
Radagast, who was no fool despite Saruman’s contemptuous remark, consciously suspected him. Aragorn was betrothed to
Arwen, his home was in
Rivendell, he was a frequent guest in
Lórien; and he, Legolas, and Gimli met Gandalf in Fangorn on his 88th birthday, so he was no youngster in
Middle-earth. Was Saruman so far estranged from his old allies that he knew nothing of Aragorn? That seems to be the implication. Can we suppose that
Elrond had discouraged Aragorn from visiting Isengard, to which Aragorn held rightful claim and which should have been a refuge and haven for him in his travels.
The old man they met in “The White Rider” moving from tree to tree is Gandalf approaching them as they stand on the hill where
Merry and
Pippin met
Treebeard.
