Related Clues:

• Covering of tree trunk
• Barking sound
• Animal sound — layer protecting tree trunk
• "Walk me!"
• Shepherd's comment
• Certain traditional medicine source
• 'Bow-wow'
• Outside of a tree
• Pooch noise
• Woof equivalent
• Tree's protective layer
• Lab report?
• Sound a child might imitate
• Source of cinnamon spice
• Woofer's sound