O-Mac MF 2500 Manual page 59

6.4.2 Work techniques
6.4.2.a Delimbing a tree
Make sure there is nothing or anybody 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. Cut downwards to prevent the bar from
getting jammed (Fig. 21).
6.4.2.b 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. 22) which allow the operator
Use a screwdriver
to turn it to the "+"
position to increase
the oil flow to the
chain; turn it to the "-"
position to decrease
the flow.
to escape to a safe zone, approximately2.5
times the height of the tree being felled;
– Stand upstream of the land onto which the
tree will probably roll or fall over after felling.
• Performing a face notch
1. Following the directional marks on the
chainsaw (Fig. 23.A), point towards a target
on the ground in the direction in which you
intend to fell the tree (Fig. 23.B).
2. Stand to the right of the tree, behind the
chainsaw.
3. Saw a horizontal face notch to 1/3 of the
diameter of the tree, perpendicular to the
direction in which it will fall (Fig. 24.A).
• Felling back cut
4. Perform the felling back cut at least 5 cm
higher than the horizontal face notch (Fig.
24.B).
5. Perform the felling back cut leaving
sufficient wood to act as a "hinge" (Fig. 24.C).
The hinge wood will prevent the tree from
twisting and falling in the wrong direction. Do
not cut through the hinge.
6. Reduce the thickness of this hinge without
pulling out the bar, until the tree falls.
7. 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. 24.D) to
open the cut. Force the tree to fall along the
desired line by hitting the wedges with a
sledge hammer.
8. 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.
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