634 

 Snow Pressure, Ice Coating and Icicles 



Just as certain regions are especially often visited by hailstorms, 

 definite zones exist (if from other causes), especially in the mountains, in 

 which injuries occur almost every year due to pressure from the snow. 

 Besides these zones, some places in all regions with an abundant snowfall 

 must be considered as especially endangered. These are depressions in 

 the soil into which the snow can be blown from above or from the sides. 

 Equal amounts of snowfall act differently according to the weather. If it 

 is very cold and windy, enough snow rarely collects on the branches to 

 cause injury; the crystals are too fine and cold to stick to one another. If, 

 on the other hand, the weather is warm and quiet, the snow falls in great 

 flakes and balls easily, large masses cling in the crowns of the trees and 

 bend or break the branches. 



If the trees stand on declivities, many injuries are noticed on the slope 

 opposite the windy side; whole strips of trees can be overthrown. This 

 occurs as a simple result of snow pressure, especially with mild winter 

 weather and soft, open soil, while, with greater cold, the more brittle trunks 

 will be broken (snow breakage). Transplanted trees, with shallow root 

 systems, are overturned more easily than specimens well anchored by tap 

 roots. Evergreen trees are especially inclined to break and of them the 

 pines seem most brittle. The tougher varieties, like firs and spruces, bend 

 more under the burden and later right themselves. Deciduous trees are 

 less injured if the snow masses come after the leaves have fallen. Oaks 

 and beeches, which often retain their foliage throughout the whole winter, 

 are more endangered than other trees, provided that a previous moist and 

 cool summer has not prevented the latter from passing into their dormant 

 period and dropping their foliage. Here too the brittleness of the variety 

 is decisive for the kind of injury. The trunks and branches of older 

 acacias almost always break. In birches and alders, also, breaking may be 

 found oftener than bending. Bernhardt^ also calls attention to the fact 

 that the resistance of the tree variety changes according to whether its 

 habitat is suited to its requirement or not. For our fruit trees, the shape 

 of the crown also enters greatly into consideration; especially in apples, 

 for with their flat, outspread branches, a true splitting of the crowns is often 

 found. If the tree's natural habit of growth does not form a pyramidal 

 crown, it is advisable to cultivate artificially the development of a strong 

 middle branch. 



With avalanches, occurring frequently in high mountains, the whole 

 effect changes according to the variety of the trees and the age of the trunk. 

 If the standing forest is old, the trees are broken at different heights and 

 thrown together in wild and irregular disorder. Where the trees are of 

 different ages, the young trees are only partially pressed downward and, 

 for a time, buried in the snow. After the snow melts, these trees right 



1 Waldbeschadigungen durch Wind-, Schnec-, Eis- und Duftbruch. Centralbl. 

 f. d. gesamte Forstwesen 1878, p. 29. 



