Roach Proof (boric acid) mixed with honey will kill carpenter ants.
Ants will take this mixture back to the nest and in time will kill the queen.

Maybe you could figure out a way to put Roach Proof/honey in a small container and fasten to trees out of reach of children to reduce the ant population. Protect from rain.

Since the mixture worked in a weeks time I did not get around to putting the mixture on trees. I did put jar lids of the mixture in the upstairs and downstairs attic.

Ants will enter a home through the weep holes of the brick.
Ants enter the home looking for water.

They much prefer wood that is softened by being wet.

Honey is expensive...use corn syrup. Or just buy a ready made boric acid and sugar mixture like Terro. It does work wonders on ants.