Code of practice for felling and conversion of trees into logs

IS 9561: Scope Summary

• Purpose: Guidance on felling and conversion of trees into logs for general purposes.
• Definitions: As per IS 707-1976 and additional definitions in IS 9561.
• Rounding Off: Final test or analysis values must be rounded following IS 2-1960 rules, retaining the same significant figures as the specified value.

Key Points on Scope

Rounding Off Rule (IS 2-1960):

• Round to the same number of significant figures as the specified value.
• Example: If specified value = 12.3 (3 significant figures), result = 12.4 or 12.2 after rounding.

flowchart LR
    A[Tree Felling] --> B[Log Conversion]
    B --> C[General Purpose Logs]
    C --> D[Testing & Analysis]
    D --> E[Rounding off per IS 2-1960]

This standard primarily sets procedural guidance rather than numeric formulas or tables. For detailed timber properties, refer IS 707.

IS 9561 - Definitions Key Points

• Reference Definitions: Clause 2.0 states that definitions from IS 707-1976 apply, supplemented by this standard's specific terms.
• Rounding Off Values: Per Clause 0.4, all test or calculation results must be rounded according to IS 2-1960 rules, matching the number of significant digits of the specified value.
• Scope: Clause 1.1 clarifies the standard covers felling and conversion of trees into logs for general use.

Important Notes:

• For detailed timber terminology, consult IS 707-1976.
• Rounding rules (IS 2-1960) ensure consistency in reporting numerical results.

Example: Rounding Rule (IS 2-1960)

If you want, I can provide definitions from IS 707 or explain rounding rules in detail.

IS 9561: General Rules for Felling - Key Points & Specifications

1. Direction of Felling (Clause 3.6)

• Trees should be felled uphill on steep slopes to ensure controlled fall and safety.

2. Use of Stem Tightener (Clause 2.11)

• A stem tightener (wire rope + lever) is fixed just above the felling cut.
• Purpose: To prevent splitting of the butt-end, especially in leaning or coniferous trees.

3. Basic Felling Procedure (Clause 6.1)

• Follow steps in Clause 5 (preparatory steps).
• Then apply procedures from 6.1.1 to 6.1.7 for normal trees.
• Modify techniques for:
  • Leaning trees
  • Buttressed trees
  • Rotten trees
  • Forked trees (Clauses 6.2 to 6.5)

4. Precautions (Clause 7)

• Always adhere to safety measures during felling to prevent accidents.

Typical Felling Cut Angles (from standard practice):

flowchart TD
    A[Start Felling] --> B{Tree Type?}
    B -->|Normal| C[Follow 6.1.1 to 6.1.7]
    B -->|Leaning/Buttressed/Rotten/Forked| D[Modify as per 6.2 to 6.5]
    C --> E[Use Stem Tightener if needed]
    D --> E
    E --> F[Ensure Direction Uphill on Slopes]
    F --> G[Take Precautions (Clause 7)]
    G --> H[Complete Felling]

Summary:

• Fell uphill on slopes.
• Use stem tightener to avoid splitting.
• Follow detailed steps for normal and special tree conditions.
• Always prioritize safety.

IS 9561 - Methods of Felling: Key Points & Procedure

1. Direction of Felling

• Clause 3.6: On steep slopes, trees should be felled uphill to ensure safety and control.

2. Methods of Felling (Clause 4.1)

• a) Axe alone
• b) Saw and axe combined
• c) Saw alone

3. Combined Saw & Axe Method (Clause 4.1.2)

• Make the lower horizontal cut (felling sink) first using the saw, perpendicular to the intended fall direction.
• The upper slanting cut is made using the axe.
• The back cut (from the opposite side) is made using the saw only.

4. General Felling Procedure (Clause 6.1)

• Follow steps under Clause 5 (not detailed here).
• Then proceed with steps 6.1.1 to 6.1.7 for normal trees.
• Modify techniques for leaning, buttressed, rotten, or forked trees as per Clauses 6.2 to 6.5.

Summary Diagram of Saw & Axe Combined Cuts

graph LR
A[Felling Direction] --> B[Lower Horizontal Cut by Saw]
B --> C[Upper Slanting Cut by Axe]
C --> D[Back Cut by Saw]

This method ensures controlled felling with directional precision and safety.

IS 9561: Preparation Before Felling – Key Points & Specifications

1. Direction Control (Clause 4.2.2)

• Wider holding wood on the side opposite the lean or heavier crown helps control the fall.
• The fall direction is perpendicular to the lower cut (sink) line.
• This ensures the tree falls safely in the intended direction.

2. Avoiding Splitting (Clause 5.7)

• Fix a stem tightener just above the felling cut line on leaning trees.
• Prevents splitting of the butt-end during felling.

3. Slope Considerations (Clause 3.6)

• Trees on steep slopes should be felled uphill for safety and control.

Summary Table: Preparation Before Felling

Diagram: Felling Direction Control

graph LR
A[Tree with Lean] --> B[Wider Holding Wood on Opposite Side]
B --> C[Fall Direction Perpendicular to Lower Cut]

Note: Always follow safe felling practices and use proper equipment as per IS 9561 guidelines.

IS 9561 – Felling Procedure: Key Points & Specifications

1. Stem Tightner (Clause 2.11 & 5.7)

• Purpose: Prevent splitting of the butt-end, especially in leaning or coniferous trees.
• Location: Fixed just above the felling cut line.
• Composition: Wire rope + lever mechanism for tensioning.

2. General Felling Rules (Clause 3.6)

• On steep slopes, trees should be felled uphill to ensure safety and control.

3. Sequence of Felling (Clause 6)

• Follow steps under Clause 5 first (preparation).
• Then proceed with 6.1.1 to 6.1.7 for normal trees.
• Modify techniques for:
  • Leaning trees (6.2)
  • Buttressed trees (6.3)
  • Rotten trees (6.4)
  • Forked trees (6.5)

4. Typical Felling Cut (Conceptual)

• Notch cut: 1/3 of stem diameter on the side facing the fall.
• Back cut: Horizontal cut slightly above the notch base to release the tree.

Diagram: Felling Cut with Stem Tightner

graph LR
A[Stem Tightner] -- Wire rope fixed --> B[Just above felling cut]
C[Notch cut] --> D[Back cut]
D --> E[Tree falls uphill]

Summary: Use a stem tightner above the cut to prevent splitting; always fell uphill on slopes; follow detailed steps for different tree conditions as per IS 9561 clauses.

Precautions During Felling (IS 9561 Highlights)

• Holding Wood Width (Clause 4.2.2):
  Maintain a wider holding wood on the side opposite to the tree’s lean or heavier crown to control the fall direction.

  • Holding wood acts as a hinge, guiding the tree fall perpendicular to the lower cut line.

• Stem Tightener (Clauses 5.7 & 2.11):
  Use a stem tightener (wire rope + lever) fixed just above the felling cut to:

  • Prevent splitting of the butt-end, especially in leaning or coniferous trees.
  • Maintain stem integrity during the cut.

• Felling Sequence:
  Follow a controlled sequence:

  1. Prepare the site and ensure safe escape paths.
  2. Make the undercut (face cut) on the side of intended fall.
  3. Apply stem tightener if necessary.
  4. Make the back cut, leaving holding wood intact.
  5. Guide the fall using wedges or ropes if needed.

Key Concept: Holding Wood & Stem Tightener

flowchart LR
    A[Felling Cut] --> B[Holding Wood (Hinge)]
    B --> C[Controls Fall Direction]
    D[Stem Tightener] -.-> B
    D -.-> E[Prevents Splitting]

Summary:

• Wider holding wood = better control of fall direction.
• Stem tightener = essential for leaners to avoid splitting.
• Follow proper cutting sequence for safety and control.

Use of Wedges in Tree Felling (IS 9561)

• Purpose:

  • Increase the tendency of the tree to fall toward the sink direction (Clause 8.1).
  • Remove saw jamming during felling and cross-cutting (Clauses 8.1, 9.7).

• Insertion Guidelines:

  • Insert wedges as soon as the felling cut is deep enough to accommodate them (Clause 8.1).
  • Hammer wedges carefully to assist in directional felling (Clause 6.1.7).

• Number of Wedges:

  • Use an odd number of wedges: 1, 3, or 5 (Clause 8.2).
  • This ensures one wedge thrusts on opposite sides for balanced force application.

Summary Table for Wedge Use

flowchart LR
    A[Felling Cut Begins] --> B{Is cut deep enough?}
    B -- No --> A
    B -- Yes --> C[Insert wedge(s) in kerf]
    C --> D[Hammer wedges to assist fall direction]
    D --> E[Continue felling cut]

Key point: Wedges improve safety and efficiency by controlling tree fall direction and preventing saw jamming.

IS 9561 provides general guidance on felling and converting trees into logs but lacks explicit formulas or detailed tables.

Key Points for Conversion of Felled Tree into Logs:

• Objective: Maximize yield from the felled tree by following proper felling and conversion methods.
• Tools: Use iron wedges with preferably wooden heads for splitting (Clause 8.3).
• Methodology: Follow a systematic sequence of felling and conversion to minimize wastage.
• Precision: Apply rounding off rules for numerical values during measurement and conversion (as per revised guidelines).

General Engineering Practices (Supplementary):

• Log Length: Usually cut to standard lengths (e.g., 2m or 3m) depending on end use.

• Diameter Measurement: Measure diameter at breast height (DBH) for volume estimation.

• Volume Estimation Formula:

  [ V = \frac{\pi}{4} \times d^2 \times L ]

  where:

  • (V) = volume of log (m³)
  • (d) = diameter of log (m)
  • (L) = length of log (m)

Summary:

• Follow IS 9561 for procedural guidance.
• Use iron wedges with wooden heads.
• Cut logs to standard lengths.
• Measure diameter accurately and estimate volume using the formula above.

flowchart TD
    A[Felling Tree] --> B[Use Iron Wedges]
    B --> C[Cut into Logs]
    C --> D[Measure Diameter & Length]
    D --> E[Calculate Volume]
    E --> F[Maximize Yield]

IS 9561: Log End Treatment - Key Points & Guidelines

• Saw Cut Orientation (Clause 9.5):
  The saw cut at the log end must be perpendicular to the log axis to minimize wood wastage and avoid oblique cuts.

• Wedges (Clause 8.3):
  Use iron wedges with preferably a wooden head for felling operations to control tree fall and reduce damage.

• Rounding Off Numerical Values:
  Follow the revised rules for rounding off measurements to maintain consistency and accuracy in log dimensions.

Practical Recommendations for Log End Treatment:

Why perpendicular cuts?

• Ensures uniform log length
• Reduces splitting and cracking at ends
• Facilitates better stacking and transportation

flowchart LR
    A[Felled Tree] --> B[Position Log]
    B --> C[Saw Cut Perpendicular to Axis]
    C --> D[Log with Treated Ends]
    D --> E[Reduced Wood Wastage]

This ensures optimal utilization of timber as per IS 9561 guidelines.