Stiga SP 316 C Manual De Instrucciones página 179

with a main power line, report the incident
immediately to the network provider.
Before commencing the felling operations:
– it is necessary to evaluate the natural
inclination of the tree, the part where the
branches are larger and the wind direction,
to assess how the tree will actually fall;
– remove any dirt, stones, pieces of
bark, nails, metal staples and wire;
– clear the area around the tree and
find a stable place to stand;
– plan obstacle-free escape routes at a 45°
angle back and away from the direction of
the fall (Fig. 17) which allow the operator to
escape to a safe zone, approximately 2.5
times the height of the tree being felled;
– Stand uphill of the land onto which the tree
will probably roll or fall over after felling.
• Performing a face notch
1. Stand to the right of the tree,
behind the chainsaw.
2. Saw a horizontal face notch to 1/3 of the
diameter of the tree, perpendicular to the
direction in which it will fall (Fig. 18.A).
• Felling back cut
3. Perform the felling back cut at least
5 cm higher than the horizontal
face notch (Fig. 18.B).
4. Perform the felling back cut leaving
sufficient wood to act as a "hinge" (Fig.
18.C). The hinge wood will prevent the
tree from twisting and falling in the wrong
direction. Do not cut through the hinge.
5. Reduce the thickness of this hinge without
pulling out the bar, until the tree falls.
6. If there is any risk of the tree not falling
in the desired direction, or that it might
lose its balance moving backwards and
bending the toothed chain, stop cutting
before completing the felling back cut and
use some wooden, plastic or aluminium
wedges (Fig. 18.D) to open the cut. Force
the tree to fall along the desired line by
hitting the wedges with a sledge hammer.
7. When the tree starts to fall, it is necessary
to withdraw the machine from the
cut, switch it off (par. 6.9), lie it on the
ground and take the foreseen exit route.
Beware of falling branches and pay
attention where you put your feet.
6.5.3 Limbing tree branches
Limbing means removing the
branches from a felled tree.
Be careful of where the branches are
lying on the ground, the risk of them being
under tension, the direction the branch may
go during cutting and the risk of the tree
being unstable after the branch has been cut.
When limbing, it is necessary to
leave the lower, larger branches to
support the trunk on the ground.
Remove the small branches with
a single cut (Fig. 19.A).
It is recommended to cut the tensioned branches
working from the bottom upwards to prevent
the chainsaw from bending (Fig. 19.B).
6.5.4 Bucking the trunk
Bucking means sawing a tree trunk into logs.
It is essential to make sure your feet are
positioned firmly on the ground, and your weight
is distributed equally on both feet. If possible,
it is recommended to raise and support the
trunk using branches, logs or blocks of wood.
It is easier to saw a log using the
spiked bumper (Fig. 1.I):
1. plant the spiked bumper into the log and use
it as a pivot. Cut with an arched motion to
make the bar penetrate the wood (Fig. 20);
2. repeat several times if necessary, changing
the point where you plant the spiked bumper.
• Trunk lying on the ground
When the entire trunk is lying on the
ground, it is bucked from the top
down (overbucking) (Fig. 21.A).
– Cut up to half the diameter, roll the log
over and finish sawing on the other side.
• Trunk resting on one end only
When the trunk is resting on one end only:
– saw through 1/3 of the diameter from the
bottom up (underbucking) (Fig. 22.A);
– then perform the final cut, overbucking
to reach the first cut (Fig. 22.B).
• Trunk resting on both ends
When the trunk is resting on both ends:
– saw through 1/3 of the diameter from the
top down (overbucking) (Fig. 23.A);
– then perform the final cut, underbucking the
lower 2/3 to reach the first cut (Fig. 23.B).
• Sloping trunk
Always stand uphill when bucking
a sloping trunk (Fig. 24).
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