Safety AGRICULTURAL MU Guide PUBLISHED BY MU EXTENSION, UNIVERSITY OF MISSOURI-COLUMBIA muextension.missouri.edu/xplor Felling, Bucking and Limbing Trees Bruce E. Cutter, School of Natural Resources David E. Baker, Extension Safety Specialist Whether you are using your chain saw to cut fire- there is an unknown amount of wood holding the wood, trim trees or harvest large timber, you will be tree up, you may not able to control the direction of performing three basic operations — felling, bucking fall of the tree or it may fall prematurely, endangering and limbing of trees. Felling involves cutting the you and others around you. standing tree and dropping it in the place you want it. Lean. Most trees display some indication of the Limbing is the removal of the branches from either direction in which they will tend to fall. This is shown standing or downed trees. Bucking is the process of by an uneven crown, as when most of the branches cutting the downed tree into appropriate lengths. For are on one side of the tree, or by a lean of the trunk of information on the selection and safe use of a chain the tree itself. An easy way to determine the lean of a saw, see MU publication G 1959, Basic Chain Saw tree is to stand back 25 to 50 feet and use a plumb line Safety and Use. to sight on the trunk of the tree. It is best to do this from two sides. This publication is not intended for the profes- Wind. The wind will push the crown of the tree. sional user but rather for the occasional chain saw In the fall and winter, the wind has less effect on operator. Wear all appropriate safety equipment hardwoods such as oak, maple and sweetgum after when operating the saw. And please remember their leaves have fallen off. A gusty, erratic wind that if you get tired while performing any of these increases the difficulty of landing the tree where you operations (felling, limbing or bucking), stop and wish. Strong winds will often force a tree to fall in an rest! Your safety depends on it. unitended direction. Landing area. Once you have evaluated the lean Felling of the tree, you will need to examine the area where you would like the tree to land. If you are in a forest, Felling a tree can literally make or break your you will have to take into account adjacent standing day! Putting the tree where you want it to land facili- timber (both live and dead), natural openings in the tates the rest of your operations. There are many doc- forest, and the terrain that you are dealing with. umented cases of persons who were cutting firewood Escape path. After you have chosen the place and dropped trees on their pickup trucks. where you want the tree to drop, you need to clear Several factors must be considered when felling a debris and underbrush away from the base of the tree. If it is smaller than 6 inches, you may be able to tree. You don’t want these impeding your movement push the tree where you want it to go. If the tree is around the base of the tree during the felling process. larger than 6 inches, it will probably be too heavy to Locate at least two escape paths on opposite sides of guide it to your chosen spot by hand. Indeed, many the tree leading away from the expected fall line. times the tree chooses where it wants to fall, in spite Make sure that these paths are free of obstacles such of your best efforts. as briars and debris that might trip you. Before attempting to cut down the tree, examine Undercut. The undercut serves as the guiding or the tree to see if there are any safety hazards present. aiming slot for the tree. Basically it is a V-shaped Typical hazards include excessive tree lean, dead or notch placed on the side of the tree in the direction of hanging branches, obstacles around the tree such as falling (Figure 1). Either a standard undercut (Figure utility lines (particularly in urban and suburban 1a) or a reverse undercut (Figure 1b) can be used. areas), and open wounds on the tree stem itself. Typically the first cut is made parallel to the ground Wounds might indicate that the center of the tree is and then the slanting cut is made. rotten or hollow, and felling a tree with a rotten or In recent years, a modified undercut known as an hollow core at stump height is a task best left to expe- “open face” undercut has become popular in many rienced or professional chain saw operators. Since areas (Figure 1c). Introduced by Scandinavian felling $.50 G 1958 Printed with soy ink on recycled paper Back cut Undercut a. b. c. Figure 1. Three types of undercuts. Note that in each case, back cut is slightly (1–2 inches) above hinge point of undercut. specialists, it is easier to make, provides good guid- Limbing ance and has additional safety features. Instead of When removing unwanted limbs from standing ending up with a 45-degree opening, the undercut timber, the basic safety rule is NEVER to limb above provides nearly a 90-degree opening. When the tree your shoulders; that is, do not attempt to cut off starts to fall, this modified undercut allows additional branches above the height of your shoulders. Cutting room for the tree to fall before the top and bottom of above your shoulders requires that you hold the the undercut come together. chain saw at or near arm’s length, and you lose con- For trees that are essentially straight, the under- trol over the saw in this position. Proper limbing tech- cut should be about one-fourth of the tree’s diameter niques to reduce damage to the tree are covered in in depth. MU publications G 5160, Pruning Forest Trees, and Back cut. For all three undercuts, the back cut is G 6866, Pruning and Care of Shade Trees. made slightly above the hinge point of the undercut Other safety rules apply to limbing a tree that is (Figure 1). The back cut releases the stresses on the lying on the ground. The first thing you should do is back of the tree allowing the tree to fall. NEVER evaluate the fallen tree. If the tree has become lodged make the back cut lower than the undercut because or wedged in adjacent trees and has not fallen all the that reverses the roles of the two cuts. NEVER cut way to the ground, do not walk underneath the tree. through the undercut, because you will lose all con- It may fall without warning. Trees that are “hung” are trol over the tree at that point. especially dangerous and need to be removed by As the saw nears the undercut, there should be a mechanical means. They can be pulled down with a small amount of wood left. This is referred to as cable and a tractor suitably equipped to protect “hinge” or “holding” wood (Figure 2). The tree actu- against roll-over and falling objects. ally pivots on this hinge and the width and angle of Do you see smaller trees that have been bent over the hinge can be used to guide the direction of the and trapped by the felled tree? Do you see branches tree’s fall. By leaving an angled hinge, the tree will holding the tree partially in the air? Is the tree on start to fall on the narrow section of the hinge while level ground? If you have just felled the tree, are there the wood at the thicker section of the hinge is still dead branches or other debris hanging above you intact. The tree is therefore pulled toward the thick that may still fall to the ground? These are called section. This is an art and requires practice. Once the tree starts to fall, shut off your saw and move down your chosen escape path. Do not stand at the base of the tree and admire your work. Falling Undercut trees have been known to bounce backward over the stump catching the unwary operator. Undercut A leaning tree presents special problems. The dif- Back cut ficulty of these problems depends on the direction and the degree of lean. Be aware that if you try to do Back cut a conventional back cut on a leaning tree, there is a Hinge good possibility that the tree will split and fall prema- Hinge turely, with the potential of serious injury to you. Consult a professional arborist. Figure 2. The direction a tree falls can be closely controlled with properly made undercuts and back cuts. Page 2 G 1958 widowmakers for good reason. There are well-docu- c mented instances of debris falling several minutes after the tree has been felled and severely injuring or killing saw operators. b You may want to wait a few minutes to allow any a additional debris to fall to the ground. This allows you to take a short rest as well. Once you have evaluated the obstacles and haz- ards, start at the bottom of the tree, working your way to the top, removing branches on the opposite side of the tree from you as you go. Never stand on the downhill side of a fallen log. If you cut a branch that is holding the log in place, the log could roll downhill and trap you.