PROCEEDINGS: Index of Abstracts

ELEVATED CO2 COMPENSATES FOR WATER STRESS IN NORTHERN RED OAK

Patricia T. Tomlinson and Paul D. Anderson

USDA Forest Service, Forestry Sciences Lab, North Central Forest Experiment Station, 5985 Highway K, Rhinelander, WI 54501.

Global climate change models predict decreased rainfall in association with elevated CO₂ in the western Lakes States region. Currently, the western edge of northern red oak (Quercus rubra L.) distribution coincides with the most xeric conditions of its ecological range. Decreased rainfall and water availability could alter ecological fitness and distribution. To better understand how climate change may affect this species, we are examining the interaction of CO₂ (400, 520, 700 ppm CO₂) with water stress (well-watered and water-stressed) on growth, and carbon and nitrogen metabolism of northern red oak seedlings through three flushes of development. In this report, we focus on growth, photosynthetic rate, and nitrogen responses to these stresses in three-flush seedlings.