Fig. 3. Radial distribution of alkali and alkali earth metals, where concentrations are shown on a dry wood basis and vertical lines in the figure show sapwood–heartwood boundaries. The Cs of Kyoto Japanese persimmon is shown with error bars of ±1 standard deviation. Concentration of Ca was analyzed by two methods. ICP represents the data by inductively coupled plasma mass spectrometry analysis and INAA by instrumental neutron activation analysis. Although Mg is not an alkali earth metal, it is included in the figure.