These woods are rare to find, tend to be more expensive but are clean. One reason that makes hardwood scarce is that they take longer to mature and season. For instance, the red oak, which is the most common type of hardwood, takes at least two years to season. Due to this maturity, the hardwood is mainly useful in long-lasting construction projects like furniture. Also, the extended maturity makes hardwood firewood burn longer, hence the best wood for warming your home during summer. Some examples of hardwood include alder, oak, walnut, teak, mahogany, balsa, and hickory.
The cord of firewood is one of the most common ways of measuring wood; it is also the official measurement of wood recognized by both the buyers and sellers. The cord of word is associated with many terms like face cord, running cord, or stove cord. However, the cord of wood is the legal term acknowledged by the US and Canada. The cord has a volume of cubic feet. This is the standard measurement used by many buyers and sellers. It contains almost twice the heat by volume of cottonwood, one of our lightest woods.
In general it is best to buy or gather dense woods such as oak, hard maple, or ash. Hardwoods, or woods from broadleaved trees, tend to be denser than softwoods or woods from conifers.
Some firewood dealers sell "mixed hardwood" firewood. This may or may not be desirable, depending on the proportion of low- density hardwoods such as cottonwood that are included. The amount of heat per cord of dry wood is presented in Table 1. Heat content is shown as a percent of dry green ash, a fairly common, dense firewood.
Values above signify a higher heat content than green ash and below a lower heat content. Table 1 also contains information on other characteristics that determine firewood quality. Ease of splitting is important because larger pieces of wood must usually be split for good drying and burning. Fragrance and tendency to smoke and spark are most important when wood is burned in a fireplace. Woods that spark or pop can throw embers out of an open fireplace and cause a fire danger.
Conifers tend to do this more because of their high resin content. Woods that form coals are good to use in wood stoves because they allow a fire to be carried overnight effectively. Though firewood dry weight is important for determining heat content, firewood is normally bought and sold by volume. The most common unit of firewood volume is the cord, also known as a standard or full cord. A cord is an evenly-stacked pile containing cubic feet of wood and air space.
Though a cord can be piled in any shape, a standard cord is generally thought of as a stack of wood 4 feet tall, 8 feet long, and 4 feet deep Figure 1. To figure the number of cords in another size or shape pile, determine the pile's cubic foot volume and divide by A randomly-piled stack of wood will generally contain more air and less wood than one neatly piled.
Some dealers sell wood by the face cord or short cord Figure 2. A face cord is a stack of wood 4 feet high, 8 feet long, and as deep as the pieces are long. Pieces are commonly 12 to 18 inches long, so a face cord may contain 32 to 48 cubic feet of wood and air. Another common firewood measure is the pickup load Figure 3.
This is a very imprecise but common measure. Small pickups hold much less. Random loading will decrease this amount further. A half-ton pickup truck, for example, is really only designed to carry 1, pounds of weight. If the truck is one of the newer models, with a four-door cab and a six foot bed, it only has enough space to haul about a third of a cord. The vast difference between these various types of wood tells us another tale as well, in addition to how much moisture they hold.
That is, not all types of wood have the same density. What that means for us, when using it for firewood, is that those woods which are denser, will provide more heat per log. How much heat, measured in BTU s, is something that is known. This table makes it clear that when buying firewood, the density of the wood is something important to consider. While some of those hardwoods might be considerably more expensive to buy, the cost per BTU could still be cheaper, due to the higher energy density contained within the wood.
Typically hardwoods which have the higher energy density are also harder to ignite. The softwood can be used to start the fire and get it blazing. Then the hardwood can be fed into the fire, gradually replacing the softwood entirely. The actual cost per cord of firewood will vary considerably by the type of wood selected and what part of the country it is being bought in. Obviously, woods that are less common in a particular area are going to cost more.
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