Ryobi P548A Operation Manual - Page 21

OPERATION  Remove dirt, stones, loose bark, nails, staples, and wire from the tree where felling cuts are to be made.  Notched Undercut. Cut a notch about 1/3 the diameter of the tree, perpendicular to the direction of fall. Make the cuts of the notch so they intersect at a right angle to the line of fall. This notch should be cleaned out to leave a straight line. To keep the weight of the wood off the saw, always make the lower cut of the notch before the upper cut. See Figure 14.  Felling Backcut. The backcut is always made level and horizontal, and at a minimum of 2 in. above the horizontal cut of the notch. See Figures 14 - 15.  Never cut through to the notch. Always leave a band of wood between the notch and backcut (approximately 2 in. or 1/10 the diameter of the tree). This is called "hinge" or "hingewood." It controls the fall of the tree and prevents slipping or twisting or shoot-back of the tree off the stump. See Figures 14 - 15.  On large diameter trees, stop the back cut before it is deep enough for the tree to either fall or settle back on the stump. Then insert soft wooden or plastic wedges into the cut so they do not touch the chain. The wedges can be driven in, little by little, to help jack the tree over. See Figure 16.  As tree starts to fall, stop the chain saw and put it down immediately. Retreat along the cleared path, but watch the action in case something falls your way. Be alert for overhead limbs or branches that may fall and watch your footing. WARNING: Never cut through to the notch when making a backcut. The hinge controls the fall of the tree, this is the section of wood between the notch and backcut. HINGE 2 in. OR 1/10 DIA BACK CUT 2 in. NOTCH APPROX. 1/3 DIAMETER OF TRUNK Fig. 14 BACK CUT HINGE NOTCH Fig. 15 WEDGE Fig. 16 21 - English