“There are two spiritual dangers in not owning a farm. One is the danger of supposing that breakfast comes from the grocery, and the other that heat comes from the furnace.”
— Aldo Leopold, A Sand County Almanac
With the winter months fully upon us, using a local energy source like wood can be a great way to supplement heating your house. It can help you become less dependent on propane, natural gas and the always-fluctuating prices associated with modern utilities. Also, if done properly, harvesting timber for firewood can be a great way to improve the overall health, economic value and wildlife habitat of your timber stand.
For anyone looking to burn wood in a wood stove, chimney, outdoor wood burner or just a campfire in the backyard, it is important to understand what type of wood is being thrown on your fire. It also helps for you to know a little terminology if you are new to buying or cutting firewood.
The heat from firewood is measured in “Btu” (British thermal units). A “cord” of wood is a standard measurement for stacked firewood. A cord is most easily described as a stack of wood measured 4-feet wide by 4-feet tall by 8-feet long. For example, a stack of black locust firewood will give off around 29 million Btu per cord. In contrast, white pine has a heating value of around 14 million Btu per cord.
A species with a higher Btu value will burn longer and hotter than a species with a lower value. Whether you plan to buy or cut your own firewood, to get the most bang for your buck it’s important to properly identify species and know their Btu rating.
Locally grown osage orange trees or “Hedge Apples” on average produce the highest Btu per log (33 million Btu/cord). As previously mentioned, black locust comes in a close second with an average of 29 million Btu/cord. These species are usually found in overgrown pasture or fence rows. For farmers, it is important to remember that these two species may have more value as fence posts, as both have high rot resistance.
Oak and hickory species come in around 24 to 28 million Btu/cord. These species can make great firewood.
However, I highly advise against cutting green oak and hickories and recommend instead only cutting dead or blown-over trees of either species. They will have much more economic value long-term if allowed to reach maturity.
White oak, shagbark hickory and pignut hickory are also very important trees for game species such as deer, turkey and squirrels. The same caution should be used when considering black walnut. Imagine throwing that priceless walnut stock from your granddad’s favorite gun in a fireplace. That’s what you’re essentially doing every time you throw a couple of black walnut logs on a fire.
American beech comes in at around 26 million Btu/cord. Beech does not have the economic value of some of the other previously mentioned trees, and with its high Btu rating, it makes a great choice for firewood.
Maples are anywhere from 20-24 million Btu/cord depending on the specific species. Sugar maple burns a little hotter, but should be saved for its value as a saw log. Red maple doesn’t burn as hot as sugar maple, but it has little economic value and less wildlife value compared to some of the aforementioned species making it a good candidate for firewood. Black cherry and American elm average around 20 Btu/cord. Black cherry can have a high economic value and choice. Black cherry should be saved for its saw log. However, low-grade cherry along with elm makes for good firewood.
I would make sure to have a hydraulic wood splitter if you end up splitting dried elm. Typically, any type of pine is not desirable for firewood use. Pine species will have a low Btu value, and will create the buildup of creosote in the chimney or stove pipe.
It’s important to note that if you are new to harvesting firewood, you should undergo some sort of chainsaw safety class. Protective equipment should always be worn while using a chainsaw. This means chaps, hard hats, safety glasses, gloves and at least 8-inch boots.
Many new beginner chainsaw users will think that cutting a tree or limbs that are already on the ground is safer than falling a tree. This can be much more dangerous as limbs will have complicated binds that could strike an operator if not cut correctly. If readers have any questions about firewood, chainsaw classes or improving their timber stand in general, please contact your local soil and water office or the Ohio Division of Forestry.
Overall, burning wood can be a money saver while also improving a timber stand. Utilizing some of the less desirable species like black cherry, American beech and red maple, is a great way to add a heat source while also thinning out a forest and creating less competition for our oaks, hickories, etc. And if nothing else, the old saying goes, “Harvesting your own firewood warms you up twice.”
(John Schumacher is the forestry/wildlife specialist for Monroe County Soil and Water Conservation District. He can be reached at 740-472-5477.)
