Question:

I’ve read that firewood can bring pests into your home. My husband is busy cutting and stacking firewood for the winter. What can we do to keep from bringing bugs in with the firewood?

Answer:

Good question, and it’s good that you’re asking it now because the first step in firewood pest prevention has to do with firewood storage. Firewood is often already infested with pests before it is even stacked. There’s a group of wood-boring beetles that infest dead trees or newly fallen trees. Their larvae can be burrowing in the wood before it is even cut up. Splitting the wood as soon as possible helps it dry faster and reduces beetle infestations.

Don’t stack firewood directly on the ground. Pests and moisture go hand in hand. There are a number of moisture-loving pests that will seek shelter in firewood stacked on the ground because the bottom logs absorb moisture. This group includes centipedes, sowbugs, millipedes, and springtails. They usually hide under the bark and don’t damage the wood. There is, however, another group of pests that will actually infest the wood itself. Termites, carpenter ants, and powderpost beetles prefer damp wood stored on the ground.

Stacking wood on the ground isn’t good for the wood either. The bottom two or three layers of wood will retain moisture and you’ll end up with wood too wet or too rotten to burn well. Stack the wood loosely up on a store-bought or homemade rack (cinder blocks and two-by-fours work just fine). Leave at least 10 inches between the firewood and the ground.

Location, location, location. Don’t locate the woodpile so that it touches the house (or shed, or garage). Be especially careful if your house has wood siding. Firewood touching a house can provide termites with a way to bypass the soil treatment around the foundation and instead move directly from the woodpile into the house. Pests in the woodpile are more likely to find their way inside if they sense warm shelter nearby.

Woodpile maintenance. Rotate the wood pile annually. Don’t let a log remain on the bottom of the pile for more than a year. Most of the pests inside a wood pile, like crickets and earwigs, are there simply because the wood provides shelter. Rotating the wood disturbs them and helps the wood dry evenly. Covering the wood with a tarp or plastic sheet helps keep it dry and the heat buildup under the tarp in hot weather repels many pests. Leave an air space between the wood and the cover.

When it’s time for a cozy fire. Burn older wood first, so that pest populations don’t have a chance to build up. Before bringing wood inside, remove the bark if possible. This will flush out many insects that hide under the bark before they can get inside. Avoid the temptation to stockpile a large wood supply indoors. Bring wood in only as you need it. If wood sits for more than a few hours indoors before it is burned, pests can warm up, become active, and move out of the wood. They will not damage the firewood once it’s inside, and only under unusual conditions will wood-boring beetles infest wood in the house. Other nuisance pests like millipedes and sowbugs will not survive long in the drier indoor air and can be vacuumed up.

Don’t even consider using pesticide. Whatever you do, don’t spray the woodpile or individual pieces of wood with pesticide—either to kill pests or as a preventative. Burning insecticide-treated wood may release toxic fumes into your living space and could be a potential health hazard. For certain serious pest problems, insecticide bait or spray can be applied outside around the woodpile, not on it. Have a pest control professional do this job. Keep in mind that burning the wood will kill the pests just as well. You might also be interested in reading our post about carpenter ants or termites in firewood.