Tree Rigging - Ropes, Rigging Hardware, and Techniques

Why this matters

Tree rigging is the use of ropes, pulleys, and friction devices to safely lower branches, limbs, and tree sections from height. Without proper rigging, large tree work requires either dropping the material (often impossible due to structures, plantings, or property below) or significant ground-side cleanup. Rigging adds capability AND safety - a properly rigged section descends in controlled motion rather than free-falling. This is one of the most consequential technical skills in tree work.

Why we rig

Three primary reasons:

1. Property protection: structures, landscaping, fences below the cut
2. Worker safety: large sections lowered controlled rather than dropped
3. Customer expectation: professional service includes clean removal

A 200-pound branch dropped from 30 feet creates significant impact damage and is dangerous to ground crew. The same branch lowered with rigging arrives safely on the ground.

Required equipment

Climbing rope vs. rigging rope

These are different:

Never use the climbing rope for rigging. Different strength specifications.

Common rigging rope materials

Standard tree rigging: 3/4 inch or 1/2 inch double-braided nylon or polyester. Capacity in the thousands of pounds.

Pulleys and hardware

A complete rigging system includes all of these. Each has specific load ratings and uses.

Lowering devices

The lowering device handles the friction needed to control the descent:

• Hobbs Lowering Device: simple metal device that wraps the rope around a drum
• Port-a-Wrap (Stein): similar concept; controls descent rate
• Cumberland's design: another lowering device

The ground worker controls the descent by adjusting friction on the rope at the lowering device. Slack out = faster descent; pull in = slower.

Basic rigging procedure

Step 1: Plan the cut and the rigging

Before any cutting:

1. Identify the section to be removed
2. Identify the tie-off point (basal anchor)
3. Plan the cut location
4. Identify the landing zone
5. Verify the rigging can handle the load

Step 2: Set the basal anchor

The anchor on the tree (typically a different tree trunk):

1. Wrap a sling around a structural part of the anchor tree
2. Verify the anchor can handle the load (not on a damaged or weak trunk)
3. Use friction saver to protect the bark
4. Attach a pulley OR direct rigging point

Step 3: Set the rope

1. From the anchor, run the rigging rope up to the cut location
2. Wrap the rope around or through the section to be lowered
3. Secure with appropriate hitch (clove hitch, Marl, or other)
4. Run the rope back down to the lowering device on the ground

Step 4: Setup at the ground

1. Lowering device attached to a separate anchor (often a different tree)
2. Rope passes through the lowering device
3. Ground worker takes position behind / beside the device
4. Verify communication signals with the climber / sawyer

Step 5: Make the cut

1. The climber positions clear of the cut + the lowering path
2. Make the cut
3. The branch / section drops slightly, taking tension on the rope
4. The lowering device begins paying out controlled rope
5. The branch descends to the ground at controlled speed
6. Ground crew receives + clears the section

Step 6: Repeat for additional sections

Multiple cuts in a tree typically require multiple rigging setups; plan ahead.

Knots and hitches

For tree rigging, common knots:

Practice these knots cold; tying them under pressure is the test.

Load ratings

Every rigging component has a Working Load Limit (WLL):

• Rope: typically 1/8 of breaking strength (8x safety factor)
• Hardware: 1/5 of breaking strength (5x safety factor)
• Slings: 1/5 of breaking strength (5x safety factor)

The rated load is the MAXIMUM the component should bear. Exceeding the WLL risks failure.

A 4-inch diameter limb weighs roughly 100-200 pounds per foot; a 20-foot section can be 2,000-4,000 pounds. Rigging components must match.

Calculation:

• Component WLL ≥ Estimated load weight × 1.5 (safety margin)

Friction in rigging

Friction is the controlled descent:

• Lowering device generates friction
• Friction converts kinetic energy (falling load) to heat (rope + device)
• Heat dissipates safely (within limits)
• Excessive friction may damage the rope; insufficient friction means uncontrolled descent

Adjust friction based on:

• Load weight (heavier = more friction needed)
• Drop height (longer drop = more friction)
• Ground worker's strength
• Rope condition

Climber-side rigging

The climber-side rigging:

The climber rigs from the position; the ground crew receives.

Tree species considerations

Different tree species behave differently:

Crane-assisted rigging

For large trees:

References

• ANSI Z133 (Safety Requirements for Arboricultural Operations)
• ANSI A300 (Tree Care Standards)
• TCIA (Tree Care Industry Association) rigging training
• ISA (International Society of Arboriculture) BMP for Rigging
• Manufacturer documentation for rope + hardware
• Manuall internal: Chainsaw Safety, Tree Removal Service SOP, Climbing Safety