Search this site:

6.5 Carbon Sequestration Discussion and Conclusions

Despite many volumes of research detailing individual tree responses to elevated CO₂ and tree stresses, the complexity of ecosystem interactions has made it difficult to understand and predict whole system responses. Currently, there is very little understanding of the relationship between carbon sequestration and species composition and interactions among CO₂, O₃, nitrogen, temperature, and precipitation (Aber and others 2001). The long-term impacts on manipulated sites are not completely understood. Consideration of site characteristics and past land use should be an important component of forest sustainability and carbon sequestration research. Maximizing carbon per acre on all land will be an important step toward increasing long-term carbon storage.

The lack of understanding of interactions in forest processes results in uncertainty when estimating current and future carbon budgets. Uncertainty is defined by Smith and Heath (2000) as the inability to precisely quantify an unknown, but unique, inventory of carbon in a given forest management unit for a particular year. Uncertainty can be minimized through multi-site, multi-factorial experiments; but the costs, time constraints, and logistics involved limit the feasibility of such an approach (Aber and others 2001). It will be important to understand both the trends and uncertainties in carbon pool estimates when making policy decisions (Aber and others 2001). Until we have a greater understanding of carbon flows and the potential interactions involved, research should be aimed toward identifying areas that will contribute most to reducing overall uncertainty (Heath and Smith 2000).

Increases in anthropogenic CO₂ emissions and the possible resulting global warming have created the need for increased carbon sequestration in forests and harvested wood. Current southern forest carbon inventory is approximately 5.5 billion tons in trees alone (Birdsey and Heath 1995). While additional research is required to further understand carbon fluxes, it is clear that southern forests offer an enormous opportunity for capturing CO₂ and storing it as carbon while still providing wood products and other benefits. Future policies involving incentive programs and forest management intensity are factors that will potentially affect carbon sequestration rates. It should be acknowledged, however, that land use change, more so than changes in climate or atmospheric chemistry, has been and will likely continue to be the most significant determinant of terrestrial carbon storage, uptake, and release.