The Shelterwood strip system is a silvicultural system where regeneration fellings are done progressively in strips against the direction of wind. Seedling fellings are done first in a narrow strip along the edge of the compartment. When the regeneration in that strip grows larger, a secondary felling is done there and a seedling felling is done in the next adjacent strip. This process continues with final fellings in the first strip once the second strip's regeneration requires secondary fellings. The strips vary in width from 20-30 meters depending on local conditions. Wagner's Blendersaumschlag is a modification where strips extend east to west and fellings progress from north to south, producing even-aged regeneration along the strip

1. Lec 24 – Shelterwood strip system
Wedge system, strip and group
system

2. DEFINITION
• The Shelterwood strip system is defined as a
silvicultural system in which regeneration fellings are done in the form of
strips successively from one side of the compartment, progressing
against the direction of wind.

3. PATTERN OF FELLING
• This system was evolved from the Uniform System for protective reasons.
• While in the Uniform System seeding fellings are done uniformly all over
the compartment, in the Shelterwood-strip System, these are done in
strips along one side (in Europe, generally eastern or north-eastern) of the
compartment, and progress against the direction of wind.
• This system differs from Progressive Clear-felling System in as much as
that successive shelterwood regeneration fellings are done in strips in the
former, whereas the strips are clear felled in the latter.

4. • In this system, first of all seeding fellings are carried out in a narrow
strip along one side of the compartment.
• When regeneration springs up and develops in this strip and requires more
light, a secondary felling is carried out therein and a seeding felling in
the second strip, adjacent to the first strip on the windward side.
• When regeneration in the second strip reaches a size requiring secondary
felling, the regeneration in the first strip may be in need of final felling.
• So final felling is done in the first strip, secondary felling in the second
and seeding felling in third strip adjacent to the second.
• In this way, regeneration fellings advance progressively against the
direction of wind in a series of strips made one after the other,
successively

6. OBJECTIVE
• The width of the strip varies according to local conditions, and may vary
from 20m to 30 m or even more.
• As the main object is protection against wind, the alignment of strip in
flat country is at right angles to general wind direction but in the hilly
country, considerations of local wind direction, transport of timber and
the general slope also affect the alignment.

7. • Shelterwood-strip System showing progress of fellings in strips.
– 0,0 Unfelled forest.
– 1,1 Strips in which seeding fellings have been carried out for the first
time.
– 2,2 Strips felled next; now under secondary fellings.
– 3,3 Initially felled strips; now under final fellings.

8. • This system does not offer any advantage over the Uniform System as
wind damage is not a serious problem in India.
• In addition, whereas organization and execution of operations in the
Uniform System is quite simple, the laying out of strips, execution of
fellings therein, logging and transport of material, tending of
regeneration and its protection against grazing and fire in the
Shelterwood-strip System present unsurmountable difficulties.
• This is why this system has not been applied in this country.

9. WAGNER'S BLENDERSAUMSCHLAG
• Wagner's Blendersaumschlag is a modification of Shelterwood-strip
System and may be
defined as a Silvicultural System in which regeneration fellings are carried out
in narrow strips extending in east west direction and advancing from
north to south.

10. CHARACTER OF THE CROP
• The crop produced in this system is even-aged along the direction of the
length of strip (i.e., E to W) but uneven-aged from the northern end of
the compartment to the southern end.
• This system has not been applied in this country as the sun is directly
overhead during summer, and strip fellings progressing from north and
south do not confer any advantage from the point of view of protection
against sun.

11. THE STRIP AND GROUP SYSTEM
• The Strip and Group System is a modification of the Shelterwood-Strip
System in which fellings done in strips conform to the Group System
instead of the Uniform System.
• Thus in the first strip the first felling frees the patches of existing
advance growth, and a seeding felling is done in a ring round them.
• If necessary, some more gaps are created in the strip artificially to induce
regeneration.
• In the second stage, a fresh strip is taken adjacent to the first for freeing
natural foci or groups of regeneration and creating artificial foci.

13. • At the same time, the groups of the initial strips are enlarged by seeding
felling round them and secondary felling over them.
• In this way, while new strips are taken for freeing natural foci creating
artificial ones, against the direction of wind, regeneration fellings are
done in the previous strips to enlarge the groups of regeneration till they
merge with each other.
• This system has not been used in this country for the same reasons due
to which Group System has been given up and/ or the Shelterwood-strip
System has not been used.

15. THE WEDGE SYSTEM
• The Wedge System is a form of strip system in which the strip instead of
being at one end of the cutting section, is located in the middle of it with
its length running in the wind direction.
• The strip does not run from one end of the cutting section to another but
stops short of the windward side of the cutting section.
• Such strips are usually 2 to 5 m wide and made at intervals of 80 m.
• As regeneration appears in this strip as a result of initial regeneration
felling, it is widened more towards the leeward side and less towards the
windward side, giving it the shape of a wedge.

17. • While the strip is widened in this way, its apex is also pushed forward.
• In course of time, the apex touches the other end of the cutting section,
the widening bases of the wedges merge with each other.
• The remaining trees are removed thereafter in strip fellings to complete
the regeneration.
• This system was developed by Dr. Eberhard in Germany and is, therefore,
referred to as Eberhard's Wedge System.
• It has not been used in India because of its complicated nature; moreover
wind damage is not a serious problem in India.

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