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Carpenter Ants Living In Tree Trunks

Every year we receive numerous calls regarding hollow tree trunks and a progression of Carpenter Ants traveling up and down the trunk and disappearing into the cavity. Professional treatment is typically NOT required because the ants are not creating the cavity in the tree, they are merely taking advantage of an existing, protected, nesting opportunity.

Ants are like termites in that they will not, and can not, eat or chew into living tissue or live wood. They merely clean out and move naturally rotting and decomposing wood to create a living environment. Most old, mature trees have cavities in them. The cavities should never be filled with cement or any other substance, and the ants that occupy them do not need to be destroyed unless you have another reason to destroy them (for example: if they start invading your house!)


Killing off a nest of ants may take a few years as they are tough to get at, as they are protected deep within their hollowed-out fortress.


The easiest way for homeowners to begin control is to spread ant powder all around the base of the tree and keep re-applying it every time it rains and disappears. The ants will need to walk through it as they leave the tree in search of food. The product will absorb through their feet and they will die at a later time, usually within the nest. As ants are carnivorous, they will cannibalize their own dead, and the poison will spread throughout the colony.

Please be aware that there is now poison around the tree, which can pose a threat to inquisitive pets or children.


We have found that ants typically live above the entrance hole. We assume this is the case so that any water that infiltrates the entrance hole can’t seep downward and flood the nest. If the entrance hole can be safely reached, activate a can of room defogger into the opening (the type that is meant to bug bomb a house for spiders and other bugs). If they are living above the hole, they will come flooding out by the thousands.

Have a few aerosol cans of Raid or Ortho Ant Killer ready and spray the ants as they evacuate their ‘protected’ environment. Between those that are killed instantly and those that will feed off of the dead ant carcasses later, the problem should be able to be brought under control fairly quickly.

Doesn’t the fact that ants are hollowing out the crevasse of a tree at a faster rate than normal compromise its stability?

Actually, no… in fact the opposite is true! When wet, spongy, and decaying wood is trapped inside a tree, the healthy wood it contacts is more apt to decay. Having ants clear out the decaying wood allows for better air flow into the cavity, allowing the area to dry out and not decompose as quickly! So, in a way, the ants many be somewhat beneficial!

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We’re fully committed to exceeding your expectations at every step. Our certified arborists not only offer you the best tree care solutions but also extend the utmost respect to your property. In a world where customer service often falls by the wayside, we’re raising the bar, one satisfied customer and healthy tree at a time.