DETERMINATION OF CALCIUM AND MAGNESIUM BY FLAME ATOMIC-ABSORPTION SPECTROMETRY IN FRASER FIR (ABIES-FRASERI) AND RED SPRUCE (PICEA-RUBENS) FOLIAGE FROM RICHLAND BALSAM MOUNTAIN, NORTH-CAROLINA

The red spruce (Picea rubens) and Fraser fir (Abies fraseri) are conif ers which grew naturally at high elevation sites in the southern Appal achian mountains. The Fraser fir has suffered a severe decline, due to an exotic insect, the Balsam woolly adelgid (BWA), while the red spru ce in the Great Smoky Mountains National Park has undergone a mild dec line that has been attributed to reduced foliar calcium and magnesium levels induced by acidic deposition. The first goal of this project wa s to develop a suitable method for the determination of conifer foliag e. A dry combustion procedure followed by flame atomic absorption anal ysis was shown to be convenient and provide good accuracy and precisio n. The second goal of the project was to analyze red spruce and Fraser fir foliage from 10 saplings at Richland Balsam Mountain, NC for calc ium and magnesium, and compare the results to a study done at this sit e in 1968-1969. Foliar red spruce concentrations of calcium and magnes ium in 1994 were 1932 +/- 712 and 330 +/- 68 mu g/g, respectively, com pared to values of 4164 +/- 388 and 788 +/- 62 mu g/g in 1968-1969 tha t were reported in the literature. For Fraser fir, a similar trend was observed: in 1994, foliar calcium and magnesium levels were 2830 +/- 873 and 387 +/- 81 mu g/g; in 1968-1969 the literature levels were 409 5 +/- 219 and 853 +/- 60 mu g/g. Statistical analysis of these data at the 0.01 critical value showed a decrease in foliar calcium and magne sium concentrations in this study compared to the earlier work, indica ting that acidic deposition may have a role in the decline of red spru ce and Fraser fir. (C) 1995 Academic Press. Inc.