The BTU's of Firewood
Updated: Mar 10, 2021
Scott Roland with Roland Brothers Logging helps load the firewood.
Lisa’s Aunt and Uncle live in Laurel Springs on a farm and have always heated with wood. Several years ago they mentioned a concern about running out of firewood. I had a logger layout some dry red oak logs and I cut them up for firewood. I took the first pickup load up to Laurel Springs and Lisa’s Aunt took a quick look and made the comment “it’s not locust” and went back in the house. Her uncle took pity and me and said he would burn the red oak in his shop.
Now as a red blooded Wilkes County native I am no stranger to cutting firewood, but most of my experience has been cutting wood for a fireplace where you are mostly concerned with pretty, not so much heat. Now that we have our wood furnace going in the office the conversations over what makes the best firewood are ongoing. As a forester, trained to identify and measure trees, I naturally started researching which trees would give off the most heat.
I’m used to measuring trees in board feet, but most sources for firewood quote MBTUs per cord. BTU stands for British Thermal Unit and is defined as the amount of thermal energy it takes to raise one pound of water one degree F. One MBTU = one million BTUs. A cord of wood is 128 cubic feet of wood bark and air. The table below ranks some of the common species in this area.
There were a few surprises for me in this information. The first was that black locust was not first on the list. Lisa’s Aunt is not often wrong. The second was that Virginia pine scores better than a number of hardwoods.
At any rate it is time to cut your firewood for next year. Get it split and out of the weather now while the temperatures are cool outside and the wood will have time to dry.
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