By Zachary Ciras on September 24, 2020.

What can we do about big, black ants in our firewood pile? I was restacking the pile for winter use and there seem to be black ants everywhere. Some of the wood looks in rough shape. Can I burn it in the fireplace or does it have to be tossed into the woods?

J.P., Millbury, MA

Various types of ants will nest in firewood piles, usually just for the protection in crevices. Chances are, though, that your ants are carpenter ants that are actually living in and excavating the wood (see Are These Carpenter Ants?). Ants, termites, and other insects that call a woodpile home are usually lured by damp wood, or at least wood that is sitting directly on damp ground. And that means that your firewood may not be in great shape to begin with. Insect infestation isn’t helping.

Wood that is damp or has been hollowed out by insects isn’t going to be of much heat value anyway so I suggest that you not even bring it into the house (an outdoor fire pit is an option). And definitely do not spray or treat the firewood with pesticides and then expect to safely burn it, either indoors or outdoors (see What Can You Do with Insect-infested Firewood?).


If you bring infested firewood in during cold weather, insects in the wood will become active as the wood warms up. People then worry that carpenter ants coming out of firewood might infest wood in their home. It’s very unlikely that firewood ants would do any damage to other wood indoors. You are relocating only a small portion of the colony, which is no doubt missing the queen. Those ants would be very confused and would probably die fairly quickly in the drier indoor air.

To help keep firewood insects out of the house you can bring in only two or three days worth of wood at a time. Removing the bark from the logs before bringing them indoors will eliminate many insects.


In the future, take steps to make sure that your firewood is stored in a way that will preserve the wood’s value by keeping it dry and will also discourage wood-infesting insects:

  • Stack cut wood as soon as possible, off of the ground, in a sheltered area at least 10 feet away from the house.
  • Stack wood in loose piles to increase air circulation.
  • Check firewood during the summer and discard or move and restack pieces that seem to be infested.
  • Burn older wood first since wood stored for more than one or two seasons can become heavily infested with insects and will develop loose bark that is more attractive to overwintering insects.
  • Don’t store extra firewood in a heated garage or basement or insects will emerge there instead.


Carpenter ants are beneficial because they help decompose decaying wood when they excavate gallery nest sites inside the wood. That doesn’t mean you want them doing their job too close to your home’s foundation, in your firewood pile, and definitely not in your home. If carpenter ants are just too abundant or too close, there are steps you can take to make the area less attractive to the ants (see Outside Maintenance Can Discourage Carpenter Ants).

Remember that the two primary requirements for carpenter ants are wood and moisture. Anything around your home perimeter that provides damp wood is subject to infestation by nesting carpenter ants (and termites). Rotting tree stumps, dead branches on the ground, lumber stacked near the foundation or in the crawlspace, grade stakes, form boards, and other construction debris left in crawlspaces or under porches, rotting landscape timbers or planter boxes, even excessive wood mulch are all invitations to carpenter ants and termites. 

One of the best steps you can take to keep carpenter ants (and other insects) out of your home is to ask us about our twice-a-year Preventative Maintenance Program. We treat around the outside of your home and that means no contact for you, and no mess on the inside. The perimeter barrier treatment intercepts carpenter ants as they move around the foundation of your home, keeping them from getting inside. 


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