Firewood can sometimes bring unexpected pests into our homes. Luckily, most of them pose no danger to us, our homes, or our belongings.
Insects and other hitchhikers are commonly found living or hiding in firewood. Some feed on dead wood, some nest inside the wood and some simply hide under the loose bark.
The following suggestions will help you avoid the annoyance of insects entering your home from your firewood. First, stack firewood off of the ground. This aids in drying and makes it more difficult for insects to crawl into the woodpile. Second, leave firewood outside until a day or two before it will be burned. Insects in firewood stored outdoors remain cold and inactive. It will generally require a couple of days before insects warm up and become active.
We strongly advise against using insecticides on firewood. Treating firewood with insecticides has little benefit and is potentially dangerous. Most insecticides will not penetrate deeply enough into wood to kill the insects. Additionally, storing and burning insecticide-treated firewood indoors could pose a health hazard, as the insecticide may be vaporized into the living area of your home.
Common firewood insects
Longhorned beetles and metallic woodboring beetles can be a nuisance if they emerge from your firewood, but they will not harm the wood in your home. Females of these beetles are attracted to dying, freshly cut or recently killed trees where they lay their eggs. The larvae emerge from the eggs, burrow into the tree and spend one to several years as borers tunneling through the wood.
Bark beetles also attack dead or dying trees, making them common in firewood cut from dead trees. These are small (less that 1/8 inch), brown or black, cylindrical beetles. The adult beetles tend to attack wood in groups, so a log cut from an infested tree can contain hundreds of individuals.
There is a wide variety of creatures that over-winter under the bark of trees and in wood piles. When you warm this wood by bringing it into your home, they will wake up and come crawling out. Pillbugs, centipedes, millipedes, and ground beetles are commonly found in firewood. None of these insects will harm you or your home. They need only be picked up and removed.
There are, however, two insects that may cause problems if you keep firewood stacked against your house - carpenter ants and termites. Wood stacked directly on the ground may be fed upon by termites. While the main termite nest, which contains the queen, is in the ground below, termite workers can tunnel into the firewood. Termites brought into your home in firewood can not establish a new nest and will not damage your home or your furniture. However, a woodpile stacked against a house can serve as an avenue for termites to infest the structure.
Carpenter ants differ from termites in that they do not eat wood. They merely hollow out galleries or nests in the wood. These galleries will be smooth and follow the grain of the wood. If infested firewood is brought into the house, the ants may warm up and move out of the wood. This can be an annoyance, but the odds of these ants establishing a nest in your house are very slim.
Remember to stack firewood off of the ground and away from your home, then make frequent trips to the woodpile to avoid firewood sitting indoors too long. However, if you do get an unexpected insect guest this winter, don't worry, just vacuum or sweep it up and discard.
The redheaded ash borer is one of many common longhorned beetles that may emerge from firewood inside the home. Photo by Marlin Rice.