Samples of mature leaves and second-year twigs were collected from 36 chestnut oaks (Quercus prinus L.) growing above two areas of subsurface manganese mineralization in northeast Tennessee. Of the metals determined to be most abundant in ore specimens and concentrates from the general area (i.e., manganese, iron, barium, cobalt, and nickel in decreasing order of abundance), all but cobalt were readily determinable spectrochemically in the ashes of leaves and twigs. The average values (weight per cent) for the tree samples collected as well as for soil specimens from the 1-foot depth at each tree locale were:
Two areas were sampled; one, the Hutchens property, was later developed into an economic ore body. The manganese bodies of the second, the Rominger property, proved to be too low in over-all concentration to be of economic value. Significantly, the samples from the Hutchens area more frequently exceeded the average values for manganese barium, and nickel given in the preceding table than did those from the Rominger area. Although nickel was not detectable in the surface soil, the appearance of nickel in excess of average in chestnut-oak leaf and twig ash was confined almost exclusively to the Hutchens area, particularly to the trees most closely overlying the subsurface manganese ore body. Nickel in chestnut-oak leaf and twig ash thus seemed to be a fairly reliable guide to ore, apparently acting as a pathfinder for manganese.