Before you worry about how to get rid of termites in your firewood, you must figure out why they are there. If you recently bought the firewood, chances are the termites were in the wood when you bought it. If that's the case, then you don't really have to worry about killing the termites. Termites do not live in wood; they live in the ground. Without a nest or a queen to reproduce, the termites won't survive. If, however, you notice termites in older wood, most likely you have a problem with termites that extends beyond your firewood. In these cases, you may need to change how you store the wood and address the termite problem on a larger scale.
Look at the wood for tunnels. Tunnels don't guarantee termites, as several different types of insects are known for this behavior in firewood--including carpenter ants, woodborers, bark beetles and horntail wasps.
Look at the tunnels in the wood. Termite tunnels are likely to be lined with mud. If the tunnels are smooth with no mud, your problem is more likely to be carpenter ants.
Look at the insects in the wood. Termites can be wingless, soft-bodied insects that are creamy white or light brown. However, they can also be darker bodied, with wings that look very similar to winged ants. However, termites have two sets of wings that are the same size and straight antennae. If you notice an object that looks like a stinger, it's a horntail wasp, not a termite.
Look around the firewood for mud tunnels. Mud tunnels in the ground near the firewood are a good indication of termites. If you find them, your problem is with termites in the ground. Call a professional to assess your home for damage and getting rid of the termites.
Check how the wood is stored. Wood stored on the ground or directly against the house is more likely to have problems with termites. Store wood off the ground, such as on poles suspended between cement blocks. Keep some space between the wood and the house to help keep the wood dry.
Keep the wood dry, and dry out any moist wood. Termites are more likely to be found in damp or wet firewood. Stacking the wood in loose piles off the ground will help keep the wood dry. Also, splitting any large logs into smaller sizes can help accelerate drying of new wood. Unsplit wood with bark is more likely to attract insects than split wood.
Store firewood under dark plastic. In the summertime, heat will build up under the plastic, which evaporates any moisture and kills any insects in the wood. Make sure you allow for ventilation if covering green, unseasoned wood.