AL-KO SOLO 127429, Operating Instructions Manual, Page: 48 / 548

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48 6436 | 6442
Working behaviour and working technique
7.2 Felling trees (14, 15)
DANGER!
Danger of fatal injury from a falling
tree!
Having no escape route when felling a
tree represents a danger of serious and
even fatal injury!
■
Do not start the felling work until you
are sure there is an unobstructed
escape route away from the tree to
be felled.
DANGER!
Danger of fatal injury from an uncon-
trollably falling tree!
Uncontrolled falling trees can lead to ex-
tremely serious and even fatal injury!
■
In order to guarantee controlled fell-
ing of a tree, leave a bridge between
the undercut and the back cut. The
length of this bridge should be ap-
prox. 1/10 of the trunk diameter.
■
Do not carry out any felling work in
windy conditions.
NOTE
Only use wedges made from wood,
plastic or aluminium.
Take the following measures before starting fell-
ing work.
■
Make sure that no other people, animals or
objects are in the danger area.
■
The safe distance from other workplaces or
objects should be at least 2½ tree lengths.
■
Watch out for power lines and other people's
property. If necessary, notify the power sup-
ply company or the property owner.
■
Judge the falling direction of the tree.
Factors influencing the falling direction of the
tree:
■
Natural lean of the tree
■
Height of the tree
■
Branches growing on one side
■
Level ground or slope
■
Asymmetrical growth, wood damage
■
Wind direction and wind speed
■
Snow load
■
When working on a slope, always work uphill
of the tree to be felled.
■
Establish your escape route in advance, and
make sure that there are no obstacles in the
way. The escape route should be at an angle
of approx. 45° diagonally behind the falling
direction (14).
■
The trunk must be free from growth, branch-
es and foreign bodies (e.g. dirt, stones, loose
bark, nails, staples, wire, etc.).
Make an undercut a back cut in order to cut down
a tree.
1. During back cuts and cross-cuts, place the
bumper spike firmly against the wood to be
cut.
2. Saw the first undercut (15/c) horizontally,
then the second undercut at an angle of at
least 45° from above. This prevents the chain
saw becoming trapped when you make the
second undercut. The undercut must be as
close as possible to the ground and in the re-
quired felling direction (15/E). The depth of
the undercut should be about 1/4 of the diam-
eter of the trunk.
3. Cut the back cut (15/d) exactly horizontally
opposite to the undercut. The back cut must
be made 3-5 cm above the horizontal under-
cut.
4. Saw in the back cut (15/c) sufficiently deep
so that a bridge (15/f) of at least 1/10 the
trunk diameter remains between the undercut
(15/C) and the back cut (15/d). This bridge
prevents the tree from twisting and falling in
the wrong direction. The tree should start to
fall when the back cut (15/d) approaches the
bridge (15/f).
If the tree falls whilst you are sawing:
■
Interrupt the back cut if the tree does fall
in the wrong direction or leans back and
traps the chain saw. To open the cut and
fell the tree, drive in wedges in the direc-
tion of the required felling line.
■
Immediately pull the chain saw from the
cut, switch it off and put it down.
■
Walk away in the direction of the escape
route.
■
Watch out for falling branches and twigs.
5. If the tree remains standing, drive wedges in-
to the back cut in order to cause it to fall in a
controlled way.
6. At the end of sawing work, immediately re-
move your ear defenders and listen out for
signals or warning calls.