Heh, well he started chewing on the other chair leg.
So I coated every single chair leg in my dining room with the tee tree oil (not completely, but enough for him to not want to chew chairs anymore).
We'll see how well it works. I figure the oil should soak right into the wood and he'll taste/smell it as soon as he gets close. He certainly stopped chewing the first chair leg.
My whole place smells of this oil now.