Tips for keeping a fire during cold, wet nights

The cold and rainy weather coupled with foggy nights in the 20s and 30s makes for a fine time to cozy up to a warm, crackling fire. Most of us look for oak logs to burn because of their high BTUs. The term BTU stands for British Thermal Unit. It is a basic measure of thermal (heat) energy. It makes sense to burn firewood that generates high BTUs so your home can stay as warm as possible. White oak and red oak contain about 25 BTUs per cord.

What determines BTU’s in wood? Density, moisture content, and efficiency of your wood burning device. Most firewood is sold green, or freshly cut, which means it could have a moisture content of 60% or more (100% moisture content means half the weight of the wood is water). Sometimes “seasoned” or kiln-dried wood can be bought but you’ll pay a premium for it. It takes 9-12 months to dry firewood from green to 20% moisture content. Burning wood with higher moisture content creates more smoke and may add creosote to the chimney. It also offers less heat, because it takes energy to boil off excess water. That means loss of efficiency. To have dry firewood for next season means it will soon be time to stack green wood again. Under-utilized high BTU species ranging from 32- 24 BTUs per cord include osage-orange, eastern hornbeam, ironwood, locust, apple, and beech.

Don’t shy away from the softwoods like pines, cedar, and willow. In the end having a variety in your wood pile can help control your burn. While hardwoods take longer to catch fire and will burn longer, softwoods ignite quickly and burn fast, making them ideal for getting your fires going.

There’s this age-old wood stacking question, bark up or bark down? The National Association of State Foresters concludes there are benefits and drawbacks to both. Bark down, it is “possible” water can collect in the u-shaped trough, prolonging drying. But if the wood is stored under a shelter it really comes down to personal preference and ease of handling. Splitting wood will increase drying due to more exposed wood surface to the air. Because it can be difficult to ensure purchased firewood is properly seasoned, the best approach may be to stack firewood from your woodlot well before it is needed.

Be wary of insect and disease spread. Don’t move firewood. Asian longhorned beetle, Emerald ash borer, Sirex woodwasp, and other invasive pests spend parts of their life-cycle within wood. Some are associated with devastating tree diseases such as laurel wilt (redbay ambrosia beetle), and thousand cankers disease (walnut twig beetle). A good rule of thumb is to use local firewood within the state and a 50 mile radius of origin. For additional information contact Anson Cooperative Extension horticulture/forestry agent at aimee_colf@ncsu.edu or 704-694-2415.