Tree Felling

one of the operations of logging. The preparation of lumber and fuel wood begins with the felling of trees. Tree felling is preceded by preparatory work: approaches to the logging road are built, a loading point is arranged, lines for hauling (skidding) are laid out, and felling areas are divided into separate plots. For the safety of workers, the felling areas are cleared of dead standing and fallen trees. The most progressive and widespread organizational form for felling trees is a small all-around team, which not only cuts trees but also hauls the logs to the logging road and, occasionally, cuts branches. The loading of wood onto rolling stock is, as a rule, a separate operation.

Tree felling begins with an undercut on the side of the direction of fall, to a depth of one-third to one-fourth of the tree’s diameter, with the cut forming a wedge. The tree is then cut in the plane of the upper edge of the undercut, on the side opposite the direction of fall. This method of tree felling prevents tree splitting, is safe, and guarantees an accurate direction of fall. The felling of trees is made easier by the use of hydrowedges powered by gasoline-engine saws. Occasionally felling levers and shovels are used for this purpose. The trees are felled so as to preserve as much of the viable forest undergrowth as possible, as well as to facilitate the cutting of branches and the preparation of loads for hauling.

Gasoline-powered saws with a one-man control and a cantilevered chain sawing apparatus are used for tree felling. The most common saw is the Druzhba, which has a 2.9-3.7 kilowatt power motor (4-5 horsepower) and weighs 13.6 kg when fueled. The frame of the saw is provided with a device to reduce vibration on the handle to an acceptable level. The gasoline-powered saw Ural, which is of the same weight, has a 4±0.37 kilowatt power (5.5±0.5 horsepower) engine, a higher sawing speed, and an automatic chain oiler. In addition to portable power saws, felling and hauling machines are used to fell trees.