Meeting global policy commitments: carbon sequestration and southern pine forests

will result in climatechange. Annual anthropogenic carbonemissions in the United States total ap-proximately 1.7 billion tons (Marlandet al. 1999). Recently, there has beenincreased international pressure to re-duce net carbon emissions in theUnited States and around the world. One potential mechanism for re-ducing net carbon emissions is throughincreased carbon sequestration intoforests. In a large-scale assessment,Birdsey and Heath (1997) estimatedthat over the past 40 years, US forestshave sequestered enough carbon to off-set approximately 25 percent of USemissions. Managed southern pine for-ests have played a large role, steadily in-creasing in land area over the past half-century. The South represents about 24percent of the land area of the UnitedStates; outside of Texas and Oklahoma,about 58 percent of this land isforested and about 20 percent of theforestland is owned by forest industry.From 1962 to 1992 the total land areaof commercial pine forest rose 27 per-cent to 27.9 billion acres (Powell et al.1993). The extent of managed forestshas increased because southern pineforests are extremely productive. Thewarm climate of the South extends thegrowing season and reduces rotationlength; pines reach sawlog size in 25 to35 years on many southern sites(Schultz 1997). Intensive managementof southern pine plantations, usingcompetition control, fertilization, andsuperior genotypes, can now increaseproductivity three-fold (Borders andBailey, in press). In managed forests, the amount ofcarbon further sequestered will be de-termined by three factors: (1) the in-creased amount of carbon in standingbiomass, due to land-use changes andincreased productivity; (2) theamount of recalcitrant carbon remain-ing below ground at the end of the ro-tation; and (3) the amount of carbonsequestered in products created fromthe harvested wood, including theirfinal disposition. Therefore, managedsouthern pine forests sequester carbonboth