The Chimney Clinic

Firewood

We are frequently asked about firewood and the best types of wood to burn. We have developed a crash course in firewood and its properties. Although most wood may look the same it's not. All wood is NOT created equal.

The main difference in wood, when referring to wood burning is Hardwood and Softwood types. Hardwood is generally a tree that has leaves, while softwoods will generally have needles. This is a good basic rule to live by. Some people ask how firewood is measured. Generally speaking, firewood is measured in what they refer to as a cord.

A cord is a measurement that translates into a pile of STACKED wood that is equal to 4 feet high by 4 feet wide and 8 feet long. Other terms that you may hear used to measure wood are the face cord, a pile, a rack and a truck load. A face cord is generally ½ a cord. The face cord measurement also depends on the log length, but generally it will be ½ cord to 2/3 cord. A pile is any amount of wood that is Un-Stacked and loose. General terms usually refer to a pile as 2/3 a cord. A rack is a partial amount of a cord. The rack is generally one stacked row of wood. Usually a standard 16" cut log 4 feet high and 8 feet long. The biggest misconception is the term Truck load. This term should be high in your list of terms to remember. A lot of firewood suppliers sell unsuspecting homeowners a cord of wood. When the delivery shows up, it is delivered on a standard pick up truck. This is known as a truck load. A standard pick up truck can only hold ½ a cord to 2/3 of a cord of firewood. So if you order a cord of firewood delivered, it should be delivered in a dump truck or a standard pick up with high sides. So be weary of the cord of firewood that comes delivered this way, because you’re not getting your moneys worth. Now that you know how much wood you need, next you need to know what kind of wood makes good firewood.

The best firewood is seasoned hardwood. Seasoned wood refers to any wood that has been stacked and air dried for no less than 6 months. Firewood should be between 15 and 20 percent moisture to burn properly. Wood that is freshly cut or dried less than 6 months is known as Green Wood. There are numerous varieties of trees. What makes the difference in good wood and bad wood is a combination of the density and water content of the wood. These two factors are a main factor in determining the BTU in a particular species of wood.

BTU is a measurement of heat which stands for (British Thermal Unit). The higher the BTU rating of a particular wood, the more heat it will produce. Now we know that hardwoods have a higher BTU rating than softwoods. We have explained what makes a good wood. Let's look at some types of wood. The Hardwoods: Red Oak Beech White Oak Ash Hard Maple Hickory Dogwood Pecan Almond Apple These all are easy to burn, produce high amounts of heat, have no heavy kind of smoke. Good firewood includes: Cherry Soft Maple Walnut These firewood types are easy to burn but they don't give heavy smoke. Fair firewood includes: Sycamore Elm Basswood Cottonwood Aspen Yellow Poplar Gum Energy content per air dried full cord, in 1000's of BTUs. The hardest species are at the top of the list.

Rock Elm …………………………………. 32,000 BTU

Shag Bark Hickory…………………………..30,600 BTU

White Oak…………………………………..30,600 BTU

Bitternut Hickory……………………………29,200 BTU

Sugar Maple…………………………………29,000 BTU

Beech…………………………………….….27,800 BTU

Red Oak…………………………………….27,300 BTU

Yellow Birch…………………………..…...26,200 BTU

Red Elm…………………………………….25,400 BTU

White Ash…………………………………..25,000 BTU

White Elm…………………………………..24,500 BTU

Red Maple………………………………….24,500 BTU

Tamarack……………………………………24,000 BTU

Black Cherry………………………………..24,000 BTU

White Birch…………………………………23,500 BTU

Black Ash…………………………………..23,400 BTU

Green Ash…………………………………..22,600 BTU

Silver Maple…………………………………22,100 BTU

Manitoba Maple……………………………..21,700 BTU

Large Tooth Aspen………………………….19,300 BTU

Trembling Aspen……………………………17,900 BTU

Butternut…………………………………..17,700 BTU

Balsam Poplar……………………………..17,400 BTU

White Pine…………………………………17,260 BTU

Basswood…………………………………17,100 BTU

White Cedar……………………………….17,000 BTU

White Spruce………………………………16,300 BTU

Balsam Fir …………………………………16,200 BTU

Hemlock……………………………………..18,200 BTU

Here is a overview of some key facts we need to remember. Wood needs to be stacked off the ground so the air can circulate around it. The wood needs to be seasoned, which is air dried for more than 6 months. Hard woods are better burning because they are denser and have lower moisture content. A full cord is 4’x4’x8’. So don’t be fooled by dishonest firewood salesmen. Dry wood burns cleaner and wetter softer wood creates more creosote which could lead to a chimney fire. Lastly believe it or not wood can be to dry, wood that is too dry will not produce any heat or very low flue gas temperatures. If you have any other questions about firewood or safe burning practices feel free to call us. Our friendly staff is waiting to give you a solution to any of your burning questions.