Assessments - 3, GPA: 4.3
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Remove the cut pieces from the cutting area. By leaving them in the cutting area, you increase the risk for inadvertently getting a kickback, as well as increasing the risk of losing your balance while working. The log is lying on the ground. There is little risk of the chain jamming or the object splitting. However there is a risk that the chain will touch the ground when you finish the cut. Cut all the way through the log from above. Avoid letting the chain touch the ground as you finish the cut. Maintain full throttle but be prepared for what might happen. If it is possible (can you turn the log?) stop cutting about 2/3 of the way through the log. Turn the log and finish the cut from the opposite side. The log is supported at one end. There is a high risk that it will split. Start by cutting from below (about 1/3 of the way through). Finish by cutting from above so that the two cuts meet. The log is supported at both ends. There is a high risk that the chain will jam. Start by cutting from above (about 1/3 of the way through). Finish by cutting from below so that the two cuts meet. ! WARNING! Never attempt to cut logs while they are in a pile or when a couple of logs are lying together. Such procedures drastically increase the risk of kickback which can result in a serious or fatal injury. 1 2 3 WORKING TECHNIQUES 28 – English 115 13 82-96 Rev.1 2009-03-26 Tree felling technique Safe distance The safe distance between a tree that is to be felled and anyone else working nearby is at least 2 1/2 tree lengths. Make sure that no-one else is in this ”risk zone” before or during felling. Felling direction The aim is to fell the tree in a position where you can limb and cross-cut the log as easily as possible. You want it to fall in a location where you can stand and move about safely. Once you have decided which way you want the tree to fall you must judge which way the tree would fall naturally. Several factors affect this: • Lean of the tree • Bend • Wind direction • 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. 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. IMPORTANT! It takes a lot of experience to fell a tree. Inexperienced users of chain saws should not fell trees. Do not attempt any task beyond your experience level! IMPORTANT! During critical felling operations, hearing protectors should be lifted immediately when sawing is completed so that sounds and warning signals can be heard. Retreat path Retreat path Danger zone Danger zone Danger zone Felling direction WORKING TECHNIQUES 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. 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. 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 1.5-2 inches (3-5 cm) above the bottom directional cut. Finish the felling cut parallel with the directional cut line so that the...