The principal greenhouse gas thought to be responsible for climate change is carbon dioxide. Carbon is found in all organic matter (fossilized or not) and when this matter is combusted or broken down naturally, carbon dioxide is released into the atmosphere. Burning fossil fuels (fossilized organic matter) releases carbon that has been sequestered (trapped under the Earth’s surface) for thousands of years producing a net addition of carbon dioxide to the atmosphere. Alternatively, burning woody biomass releases carbon dioxide that is a part of the present day carbon cycle. By growing or replanting to replace harvested trees, carbon will be taken in, therefore making it “carbon neutral”.