Climate change impacts on the hydrology and productivity of a pine plantation

There are increasing concerns in the forestry community about global climat e change and variability associated with elevated atmospheric CO2 Changes i n precipitation and increases in air temperature could impose additional st ress on forests during the next century. For a study site in Carteret Count y, North Carolina, the General Circulation Model, HADCM2, predicts that by the year 2099, maximum air temperature will increase 1.6 to 1.9 degrees C, minimum temperature will increase 2.5 to 2.8 degrees C, and precipitation w ill increase 0 to 10 percent compared to the mid-1990s. These changes vary from season to season. We utilized a forest ecosystem process model, PnET-I I, for studying the potential effects of climate change on drainage outflow , evapotranspiration, leaf area index (LAI) and forest Net Primary Producti vity (NPP). This model was first validated with long term drainage and LAI data collected at a 25-ha mature loblolly pine (Pinus taeda. L.) experiment al watershed located in the North Carolina lower coastal plain. The site is flat with poorly drained soils and high groundwater table. Therefore, a hi gh field capacity of 20 cm was used in the simulation to account for the to pographic effects. This modeling study suggested that future climate change would cause a significant increase of drainage (6 percent) and forest prod uctivity (2.5 percent). Future studies should consider the biological feedb ack (i.e., stomata conductance and water use efficiency) to air temperature change.