WORKING TECHNIQUES
•Arrangement of branches
•Weight of snow
•Obstacles within the reach of the tree: for example, other trees, power lines, roads and buildings.
•Look for signs of damage and rot in the stem, this makes it more probably that the tree will break and start to fall before you expect it to.
You may find you are forced to let the tree fall in its natural direction because it is impossible or dangerous to try to make it fall in the direction you first intended.
Another very important factor, which does not affect the felling direction but does affect your safety, is to make sure the tree has no damaged or dead branches that might break off and hit you during felling.
The main point to avoid is letting the tree fall onto another tree. It is very dangerous to remove a trapped tree and there is high accident risk. See instructions under the heading Freeing a tree that has fallen badly.
IMPORTANT! During critical felling operations, hearing protectors should be lifted immediately when sawing is completed so that sounds and warning signals can be heard.
Clearing the trunk and preparing your retreat
Delimb the stem up to shoulder height. It is safer to work from the top down and to have the tree between you and the saw.
Remove any undergrowth from the base of the tree and check the area for obstacles (stones, branches, holes, etc.) so that you have a clear path of retreat when the tree starts to fall. Your path of retreat should be roughly 135 degrees away from the intended felling direction. (39)
Felling
WARNING! Unless you have special
! training we advise you not to fell trees with a diameter larger than the bar length of your saw!
Felling is done using three cuts. First you make the directional cuts, which consist of the top cut and the bottom cut, then you finish with the felling cut. By placing these cuts correctly you can control the felling direction very accurately.
Directional cuts
To make the directional cuts you begin with the top cut. Stand to the right of the tree and cut on the pull stroke.
Next make the bottom cut so that it finishes exactly at the end of the top cut. (40)
The directional cuts should run 1/4 of the diameter through the trunk and the angle between the top cut and bottom cut should be 45°.
The line where the two cuts meet is called the directional cut line.This line should be perfectly horizontal and at right angles (90°) to the chosen felling direction. (41)
Felling cut
The felling cut is made from the opposite side of the tree and it must be perfectly horizontal. Stand on the left side of the tree and cut on the pull stroke.
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.
(43)
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.
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.
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.
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).
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.
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.
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.
Continue to cut deeper until tree/limb bends and tension is released.
Cut tree/limb from outside the bend, after tension has been released.
18 – English |
