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Rotational Activity of Trunk Parts in Scots Pine Trees: Seasonal Dynamics and Patterns
S A Shavnin1, D Yu Golikov2, A A Montile3
1Institute Botanic Garden, Ural Branch, Russian Academy of Sciences, 620144, Yekaterinburg, Russia. sash@botgard.uran.ru.
Abstract:
The seasonal dynamics and relationships between the characteristics of the angles of rotation of outer sapwood layers in trunks of Scots pine (Pinus sylvestris L.) trees growing in natural stands have been studied for two years in order to improve the understanding of the trunk twisting phenomenon and its role in the tree growth and morphogenesis. The trunk twisting phenomenon is observed in all trees during the entire vegetation period, and its characteristics do not depend on the exposition and differ in various trunk parts. The rotation angles and directions of rotation of the adjacent trunk parts are positively correlated with each other. The counterclockwise direction of rotation dominates, which provides an increase in the total rotation angle over time. The directions and values of the forces causing rotation of outer sapwood layers seem to be explained by the gradients of mechanical stresses appearing between neighboring xylem parts due to their nonuniform moisture content.
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