Indentation of Juvenile Annual Growth Rings and their Impact on Morphology of Wood Cells

The morphology of cellular elements of juvenile wood of spruce has, in comparing to mature wood, different parameters. Subsequently, indented growth ring zones, caused by genetic predisposition and cambial injury, can significantly change the morphology of these tissues. The aim of the paper compared the morphology of cellular elements of juvenile wood originating in the indented and the normal growth rings. The results confirmed a significant difference in the proportion, the dimensions and shape of parenchyma cells and tracheids. While, in zones containing the indented growth rings the proportions were 15.6 % and 84.4 %, in normal growth rings were 10.4 % and 89.6 %. Tracheids in the indented growth ring zones were shorter and narrower (1.47 mm and 25.4 µm), but in normal growth ring zones longer and wider (2.14 mm and 28.3 µm). Tracheids from marginal and central zones normal growth rings showed considerable inhomogeneity in longitudinal shape (they were twisted). On the basis of change tissue morphology in the juvenile growth phase we can expect the impact of these growth disproportions on the quality production of pulp and paper, mainly in assortments with small diameter.