The controlled felling of a tree requires precision and meticulous planning to ensure the tree falls exactly where intended. Directing the descent is essential for the safety of people, surrounding structures, and the environment. Mastering this technique transforms a potentially hazardous operation into a predictable event. This guide provides the foundational knowledge necessary to achieve directional control during tree felling.
Essential Pre-Felling Assessment
Before any cutting begins, a thorough assessment of the tree and its surroundings must be completed to determine the safest and most accurate felling direction. Determine the tree’s natural lean using a plumb line or a simple level held against the trunk. Felling the tree in the direction of its lean requires less force, while felling against it requires specialized tools and techniques.
The intended drop zone must be identified and completely cleared of obstacles, ensuring it is at least as long as the tree’s total height. Inspect the tree canopy for potential hazards, such as dead branches, known as “widow-makers,” or signs of decay. Nearby power lines, buildings, or other structures must be noted, as these define the limits of the safe felling area.
Establish and clear escape routes before any cuts are made. At least two routes should be prepared, both leading away from the tree at a 45-degree angle from the planned line of fall. These routes allow the operator to quickly retreat once the tree begins its descent. The individual performing the felling must wear appropriate personal protective equipment (PPE), including:
- A hard hat
- Eye protection
- Hearing protection
- Cut-resistant chaps
The Mechanics of Directional Felling
Directional felling relies on creating a precise geometry of cuts in the tree trunk to steer the fall. The process begins with the directional notch, or face cut, made on the side of the tree facing the intended drop zone. This notch removes a wedge of wood, establishing the precise direction and depth of the fall.
The notch involves two cuts: a downward-sloping top cut and a horizontal bottom cut, removing about one-fifth to one-third of the tree’s diameter. An open-face notch, with an opening angle of 60 to 80 degrees, is preferred because it allows the hinge to remain intact longer. The apex of this notch must be perpendicular to the line of the desired fall.
The felling cut, or back cut, is made on the opposite side of the trunk, parallel to the horizontal cut of the notch. This cut must stop short of the notch, leaving a strip of uncut wood known as the hinge. The hinge is the mechanical guide that prevents the tree from twisting or falling backward and controls its speed as it falls.
The hinge’s performance is paramount, and it must be uniform in thickness across the trunk to ensure even guidance. For optimal control, the hinge should be about 10% of the tree’s diameter in thickness and span 80% of the diameter’s length. The felling cut is placed slightly above the horizontal plane of the notch to encourage the tree to tip forward. The final portion of the back cut acts as the trigger, guiding the tree down the pre-determined path.
Utilizing Mechanical Aids for Control
External mechanical aids are necessary to overcome a tree’s natural lean or ensure precision in challenging conditions. Felling wedges are the most common aid, used to prevent the chainsaw bar from becoming pinched as the back cut progresses. Wedges are inserted into the back cut, away from the hinge, once enough depth has been achieved.
Tapping the wedges deeper with a hammer or axe creates leverage, acting as a lever to lift and push the tree over its pivot point, the hinge. This leverage can change the center of gravity just enough to initiate the fall in the correct direction. Plastic or aluminum wedges are recommended over steel, as they prevent damage to the chainsaw chain if the saw accidentally contacts the wedge.
For trees with a heavy back lean, rope and winch systems provide the safest and most powerful means of directional control. A durable rope is secured to a high point on the tree and anchored to a sturdy object in the line of the intended fall. Tension is applied using a winch or mechanical puller before the final cuts are made.
This pre-tensioning helps counteract any undesirable lean and ensures the tree will begin to move in the desired direction once the hinge is sufficiently weakened. For smaller trees, felling levers or breaking bars can be used, providing a direct point of leverage to push the tree over. The combination of precise cuts and external force application ensures the tree falls exactly where planned.