Possible Clues:

• Tonsillitis docs
• Literary tree dwellers
• Fangorn Forest beings
• Tolkien tree race
• Tolkien tree-creatures
• Middle-earth beings
• Otolaryngologists, for short
• "Lord of the Rings" tree beings
• Drs. eliciting 59-Acrosses
• Tolkien's Treebeard and kin