This element focuses on the advanced techniques and safety protocols required for felling and processing large trees (diameter 380mm-760mm) using a chainsa
Topic Synopsis
This element focuses on the advanced techniques and safety protocols required for felling and processing large trees (diameter 380mm-760mm) using a chainsaw. Learners will develop competence in site preparation, hazard identification, controlled felling, and the safe takedown of hung-up trees, while adhering to current legislation and industry best practice. The unit emphasizes productive and sustainable working methods to ensure both personal safety and environmental responsibility.
Key Concepts & Core Principles
- Advanced notch types: The open-faced notch (70° angle) and the conventional notch (45° angle) are used for large-diameter trees to provide greater control and hinge wood strength. The choice depends on tree lean, wind, and desired felling direction.
- Bore cutting technique: Used to create a hinge without cutting through the tree's centre, reducing the risk of barber chair (splitting) and allowing precise directional control. The bore cut is made from the side, leaving a holding wood at the back.
- Hinge wood management: The hinge (uncut wood between the notch and back cut) must be of consistent thickness (typically 10% of tree diameter) to guide the tree's fall. Incorrect hinge thickness can cause the tree to twist or fall off-line.
- Escape routes and retreat paths: Before felling, two escape routes at 45° angles away from the expected fall direction must be planned and cleared. The operator must retreat along these routes immediately after the back cut is complete.
- Risk assessment for large trees: Factors such as decay (e.g., fungal brackets, cavities), lean, wind loading, and nearby structures must be assessed. A dynamic risk assessment is performed throughout the operation.
Exam Tips & Revision Strategies
- Always reference current Lantra guidance and the latest edition of the appropriate chainsaw operations manual in your risk assessments.
- Practice felling cuts on simulators or in a controlled environment before performing the assessed task to build confidence and precision.
- During the practical assessment, verbalize your actions as you perform them to demonstrate understanding of each step.
- Prepare a detailed site plan in your portfolio, noting environmental considerations and wildlife habitats to show full compliance with sustainable practices.
Common Misconceptions & Mistakes to Avoid
- Incorrectly estimating the tree's lean and weight distribution, leading to unpredictable felling direction.
- Neglecting to establish and maintain clear escape routes, resulting in being in the danger zone during the fall.
- Using an inadequate hinge wood thickness, causing loss of control or barber chair.
- Attempting to fell a hung-up tree by cutting the supporting tree without mechanical assistance, increasing risk of sudden release.
Examiner Marking Points
- Award credit for thorough documentation of risk assessments, including identification of overhead hazards, ground conditions, and proximity to utilities.
- Require demonstration of correct felling cuts with accurate gob cut depth and hinge wood thickness, ensuring controlled direction of fall.
- Check for effective use of a felling lever or wedge to assist the fall and prevent bar pinch.
- Assess safe takedown of hung-up trees using a winch or hand-powered device, ensuring no one enters the danger zone.
- Evaluate the processing of timber: correct cross-cutting without chain contact with ground, and proper stacking of products.