Typically any piece of firewood over 8 inches in diameter should be split. Firewood should be split as soon as possible after it is cut. It is much easier to split green wood than seasoned wood. It is best to select a good hard wood verses a soft wood like pine to burn.
Place your firewood rack 20 to 25 feet from your home or any building if possible. Firewood attracts many insects such as ants and termites. Keeping a proper distance from any structures will keep the insects from entering your home. A log rack should be designed to