GROWTH AND WATER-USE OF RED SPRUCE (PICEA-RUBENS SARG) EXPOSED TO OZONE AND SIMULATED ACIDIC PRECIPITATION FOR 4 GROWING SEASONS

Red spruce (Picea rubens Sarg.) saplings from a pristine site in Maine were transplanted in native soil to 360 liter pots and relocated to I thaca, New York. After a 1 yr establishment period; 90 saplings were c hosen for use, assigned to treatments, placed in large open-top chambe rs, and exposed to ozone (0.5 to 2.0 x ambient concentration) and simu lated acidic precipitation (at pH 3.1, 4.1, or 5.1) for 3 or 4 consecu tive growing seasons (total ozone exposures of about 165 ppm.hr to alm ost 570 ppm.hr). Forty-five trees were grown on weighing lysimeters an d were used to develop whole-tree water-use budgets. After 3 yr of exp osure, the 45 trees not grown on lysimeters were harvested, and the pl ant tissues were weighed, After the fourth growing season, the remaini ng 45 trees were harvested, and the weight of the plant tissues was de termined, Significant effects of ozone or simulated acidic precipitati on were not detected, with the exception of a trend for increased need le dry weight with increasing ozone and, in 1990 needles only, with de creasing pH. No effects were detected in total dry weight, aboveground dry weight, coarse or fine root weight, stem dry weight, or relative growth rate. No significant interactions of ozone and pH treatment wer e detected. Neither ozone nor pH treatment affected the rate df water use by red spruce saplings, even when they were subjected to a dry-dow n period resulting in drought stress.