How do you get the boy out of the tree in The Legend of Zelda the windwaker

Do you mean the girl in the tree in the beginning of the game? Because if you do then all you have to do is walk up to her.

You can get the boy (one of the Killer Bees for the Hide and Seek sidequest) out of the tree by slide dashing into it. You can do this by rolling into the tree.