The role of snow in coniferous stem bend formation

Wien

1988

8 Abb., 2 Tab., 5 Lit. Ang.

Unselbständiges Werk

673

200005050

Sugi ( Cryptomeria japonica D. Don) was used for the study of the cause of stem bend of coniferous trees in snowy region. Until the tree height reached 2 or 2.5 times the average maximun snow depth, sugi, afforested in snowy region, would be buried in snow. The trees are pressed to the ground by snow weight and settling pressure of snow. The soft stems of 1- and 2-years-old trees bend only where pressed. Trees over 3-years-old are hard to bend as bending stiffness of the stem increases. The stem, together with its root system, is inclined to suffer damage and defomation when buried by snow. In early spring, after release from snow pressure, the stem started straighening with vanishing rapid simple elasitic strain and elastic after-strain, and consequently straightening by formation of compression-wood. Basal bending was the result of stem recovery, because the recovery rate decreases towards the lower part of the stem. This is main cause of the stem bending in coniferous trees.