In Time For Arctic Blast: The Heat Value of Firewood

An “arctic blast” is expected to hit Kansas this weekend, dropping temperatures to near zero or below. With the possibility of extended cold winter weather settling in, now is a good time to talk about the selection of firewood because not all firewood is created equal.

Firewood is typically sold as a volume – usually a cord – which is 128 cubic feet. However, the heating value of various types of firewood can vary greatly. For example, K-State Research and Extension horticulturist Ward Upham says there’s a big difference between a pound of cottonwood and a pound of hedge.

The heat value of firewood is measured in thermal units. Cottonwood ranks at the bottom for heat value, along with elms and sycamores. While oak isn’t at the top of the list, Upham says it’s still a solid choice.

Honey locust has a good heat value but can spark and should not be used in an open fireplace. Black locust is a better choice because it’s a dense wood, burns well and produces a nice bed of coals. However, the firewood with the best heat value is Osage orange and hedge.

In addition to selecting firewood with a good heat value, it should be purchased locally to avoid the possibility of transporting pests. Upham says Emerald Ash Borer is now in Kansas because of transported wood.