Trees and soil may not have lungs, but they are constantly exhaling and inhaling. In addition to absorbing CO2, trees produce oxygen and store carbon in their trunks through photosynthesis.
Deforestation is leading to the disappearance of tropical forests at an alarming rate, although they have the ability to recover naturally in abandoned areas. Differences in tropical forests seem to control how a forest naturally recovers from abandoned fields and cow pastures.