DETERMINATION OF ALUMINUM, CALCIUM, AND MAGNESIUM IN FRASER FIR (ABIES FRASERI) FOLIAGE FROM 5 NATIVE SITES BY ATOMIC-ABSORPTION SPECTROMETRY - THE EFFECT OF ELEVATION UPON NUTRITIONAL-STATUS

The Fraser fir (Abies fraseri) is a conifer native to high elevation s ites in the southern Appalachians that has recently suffered severe mo rtality because of an exotic insect, the balsam woolly adelgid (BWA). The companion tree of the Fraser fir, the red spruce (Piceae rubens) h as suffered relatively mild decline induced by acidic deposition, due to reduction of extractable calcium and magnesium levels in the soil, while causing an increase in extractable aluminum. We hypothesized tha t acidic deposition may be involved, along with the BWA, in inducing F raser fir decline. Our hypothesis was tested by collecting Fraser fir foliage and soil from five sites-on Clingman's Dome, NC/TN, Roan Mount ain, NC/TN, and Mount Rogers, VA, and determining foliar and extractab le soil aluminum, calcium, and magnesium. Foliar aluminum was done by graphite furnace atomic absorption (GFAAS) with continuum source backg round correction, while all other analyses were done by dame AAS. The analysis of composite samples was shown to provide improved precision by a factor of 2-4 for elemental analysis of a class of conifers compa red to averaging individual analyses. Although aluminum levels were la rger and calcium/aluminum ratios were smaller at the high elevation si tes at two mountains, calcium levels were statistically the same at th e high and low elevation sites. Consequently, it is difficult to defin itively conclude that acidic deposition has contributed to Fraser fir decline. (C) 1997 Academic Press.