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TRAINING & EDUCATION A side view of a knee or hinge notch with the plunge cut creating the hinge. The final back cut would be below the hinge, and the farther below would likely require more force or pull to separate. A close view of a completed key notch to show the various cuts. Obviously, wedges would need to be in place during the utilization process, but this view shows the cuts more clearly. hinge must be set up using a bore cut,so small-diameter trees are not well suited to this technique.The goal is to be out and away from the tree at release, so the usual practice of cutting the "strap" right at hinge level or slightly below is not an option in this technique.A mismatched back cut is used below the level of the hinge, shorter in large-diameter and strong wood, farther in small-diameter or weak wood, to allow the whole thing to hold together until the crew pulls the installed line from a distance to start the process.A tree thrown over with the roots still attached can present some contravening forces that make the knee cut challenging,so in those situations the crew might wish to consider another technique. Key notch This technique is the most gear-heavy and complex of those discussed here. But given the right situation can be as "slick as a minner in springtime." It requires a great deal of force to achieve release,thus a winch,GRCS, or some form of mechanical advantage system is a required component. A tongue or key is created in the trunk of the tree that "locks" the two parts together until the crew is ready to pull them apart.The key should be at least as long as the diameter of the tree;and trees experiencing more forces may very well benefit from the use of a longer tongue.The tongue will consist of basically the middle third of the tree when viewed from the side;and thus is created by carrying out two vertical,parallel-to-the-sidesof-the-tree bore cuts down until the chosen length is achieved.A horizontal bore cut is then made to create the end of the tongue, with care being taken not to cut into the outer thirds of the tree.Wedges are placed in this cut from both sides to lessen the likelihood of the saw being pinched as the cut is completed.The key notch is completed by cutting in from the sides to meet the edges of the tongue.As always, cut compression wood first and tension last, putting a wedge in the compression cut to aid with control of the existing forces.The tree should now be "locked" together by the key,and can be pulled apart from a safe distance with the aforementioned winch,GRCS,or mechanical advantage.Prior to pulling,the crew should remove the wedge from the end of the tongue on the side being pulled toward to avoid frustration and possible inappropriate language. 20 Arbor Age / January/February 2013 A key notch ready to go viewed from the side as it would appear if the tree was atop a trailer or utility wires. This brief introduction to specialized cutting techniques obviously does not discuss all the "ins and outs" of their safe and effective use, but it does provide some beginning concepts and knowledge that will assist tree crews in making them a part of their mental toolboxes. Once again, there is no substitute for "hands on" training and practice in any tree industry skill or method; and specialized cutting techniques, given the presence of sharp motorized cutting implements and large heavy woody objects, is definitely a skill that calls for practice prior to use. Michael "House"Tain is a contract climber, splicer, educator and writer associated with North AmericanTraining Solutions www.northamericantrainingsolutions.com and Arbor CanadaTraining and Education www.arborcanada.com.He is currently located in Lancaster,Ky.,and can be reached via e-mail at house@houseoftain.com. www.arborage.com