haha i suddenly became paranoid i was giving you a wive's tale and not a "fact" (ya know, verify, don't trust...). Google's answer made me chuckle:

Cinnamon is often regarded as an effective DIY ant control option. It is believed that cinnamon acts as a natural repellent because ants cannot stand the smell. Also, if an ant inhales cinnamon, it can suffocate and die. Ground cinnamon can be sprinkled on an ant's pathway for them to inhale.

SUFFOCATE AND DIE, ANTS!!

Odd, it didn't mention the bark-of-tree thing. Guess that's "in the details"...