Ge Sun presented preliminary results from SGCP's carbon flux tower research through the NCSU Forestry Department's ongoing seminar series. Ge will elaborate on the study objectives, methods, and results at the upcoming Hydrology and Management of Forested Wetlands conference in New Bern, NC. The conference is sponsored by the American Society of Agricultural and Biological Engineers (ASABE) and Weyerhaeuser.

Effects of Forest Management on Water, Energy, and Carbon Fluxes in Loblolly Pine Plantations on the North Carolina Coastal Plain

Abstract

Most scientists, as well as the public, now believe global climate has been changing and is related to human activities like excessive carbon emission and land use change. Recent studies suggest future land use change will have great impacts on total US carbon emissions and water balances at the regional to continental scale. Water, energy, and carbon cycles are intimately linked at multiple scales through the complex interactions of ecosystem biogeochemical cycling processes.

Loblolly pine is the most widely planned tree species in the southeastern US. In the North Carolina coastal plain region, large areas of forested wetlands have been drained for growing intensively managed pine plantations. Little is known about how this practice has altered the biogeochemical balances in this type of landscape, characterized by high ground water table, poorly drained organic soils, and high ecosystem productivity. Most of the existing US carbon flux studies focus on natural upland forests with little attention to managed, forested wetlands.

The presentation reports an ongoing collaborative study in eastern North Carolina. Its objectives are to quantify the causal effects of forest management and climate on energy, water, and carbon fluxes in intensively managed loblolly pine plantations. The research site is located in Weyerhaeuser’s Parker Track watershed, near Plymouth, Washington County, in the lower coastal plain. Two eddy flux towers were instrumented in 2004 to measure micro-meteorology, net ecosystem exchange of CO2, and water and energy fluxes in a 12-year-old loblolly pine stand and a 2-year old stand converted from natural hardwoods. Other major measurements on hydrology and carbon include drainage from the forested watershed, tree canopy interception, tree sapflow, ground water table height, soil moisture, forest biomass growth and production, and soil respiration. Preliminary data suggest that land conversion (from natural hardwoods to young pine plantation) had minimal influence on energy flux and evapotranspiration at multiple temporal scales for this wetland site. The young stand is losing large amounts of carbon through soil respiration, but the duration of this loss is uncertain.