CARBON STORAGE IN EUCALYPTUS AND PINE PLANTATIONS IN SOUTH-AFRICA

Carbon (C) is stored by plantation forests either when ecosystems with a low C density (such as tropical grasslands) are afforested or when timber is converted to semipermanent products. If the afforestation ra te is relatively constant and the plantations are not harvested immedi ately upon reaching maturity, the amount of C stored in trees as a res ult of afforestation can be calculated by a simple ''static'' approxim ation. Rotation forestry requires a mean C storage method that average s C density over the rotation. Plantation forestry as practiced in Sou th Africa requires a more detailed dynamic approach that accounts for time-varying rates of afforestation and the age-dependence of C accumu lation rates in plantations. To determine C storage in products, the o utput of long-lived plantation products and their C content once all p rocessing losses are accounted for must be known. The South African ca se study shows that new afforestation stored approximately 2.54 Tg C i n 1990, and storage in forest products accounted for an additional 1.1 5 Tg C. Together, these two activities offset approximately 3.8% of th e carbon dioxide emissions from South Africa.