At today’s fuel prices, burning wood remains a wise and viable option for reducing home-heating bills. Unlike coal, oil and gas, which are nonrenewable fossil fuels that contribute to greenhouse emissions, Wayne Clatterbuck, professor of forest management and silviculture with University of Tennessee Extension, says wood is a carbon neutral, renewable and a local energy resource.

The forests in Tennessee are dominated by high-density hardwoods, such as oak and hickory that are among the best burning woods for stoves and fireplaces Clatterbuck says. Denser hardwoods have a green weight of 3.5 to 4.0 tons per cord (a stack of wood 4 feet wide by 4 feet tall by 8 feet long).  Lighter woods, such as pine and yellow poplar, weigh only 2.0 to 2.5 tons per cord. “Pound per pound, less dense woods have about half of the heating value per unit volume than denser woods,” said Clatterbuck.

Firewood is best for burning when its moisture content is around 20 percent or less. Clatterbuck says to attain these moisture contents, wood should be stacked and allowed to dry under a roof and off the ground for at least 6 months prior to burning. Green wood has moisture contents of more than 50 percent. Green wood can contain more weight in water than it does weight in wood depending on the tree species. Air-dried or seasoned wood by contrast is 20 to 25 percent moisture content.

“Burning green wood wastes energy as the moisture has to be driven off before combustion can occur, and it can create more creosote build-up problems,” Clatterbuck said.  He added that split wood dries faster because of greater exposed wood surface area.

If purchasing wood for burning, Clatterbuck says consumers should consider the quantity and quality of the firewood. He recommends assessing the unit volume measure, the moisture content (dried, seasoned wood), and the species (wood density). “Split wood with end checks are indications that firewood is dried or is drying. Firewood should also be cut to the size needed for burning in your stove or fireplace,” he said.

Presently several counties in East Tennessee are under a firewood quarantine because of pests such as the non-native, invasive Emerald ash borer and thousand canker disease of walnut. Clatterbuck says if you buy or collect your own firewood, do not move it outside the local region or quarantine area. “Burn the firewood close to its source. Doing so will assist in protecting forests against the spread of these invasive pests,” he said.

For more information contact your local county UT Extension office.

UT Extension provides a gateway to the University of Tennessee as the outreach unit of the UT Institute of Agriculture. With an office in every Tennessee county, UT Extension delivers educational programs and research-based information to citizens throughout the state. In cooperation with Tennessee State University, UT Extension works with farmers, families, youth and communities to improve lives by addressing problems and issues at the local, state and national levels.

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Contact:

Wayne K. Clatterbuck, Professor, Department of Forestry, Wildlife and Fisheries, 865-974-7346,
wclatter@utk.edu

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