Key Considerations for Seasoning Firewood
Moisture Content
For firewood to burn efficiently, it must have a low moisture content. A moisture meter is an essential tool to determine how much water remains in your logs. Aim to dry your firewood until the moisture content drops below 20%, with an ideal target of under 10% for maximum heat output and minimal smoke.
Freshly cut, green wood often contains more than 50% moisture, requiring thorough seasoning. The greener the wood, the longer the drying process will take, so plan accordingly if you’re cutting your own firewood.
Humidity and Temperature
Wood is hygroscopic, meaning it absorbs or releases moisture based on the surrounding air’s humidity. High-humidity environments cause wood to absorb moisture, while low-humidity conditions help it release moisture.
The best time to season firewood is during periods of low humidity and high temperatures, such as late spring and summer. For example, in an environment with 99% relative humidity, wood stabilises at a moisture content of 23-30%. However, in areas with 75% relative humidity, the moisture content can drop to around 14%, which is ideal for burning.
Type of Wood
Different wood species season at varying rates and provide distinct burning characteristics:
Hardwoods: These dense woods burn longer and produce more heat but require about 18 months to fully season. Common examples include oak, ash, birch, fruitwoods, and eucalyptus.
Softwoods: These lighter woods dry faster, typically within 6-12 months, and are easier to cut and split. They’re excellent for kindling or starting a fire. Popular options include cedar and pine.
Pro tip: Start your fire with softwoods for quick ignition, then add hardwoods for sustained, long-lasting heat.
Stacking and Storage
Proper stacking and storage are critical to ensure effective seasoning. Follow these guidelines:
Elevate your wood: Keep logs off the ground to prevent moisture absorption. Use pallets, firewood racks, or similar tools.
Ensure airflow: Stack logs with enough space between them for ventilation. This allows moisture to escape more effectively.
Choose the right location: Season your firewood outdoors in a sunny spot with good airflow. If your area experiences heavy rain, store wood in a covered structure like a barn or shed, but maintain proper ventilation.
Avoid indoor seasoning: Drying wood indoors can attract pests like termites and may not allow proper airflow for seasoning.
Protect from weather: Use a waterproof cover to shield your wood from rain or snow, but leave the ends of the logs exposed for air circulation.
Cut logs to uniform sizes, such as 16-inch lengths, for easier stacking. Splitting logs into smaller pieces also speeds up the drying process.
Average Seasoning Time
The time required to season firewood depends on its size, type, and environmental conditions. Here are some general guidelines:
Wood cut directly from a tree typically takes about 12 months to season.
Purchased firewood often requires an additional 6 months to dry, depending on its initial moisture content.
Smaller logs dry faster, as wood typically loses moisture at a rate of about one inch per year. For example, a one-inch-wide log may season in one year, while a two-inch-wide log could take two years.
To accelerate the drying process, consider the following:
Dry wood during warm, sunny months like late spring and summer.
Stack wood with ample airflow and ensure the ends are exposed to sunlight.
Split logs into smaller pieces for faster drying.
Use a kiln to significantly reduce seasoning time.
