This article is published by the Illinois University USA
The use of wedges in logging has a long history. The mechanics involved are quite simple.
Depending on the height and diameter of the tree, it is possible to fell it in a direction opposite of its lean with a wedge that gives no more than one inch of lift (the procedure will be explained below). Today, most wedges are made from space-age plastics.
They are light-weight and do little damage to chain teeth if the saw comes in contact with them. The wedge is used to support the weight of the tree’s trunk (bole) or limbs to keep the saw from binding or for changing the direction of fall during harvesting. The procedure is quite elementary, but can be tiring if you’re not in shape!
After placing the notch in the tree’s bole and setting up the hinge, the backcut is initiated (see Illustration 1). Depending on the tree’s size and any immovable obstructions nearby, the backcut can be made in one cut if the tree is small or in a series of cuts if the tree’s diameter is greater than the length of the chain bar on the saw. For trees with a diameter less than the bar length, the backcut is performed in one step from the good side of the tree. Tree’s with a diameter larger than the chain bar requires the backcut to be made in at least two steps.
