In general, wood fixes carbon dioxide and releases it when it is burnt. As long as one produces its own wood, it won't change the balance of carbon dioxide in the atmosphere when burning it. When quick-growing trees, such as poplar, acacia, or willow, have grown 15 to 20 cm in diameter, they can be cut to 1m to 1.5m above the ground. New branches grow very rapidly and can be used as firewood, this process is called coppicing. If the wood is carbonated, it becomes more convenient to use for cooking in the kitchen.