The Science of Tree Carbon Sequestration: Photosynthesis and Biomass
Trees are natural carbon sinks, capturing carbon dioxide from the atmosphere through the process of photosynthesis and converting it into solid biomass (wood, bark, and roots). The carbon stored in a tree constitutes approximately 50% of its dry biomass. To estimate the annual carbon sequestration of a tree, foresters model its growth rate, which varies dynamically based on species, age, and environmental conditions.
Young trees (0-5 years) grow slowly and have small leaf areas, resulting in low sequestration rates (2 to 5 kg of CO2/year). As trees enter their rapid growth phase (6-20 years), their carbon uptake accelerates. Mature trees (21+ years) maintain a large canopy, capturing up to 22 kg (48 lbs) of CO2 annually. Hardwood trees (e.g., oak, maple) have denser wood and store more carbon over their lifetime, whereas conifers (e.g., pine, fir) grow faster initially but store less carbon per unit volume.
To model agricultural and garden carbon inputs, check our garden carbon sequestration calculator or calculate organic composting offsets with the compost impact calculator.