WORKING TECHNIQUES
Make the felling cut about
Finish the felling cut parallel with the directional cut line so that the distance between them is at least 1/10 of the trunk diameter.The uncut section of the trunk is called the felling hinge.
The felling hinge controls the direction that the tree falls in.
(82)
All control over the felling direction is lost if the felling hinge is too narrow or
When the felling cut and directional cut are complete the tree should start to fall by itself or with the aid of a felling wedge or breaking bar. (84)
We recommend that you use a bar that is longer than the diameter of the tree, so that you can make the felling cut and directional cuts with single cutting strokes. See instructions under the heading Technical data section to find out which lengths of bar are recommended for your saw.
There are methods for felling trees with a diameter larger than the bar length. However these methods involve a much greater risk that the kickback zone of the bar will come into contact with the tree. (4)
Freeing a tree that has fallen badly
Freeing a ”trapped tree”
It is very dangerous to remove a trapped tree and there is high accident risk.
Never try to fell the tree that is trapped.
Never work in the risk zone of the hanging trapped tree.
(85)
The safest method is to use a winch.
•
•Portable
Cutting trees and branches that are in tension
Preparations:Work out which side is in tension and where the point of maximum tension is (i.e. where it would break if it was bent even more). (86)
Decide which is the safest way to release the tension and whether you are able to do it safely. In complicated situations the only safe method is to put aside your chain saw and use a winch.
General advice:
Position yourself so that you will be clear of the tree or branch when the tension is released. (87)
Make one or more cuts at or near the point of maximum tension. Make as many cuts of sufficient depth as necessary to reduce the tension and make the tree or branch break at the point of maximum tension. (88)
Never cut straight through a tree or branch that is in tension!
If you must cut across tree/limb, make two to three cuts, one inch apart, one to two inches deep. (89)
Continue to cut deeper until tree/limb bends and tension is released. (90)
Cut tree/limb from outside the bend, after tension has been released.
How to avoid kickback
WARNING! Kickback can happen very
! suddenly and violently; kicking the chain saw, bar and chain back at the user. If this happens when the chain is moving it can cause very serious, even fatal injuries. It is vital you understand what causes kickback and that you can avoid it by taking care and using the right working technique.
What is kickback?
The word kickback is used to describe the sudden reaction that causes the chain saw and bar to jump off an object when the upper quadrant of the tip of the bar, known as the kickback zone, touches an object. (61)
Kickback always occurs in the cutting plane of the bar. Normally the chain saw and bar are thrown backwards and upwards towards the user. However, the chain saw may move in a different direction depending on the way it was being used when the kickback zone of the bar touched the object. (7)
Kickback only occurs if the kickback zone of the bar touches an object. (4)
Limbing
WARNING! A majority of kickback
! accidents occur during limbing. Do not use the kickback zone 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 toward you and cause loss of control resulting in injury.
Make sure that you can stand and move about safely. Work on the left side of the trunk. Work as close as possible to the chain saw for maximum control. If possible, let the weight of the chain saw rest on the trunk.
Keep the trunk between you and the chain saw as you move along the trunk.
Cutting the trunk into logs
See instructions under the heading Basic cutting technique.
English – 25 |
