The Effect of Rot on the Resistance of Trees to Snowbreak

1991

S. 577-589

9 Lit. Ang.

Unselbständiges Werk

200062031

Wet snow is a great danger to trees and to the forest stands. In the period since 1980 tha amount of snow-broken trees has doubled, compared with the preceding 80-year period. The resistance of trees to breaking by snow is influenced by a number of factors, including the weather, height above sea level, the terrain morphology, properties of the site and the stands, their shape, age, height, density. The stability of the stands and trees is affected by changes in the species composition and, by poorer tending. Importance is attached to the state of the separate trees, their height, shape, diameter and slenderness. The great increase in the snowbreaks can be largely ascribed to the worsened state of health of the trees after browsing and peeling by the red deer, fallow deer and mouflon, and by negligent skidding. All this causes mechanical damage, conducive to rot. The study demonstrates how greatly the rot affects the stability of the trees. Surface rots are much more dangerous to the stability of the trees (surface rots progress from the surface to the centre of the trunk), as compared with the centre rots which usually starts from the roots. There is no substantial difference between surface rot in the shape of circle segment and circle sector. The major measures for the control of the rots include selection by health and the control of all factors that may lead to tree injury.