 Plants sequester carbon through photosynthesis, by absorbing CO2 and subsequently releasing O2 (oxygen).The plants exchange O2 for CO2 by splitting the CO2 molecule, releasing the oxygen part (O2) back to the atmosphere and keeping the carbon part (C) to itself.The carbon accumulated in the plant's roots does not stay below ground forever however; "[…] soil carbon is a balance between the decay of the initial soil carbon and the rate of input […]."