Tree Climbing Safety Reference

Why this reference exists

Climbing is the highest-risk task tree services do. ANSI Z133 + OSHA regulate the practice in detail. This reference is the daily checklist for climbers + an audit document for owners. Insurance investigators read these documents after incidents; the better the operating standard, the better the coverage holds.

Two-rope (two-tie-in-point) system

ANSI Z133-2017 requires TWO independent anchored climbing systems any time a climber is moving in a tree. This is not optional; it's the headline safety advance of the past decade.

Two independent ropes mean:

• Rope failure (cut, abrasion, knot slip) does not mean a fall
• One rope can be repositioned for the next cut while staying tied in

If a climber needs to be on one rope momentarily (rare; usually for limb walks), it must be planned + briefly.

Pre-climb checks

Every climb. Every day. No exceptions.

Climber's gear (head to toe):

• Helmet with chinstrap engaged (Class E or G, hard hat + climbing version)
• Eye protection (clear or amber)
• Hearing protection (95+ dB chainsaw operation)
• Saddle (climbing harness) - leg straps + waist all snugged + inspected for cuts/abrasion
• Lanyards (2): 1/2" arborist rope or 12.7 mm cordura with mechanical adjuster
• Climbing rope 1/2"-5/8" arborist line (ArborMaster, Yale Blaze, Samson XLS, etc.)
• Chainsaw lanyard
• Throwline + throwball
• Friction hitch + hitch cord (Distel, VT, Knut) OR mechanical climbing device (Rope Wrench, ZigZag, Akimbo, Hitch Hiker)
• Spurs ONLY for removal (NOT for pruning live keepers)

Rope inspection:

• Run hand the entire length, check for cuts, glazing, soft spots, kinks
• Retire rope showing core damage (lumpy feel)
• Wash dirty rope in mild detergent (no bleach); rinse + dry away from sun
• Retire after 5 years from manufacture date OR after any shock load

Tree inspection (separate, before climb):

• Look up: dead wood, broken limbs, cavities, lean
• Look at trunk: cracks, fungal conks, peeling bark
• Look at base: root plate movement, soil mounding/cracking
• Listen: any creaking, popping, settling
• If ANY doubt about tree integrity, do not climb without rigging from outside

Anchor selection

The anchor point determines life.

Acceptable:

• Live wood > 6" diameter
• Crotch above the climber (not below)
• Cleared of dead branches that could be loaded
• Tested by hand-pull before weight commitment

NOT acceptable:

• Dead wood (ANY dead wood)
• Tight V-crotch (high split potential)
• Cracked or peeling limb
• Cavity wood
• Limbs under existing tension (other ropes, leaning trees)

A false crotch (rigging device + saver) protects the tree + creates a smooth anchor point. Highly recommended.

Ground-to-climb communication

Before any cut + before any drop:

• "Cut coming" + reply "clear"
• "Headache!" if anything falls unexpectedly
• "All clear" before resuming
• Hand signals when chainsaw drowns out voice

Two-way radio (Motorola CLP or equivalent) for any tree > 50 ft tall.

Chainsaw use in tree

In-tree chainsaw work has specific rules:

• Top-handle saw ONLY (Stihl MS 201T, Echo CS-2511T) - never a rear-handle in-tree
• Chainsaw lanyard attached at all times
• Saw ON only when in cutting position
• Chain brake ENGAGED when not actively cutting
• Saw operated one-handed only when the off-hand is anchoring climber + saw safety justifies
• Eye + ear protection always

Chainsaw injuries in tree: 60% are leg lacerations (foot kicks ahead during cut). Climber must position cut so saw + body trajectory diverge.

Fall + suspension trauma

Suspension trauma: a climber hanging motionless in a saddle can lose consciousness within 30 minutes from venous pooling. This is fatal if not rescued.

Rescue plan:

• Ground crew knows climber's location + planned position at all times
• Aerial rescue kit on truck (mechanical advantage system)
• Aerial rescue training annually
• 911 is BACKUP, not primary - rescue must start in minutes

Self-rescue first option:

• Conscious climber descends own rope
• Or ascends to a safer position to wait

Crew rescue if climber unable:

• Second climber ascends with a Z-rig or 3:1 mechanical advantage
• Lowers victim safely
• AED + trauma kit ready at ground

Practice rescue scenarios quarterly. Most crews can't perform a real rescue cold.

Storm + weather

• Wind: stop climbing above 25 mph sustained
• Lightning: stop work + shelter in vehicles when storms within 6 miles
• Ice on tree: do not climb
• Rain: increases rope wear + slippery footing; reduce pace

Power lines + tree work

10 ft minimum clearance from any energized line for non-utility-certified crews. 6 ft for secondary (240V residential) - refer to utility-certified crew if uncertain. Never approach downed lines (storm + falling-line scenarios).

For tree work within 10 ft of lines, a Line-Clearance Tree Trimmer (LCT) certified crew must perform the work. Most general arborists are not LCT-certified. Refer.

Daily climbing checklist

Print + carry:

• Tree inspection complete
• Saddle inspected
• Helmet + chinstrap
• Eye + ear + chaps
• Two ropes confirmed
• Rope inspection logged
• Anchor point verified
• Ground crew briefed
• Drop zone established
• Communication tested
• First-aid + AED + rescue kit positioned
• Power line clearance verified

Insurance + documentation

Climbing operations affect insurance + workers comp rates. Documentation matters when claims are filed:

• Daily safety briefing log signed by crew
• Equipment inspection log
• Incident reports (any near-miss filed within 24 hours)
• Annual rescue drill log
• Per-climber certification + medical clearance

References

• ANSI Z133 Safety standard for tree-care operations
• OSHA 1910.269 utility-line work
• TCIA Climbing Safety Best Practices
• ISA Certified Tree Worker / Climber Specialist curriculum
• Manuall internal: Tree Pruning Service SOP, Tree Removal Service SOP, Storm Response and Emergency Tree Service SOP