Termites in firewood are common, and spotting them early keeps a minor outdoor problem from becoming an indoor one. The most reliable signs include mud-lined tunnels inside the wood, small piles of sawdust-like droppings near the stack, and wood that sounds hollow or crumbles when you knock logs together. Here’s how to identify each sign and what to do about it.
Why Termites Target Firewood
A firewood pile offers insects a trifecta of food, water, and shelter. Stacked wood, especially pieces sitting on bare ground, holds moisture and stays relatively protected from temperature swings. Termites are naturally drawn to dead wood. Finding them in a log pile doesn’t mean your home is at risk; it means the termites are doing exactly what they do in nature, breaking down and recycling dead wood. The concern starts when that infested wood gets carried inside or stacked against your house.
Mud in the Galleries
Subterranean termites, the most common type in most of the U.S., build their colonies in the soil and travel to wood through pencil-width mud tubes. When you split a log and see networks of small tunnels packed with dried dirt or mud, that’s termite damage. The tunnels (called galleries) follow the grain of the wood and look distinctly different from the random crumbling of ordinary wood rot. If the mud is dried out and no live insects are visible, the infestation may be old. If you see pale, soft-bodied insects inside the galleries, the colony is actively feeding.
You may also notice mud tubes running along the outside of logs near the bottom of the stack, especially where wood contacts the ground. These tubes are about the diameter of a drinking straw and serve as protected highways between the soil colony and the food source above.
Droppings That Look Like Tiny Seeds
Drywood termites, more common in southern coastal states, leave behind a different calling card. Because they live entirely inside the wood (no soil contact needed), they push their droppings out through small holes in the surface. These pellets are tiny, about the size of a grain of sand, and have six flat sides that give them a hexagonal shape under close inspection. To the naked eye, they look like a small pile of coarse, dark sawdust beneath a log or at the base of a stack.
Dampwood termites produce similar pellets, but theirs are more football-shaped and rounded at the ends, lacking the sharp ridges of drywood droppings. Dampwood termites tend to infest wood that stays consistently wet, so they’re more likely in firewood stored in shady, poorly drained spots or wood cut from green, unseasoned trees.
Hollow Sound and Soft Spots
Termites eat wood from the inside out, leaving a thin outer shell intact. A log that looks perfectly solid on the surface can be nearly hollow inside. Tap two logs together or knock on a suspect piece with your knuckle. A healthy log produces a solid thud. An infested log sounds distinctly hollow or papery. You might also notice that the wood feels lighter than you’d expect for its size, or that pressing a screwdriver into the surface meets almost no resistance before breaking through into empty galleries.
Swarmers Around the Woodpile
Once a year, usually in spring or early summer, mature termite colonies release winged reproductive insects called swarmers. These look like small flying ants with straight antennae, a thick waist, and two pairs of wings that are equal in length. If you see a cloud of these insects emerging from your firewood stack, or find piles of discarded wings on top of or around the logs, the colony is well established. Dampwood termites can also swarm during summer and fall, and they’re noticeably larger than other species.
Swarmers emerging from a log pile well away from your home (25 feet or more) are a normal part of the ecosystem, not an emergency. Swarmers near your foundation are a different story.
How to Store Firewood Safely
The biggest risk isn’t the termites in the wood itself. It’s what happens when infested logs create a bridge between a ground colony and your home’s structure. A few storage habits eliminate most of the danger.
- Keep wood away from the house. Store your main supply at least 20 to 30 feet from the foundation. A smaller working stack can sit closer, but keep it at least one to two feet from any wall, and never stack firewood directly against your home’s siding or foundation.
- Elevate the stack. Raising firewood off the ground on a metal rack or concrete blocks removes direct soil contact, which subterranean termites need to survive. Even a few inches of clearance makes a significant difference.
- Keep it dry. Cover the top of the stack to shed rain, but leave the sides open for airflow. Wood that dries out below about 20 percent moisture becomes far less attractive to dampwood termites and slows decay that draws subterranean species.
- Never store wood in crawlspaces. Firewood, lumber, cardboard, and newspapers stored under or against a home attract termites and give them hidden entry points that bypass any soil treatments around the foundation.
Bringing Firewood Inside
Only bring in what you plan to burn within one to two days. Infested wood that sits unused indoors gives termites time to leave the log and move into your home’s framing. Before carrying logs inside, knock them together firmly to dislodge insects and brush off any visible mud, webbing, or cocoons. A quick visual check of the log ends for gallery tunnels or packed mud takes seconds and can save you from carrying an active colony into your living room.
If you find obvious signs of active termites in a log, the safest move is to burn it promptly or leave it outside. Termites pulled away from soil contact and their colony won’t survive long on their own, so a few stray insects that make it indoors on a log you burn that evening pose very little risk. The danger comes from stacking infested wood next to an interior wall and forgetting about it for weeks.
Termite Damage vs. Other Wood Damage
Not every crumbling log has termites. Carpenter ants carve smooth, clean galleries without any mud or dirt inside them, and they leave behind coarse shavings that look like tiny wood shavings rather than the gritty pellets termites produce. Wood rot caused by fungus makes wood feel spongy and often discolored, but the damage is uniform rather than following a network of tunnels. Bark beetles leave tiny round exit holes on the surface, typically the diameter of a pencil lead, and pack their tunnels with fine sawdust.
The most reliable distinguishing feature of termite damage is the presence of dried mud or soil inside the galleries. If you split a damaged log and find dirt-packed tunnels running with the wood grain, termites are the cause. If the tunnels are clean and smooth, suspect carpenter ants. If there are no tunnels at all and the wood simply crumbles apart, moisture and fungal decay are the likely culprits.