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Show 13 The observations in influence of earth terraces on gliding, stretching over five winters, have also produced discouraging results. In two winters, glide paths of around 10 cm were measured on 3- meter wide terraces at Mattstock. The snow cover was pushed over the terraces in a body. These facts show that glide protection for afforestation and the supporting structures themselves is far from being solved. Our measurements and observations, especially regarding the damage to supporting structures and afforestation by gliding snow, demonstrate the weakness of current preventive measures. The practical man will ask himself the question: Can the expected glide motion, including that in the zone of influence of defense structures, be tolerated for afforestation? An answer was reached in the winter of 1965/ 66: For many afforestation projects, it unfortunately was in the sense that the setbacks cancelled a year's gain. Within afforestation zones where the trees do not yet extend above the maximum snow depth, or at most do so occasionally, a significant suppression of snow gliding has been observed. In extreme winters this braking action is achieved by the trees at the cost of self- destruction. We have to admit that chance plays a critical role for afforestation of glide- damage locations. If a series of normal or practically harmless winters occurs so the next glide winter finds a strong stand of young trees, then the afforestation can be saved. On the other hand, when adverse circumstances come into play and the fragile young stand of trees encounters one or more glide winters in a row, many a promising |
