Home Improvement in East Tennessee
Tree Origami – diagonal felling
|To do a diagonal fall, cut out a wedge shaped piece of wood and leave a hinge-like piece about two or three inches thick. This will help determine the initial direction of tree fall. The tree will move down and to one side. This makes leaning trees more controllable in terms of the range of felled positions. With ordinary cuts, the tree falls same direction each time, forward. If the tree does not favor any other direction by leaning, that is. If the tree leans, the task is less predictable. Visualize a small river or creek with a Sycamore leaning over the water at about 45 degrees, half way between up and down. You want the tree to fall on the bank. That is not going to happen with a traditional cut. Using diagonal cuts, the tree can be made to swing around in an arc by as much as 90 degrees and possibly more. The tree will fall in a curve moving both down and to one side at the same time. A tree leaning only a few degrees off center can be made to fall almost anywhere. The greater the angle at which the tree leans, the more difficult to control the direction of fall. A tree leaning 45 degrees can be made top rotate more than 90 degrees during the fall given all other factors are favorable. An important factor is the type of top the tree has. A broad short top is harder because of air resistance and resistance created when the branches begin brushing the ground. Tall trees with narrow tops, such as evergreens are easiest. The process is reminiscent of Sailing, and Tacking into the Wind. You’re redirecting a vector force to your advantage. The key concept here is the use of Vectors. If you’re familiar with them, you won’t have too much trouble understanding this. This remaining piece of trunk in the cut keeps the tree from sliding down due to gravity long enough for a horizontal vector to be created and put into action. The downward force becomes a combination of gravity pulling the top of the tree down (since the bottom end won’t move) and the horizontal motion caused by the resistance created by the remaining chunk of wood in the cut. One other factor is the prevailing direction and force of the wind. The bigger the top and the more leaves on the tree, the more air effects the rate of fall. If wind reduces the rate the tree moves, the slack in energy consumption is taken up in the downward direction. 1. Shape of tree top. 2. Angle of lean (and the location of the center of balance in general). 3. Prevailing wind force and direction. 4. Hardness of wood (harder woods take less hinge thickness than soft woods).
*The wedge – The upper section of a typical cut is level and straight in. The lower section is an angled cut into the upper cut. The diagonal is a rotated version of this basic cut
WARNING – All the usual caveats apply when cutting down a tree diagonally. Watch for obstructions on the ground and above (wire), people and animals. If you’ve felled trees before, start with four inch diameter test runs before cutting anything big such as a one hundred footer with a two and a half feet thick trunk. Start with a slight angle before working up to large angles. Observe safety precautions and use safety glasses.
Diagonal(right top)and typical (bottom left) cuts.