Cutting action pushing the chain (from bottom to top) (fig.3) will lead to the danger of a sudden movement of the machine in the direction of the user, with the risk of hitting the user, or an impact of the “kickback danger zone” on the trunk resulting in strong kickback; extreme care must be taken when cutting in this manner.
The safest method for using the machine, is to block the log on a sawhorse, cutting from top to bottom, on the portion outside the sawhorse. (fig.4)
Spiked bumper use.
Where possible, use the spiked bumper to ensure safer cutting action: plant it in the bark or surface of the trunk in order to maintain more control over the machine.
Below are descriptions of typical cutting procedure to be adopted for specific situations. However, these should be assessed each time to calculate whether the method is most suitable or not, In order to use a method with the least possible risk.
Trunk on the ground. (Risk of touching the ground with the chain once the bar has passed trough the trunk).
(fig.5)
Cut from top to bottom through the whole trunk. Towards the end of the cut, proceed very carefully to prevent the chain from hitting the ground. If it is possible, cut 2/3 of the trunk, roll it over, and cut the remaining third from top to bottom to limit the risk of the chain touching the ground.
Trunk supported at one end only (Risk of trunk breaking during cutting action). (fig.6)
Begin the cut from underneath for about 1/3 of the diameter, and then finish the cutting action from the top to meet the undercut.
Trunk supported at both ends. (Risk of pinching the chain). (fig.7)
Begin the cut from above for about 1/3 of the diameter, and then continue from underneath to meet the overcut.
Trunk laying on a slope. Always stand on the uphill side of the log. When ʻcutting throughʼ, to maintain complete control, release the cutting pressure near the end of the cut without relaxing your grip on the chainsaw handles. Do not let the chain contact the ground.
Tree felling.
ATTENTION!: Never attempt to fell a tree if you do not have the necessary experience, and in any case never fell trees that have trunks with a diameter larger than the length of the bar! This operation is reserved for expert machine users with adequate equipment.
When felling a tree, the aim is to have the tree fall in the most convenient position for the following limbing and bucking operations. (Avoid trees falling on top of other trees: Felling trees that are entangled with other trees is a very dangerous operation).
First of all decide which is the best direction for the tree to fall by evaluating the following: objects or other plants around the tree, the inclination, the curve, wind direction, and greatest branch concentration. Take into account dead or broken branches that may break off during felling creating a further danger risk.
ATTENTION! During tree felling operations in critical conditions, always remove ear protection immediately after cutting operations to be able to listen for unusual noises and any warning signals.
Preliminary cutting operations and identifying the retreat path.
Eliminate any branches that interfere with the job (fig.8), starting from top to bottom, and then, always keeping the trunk between the user and the machine eliminate the more difficult branches afterwards, piece by piece. Eliminate all plants that interfere with work operations and control the area for possible obstacles (rocks, roots, ditches,etc.) when planning the retreat path (to follow during tree fall); Refer to the illustration (fig.9) for the directions to be maintained (A. predicted tree fall direction. B. Retreat path. C. Danger zone).
FELLING CUTS (fig.10)
In order to ensure that the user has complete control over the tree fall, the cutting instructions are as follows:
The cut that controls the fall direction of the tree is to be executed first: First of all cut the UPPER PART of the directional notch on the side the tree must fall. Remain on the right hand side of the tree and cut using the chain pull method; then cut the LOWER PART that must meet the end of the upper part. The depth of the directional notch must be 1/4 of the trunk diameter, with an angle of at
least 45° between upper and lower cut. The meeting point between the two sides of the notch is called “directional cut line” This line must be perfectly horizontal at right angles (90°) to the felling direction.
The felling cut that provokes the tree fall, is performed at
3 to 5cm above the lower part of the directional felling cut line, finishing at a distance of 1/10 of the trunk from the notch. Remain on the left hand side of the tree and cut using the chain pulling method and the spiked bumper. Check that the tree does not move in a direction other than that predicted for the fall. As soon as possible insert a felling lever or wedge into the cut. The uncut part of the trunk is called the “hinge”, as it is intended to guide the tree as it falls; in cases where the cuts are not sufficient, not straight, or have been cut through completely, the tree fall cannot be controlled (extremely dangerous!). For this reason the various cuts must be performed with great precision.
When cutting operations are completed the tree will begin to fall. Where necessary help tree fall using wedges or felling levers.
Limbing
Once the tree has been felled, the trunk must be limbed: in other words, the branches are removed from the trunk. Do not underestimate this operation because the large majority of kickback accidents occur during this stage. For this reason pay close attention to the position of the bar nose during cutting operations and always work on the left hand side of the trunk.