You are here: Home Contents Miners Path Protection Forest
Document Actions

Protection Forest

by Alexander Sohm last modified 2007-01-08 13:30

The mountain forests offer the most efficient and the cheapest protection from natural catastrophes in the Alpine region.  Without the mountain forests we wouldn’t be able to settle on the Alps because the costs for technical protection measures would be too high.  The mountain forest protects from rock falls, floods, mudslides and avalanches.  The following is a detailed description of how the forest protects against avalanches.

The importance of the forest as protection again avalanches was discovered early on.  In the first book “Common Forest Regulations” for the Montafon, Kaiser Maximilian kept his eye on lumbering.  In 1535 an edict was defined for the special treatment of the avalanche forests and it was ordered that anyone that didn’t follow the guidelines would be severely punished.

The protection function of the forest lies in the fact that it stops avalanches from forming in the forest bit if an avalanche starts above it, even an intact forest cannot stop the masses of snow from moving.  The stabilizing effect of the forest on the snow mantle and with that the hindering of avalanches is based on various characteristics of the forest which do not exist in the open.  These are: the interception of snow, the amount of sunrays, wind and the supporting effect of the tree trunks.

1) The Interception of Snow:  This is when part of the snow is intercepted and caught in the crown of the trees.  A small portion of the snow evaporates and the larger portion eventually falls to the ground in clumps or as melt water.  Because of this the snow mantle in the forest isn’t as strong and is a lot more structured.

2) The Amount of Sunrays:  The micro climate in a dense, winter green forest is more balanced than in the open.  Warming of the snow mantle during the day and cooling during the night are not as extreme.  This is why there isn’t as much surface frost in the forest as there is in the open.  Surface frost forms a dangerous weak layer in the formation of the snow mantle and can lead to avalanches forming when there are new snow falls.

3) Wind:  The wind blows the snow away from exposed areas and piles it up at other places forming snow drifts.  Here, layers of different density and firmness are formed which leads to tension in the snow mantle and in turn supports the forming of avalanches.  The effects of the wind are much less in a closed forest than out in the open.

4) Support of the Tree Trunks: The tree trunks support and stabilise the snow mantle.

Because the forest protects settlements and transportation routes, it is important to preserve this protection function by planting forests or, if necessary, by using technical measures.  You are in a construction project area for torrent and avalanche constructions.  The next point deals with this subject in detail.


P09-1 protection forest .mp3

Powered by Plone CMS, the Open Source Content Management System

This site conforms to the following standards: