Firewood Explained

How is Firewood sold?

Firewood is sold a couple of different ways. The only way to understand what you should expect is to understand how people sell it. The first term you may hear is the term "cord". A cord of wood is defined as a stack of wood measuring four feet by four feet by eight feet (4 X 4 X 8) or 128 cubic square feet. For a reference a small truck can fit about 1/3 of a cord in it stacked, while a standard 1/2 ton truck can fit about 1/3 of a cord lightly thrown in it.

A 1/3 of a cord is also known as a "face cord" and should measure 8 feet by four feet by sixteen inches (8 ft. X 4 ft. X 16 in.) or 42.6 cubic square feet. Some states will legally only allow firewood producers to sell by the full cord or by a cubic foot amount. Many times people who are selling firewood as a side business will use the terms cord and face cord interchangeably. For this reason, it is very important that you have them define the amount of wood you will be receiving.

A "rick" of wood is used to define a pile of stacked wood four feet by eight feet (4 ft. X 8 ft.) You will notice that the width of the pile is not defined when the term "rick" is used. Many times the logs can be cut anywhere from 12 inches to 24 inchs. If someone is selling by the rick it is very important that you have them define the dimensions of the amount of firewood you are receiving.

Very rarely will you buy firewood by the cubic foot unless it is in very small quantities. Generally, the small bags of wood you would find in a store are sold this way.

When selling in large quantities (over 2 cords), some producers will sell by weight. The largest problem with this method is the fact that weight fluctuates a great deal base on how green (wet) the wood is and what species of wood it is. ​

What does "green" and "seasoned" firewood mean and does it matter?

After a tree is cut down it has a lot of moisture in it. Some species weight can be up to 60% moisture content. This moisture makes the wood difficult to burn and actually reduces the amount of heat a fire can produce. When someone says the firewood is "green", the person is indicating that it is still full of moisture and/or has recently been cut.

​To naturally dry or "season" firewood it must be cut and split for anywhere between 8 months to 2 years (depending on the species). Due to the difference in BTU's produced (the heat output of the firewood), green wood will usually be a little cheaper than seasoned wood.

The dryest firewood a person can buy is kiln dried wood. This wood is placed inside a box which can reach temperatures up to 200 degrees Fahrenheit. These temperatures kill pests within the firewood and dry the wood to anywhere from 10-20% moisture content. Comparatively, naturally seasoned firewood will only get down to about 35% moisture content. Kiln drying does come at a price; many times kiln dried wood can be twice the cost of naturally seasoned wood.

What is the difference between "hard woods" and "soft woods"?

​There are two broad types of trees; hard wood and soft wood. The names are deceiving because they don't indicate either the hardness or density of the actual tree. Rather the term hard word refers to the fact that the tree has leaves (like a maple or oak tree), where as a soft wood has needles (like a pine tree).

Most people will tell you that softwood is unsafe to burn due to cresol. Cresol is a substance that can cause a chimney fire if not cleaned. The truth of the matter is that all wood produces cresol. When a person burns green wood, the sap and unburned particles rise up the chiming with the smoke. As the smoke cools down the sap, moisture, and particles begin condensing in the chimney. If not cleaned annually, this build up can reach a flash piont, thus starting a fire.

The reason wood such as pine is known for cresol deposits is that pine burns much better green than most other woods. The point is that as long as the wood you burn is correctly seasoned, than cresol build up is not nearly as big of a deal as people make it out to be.

​What is important is the fact that harder, more dense woods have more BTU's per cubic foot that less dense woods. A common misconception is that less dense woods do not burn as hot as more dense woods. In truth, all woods burn about the same temperature (as long as they have the same relative moisture content) however the more dense wood will burn longer, producing more overall BTU's.