Tree Carbon Benefits Calculator

Trees absorb carbon dioxide during photosynthesis, converting it into glucose and oxygen. The carbon is then incorporated into the tree's biomass: wood, bark, leaves, and roots. Approximately half of a tree's dry weight is carbon. A mature deciduous tree in a temperate climate absorbs roughly 20-25 kg of CO2 per year, while fast-growing tropical species can absorb 30-50 kg per year. Carbon sequestration rates vary considerably over a tree's lifetime. Young trees grow slowly and absorb relatively little CO2. As they mature and add more leaf area, absorption rates increase. Maximum sequestration typically occurs during the active growth phase (roughly age 10-50 for temperate species). Very old trees still absorb CO2 but at a declining rate, though their massive biomass represents an enormous carbon store. Forests provide additional climate benefits beyond direct CO2 absorption. They reduce local temperatures through evapotranspiration, modify rainfall patterns, prevent soil erosion (which releases stored carbon), and support biodiversity that maintains ecosystem resilience. Urban trees also reduce building energy consumption by providing shade in summer and windbreaks in winter. When assessing tree-planting projects for carbon credits, it is important to consider permanence (the risk that stored carbon is released through fire, disease, or logging), additionality (whether the trees would have been planted anyway), and leakage (whether protecting one forest simply shifts deforestation elsewhere). Credible carbon offset standards require monitoring and verification over decades. The values in this calculator are simplified averages. For accurate project-level accounting, species-specific allometric equations that relate tree diameter and height to biomass should be used, along with local growth rate data.