Jonsered CS 2238S Manual Del Usuario página 18

Tree felling technique
IMPORTANT! It takes a lot of experience to fell a tree.
Inexperienced users of chain saws should not fell
trees. Do not attempt any task beyond your experience
level!
Safe distance
The safe distance between a tree that is to be felled and
anyone else working nearby is at least 2 1/2 tree lengths.
Make sure that no-one else is in this "risk zone" before or
during felling. (37)
Felling direction
The aim is to fell the tree in a position where you can limb
and cross-cut the log as easily as possible. You want it to
fall in a location where you can stand and move about
safely.
Once you have decided which way you want the tree to
fall you must judge which way the tree would fall
naturally.
Several factors affect this:
• Lean of the tree
• Bend
• Wind direction
• Arrangement of branches
• Weight of snow
• Obstacles within the reach of the tree: for example,
other trees, power lines, roads and buildings.
• Look for signs of damage and rot in the stem, this
makes it more probably that the tree will break and
start to fall before you expect it to.
You may find you are forced to let the tree fall in its natural
direction because it is impossible or dangerous to try to
make it fall in the direction you first intended.
Another very important factor, which does not affect the
felling direction but does affect your safety, is to make
sure the tree has no damaged or dead branches that
might break off and hit you during felling.
The main point to avoid is letting the tree fall onto another
tree. It is very dangerous to remove a trapped tree and
there is high accident risk. See instructions under the
heading Freeing a tree that has fallen badly.
IMPORTANT! During critical felling operations,
hearing protectors should be lifted immediately when
sawing is completed so that sounds and warning
signals can be heard.
Clearing the trunk and preparing your retreat
Delimb the stem up to shoulder height. It is safer to work
from the top down and to have the tree between you and
the saw.
Remove any undergrowth from the base of the tree and
check the area for obstacles (stones, branches, holes,
etc.) so that you have a clear path of retreat when the
tree starts to fall. Your path of retreat should be roughly
135 degrees away from the intended felling direction.
(38)
18 – English
WORKING TECHNIQUES
Felling
WARNING! Unless you have special
!
training we advise you not to fell trees
with a diameter larger than the bar
length of your saw!
Felling is done using three cuts. First you make the
directional cuts, which consist of the top cut and the bottom
cut, then you finish with the felling cut. By placing these cuts
correctly you can control the felling direction very accurately.
Directional cuts
To make the directional cuts you begin with the top cut.
Stand to the right of the tree and cut on the pull stroke.
Next make the bottom cut so that it finishes exactly at the
end of the top cut. (39)
The directional cuts should run 1/4 of the diameter
through the trunk and the angle between the top cut and
bottom cut should be 45°.
The line where the two cuts meet is called the directional
cut line. This line should be perfectly horizontal and at
right angles (90°) to the chosen felling direction. (40)
Felling cut
The felling cut is made from the opposite side of the tree
and it must be perfectly horizontal. Stand on the left side
of the tree and cut on the pull stroke.
Make the felling cut about 1.5-2 inches (3-5 cm) above
the bottom directional cut. (41)
Finish the felling cut parallel with the directional cut line
so that the distance between them is at least 1/10 of the
trunk diameter. The uncut section of the trunk is called
the felling hinge.
The felling hinge controls the direction that the tree falls
in. (42)
All control over the felling direction is lost if the felling
hinge is too narrow or non-existent, or if the directional
cuts and felling cut are badly placed.
When the felling cut and directional cut are complete the
tree should start to fall by itself or with the aid of a felling
wedge or breaking bar.
We recommend that you use a bar that is longer than the
diameter of the tree, so that you can make the felling cut
and directional cuts with single cutting strokes. See
instructions under the heading Technical data section to
find out which lengths of bar are recommended for your
saw.
There are methods for felling trees with a diameter larger
than the bar length. However these methods involve a
much greater risk that the kickback zone of the bar will
come into contact with the tree.
Freeing a tree that has fallen badly
Freeing a "trapped tree"
It is very dangerous to remove a trapped tree and there
is high accident risk.
Never try to fell the tree that is trapped.
Never work in the risk zone of the hanging trapped tree.
The safest method is to use a winch.
• Tractor-mounted
• Portable
5451867-95 Rev.3 2008-12-18