Oh, the tree's magical seed is actually inside the tree, they're inside said giant tree when this scene is happening. (The plot of the second book is they return to their giant tree that they lived in when Stone was a child, hundreds of years ago, only to find its magical seed that keeps it alive has been stolen, so they go get it back.)

I can remove the knowledge of the giant tree outside the room with the seed in it, though, if that's too much for one echo ^^