Tree Talk: Insects That Live in Firewood

Many of us feel that one of the compensations of cold winter weather is relaxing in front of a roaring fire. When we bring firewood into our homes though, we may also be bringing some uninvited guests. Here is some information about insects that live in firewood along with some tips for storage.

Does your firewood have insects? Almost certainly yes! Should you be concerned about that? No, but there are some important precautions to take.

Many types of insects inhabit trees. Hundreds of species of beetles lay their eggs in trees, as well as many wasps and moths. Some live under the bark, while others burrow into the wood, carving galleries for their larvae who then munch their way through the wood as they develop, creating patterns that look like primitive art. As trees decline, opportunistic insects move in: few insects are attracted to healthy trees.

Even after trees have been cut down, some of these insects will continue to build their homes there. As firewood dries though, it becomes less hospitable to most insects—which is why it’s always a good idea to keep firewood covered and raised off the ground. This is also why trees should be cut into smaller pieces as soon as possible: smaller pieces dry faster. In addition to the insects that inhabit living trees, there are also insects such as termites and carpenter ants, which are attracted to damp, dead wood.

When you buy firewood, look for wood that is well-dried. It will feel lighter than freshly cut wood and the bark will be loose. Holes are a good sign—they are usually made when insects leave. Most of all—BUY LOCALLY.

I can’t stress this last point enough. Moving firewood has spread and accelerated infestation from several major pests and diseases, including the emerald ash borer and the Asian long-horned beetle. A simple act, such as taking a few pieces of firewood back home from a camping trip, has brought devastating insects into new areas and caused millions of dollars worth of damage.

There’s no reason to panic about the possibility of insects in local firewood: They are the same insects that are living in trees in your area. If one should emerge, bewildered, from a log in your living room, there is virtually no danger to you or your home (even the wasps that live in wood are non-stinging).  

To avoid the possible danger from insects such as termites, keep your firewood outside and away from the house or any other wooden structure, and keep it as dry as possible. You can buy or make a rack to raise it a few inches off the ground. Companies like Brookstone and L.L. Bean offer some attractive solutions, but some cement blocks and pipe or 2x4s and plastic sheeting will also do the job. This also should minimize intrusion from ground insects like millipedes and woodlice. Leave space for air between the wood and the cover.

Even dry firewood is no guarantee against insects. Some, like carpenter bees and powder post beetles, are only attracted to dry wood. Also, some beetle larvae can still develop after two years.

Winter is down time for insects. As long as the wood is outside in the cold, the insects will be dormant. There’s little chance of meeting any bugs if you only bring the wood inside your home when you’re about to use it. Bring any unused logs outside again for storage.

If you don’t like the possibility of insects in your firewood, don’t resort to using pesticides. First of all, pesticides don’t work on insects inside the wood—nor does a pesticide application prevent them from entering. The danger from inhaling the burning pesticide is far greater than that from a stray beetle.

Here is the short list of do’s and don’ts:

DO keep firewood outdoors until you use it.

DO store firewood away from any wooden structures.

DO keep firewood dry, covered and lifted off the ground.

DON’T use pesticides on firewood.

DON’T move firewood more than 20 miles.

DO enjoy your roaring fire!