Tecnicamente, ele não conheceu Merry e Pippin em Fangorn. Ele estava lá se recuperando de sua "luta com o Olho de Mordor", e passou a ver Barbárvore passando. Nenhum dos dois falou com o outro, e o encontro ocorreu dois dias antes de Barbárvore encontrar Merry e Pippin.
Tanto quanto me lembro, Gandalf nunca explica por que ele estava em Fangorn no momento em que ele e Barbárvore mancharam um ao outro, e eles não falaram um com o outro até uma data posterior. Só então ele percebeu que Barbárvore havia encontrado os hobbits e os colocou sob sua asa (err - quero dizer, sob o galho dele)."For [Treebeard] came here two days ago and bore [Merry and Pippin] away to his dwelling far off by the roots of the mountains. He often comes here, especially when his mind is uneasy, and rumours of the world outside trouble him. I saw him four days ago striding among the trees, and I think he saw me, for he paused; but I did not speak, for I was heavy with thought and weary after my struggle with the Eye of Mordor, and he did not speak either, nor call my name."
-Gandalf, The Two Towers, "The White Rider"
A reunião em Fangorn entre Gandalf, Barbárvore e os dois hobbits só ocorre no filme. No que diz respeito ao livro, Gandalf descobriu onde os hobbits estavam quando Gwaihir, o Senhor do Vento, lhe disse:
“Will you not first give us news of the hobbits,” [asked Aragorn] “Did you find them, and are they safe?”
“No, I did not find them,” said Gandalf. “There was a darkness over the valleys of the Emyn Muil, and I did not know of their captivity, until the eagle told me.”
“The eagle!” said Legolas. "I have seen an eagle high and far off : the last time was three days ago, above the Emyn Muil,”
“Yes,” said Gandalf, “that was Gwaihir the Windlord, who rescued me from Orthanc. I sent him before me to watch the River and gather tidings. ..”
- ibid