Firewood is an ideal habitat for many common insects, including wood-boring beetles, termites, and spiders, which seek shelter, food, and moisture. When logs are brought inside for burning, these pests can become unwelcome houseguests, potentially leading to indoor infestations or structural damage. Keeping wood pest-free relies on strategic outdoor storage, proper wood preparation, and guidelines for handling existing insect problems. The goal is to create an environment that is too dry and exposed for these creatures to thrive, while maintaining a convenient supply of fuel for the fire.
Strategic Storage and Stacking
The location and structure of the woodpile are the first lines of defense against insect infestation. Firewood should be stacked at least 20 feet away from any structures, such as a home, garage, or fence, to prevent pests from using the pile as a bridge to migrate indoors. This distance reduces the risk of ground-dwelling pests like termites and carpenter ants moving from the wood supply to the building foundation.
Elevating the wood off the ground is important for discouraging moisture and access for pests. Logs should be stacked 6 to 12 inches above the soil or concrete using a specialized rack, concrete blocks, or old pallets. This elevation promotes air circulation beneath the stack, which helps dry the wood and makes it less inviting to moisture-loving insects like earwigs and sowbugs.
The stacking method should maximize airflow and sunlight penetration. Stacking logs in a single row or a loose crisscross pattern allows air to move freely through the pile, inhibiting the damp conditions many insects require for habitation. To shield the wood from rain, a cover should only be placed over the top third of the stack, leaving the sides completely open for ventilation.
Wood Preparation and Seasoning
The internal condition of the wood is a powerful factor in determining its attractiveness to pests. Seasoning, or drying, the wood reduces the moisture content, which is a primary driver of insect activity. Wood-boring insects are strongly deterred when the moisture level of the wood falls below 20%, as this creates an unsuitable environment for their larvae to survive and develop.
Freshly cut wood, often referred to as green wood, can have a moisture content exceeding 50%. Hardwoods like oak typically require 12 to 24 months to season, while softer woods like pine can dry in six to twelve months. Splitting logs soon after cutting increases the exposed surface area, accelerating the evaporation process and helping the wood reach the target moisture content quickly.
Another preventative measure is removing the bark from the logs before stacking them for seasoning. The bark provides a protected, moist space that serves as a hiding place and initial food source for many species of beetles and their eggs. During the splitting and stacking process, any pieces showing evidence of heavy infestation, such as tunnels or sawdust-like frass, should be discarded or moved away from the main pile.
Addressing Existing Pest Problems
When preventative measures fail, and pests are found, the immediate focus shifts to isolation and elimination. Any wood showing signs of infestation should be moved away from the main stack and the house to quarantine the problem and prevent further spread. Moving the affected logs to a new, sun-drenched location can be an effective initial treatment.
Spreading infested logs out in direct sunlight, preferably on a dark-colored tarp, uses heat and desiccation to kill pests. Intense sun exposure can achieve temperatures sufficient to drive out or eliminate many insects and their larvae. This method is preferred because chemical insecticides are discouraged for firewood due to the potential for toxic fumes when burned indoors.
To prevent indoor pest migration, limit the amount of wood stored inside the home. Only a small, manageable amount—enough for perhaps 24 hours of burning—should be brought inside at a time. This prevents insects that are already present in the wood from having enough time to emerge from the logs and establish themselves within the structure of the house.