Ryobi PCN4545-RY74007D Manuel de l'opérateur télécharger pdf (Page 13)

On large diameter trees, stop the back cut before it is deep

enough for the tree to either fall or settle back on the stump.

Then insert soft wooden or plastic wedges (F) into the cut so

they do not touch the chain. Drive wedges in, little by little,

to help jack the tree over.

When bucking or felling with a wedge, it may be necessary

to remove the SAFE-T-TIP® anti-kick-back device to allow

the bar to be drawn through the cut. After you complete the

cut, reinstall the tip immediately.

5. As tree starts to fall, stop the chainsaw and put it down

immediately. Retreat along the cleared path, but watch

the action in case something falls your way.

WARNING:

Never cut through to the notch when making a back cut.

The hinge controls the fall of the tree: this is the section

of wood between the notch and back-cut.

REMOVING BUTTRESS ROOTS

See Figure 32.

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 (A) into the buttress first,

followed by the vertical cut (B). Remove the resulting loose

section (C) from the work area. Follow the correct tree felling

procedure after you have removed the large buttress roots.

Refer to “Operation – Proper Procedure for Tree Felling” earlier

in this manual.

BUCKING

See Figure 33.

Bucking is the term used for cutting a fallen tree to the desired

log length.

■■

■ Cut only one log at a time.

■■

■ Support small logs on a sawing stand or another log while

bucking.

■■

■ Keep a clear cutting area. Make sure that no objects can

contact the guide bar nose and chain during cutting: this

can cause kick-back (A). To avoid the danger, keep the

SAFE-T-TIP® anti-kick-back device attached while cutting.

Refer to “Safety – Kick-back” earlier in this manual.

■■

■ During bucking operations, stand on the uphill side so that

the cut-off section of the log cannot roll over you.

■■

■ Sometimes it is impossible to avoid pinching (with just

standard cutting techniques) or difficult to predict which

way a log will settle when cut.

BUCKING WITH A WEDGE

See Figure 34.

If the wood diameter is large enough for you to insert a soft

bucking wedge (B) without touching the chain, you should use

the wedge to hold the cut open to prevent pinching.

NOTE: When bucking or felling with a wedge, you may need to

remove the SAFE-T-TIP® anti-kick-back device to allow the bar

to be drawn through the cut. After you have finished, reinstall

the tip.

BUCKING LOGS UNDER STRESS

See Figure 35.

(D) LOG SUPPORTED AT BOTH ENDS.

Make the first bucking cut (E) 1/3 of the way through the log and

finish with a 2/3 cut (F) on the opposite side. As you cut the log,

it will tend to bend. The saw can become pinched or hung in the

log if you make the first cut deeper than 1/3 of the diameter of

the log.

Give special attention to logs under stress (G) to prevent the bar

and chain from pinching.

OVERBUCKING

See Figure 19.

Begin on the top side of the log with the bottom of the saw

against the log; exert light pressure downward. Note that the

saw will tend to pull away from you (A).

UNDERBUCKING

See Figure 19.

Begin on the under side of the log with the top of the saw

against the log; exert light pressure upward. During

underbucking, the saw will tend to push back at you (B).

Be prepared for this reaction and hold the saw firmly to

maintain control.

LIMBING AND PRUNING

See Figure 36.

■ Work slowly, keeping both hands on the saw with a firm

grip. Maintain secure footing and balance.

■ Keep the tree between you and the chain while limbing.

Cut from the side of the tree opposite the branch you

are cutting.

■ Do not cut from a ladder: this is extremely dangerous.

Leave this operation for professionals.

■ Do not cut above chest height as a saw held higher is

difficult to control against kick-back.

WARNING:

Never climb into a tree to limb or prune. Do not stand on

ladders, platforms, a log, or in any position which may

cause you to lose your balance or control of the saw.

■ When pruning trees it is important not to make the flush cut

next to the main limb or trunk until you have cut off the limb

further out to reduce the weight. This prevents stripping the

bark from the main member.

1. Underbuck the branch 1/3 through for your first cut (A).

2. Overbuck the branch to drop it (B).

3. Finish by cutting smoothly and neatly against the main

member (C) so the bark will grow back to seal the wound.

WARNING:

If the limbs to be pruned are above chest height, hire

a professional to perform the pruning.

OPERATION

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Ryobi PCN4545-RY74007D Manuel de l'opérateur Page 13

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