Voices of the Tree

In the episode Do the Right Thing (unknown season), Max takes his bulldozer to Dragon Land and ruins the nodlings' wagon. Later in the episode, the nodlings and their wagon end up inside a tree tied to a zipmunk.

I swear that tree is voiced by John Ratzenburger, the same guy who did the voice of Mack in Cars and the fish school in Finding Nemo, among others. Can anyone confirm or refute this? It's not in the credits that I can see.