“IS IT SAFE TO BURN FIREWOOD THAT’S INFESTED WITH INSECTS?”
By Chris Williams on November 26, 2019.
My wife finally pushed me to move some firewood inside so we can start using the fireplace. I didn’t realize my woodpile was in such bad shape. Some of the logs seem to be infested with some kind of wood borer because there are lots of little holes and quite a bit of sawdust below. Can I still burn this wood in my fireplace?
Sure, you can still burn insect-infested firewood, assuming that it hasn’t been sprayed with any pesticide (see What Can You Do With Insect-Infested Firewood?). Insects are just protein after all and grilling them won’t hurt you, but you need to decide if it’s worth it.
IS THAT WOOD EVEN WORTH THE EFFORT?
Whether the wood is worth burning depends on the condition of the wood (dry and seasoned versus damp and rotting) and the type and degree of insect infestation. You don’t say how old the woodpile is but if it’s been stacked there for more than two seasons, the wood is probably deteriorated and may be damp and rotting. The fact that at least some of it is infested by insects is a clue that this may be the case.
If there is extensive tunneling inside the wood, there may not be much interior wood left to burn and it may not be worth the effort to haul it inside. Maybe an outdoor bonfire, complete with marshmallows, is a better idea!
The condition of the wood depends a great deal on how you have it stored. Is it stacked up off of the ground? If it’s been sitting on the ground, you probably have more than borers in that wood. Termites or carpenter ants would be a good bet (see Carpenter Ants From Firewood). These two potential firewood pests also tunnel into the wood while many other insects and spiders are just hiding under bark or in the woodpile to escape the elements.
If your wood is dry and not too old, it’s possible that only a few logs (from the same tree?) are infested. You may be able to discard those and burn the rest without a problem.
KEEP FIREWOOD PESTS FROM EMERGING INDOORS
If you decide to burn the wood inside, take some precautions so that you don’t have a bunch of sluggish insects emerging from the wood and wandering around:
- Bring in only the amount of wood that you are going to burn at the time. It takes several hours to a day or more for insects in firewood to warm up enough to become active.
- Removing the bark before you bring the wood in will help to eliminate many insects that hide under bark but, of course, is extra work (is that bonfire idea starting to sound better?).
- While you should never spray pesticides on wood that you intend to burn in a fireplace (or outside), you can sometimes spray the indoor wood holding area with a properly labeled insecticide to kill pests that are emerging from the wood.
You shouldn’t have to worry that any emerging insects will infest and reproduce in your home (see Insects in Firewood Are Usually Harmless). Insects that find their way out of firewood indoors don’t usually survive long in drier indoor air. And because they are slow moving at first, a vacuum, broom, or fly swatter will do the job.
For more on preventing insects in your firewood supply, see: