The most commontype of fire wood is birch wood. Wood preparation begins in mid-summer. Dried and stored in a dry place. If birch wood stored for more than two years, a significant reduction of its flavor. Birch wood ignite easily and burn with a long, steady flame and spark. Dry birch firewood burning off the heat for more than 25% of aspen wood and 15% more than the pine wood. A good birch firewood calorific value (heatceded) is greater than softwood firewood. To use the appropriate wood, it should contain no more than 20 percent moisture.