Monthly Archives: January 2015

Hazards Of Felling Storm-Damaged Trees-Part I

Perhaps the most difficult and dangerous trees to cut are ones that have been damaged by storms.

These trees should be tackled only by the most skilled and experienced tree cutters, for they are, in a word, unpredictable. This is primarily due to the tremendous compression and tension forces exerted on the parts of the tree under pressure. It is critical that release cuts be made correctly in order to avoid injury. The methods for making these cuts, and the principles behind them, are the same as those for bucking logs. There are countless scenarios of storm damage to trees, but the ones my crew and I most frequently encounter are of two general types: trees that have been uprooted (partially or completely), or trees that have broken off but remain attached to the trunk.

Felling partially uprooted and/or tipped trees requires an understanding of the various stresses exerted on the trunk as well as the possible reactions of these stresses to an arborist’s cutting technique.

Uprooted trees (or windfalls)

Strong winds often uproot trees, leaving them in one of three conditions:

  1. hung-up in another tree (or perhaps lying on a structure, such as a house)
  2. partially uprooted and severely
  3. uprooted and lying on the ground.

Hung up trees can be safely felled using various bucking methods, and the latter two conditions can be addressed using the following methods. 

Safety is important; never stand on or straddle the trunk of an uprooted tree while cutting to sever the root mass from the rest of the tree.

Partially uprooted and severely tipped trees

At first, felling partially uprooted and tipped trees appears simple until you consider, or experience, the dangers involving the tremendous pressure being exerted on the trunk, and what happens when the remaining root mass slams back down after the trunk is cut. To minimize some of the risk, do not attempt to make the following felling cuts above your shoulder height.

  • Cut an open-face notch on the compression side of the tree (the bottom side of the trunk) to a depth of about one-quarter of the trunk diameter.
  • Make the back cut on the tension, or top, side of the trunk. Be prepared for a potentially explosive response as the tree falls down and the root mass tips backward as pressure is released when the trunk is cut.
  • When cutting larger-diameter trees, consider using the bore cut method that’s used for trees with a heavy forward lean, or securing the trunk with a chain or strap to prevent the trunk from barber chairing.
To avoid being injured by the sudden upright shift of the root mass, remove sections of the trunk incrementally; this will allow the root mass to counterbalance the tree gradually.

Jeff Jepson is an ISA Certified Arborist with more than 25 years of experience in felling trees. He is the owner of Beaver Tree Service in Longville, Minnesota and author of “The Tree Climber’s Companion” (1997).

Editor’s Note: This article is an excerpt from “To Fell a Tree: A Complete Guide to Successful Tree Felling and Woodcutting Methods” (2009), printed with the permission of Jeff Jepson. For more information regarding methods and techniques for cutting large-diameter trees, rope installation methods, and more as they relate to working on hung up trees, Jepson’s book provides many examples.

(Article courtesy of Tree Services Magazine: http://www.treeservicesmagazine.com)

Hazards Of Felling Storm-Damaged Trees-Part II

Uprooted trees lying on the ground (or supported by another object)

There are two potentially dangerous circumstances that can occur when the trunk is cut free from the remaining root mass. First, the remaining root mass could fall forward and on top of the saw operator. The other potentially dangerous result is that the root mass and remaining trunk could whip upright and back into the ground after the bucking cut is made. For this reason, never stand on or straddle the trunk of an uprooted tree while making these cuts. Trying to determine which of these two situations is likely to occur is a difficult assessment and only becomes easier after years of experience in working on these types of trees.

Fortunately, there are options for dealing with these types of trees.

  • Option 1: To avoid the threat of the remaining root mass falling toward you, cut the trunk at a distance that is beyond the reach of the highest part of the root mass. Remove any branches that are in the way or that could potentially strike you after the tree is cut free from the stump. After being cut, the root mass will fall forward only until it is stopped by the remaining trunk section striking the ground.
  • Option 2: This is a good method when you anticipate the root mass and remaining trunk will right itself after the bucking cuts are made. Start your cuts at the top of the tree, working toward the butt, cutting the trunk into short sections. This incremental removal of trunk sections allows the root mass to counterbalance the tree gradually, standing upright slowly and safely. At this point, fell the remaining upright trunk section using normal felling methods.
  • Making the cuts: If the tree appears to be under significant upward pressure from both ends, then make an open-face notch on the compression side of the tree followed by an undercut directly opposite the notch.

If it appears that the root mass is creating a significant back pull (indicating the root mass wants to fall back in the hole), the cuts should be reversed (notch the bottom, back cut from the top). In many instances it won’t be necessary to make a notch or top cut; an undercut only will suffice.

Another common type of storm damage includes trees that have broken off but still remain attached to the trunk. The upper portion may be hung up in another tree or resting on the ground. These situations are extremely hazardous as they are difficult to assess. These trees will often respond unpredictably, even when a felling plan has been carefully considered and executed. The greatest risk of felling these trees is if the broken portion detaches unexpectedly. Other hazards arise from the broken portion of the tree exerting pressure against the tree trunk, which can cause the tree to barber chair or fall in the wrong direction when the felling cuts are made.

Assess the tree and site carefully before making any cuts. Try to visualize how the broken top will respond to the release cuts you intend to make. As these cuts are made, be prepared for the broken portion to detach at any time, and be ready to retreat along one of several preplanned and cleared escape routes. Finally, avoid working under the hung up or hanging portion of the tree.

Broken trees with top on the ground

  • Carefully inspect and test the broken part of the tree to get a sense of how well attached it is to the trunk.
  • Remove the limbs supporting the broken portion of the tree using limbing and bucking methods. Cut back as high as can safely be reached (below shoulder height). Cut slowly and watch how the tree responds as pressure is released from the wood. Keep cutting until the broken portion is free of ground support. Be ready to move if the trunk begins to shift or roll.
  • Make an open-face notch on the same side of the tree that the broken top is lying on, or where the lean of the tree is the heaviest.
  • Execute the back cut while standing on the good side of the tree. If necessary, use felling wedges to help support the tree and prevent a pinched saw bar while cutting and to force the tree into the lay. When using a pull line, secure the rope to the main trunk (not the broken portion) as close to the break as possible.

Broken trees with hung up top

If the broken portion is located high on the trunk and out of reach, I would recommend using the following method. Caution: Felling these trees puts the tree cutter at great risk since it usually requires working under the hung up top and involves outwitting and outrunning two separate falling tree sections: the trunk and the top of the tree.

Set a pull line around the hung up section of the tree close to where it broke off.

Felling broken trees with a hung up top is one of the most difficult and dangerous circumstances. This example uses a winch and pulley system.

Attach to the pull line a means of pulling the hung top free. A come-along or MA [mechanical advantage] pulley system is satisfactory in most instances with smaller trees, but I prefer using a portable winch instead (one that accommodates rope usage), because of the extra pulling force it offers. Securely anchor the pulling tool of choice in the direction you intend the trunk to fall (the lay).

Cut an open-face notch in the direction of the lay.

Make the back cut, leaving an extra thick hinge so the tree will not fall before you can retreat from the work area. Retreat at a 90-degree angle from the trunk in either direction to a distance beyond the felling radius of the tree.

Only when the tree cutter is at a safe distance away from the tree should pulling efforts begin.

Jeff Jepson is an ISA Certified Arborist with more than 25 years of experience in felling trees. He is the owner of Beaver Tree Service in Longville, Minnesota and author of “The Tree Climber’s Companion” (1997).

Editor’s Note: This article is an excerpt from “To Fell a Tree: A Complete Guide to Successful Tree Felling and Woodcutting Methods” (2009), printed with the permission of Jeff Jepson. For more information regarding methods and techniques for cutting large-diameter trees, rope installation methods, and more as they relate to working on hung up trees, Jepson’s book provides many examples.

(Article courtesy of Tree Services Magazine: http://www.treeservicesmagazine.com)