Energy from sunlight is stored as chemical energy in wood and other organic material, using a process called photosynthesis. This energy is released as heat when wood is burned.
People have been using the energy generated by burning wood for thousands of years to stay warm and cook their foods.
According to the US. Department of Energy, burning wood and wood waste only generate about 2 percent of the United States' total energy.
Because more trees can always be grown, wood is a renewable resource. It's usually grown in the country where it is used, reducing dependence on foreign sources of energy such as oil.
According to the US. Environmental Protection Agency, when wood is burned it releases carbon monoxide, cancer-causing chemicals and particulate matter (PM) that can aggravate asthma and heart disease.
Although burning wood releases carbon dioxide, a major greenhouse gas, the photosynthesis process (how plants convert sunlight into chemical energy) captures an equivalent amount of carbon dioxide.