Hem fold

The seam hitting referred to in the forestry a harvest procedures for rejuvenation of the forest. Initially, only partial areas will be rejuvenated in the form of strips in order to consciously promote tree species with certain ecological requirements. Hems ( border = edge area of a forest) with widths of 30 to 50 meters are cleared in succession at intervals of five to ten years. In principle, the period of time in which the seam is driven depends on the need for felling of the respective farm and on the progress of natural rejuvenation. The cleared seams can either be reforested by means of natural regeneration , but also by means of planting. Further combined rejuvenation methods of the hem hitch are the hem screen hitch and the hem hem hitch.

history

The form of rejuvenation at the edge of a forest had already been practiced occasionally in the past. The Württemberg forester Christoph Wagner (1912) used this form of rejuvenation more intensively for the first time and developed a self-contained silvicultural system from it for the first time, the "Blendersaumschlag".

Rejuvenation goal

With the method, mixed stands of shady , semi- shady and light tree species can be rejuvenated, taking into account the spatial order to avoid felling and back damage.

Ecological conditions

The rejuvenation areas are protected from different weather conditions by one side of the forest due to the border-like clearcuts . The effect of the side protection depends, of course, on the climate, the shape of the terrain, the height of the stand in front of it and the tree species forming it, the width of the border and its orientation in the terrain.

A tapered edge in a south-westerly direction is exposed to a significantly higher level of radiation and wind than a edge in a north-east direction. In order to avoid the negative influences of the sun and the wind, the hemming operation is carried out from the north, northeast and east. Three zones can be distinguished within the cleared hem. On the one hand, the zone directly on the edge of the old wood, which is well protected from sun and wind, and is therefore suitable for shade tree species . On the other hand, the following zone as the middle area of the cleared border, in which the young plants are already significantly more exposed to the sun and rain, but are still protected from the wind and are exposed to a reduced risk of frost. The last zone, in the outermost area of the border, on the other hand, resembles the proportions of an open area. This zone is particularly suitable for light tree species, frost-hard and fast-growing wood species. The first zone forms the inner hem and the third zone the outer hem of a hem fold.

Advantages and disadvantages

According to Burschel and Huss, the hem stroke is scored as follows:

advantages

A very clear field and forest order emerges
The annual amount of wood can be realized evenly and easily
In the course of the harvest and regeneration process, tree species with different light-ecological characteristics have a chance to arrive and develop
Bald areas with their disadvantages are avoided
If the hem direction is chosen correctly, the risk of storms on hems remains low, because there is no significant roughening of the canopy in the part of the stand upstream of the hem.

disadvantage

There is something schematic about the process, which is visually strong
Larger existing complexes must be subdivided using several straight lines. If rapid cutting progress is planned, the number of such lines will be very large, but even if progress is very slow it is still considerable.
If stands that are already ready for cutting are to be treated in this way, either very rapid cutting progress is required, with which the arrival of the rejuvenation may not keep pace, or the parts that have been kept for the longest time will become obsolete
If, in order to avoid obsolescence, the inlay of hems is already begun in stocks that are not yet ready for cutting, then growth losses must be accepted
There is little flexibility in relation to fluctuations in the timber market or overcuts born from emergency situations, since every change in the progress of the cut endangers the continuity of the rejuvenation. Overcuts have a greater effect than if they are reluctant to felling

literature

Ernst Röhrig , Norbert Bartsch , Burghard von Lüpke : Silviculture on an ecological basis, 7th edition, Verlag Eugen Ulmer Stuttgart, Stuttgart 2006, ISBN 3-8001-4595-2

Individual evidence

^ Hannes Mayer: Silviculture on a sociological-ecological basis, 4th, revised edition, Gustav Fischer Verlag, Stuttgart, Jena, New York 1992, ISBN 3-437-30-684-7 .
^ Alfred Bonnemann and Ernst Röhrig : Choice of tree species, establishment of stands and maintenance of stands , 2nd volume, Paul Parey publishing house, Hamburg and Berlin 1972, ISBN 3-490-01416-2 .
^ Peter Burschel / Jürgen Huss : Grundriss des Waldbau, 3rd, unchanged edition, Verlag Eugen Ulmer, Stuttgart 2003, ISBN 3-8001-4570-7 .

[1] Hannes Mayer: Silviculture on a sociological-ecological basis, 4th, revised edition, Gustav Fischer Verlag, Stuttgart, Jena, New York 1992, ISBN 3-437-30-684-7 .

[2] Alfred Bonnemann and Ernst Röhrig : Choice of tree species, establishment of stands and maintenance of stands , 2nd volume, Paul Parey publishing house, Hamburg and Berlin 1972, ISBN 3-490-01416-2 .

[3] Peter Burschel / Jürgen Huss : Grundriss des Waldbau, 3rd, unchanged edition, Verlag Eugen Ulmer, Stuttgart 2003, ISBN 3-8001-4570-7 .