Trace elements such as Na, K, Rb, Cs, Mg, Ca, Cl, Br, Sc, Ti, V, Cr, Mn, Fe, Co, Al, Sb, La, Ce,
and Sm
in Sugi (Cryptomeria japonica D. Don) with 1369 annual rings taken from Yaku island were determined for individual rings by means of the neutron activation analysis. It was found that: (1) Profiles of the concentrations of the elements belonging to the same group are similar to each other along the radial direction of the annual rings, though the level of the concentration varies according to the elements. (2) Concentrations of most elements 'drastically vary in the nearest region of the sap- and heartwood border, and (3) concentrations of some elements such as halogen, main transition elements, and rare earth elements are the highest near the cambium. We can thus conclude that the concentrations of the most trace elements vary along the radial direction due to physiological effects. When the annual rings are used as an environmental indicator, hence, the mobility of trace elements in a tree must be taken into consideration.
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