Shindaiwa 490 Manual Del Operador página 13

Felling Trees (continued)
Felling Larger Trees
(Over 6" (15 cm) diameter)
Direction of
Fall
Notch
n If a tree is otherwise healthy and not
seriously out of balance, its direction
of fall can often be encouraged by
first "notching" the tree on the side
facing the desired direction of fall.
n After the notch is completed, start
the felling cut slightly higher and on
the opposite side of the tree, away
from the direction of fall.
n The goal of the method is to leave a
sturdy wooden "hinge" for the tree to
pivot on while falling.
1. Determine the direction of fall.
2. On the side of the tree facing the
direction of fall, make a single 90
cut through approximately 1/3 of the
tree's diameter.
3. Working from the same side of the
tree and at a 45° angle to the first cut,
make your second cut in an upward
direction to remove a notch from the
tree as shown.
Bucking
WARNING!
Always cut downed timber
from the uphill side of the
wood! Be alert for potential injury
from rolling or shifting logs! Downed
timber may shift or roll unpredictably
during cutting or handling operations!
Techniques
n If the log is well supported, start your
cut from the top of the log. Keeping
the guide bar parallel to the ground,
cut straight down but do not allow
the saw to cut into the ground.
n Cutting downed timber, or "bucking,"
increases the possibility of the wood
settling and pinching the guide bar.
Driving one or more soft plastic or
wooden bucking wedges can help
prevent bar-pinching during a cut.
n Use two cuts when bucking near the
inboard end of an unsupported log.
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WARNING!
Failure to leave a proper
wooden hinge during the
falling or "back cut" can cause the
tree to pinch the saw's guide bar
and may also change the direction
of fall!
Wooden
Hinge
WARNING!
Always make your falling
Felling
cut parallel to the bottom
Cut
cut! An angled falling cut may cause
the tree to split, possibly changing
the direction of fall!
Wooden
Hinge
Direction
Of Fall
Bumper
Spike
4. Working on the opposite side of the
o
tree and starting approximately 2"
(5 mm) higher than the bottom of
the notch created in steps 1-3. Set the
bumper spike just behind the felling
hinge. Use full throttle and bring the
bar and chain slowly into the tree.
Make sure the tree does not start
to move in the opposite direction to
your intended felling direction. Drive
a wedge or breaker bar into the cut
as soon as it is deep enough.
1. Make the first cut as an overbuck
approximately 1/3 the diameter of
the log.
2. Finish the job with an underbuck
coming up from beneath and joining
the first cut.
Second Cut
n Use two cuts when bucking the
outboard end of an unsupported
log. Your first cut should be an
underbuck, cutting upward through
approximately 1/3 the diameter of
the tree. Finally, move to the top of
the log and finish the cut by bucking
down (overbucking) to your first cut.
If the cut appears to be closing on the bar,
use a mallet to drive one or two plastic or
wooden wedges into the cut behind the
bar.
5. When the tree begins to fall, stop the
6. Use your retreat path to exit the area
Limbing
Limbing a standing tree is usually
accomplished in the same manner as
45°
bucking, with a third and final cut used
to remove the remaining stub of the
limb.
Escape
Path
45°
When cutting unsupported logs or limbs,
starting with an underbuck cut will mini-
mize the possibility of the wood splitting
during the bucking cut.
First Cut
NOTE:
saw, and put it down on the ground.
quickly.
3 2
1
WARNING!
Kickback danger increases
in over-height or out of
position cutting! Do not overreach
or attempt to cut above shoulder
height!
NOTE:
Second Cut (overbuck)
First Cut (underbuck)
About 1/3 of Tree Diameter
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