Ryobi RCS1935B Traduction Des Instructions Originales page 7

The chainsaw operator should keep on the uphill side of
the terrain as the tree is likely to roll or slide downhill after
it is felled.
An escape path should be planned and cleared as
necessary before cuts are started. The escape path should
extend back and diagonally to the rear of the expected line
of fall.
Before felling starts, consider the natural lean of the tree,
the location of larger branches, and the wind direction to
judge which way the tree will fall.
Remove dirt, stones, loose bark, nails, staples and wire
from the tree.
Do not attempt to fell trees which are rotten or have been
damaged by wind, fi re, lightning, etc. This is extremely
dangerous and should only be completed by professional
tree surgeons.
■ Notching undercut
See page 273 - 274.
Make the notch 1/3 the diameter of the tree,
perpendicular to the direction of the fall. Make the
lower horizontal notching cut first. This will help to avoid
pinching either the saw chain or the guide bar when the
second notch is being made.
■ Felling back cut
See page 273 - 274.
Make the felling back cut at least 50 mm. / 2 in. higher
than the horizontal notching cut. Keep the felling-back
cut parallel to the horizontal notching cut. Make the
felling back cut so enough wood is left to act as a hinge.
The hinge wood keeps the tree from twisting and falling
in the wrong direction. Do not cut through the hinge.
As the felling gets close to the hinge, the tree should
begin to fall. If there is any chance that the tree may
not fall in desired direction or it may rock back and
bind the saw chain, stop cutting before the felling back
cut is complete and use wedges of wood, plastic or
aluminium to open the cut and drop the tree along the
desired line of fall.
When the tree begins to fall remove the chainsaw from
the cut, stop the motor, put the chainsaw down, and use
the retreat path planned. Be alert for falling overhead
limbs and watch your footing.
Removing buttress roots
See page 274.
A buttress root is a large root extending from the trunk of
the tree above the ground. Remove large buttress roots
prior to felling. Make the horizontal cut into the buttress fi rst,
followed by the vertical cut. Remove the resulting loose
section from the work area. Follow the correct tree felling
procedure after you have removed the large buttress roots.
Push and pull
The reaction force is always opposite to the direction the
chain is moving. Thus, the operator must be ready to control
the tendency for the product to pull away (forward motion)
when cutting on the bottom edge of the bar. Engage always
fi rmly the bumper spike to avoid such movement. The
product can be pushed backwards (towards the operator)
when cutting along the top edge. To avoid this make sure
the chain is not jammed when cutting along the top edge.
Saw jammed in the cut
Stop the chainsaw and make it safe. Do not try to force the
chain and bar out of the cut as this is likely to break the
chain, which may swing back and strike the operator. This
situation normally occurs because the wood is incorrectly
supported which forces the cut to close under compression,
thereby pinching the blade. If adjusting the support does
not release the bar and chain, use wooden wedges or a
lever to open the cut and release the saw. Never try to start
the chainsaw when the guide bar is already in a cut or kerf.
Skating / Bouncing
When the chainsaw fails to dig in during a cut, the guide
bar can begin hopping or dangerously skidding along the
surface of the log or branch, possibly resulting in the loss
of control of the chainsaw. To prevent or reduce skating or
bouncing, always use the saw with both hands. Make sure
the saw chain establishes a groove for cutting.
Never cut small, fl exible branches or brushes with your
chainsaw. Their size and fl exibility can easily cause the
saw to bounce towards you or bind up with enough force
to cause a kickback. The best tool for that kind of work is
a hand saw, pruning shears, an axe or other hand tools.
Bucking a log
See page 275.
Bucking is cutting a log into lengths. It is important to
make sure your footing is fi rm and your weight is evenly
distributed on both feet. When possible, the log should be
raised and supported by the use of limbs, logs or chocks.
Follow the simple directions for easy cutting. When the log
is supported along its entire length, it is cut from the top
(overbuck).
When the log is supported on one end, cut 1/3 the diameter
from the underside (underbuck). Then make the fi nished
cut by overbucking to meet the fi rst cut.
When the log is supported on both ends, cut 1/3 the
diameter from the top (overbuck). Then make the fi nished
cut by underbucking the lower 2/3 to meet the fi rst cut.
When bucking on a slope always stand on the uphill side of
the log. To maintain control when "cutting through", release
the cutting pressure near the end of the cut without relaxing
your grip on the chainsaw handles. Don't let the chain
contact the ground. After completing the cut, wait for the
saw chain to stop before you move the chainsaw. Always
stop the motor before moving from tree to tree.
Limbing a tree
See page 276.
Limbing is removing the branches from a fallen tree. When
limbing, leave larger lower limbs to support the log off the
ground. Remove the small limbs in one cut. Branches
under tension should be cut from the bottom up to avoid
binding the chainsaw.
Springpoles
See page 276.
A springpole is any log, branch, rooted stump, or sapling
which is bent under tension by other wood so that it springs
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