ST CS 100 Li 20 A Manual De Instrucciones página 168

Make sure the bar and the chain are
in place when you check the oil delivery.
Start the motor (par. 6.3) and check if the chain oil
is delivered as shown in (fig. 14).
6.5 FORESTRY WORK
6.5.1 Delimbing a tree
Make sure there is nothing or nobody in
the area where the branches will fall.
1. Stand opposite the branch you want to cut.
2. Start cutting lower branches
followed by the higher ones.
3. Make first cut from the bottom towards the
top (Fig. 15.A). Complete delimbing by cutting
from top to bottom, as shown in (Fig. 15.B).
6.5.2 Felling a tree
IMPORTANT Where two or more persons
are working together on felling and bucking
operations, such operations must be performed in
separate areas at a distance from each other of at
least 2.5 times the height of the tree being felled.
Do not fell trees if this involves risks of injuring
people, coming into contact with a power line or
causing any form of damage. If the tree should
come into contact 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. 16) which allow the operator to
escape to a safe zone, about 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. 17.A).
• Felling back cut
1. Perform the felling back cut at least 5 cm
higher than the horizontal face notch (Fig.
18.B).
2. 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.
3. Reduce the thickness of this hinge without
pulling out the bar, until the tree falls.
4. 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. 19.D) to
open the cut. Force the tree to fall along the
desired line by hitting the wedges with a
sledge hammer.
5. When the tree starts to fall, it is necessary to
withdraw the machine from the cut, switch it
off (par. 6.6), 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.
20.A).
It is recommended to cut the tensioned branches
working from the bottom upwards to prevent the
chainsaw from bending (Fig. 20.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. 1H):
EN - 11