Trees capture carbon through a process called photosynthesis. During photosynthesis, trees take in carbon dioxide from the air and use energy from sunlight to convert it into glucose, a sugar molecule. The glucose is then used by the tree to produce energy and build its structural tissues, such as wood and leaves. Some of the carbon dioxide is also converted into lignin, a structural compound that helps strengthen the tree’s cell walls. This process results in the tree storing carbon in its tissues and releasing oxygen back into the atmosphere.