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The reaction of the chain drives the saw straight back toward the operator causing loss of saw control. Pushback fre- quently occurs when the top of the bar is used for cutting (fig. 14). To avoid pushback 1. Be alert to forces or situafions that may cause material to pinch the top of the chain. 2. Do not cut more than one log at a time. 3. Do not twist the saw when withdrawing the bar from a plunge cut or under buck cut (figures 25 to 27 and 33, pages 13 and 15), because the chain can pinch. Pull-in: Pull-in occurs when the chain on the bottom of the bar is suddenly stopped. The chain on the bottom of the bar stops when it is pinched, caught or encounters a foreign object in the wood (see fig. 15). The reaction of the chain pulls the saw forward, causing the operator to lose control. Pull-in frequently occurs when the spike bar of the saw is not held securely against the tree or limb and when the chain is not rotating at full speed before it contacts the wood. To avoid pull-in 1. Always start a cut with the chain rotating at full speed and the spike bar in contact with the wood. 2. Pull-in may also be prevented by using plastic wedges to open the kerf or cut. Cutting techniques Felling Felling is cutting down a tree. Before felling a tree, consider carefully all conditions which may affect the direction of fall, including: The intended direction of the fall. The neutral lean of the tree. Any unusually heavy limb structure. Surrounding trees and obstacles. The wind direction and speed. WARN1 NG! Always observe the general condition of the tree. Look for decay and rot in the trunk. If it is rotted inside, it could snap and fall toward the operator while being cut. Also look for broken or dead branches which could vibrate loose and fall on the operator. When felling on a slope, the operator should stand on the up-hill side. When felling in the vicinity of roads, railways and power lines, etc., take extra precautions (see fig. 16). Inform the police, utility company or railway authority before beginning to cut. WARN1NG! Use extreme caution when cutting small size brush and saplings which may easily catch the chain and pull you off balance. 1- --_ 45" +,,. ... , * * 2 Y2 \ 1 I . I . \ \ -_---____ , __-- I I i = cutting down area - - --"'A I 17 When felling, maintain a distance of at least 2 112 tree lengths from the nearest person (see fig. 17). Note: The noise of your engine may drown any warning call. Felling instructions: 18 First clear the tree base and work area from inter- fering limbs and brush and clean its lower portion an axe (see fig. 18). _..._._..---- Then, establish a path of escape and remove all obstacles. This path should be opposite to the planned direction of the fall of the tree and at a 45"angle (fig. 19). An alternate path must also be selected. Place all tools and equipment a safe distance away from the tree, but not on the escape path. First cut 20 If the tree has large buttress roots, cut into the largest buttresses vertically first (horizontally next) and re- move (fig. 20). ~ Felling cut Hinge , Felling notch 22 Felling notch 1 I Hinge 23 Then, determine the placement of the felling notch (fig. 21). The felling notch when properly placed de- termines the direction in which the tree wil! fall. It is made perpendicular to the line of fall and should be as close to theground as possible. Cut the felling notch to a depth of about one-fifth to one-fourth of the trunk diameter (fig. 22). It should be in no case higher than it is deep. Make the felling notch very carefully. Begin the felling cut slighty higher than the felling notch and on the opposite side of the tree (fig. 22). Then cut horizontally through towards the felling notch. Apply the chain saw with its spikes directly behind the uncut portion of wood and cut toward the notch (fig. 23). Leave approximately 1/10 of the tree diameter uncut! This is the hinge (fig. 23). Do not cut through the hinge because you could lose control of the direction of the fall. Drive wedges into the felling cut where necessary to control the direction of the fall. Wedges should be of wood, light alloy or plastic -never of steel, which can cause kickback and damage to the chain. Always keep to the side of the falling tree. When the tree starts to fall, shut off the engine, withdraw the bar and walk away on the pre-planned escape path. Watch out for falling limbs. WARNING! Be extremely careful with partially fallen trees which are poorly supported. When the tree hangs or for some other reason does not fall completely, set the saw aside and pull the tree down with a cable winch, block and tackle or tractor. If you try to cut it down with your saw, you may be injured. Sectioning Method WARNING! Felling a tree that has a diameter greater than the length of the guide bar requires use of either the sectioning or plunge-cut method. These methods are extremely dangerous because they involve the use of the nose of the guide bar and can result in kickback. Only pr...

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