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Variability of anatomical characters within a 15 year old stem is presented by the method of contour lines, where against a schematic longitudinal section of a stem points corresponding to the same values for a character are joined by lines, similarly as altitudes in cartography. The method permits prediction of future trends in character changes. It was thus established that tracheid dimensions and diameter of bordered pits in early wood tracheids increase with age of tree and do not reach maximal values before the 15th year. The annual ring width and the height of the rays attain maximal values before the 15th year while the dimensions of ray cells and the percentage of late wood reach almost constant values during the first year or two.

Tannin cells occur throughout the bud except the distal and peripheral meristem zones of the apical meristem, and the youngest cataphyll primordia. Starch is absent in winter buds. The earliest structural manifestation of spring awakening in the bud are fragmentation of tannin vacuoles and synthesis of starch in the green cells of the bud. The tannins occurring in the vacuoles are hydrolysable giving a positive reaction for sugars (PAS). During their spring hydrolysis glucose is released. It is probably one of the sources of sugars for the synthesis of starch. During extension growth of the bud there occurs a degradation of tannin cells in the pith, which consist in the precipitation of tannins to a condensed form.