A faller does not cut the backcut clear through to the undercut. As the tree starts to fall, the saw is withdrawn and a hinge of wood is left between the undercut and backcut.Since the backcut is put in slightly higher than the apex of the undercut, a step is created with the holding wood. This helps keep the tree from kicking back over the stump and hazarding the faller. Angling the amount of holding wood on each side of the backcut can also give some increased directional control, along with wedges, to fall the tree off the lean direction.
If the falling process is not done correctly, the tree will not fall in the desired location or a barberchair may be created. Shown below is a felled tree showing the slight stump pull in the holding wood.
A schematic of what is being done in the falling procedure is shown below.
