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9
Fig. 17
○ There is a risk of kickback if the saw is pushed far enough so that
you begin to cut with the nose of the bar.
The safest cutting method is to cut with the bottom part of the
chain. Sawing with the upper part makes it much more
diffi cult to
control the saw and increases the risk of kickback.
○ In case the chain locked, immediately release the throttle lever.
If the throttle lever keeps rotating at high speed with the chain
locked, the clutch will overheat causing trouble.
NOTE
Always keep the spiked bumper face to a tree,
because the
chain may suddenly be drawn into a tree.
FELLING
Felling is more than cutting down a tree. You must also bring it down
as near to an intended place as possible without damaging the tree
or anything else.
Before felling a tree, carefully consider all conditions which may
eff
ect the intended direction, such as:
Angle of the tree. Shape of the crown. Snow load on the crown.
Wind conditions. Obstacles within tree range (e.g., other trees,
power lines, roads, buildings, etc.).
WARNING
○ Always observe the general conditions of the tree. Look for
decay and rot in the trunk which will make it more likely to snap
and start to fall before you expect it.
○ Look for dry branches, which may break and hit you when you
are working.
Always keep animals
and people at least twice the tree length
away while felling. Clear away shrubs and branches from around
the tree.
Prepare a path of retreat away from the felling direction.
BASIC RULES FOR FELLING TREES
Normally the felling consists of two main cutting operations, notching
and making the felling cut. Start
making the upper notch cut on the
side of the tree facing the feeling direction. Look through the kerf as
you saw the lower cut so you do not saw too deep into the trunk. The
notch should be deep enough to create a hinge of suffi cient width
and
strength. The notch opening should be wide enough to direct
the fall of the tree as long as possible. Saw the felling cut from the
other side of the tree between one and two inches (3–5 cm) above
the edge of the notch. (Fig. 18)
18
19
20
21
Fig. 18
18. Felling direction
19. 45° minimum notch opening
20. Hinge
21. Felling cut
Never saw completely through the trunk. Always leave a hinge.
The hinge guides the tree. If the trunk is completely cut through, you
lose control over the felling direction.
Insert a wedge or a felling lever in the cut
well before the tree
becomes unstable and starts to move. This will prevent the guide
bar from binding in the felling cut if you have misjudged the falling
direction. Make sure no people have come into the range of the
falling tree before you push it over.
FELLING CUT, TRUNK DIAMETER
MORE THAN TWICE GUIDE
BAR LENGTH
Cut a large, wide notch. Then cut a recess into the center of the notch.
Always leave a hinge on both sides of the center cut. (Fig. 19)
Fig. 19
Complete the felling cut by sawing around the trunk as in the
Fig. 20.
Fig. 20
WARNING
These methods are extremely dangerous because they involve
the use of the nose of guide bar and can result in kickback.
Only properly trained professionals should attempt these
techniques.
LIMBING
Limbing is removing the branches from a feller tree.
WARNING
A majority of kickback accidents occur during Iimbing.
Do not use the nose of the guide bar. Be extremely cautious and
avoid contacting the log, other limbs or objects with the nose
of the guide bar. Be extremely cautious of limbs under tension.
They can spring back towards you and
cause loss of control
resulting in injury. (Fig. 21)
Fig. 21
Stand on the left side of the trunk. Maintain a secure footing and
rest the saw on the trunk. Hold the saw close to you so that you are
in full control of it. Keep well away from the chain. Move only when
the trunk is between you and
the chain. Watch out for spring back of
limbs under tension.