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

Abstract

The red spruce (Picea rubens) and Fraser fir (Abies fraseri) are conifers which grew naturally at high elevation sites in the southern Appalachian mountains. The Fraser fir has suffered a severe decline, due to an exotic insect, the Balsam woolly adelgid (BWA), while the red spruce in the Great Smoky Mountains National Park has undergone a mild decline that has been attributed to reduced foliar calcium and magnesium levels induced by acidic deposition. The first goal of this project was to develop a suitable method for the determination of conifer foliage. A dry combustion procedure followed by flame atomic absorption analysis was shown to be convenient and provide good accuracy and precision. The second goal of the project was to analyze red spruce and Fraser fir foliage from 10 saplings at Richland Balsam Mountain, NC for calcium and magnesium, and compare the results to a study done at this site in 1968-1969. Foliar red spruce concentrations of calcium and magnesium in 1994 were 1932 ± 712 and 330 ± 68 μg/g, respectively, compared to values of 4164 ± 388 and 788 ± 62 μg/g in 1968-1969 that 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 μg/g; in 1968-1969 the literature levels were 4095 ± 219 and 853 ± 60 μg/g. Statistical analysis of these data at the 0.01 critical value showed a decrease in foliar calcium and magnesium concentrations in this study compared to the earlier work, indicating that acidic deposition may have a role in the decline of red spruce and Fraser fir.