Carpenter Ants in Trees

Trees are used by thousands of mammals and birds. Squirrels use cavities for nesting areas and sometimes build nests in the branches. Many birds make nests to lay eggs and rear their young, and turkeys use the branches to roost at night to keep them safe from ground predators.  Many insects also use trees in one way or another, sometimes to the detriment of the tree.

One insect that can be found living in trees is carpenter ants. Carpenter ants get their name from their ability to excavate wood to make areas for nests. They are commonly found nesting in trees and can sometimes cause damage to wooden structures as well. If there are carpenter ants in a tree or trees in a forest, are they causing harm to the tree?

Carpenter ants do not actually feed on the wood itself. They feed on insects, both living and dead, as well as honeydew, which is a sugary substance produced by sap-feeding insects like aphids. These ants do, however, create galleries in wood for nesting areas and travel tunnels. Since they do not actually eat the wood the same way termites do, sawdust piles can often be found near the infested area as they remove the wood from the galleries. 

It is important to note that carpenter ants prefer to excavate soft wood, such as decaying wood, so they do not typically tunnel through healthy wood. Their presence in a tree is more of an indicator that decay is already present within the tree.  Often, when they are found tunneling in a wooden structure, they are in an area where a moisture-related issue has caused the wood to soften or decay, creating conditions that are ideal for the ants to do their work. In homes, common places where they are found are around wooden windowsills that are no longer sealed tight, wood around sinks that frequently get wet, and even roof rafters from a leaking roof. 

While carpenter ants are not necessarily causing harm to the tree, their excavation work may create a weaker area within the tree that could cause it to break off in a windstorm. It really depends on how much healthy wood is left in the tree.  While these ants are not considered a forest pest, if they are nesting in a tree near a home, it may be beneficial to eradicate the nest to help prevent them from moving into a structure, causing damage. Ants can be difficult to so consult a reliable exterminator if the decision is made to treat the ants.