The Biology of Carbon Sequestration: Photosynthesis and Soil Storage
Carbon sequestration is the process by which plants capture carbon dioxide (CO2) from the atmosphere through photosynthesis and store it as carbon in their leaves, wood, and roots, and in the surrounding soil. In a residential garden, this carbon cycle occurs actively. Trees, shrubs, turfgrass, and vegetables act as carbon sinks, converting atmospheric gas into stable organic carbon molecules.
This calculator uses flat annual sequestration rates drawn from forestry and horticultural averages: a young-to-mature tree sequesters about 48 lbs of CO2 per year, and a shrub sequesters about 12 lbs per year, regardless of species. These are simplified planning averages, not diameter-based allometric formulas — a good rule-of-thumb estimate rather than a forestry-grade biomass inventory.
To optimize your home ecosystem, you can compost kitchen waste using the compost impact calculator or estimate roof runoff collection with the rainwater harvesting calculator. Recycling nutrients and water maximizes plant biomass growth, accelerating carbon capture.
The rate of carbon storage is highly dependent on the age and species of the plant. Fast-growing trees capture carbon quickly in their initial years, but mature forests store far larger total reserves of carbon in their dense trunk wood and extensive root networks. Sizing your planting plan to incorporate a mix of fast-growing shrubs and long-lived canopy trees ensures a continuous, high-capacity carbon capture cycle that operates passively for decades.
Furthermore, the density of the wood (specific gravity) varies significantly between tree species. Hardwood trees like oak and maple have dense cellular structures and store more carbon per cubic foot of wood than softwoods like pine and cedar. Because this calculator applies one flat rate per tree, you can model species mix qualitatively by simply adjusting your tree count and comparing scenarios.