Carpenter ants often get a bad rap. Callers often tell me that these big black ants are killing their trees, or are invading their home and might be causing damage. I try my best to explain that carpenter ants do not cause problems, they hang around because there is a problem.
Ants of the genus Camponotus are known as carpenter ants because they prefer to establish their colonies in galleries (nests) excavated from damp or damaged wood. They cut galleries into the wood grain to form their nests and provide passageways for movement from section to section of the nest. When a fallen tree exposes a carpenter ant gallery, you often see signs of rot and softened wood, as well as ant eggs, larva and a bunch of soldier ants trying to protect their young. Chances are, this rotten area has been growing in the heart of the tree for years, and the ants are there taking advantage of the softened wood.