They may not have lungs like we do, but the soil and trees are breathing in and out all of the time. Trees take in carbon dioxide (CO2), release oxygen by way of photosynthesis, and store carbon in their trunks. And when the leaves land on the ground, soil microbes work to decompose the leaves and other organic matter, which releases carbon dioxide.
Click here for original story, City trees and soil are sucking more carbon out of the atmosphere than previously thought
Source: Phys.org