1. Introduction Many tree species are able to adapt to harsh environmental conditions in order to survive. The degree of adaptability can determine how long a species can survive during prolonged environmental stress. This experiment monitored the effects of flooding on the photosynthesis, transpiration, and stomatal conductance of three bottomland hardwood tree species: water oak (Quercus nigra), willow oak (Quercus phellos), and bald cypress (Taxodium distichum). Results During the experiment, willow oak had the highest photosynthesis, transpiration and stomatal conductance and bald cypress had the lowest. No differences in photosynthesis between flooding treatments were observed for seedlings in the growth chamber. Photosynthetic rates were higher for seedlings in moist well-drained soil conditions during the first week of flooding in the greenhouse. During the first week of flooding, transpiration and stomatal conductance were higher for seedlings at both study locations in the moist, well-drained soil. Subsequent weeks, in general, showed no differences in photosynthesis, stomatal conductance and transpiration between treatments. Methods Ten, 1-year-old bareroot seedlings of each species were planted in 1 gallon pots with a soil of 1:1 ratio sand and commercial mix composed of peat, perlite, and vermiculite. Three seedlings of each species were placed in two growth chambers, and four seedlings of each species were also placed in the greenhouse. Growth chambers were set to a 14-hour photoperiod with a day temperature of 28º C and a night temperature of 20º C. To simulate flooding, half of the seedlings for each species in the growth chambers and greenhouse were placed in 5 gallon containers and filled with tap water to 10 cm above the soil surface The duration of the experiment was 5 weeks: 4 weeks of flooding and 1 week drained. Each week, photosynthesis (umol CO 2 m -2 s -1 ), transpiration rate (mmol H 2 0 m -2 s -1 ), and stomatal conductance (mol H 2 O m -2 s -1 ) of each seedling were measured using a Li-Cor LI-6400 portable infrared gas analyzer Discussion Willow oak and water oak are considered to be moderately tolerant of flooding, and bald cypress is tolerant. The literature supports the observations of an initial reduction in photosynthesis, transpiration and stomatal conductance to flooding followed by recovery (Conner and Brody 1989, Hodges and Switzer 1979, Hosner and Boyce 1962). The literature suggests that, if the flooding had continued beyond five weeks, rates for willow and water oak would have likely declined, while bald cypress may have showed no significant change. Acknowledgments Financial, technical, and logistical support provided by Arthur Temple College of Forestry and Agriculture, Stephen F. Austin State University, and the McIntire-Stennis Cooperative Forestry Research Program. Literature Cited: Hodges, John D.; Switzer, George L. 1979. Some aspects of the ecology of southern bottomland hardwoods. In: North America's forests: gateway to opportunity: Proceedings, 1978 joint convention of the Society of American Foresters and the Canadian Institute of Forestry. Washington, DC: Society of American Foresters: 360-365. Hosner, John F.; Boyce, Stephen G. 1962. Tolerance to water saturated soil of various bottomland hardwoods. Forest Science. 8(2): 180-186. Conner, William H.; Brody, Michael. 1989. Rising water levels and the future of southeastern Louisiana swamp forests. Estuaries. 12(4):318-323.