Quote Originally Posted by Abdula
Um, because Orochimaru said that he wanted the first's mokuton because it gave him the ability to control the bijuu and he also said that that must be why they made Yamato the leader of Naruto's group because the mokuton gives him that ability. Something the flashback with Jiraiya and the others confirmed. Weren't you watching/reading?
The First apparently had two unique abilities: using wood element jutsu and controlling biyuu. I don't see how the latter would 'obviously' be a consequence of the former, they could just as well be totally unrelated. I haven't heard anyone say that the first controlled the tailed beasts with his wood element jutsu.