Arbor Age

Arbor Age Jan/Feb 2013

For more than 30 years, Arbor Age magazine has been covering new and innovative products, services, technology and research vital to tree care companies, municipal arborists and utility right-of-way maintenance companies

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All photos by Michael "House" Tain An example of using the bore cut to set up the hinge in a felling situation, note the presence of the "strap" at the back to keep the tree secure. Forces One of the important concepts to keep in mind when using any specialized cutting technique is the presence of compression and tension forces.These are present in every tree whether it's upright, on the ground, or sitting on top of a double wide, but the location and the reactions they create can vary widely with how the tree lays.An example would be a tree laying on utility lines without an excessive amount of wood beyond the lines. In most cases, the compression forces are going to be on the top or upper side of the trunk, with the tension forces on the bottom, or underside.Take the same tree and put enough of it over and beyond the wires and the forces will change, with compression underneath and tension on top. Operators must always evaluate what they are cutting for the location of these forces prior to the first bit of saw dust flying.To not do so can lead to both property and personal damage of an unfixable nature. Once the forces' locations have been identified, the saw user can start thinking about how to sever the wood and release the forces.An excellent and simple way to remember how to sever compression and tension fibers,developed by the instructors at Arbor Canada,is the acronym "CUT." Begin the cut on the Compression side Finish the cut on the Tension side "U" are in the middle Mismatch/bypass This is the simplest of the specialized cutting techniques;and one many climbers have used even if they didn't know the name of it. It is the same basically as the cuts used when "cutting and chucking"on the trunk or horizontal branch when aloft.In the case of a completely fallen tree that is being removed from wires or a trailer, the breaking and "chucking" part should be done from a distance with a pull rope or push stick.If breaking the cut in this manner, folks will find it much easier if they are pushing or pulling toward the side with the lower cut.The two cuts are offset from opposite sides of the tree or branch, depending on the location of those all-important forces,tension and compression.Also,species and wood size will dictate www.arborage.com Looking down on a mismatch or bypass cut with rope in place to snap it apart to the low cut side. Note the overlap or bypass of the cuts, which will vary with diameter and species. Looking at a mismatch showing the orientation of the pull line in order to pull it toward the side of the "low" cut. The top of this small tree would likely be hung in another or atop wires or houses. the amount of cut overlap required along with the distance between the cuts, but better to start out with too little and have to cut a wee bit more than to take too much and have the tree or branch collapse uncontrolled. Knee cut or hinge This technique works very similarly to the felling notch used to fell a tree, except, in this case, the operator desires to "fold" the tree back upon itself, out, away, and off whatever object it might be lodged in.An openface notch is used on the upper side of the fallen tree, and needs to have at least a 90-degree opening to achieve the desired result.The hinge thickness needs to be about five percent of the tree's diameter in this usage and requires good wood fiber present to be a viable option. In addition, the Arbor Age / January/February 2013 19

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