Need organic solution for carpenter ants

My neighbor and I both have silver maple trees that are prone to a virus which slowly kills the tree. In the interim, the carpenter ants invade. He has small children and like me, doesn't really like to use chemicals. The ants aren't as much of a problem for me as they are for him (I think that is due to the fact the my woodpecker takes care of a lot of them - he cut down the woodpeckers nest in his maple -- and now he's MINE!) haha!

Seriously though does anyone know of an organic way to get rid of these pests? They seem pretty much impervious to anything short of nukes or chemicals. (Except the bottom of your boot!)
Thanks!

Boric acid should work. If you mix a couple tesapoons of the powder with a sweet bait (something the ants would be attracted to) and put it in sometype of container with holes in it so the ants can enter it should do fine.
I've also had great luck with vinegar, or even a mix of vinegar and water. Use it as a spray or pour down their holes.
And if you have plenty of wood ash from your fireplace or woodstove that is also good. Keep the area dusted with that and they will move on.
By the way, do they climb the tree? If so maybe a glob of some sort of "sticky trap" substance applied all the way around the trunk to block them from going up will help.