The Faces Tree Kit included with the Wargamer Tree Set contain models that have a face carved into the bark. They are the precursor to full-blown bipedal tree designs that are currently being designed and scheduled for release next year.
Face trees can be played as Wizards or Sages. They can be used for revealing important bits of information, or as a branching point to another direction in the campaign story.
Another possible scenario could be a character delivering an object to the tree. In exchange for the object, incantations from the Wizard can give the character a special power, or reveal a secret to be used at a future time.