This week, I’m turning over the column to Glen Holt, our Extension Forestry Agent. He is our expert on harvesting and burning wood. Here are his words of wisdom on the value of seasoned firewood.
Burning firewood can save money compared to using fuel oil for heat. If you burn firewood, would you like to save 20 percent or more on your wood?
A wood stove using seasoned firewood will save at least 20 to 40 percent on the wood budget. Many in Interior Alaska are turning back to locally abundant renewable forests to get less expensive heat. Seasoning firewood is about saving money, improving efficiency, saving wear and tear on your saws, gear and on your body. It’s also about improving air quality and conserving forest resources.
Getting the most value for your money means burning the wood only after it has been cured or “seasoned,” whether you cut your own, have it delivered log length and saw it up and split it yourself, or purchase wood cut and split. Live winter-cut trees contain about 40 percent moisture content. Timber cut in the summer or fall may have higher moisture content due to the sap being up in the tree. Seasoned firewood is 20 percent or less moisture content. Moisture content can be measured using a moisture meter, which may be purchased at local hardware stores.
Research by the Cold Climate Housing Research Center in Fairbanks determined that firewood cut in spring, immediately split, stacked off the ground and covered will become seasoned firewood within six weeks to three months. It’s best to build stacks a couple of inches apart to allow for airflow. Seasoned wood remains cured if protected from rain on top and has plenty of airflow circulating through the stacks. Fall-cut and split firewood did not completely season over winter and had to finish during the warm summer to be seasoned by the following winter.
Burning unseasoned firewood means burning extra to cook off moisture still trapped in the wood in order to get the same heat value obtained from burning less wood that is seasoned. The same effective heat value is obtained from fewer cords of seasoned wood. You save at least 20 percent or more of your woodpile by burning it seasoned at 20 percent rather than unseasoned at 40 percent moisture content.
The following are just examples for comparison and only hypothetical.
If seasoned wood can be purchased, delivered, cut and split for $375/cord, it would cost $3,000 for eight cords. This wood should have been split to cure to 20 percent moisture content or less. If the difference between seasoned and unseasoned wood is 20 percent and 40 percent moisture content, 10 cords of unseasoned or wood is needed to have the same heat equivalent as eight cords of seasoned wood if burned immediately.
From our example: If unseasoned or “green” wood can be purchased, delivered, cut and split for $275/cord, it would cost $2,750 for 10 cords. In actual fact, less than a cord’s value in green wood is saved by burning 10 cords of green wood compared to eight cords of seasoned.
The Cold Climate and Housing Research Center also found that drying to get seasoned wood only really begins when the wood is also split. Stacking the wood off the ground and covering the top of the pile is recommended to help it dry and keep its cure.
Forest resources are conserved and our timber stands will last at least 20 percent longer by the conservation that comes from burning seasoned firewood. Our air quality will be enhanced, less wood is being burned to keep our homes warm and burning seasoned wood is not laden with moisture burned off by using it unseasoned. Using well-seasoned firewood is a personal decision that allows your household budget to go a lot further.
Glen Holt is the Eastern Alaska forester for the University of Alaska Fairbanks Cooperative Extension Service. Contact him at 907-474-5271 or by e-mail at firstname.lastname@example.org