Respectively, Research Ecologist and Project Leader, USDA Forest Service, Coweeta Hydrologic Laboratory, 3160 Coweeta Lab Road, Otto, North Carolina 28763; and Program Manager, Southern Global Change Program, USDA Forest Service, 1509 Varsity Dr., Raleigh, North Carolina 27606
REGIONAL HYDROLOGIC RESPONSE OF LOBLOLLY PINE TO AIR TEMPERATURE AND PRECIPITATION CHANGES1
Article first published online: 8 JUN 2007
JAWRA Journal of the American Water Resources Association
Volume 33, Issue 5, pages 1011–1022, October 1997
How to Cite
McNulty, S. G., Vose, J. M. and Swank, W. T. (1997), REGIONAL HYDROLOGIC RESPONSE OF LOBLOLLY PINE TO AIR TEMPERATURE AND PRECIPITATION CHANGES. JAWRA Journal of the American Water Resources Association, 33: 1011–1022. doi: 10.1111/j.1752-1688.1997.tb04120.x
Paper No. 96075 of the Journal of the American Water Resources Association (formerly Water Resources Bulletin). Discussions are open until June 1, 1998.
- Issue published online: 8 JUN 2007
- Article first published online: 8 JUN 2007
- forest hydrology;
- climate change;
- soil water stress;
ABSTRACT: Large deviations in average annual air temperatures and total annual precipitation were observed across the southern United States during the last 50 years, and these fluctuations could become even larger during the next century. We used PnET-IIS, a monthly time-step forest process model that uses soil, vegetation, and climate inputs to assess the influence of changing climate on southern U.S. pine forest water use. After model predictions of historic drainage were validated, the potential influences of climate change on loblolly pine forest water use was assessed across the region using historic (1951 to 1984) monthly precipitation and air temperature which were modified by two general circulation models (GCMs). The GCMs predicted a 3.2°C to 7.2°C increase in average monthly air temperature, a -24 percent to + 31 percent change in monthly precipitation and a -1 percent to + 3 percent change in annual precipitation. As a comparison to the GCMs, a minimum climate change scenario using a constant 2°C increase in monthly air temperature and a 20 percent increase in monthly precipitation was run in conjunction with historic climate data. Predicted changes in forest water drainage were highly dependent on the GCM used. PnET-IIS predicted that along the northern range of loblolly pine, water yield would decrease with increasing leaf area, total evapotranspiration and soil water stress. However, across most of the southern U.S., PnET-IIS predicted decreased leaf area, total evapotranspiration, and soil water stress with an associated increase in water yield. Depending on the GCM and geographic location, predicted leaf area decreased to a point which would no longer sustain loblolly pine forests, and thus indicated a decrease in the southern most range of the species within the region. These results should be evaluated in relation to other changing environmental factors (i.e., CO2 and O3) which are not present in the current model.