Wood as Fuel - Renewable Energy

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The Earth has an abundant wood supply. Rotting trees emit similar greenhouse gases and heat energy to those burned in your stove. It is important to manage the cutting of dying or damaged trees as these are potential fuel for any home. Your heating system will function according to the wood's type and quality. Freshly-cut or wet wood contains about 50% moisture: ignition is difficult and less heat is produced, with high pollution. Well-dried, old wood ignites quickly to give double the heat with less effort.

Firewood is best cut and split to be stacked neatly in covered rows with spaces in between for the circulation of air which dries the wood and makes it lighter to carry. Moreover, this ensures that the stored energy will not be wasted. When wood ages, it should crack and split at the ends, turning grayish. When you bang two pieces together, you will hear a clear ringing tone, whereas freshly-cut wood gives a dull thud. Purchased woods have their differences, too.

Softwoods like white birch and poplar work well for fall and spring, but in cold winters you are better off with maple, elm, oak, and ironwood because of their higher density and heat output. Compare white birch with maple and you will find that maple feels much heavier – and gives double the energy. Volume purchases of the hardest woods save you money and time. Aim to use softwoods in spring and fall when solar power can help with your energy needs. If hardwoods cannot be obtained or lower heating loads are common, try softwoods or pellet fuels.

Purchasing Firewood

You may be tempted to purchase a variety of wood: soft, mixed, greens and seasoned (aged). Be sure to understand all the implications, otherwise you might not get the best out of your wood heating system and feel like you're living in colonial times. Firewood is usually sold in pre-cut 16-inch (41 cm) logs. The logs are stacked in three tight rows, giving a "full cord" measuring 4' deep, 4' high and 8' long (1.2 m x 1.2 m x 2.4 m).

A "face cord" is only one-third the full cord, giving measurements 16" deep, 4' high and 8' long (0.4 m x 1.2 m x 2.4 m). However, if the face cord logs are cut into lengths of 12 inches (30 cm), it gives only a quarter full cord. Exercise caution when purchasing firewood by the truckload or pile as it is difficult to gauge the wood volume. Green firewood refers to unseasoned wood; if there is a discount available and you have time to season the wood, it is a worthwhile buy. You can also purchase wood in lengths of 4 feet or 8 feet which require self-cutting for some savings (and exercise). As Thoreau said: "Wood heats you twice; once when you cut it, and once again when you burn it."