Tree wedging is a technique used in directional felling to provide mechanical lift and control the trajectory of a tree as it falls. The primary purpose of a felling wedge is twofold: to prevent the weight of the tree from pinching the chainsaw’s bar in the cut and to act as a powerful lever. By driving a wedge into the back cut, a small upward force at the base translates into a significant horizontal movement at the tree’s crown, effectively shifting its center of gravity. This method is particularly useful when a tree is leaning slightly against the intended line of fall or when its crown is unbalanced, giving the operator precise influence over the final moments of the fall.
Necessary Equipment and Safety Preparation
The most common type of felling wedge is made from high-impact plastic or polyurethane because a chainsaw chain will cut through it without damage if accidentally struck. Aluminum wedges offer greater strength and are also safe for the saw chain, but they are generally heavier and more expensive.
The wedge requires a dedicated striking tool, such as a sledgehammer, heavy wooden mallet, or a specialized impact bar, for driving it into the cut. Using the back of an axe for this purpose is strongly discouraged, as it can damage the axe head and is less effective.
Personal protective equipment (PPE) is mandatory before starting work:
- Hard hat
- Eye protection
- Hearing protection
- Chainsaw chaps
- Steel-toed boots
Before any cut is made, a clear and safe escape route must be established and cleared of brush or debris that could cause tripping. The path should be planned at an angle of approximately 45 degrees away from the intended line of fall and slightly behind the tree stump. This angled retreat minimizes the risk of injury from kickback or from the tree trunk kicking back off the stump as it begins to fall. Identifying and clearing both a primary and secondary escape route ensures a quick and safe exit the moment the tree begins to move.
Performing the Felling Cut for Wedge Insertion
After establishing the directional notch cut on the side of the intended fall, the felling cut is executed using the bore cut method. This technique allows the operator to insert the wedge before the tree’s stability is compromised, preventing the trunk from settling backward and binding the saw.
To perform the bore cut, the saw is fully revved, and the operator plunges the tip of the bar into the trunk. This plunge cut must be made slightly above the horizontal plane of the directional notch to ensure a proper hinge remains. The saw is then maneuvered within the trunk to cut parallel to the notch, establishing a consistent hinge width that should be about ten percent of the tree’s diameter.
The cut is then extended backward, leaving an intact section of wood, known as the holding strap or backstrap, at the rear of the tree. This backstrap, along with the hinge, holds the tree securely upright.
The bore cut method creates a kerf behind the hinge and in front of the holding strap. This allows the operator to place and seat the wedges while the tree remains fully supported.
Driving the Wedges to Control the Fall
The felling wedge is placed into the kerf directly behind the hinge. If the tree is large, multiple wedges may be necessary, and they should be positioned several inches apart or slightly overlapped at an angle, such as 70 degrees, to maximize the lifting force and prevent one wedge from ejecting the other.
The wedges are first tapped lightly with the striking tool to ensure they are seated firmly. Once seated, a series of progressively harder strikes are delivered to the wedge head. This action forces the trunk to pivot on the hinge. Alternating strikes between two wedges, if used, ensures a uniform lift and prevents the hinge from twisting or breaking unevenly.
If the tree is heavy or severely back-leaning, the initial wedge may be driven in fully, and a second, thinner wedge may be driven on top of it or alongside it to increase the lift. The operator continues driving the wedges until the tree begins to move, or the holding strap is visibly strained.
The moment the tree begins its controlled descent, the operator must immediately disengage the striking tool and retreat along the pre-planned 45-degree escape route. For a tree that is slow to move, the final step is to cut the remaining backstrap from the side opposite the wedge, releasing the tension and allowing the wedge-induced force to complete the felling.