Szekessy Vilmos (szerk.): A Magyar Természettudományi Múzeum évkönyve 62. (Budapest 1970)

Kováts, D.: Quantitative xylotomic investigations on the xylem of our home ash trees

Fig. 9. Correlation between growth ring width and fibre length. Fraxinus excelsior L. (Dobogókő). — Accessory graph for the co- and counterdecurrence of the tension and pression wood graphs. — r.c. = rate of co-decurrence, — h.c. = heterogeneity of counterdecurrence Summary An interesting result, deviating from general views held heretofore, of my quantitative xylotomic investigations is that after an initial increase of the fibre length it more or less gradually decreases in later years. As regards absolute value s, a Fraxinus ornus L. tree, living north to its area, exceeds those of the other investigated specimens. According to my measurements, fibre length and also the medullary ray percentage decrease, though with considerable fluctuations, in the xylem, from the pith towards the bark. Nor does growth ring width decrease evenly in this direction. On the basis of these measurement data and provided a more detailed comparison between the course of the several graph sections for all examined trees, a direct proportion is to be inferred between fibre length and growth ring