The Barking Dogwood is an animated form of dogwood tree residing on the Isle of Wonder.
Hark, hark, the dogwood does "bark".
The tree is near the swampland, and part of its trunk is shaped like a dog's head. The head actually barks, and doesn't seem to like anyone getting too close. Alexander wondered if its "bark" was worse than its bite.
Behind the scenes[]
The dogwood tree is given the name 'Barking Dogwood' in the King's Questions.
Not quite an ent, but certaintly similar animated tree.