Trees Build Most of Their Mass From Carbon Dioxide in the Air

Most of a tree mass comes from carbon dioxide in the air, which photosynthesis turns into carbon-rich compounds used to build wood and other tissues.

Biology

Details

A tree may look as if it grows mainly from the soil beneath it, but most of its dry mass comes from the atmosphere. Leaves take in carbon dioxide, and photosynthesis uses light energy to turn that carbon into organic compounds. Those compounds become sugars and then materials such as cellulose that form much of the wood, bark, roots, stems, and leaves. Water and minerals from the soil are still essential for growth, but they supply a much smaller share of the final dry structure. This is why a tree can gain substantial mass without the soil losing an equivalent amount of material. The carbon in a growing tree is largely atmospheric carbon that has been pulled into plant tissue and stored there. When wood eventually burns or decomposes, much of that stored carbon can return to the atmosphere, linking tree growth to the larger carbon cycle.

More videos

Up nextThe Bacteria That Can Double in Under 10 Minutes