Tree climbing spikes support your feet while a harness holds you if a gaff slips — you need both, plus training, a climbing line, and a second fall-protection system.
A gaff punches through bark on every step up, and it hops out of the wood just as easily. The rope system does that job, and no harness can substitute for it, which is why the setup matters more than the gear.
Spikes — also called climbers, spurs, or gaffs — are demolition tools. They belong on trees being removed, not on ones you’re pruning or maintaining, because each puncture opens living tissue to disease and pests. Once you accept that limit, the rest is a short, rigid sequence: train, inspect, fit, tie in, then climb deliberately.
What Equipment Does Tree Climbing Require?
A complete system needs four things working together: spikes with the right gaffs, an arborist saddle rated for tree work, a positioning lanyard or second climbing line, and an overhead life-support line.
The harness choice is where people cut corners. A general construction harness may lack the attachment points and work-positioning function a rope-climbing setup requires, so look for a saddle built for tree work, rescue, and rappel instead. On the spikes themselves, gaff length decides where they work.
Materials trade weight against cost: steel is heaviest, aluminum lighter, carbon fiber lightest and usually the priciest.
Shopping by spec is easier when you can compare gaff lengths and load ratings side by side — our breakdown of tested climbing spikes and gaff options covers the differences that actually matter.
How Do You Set Up Spikes and a Harness Safely?
Training comes first, before any gear touches a tree. Workers must be trained in climbing techniques, hazard recognition, spur use, and PPE, and use is limited to competent people or those under direct visual supervision.
From there, the order matters:
- Inspect everything before every climb. Check leg irons, gaffs, gaff bolts, straps, buckles, the harness, lanyard, climbing line, connectors, and the overhead system. Anything damaged, worn, modified, or working improperly comes out of service.
- Match the gaff to the job. Tree gaffs for trees, pole gaffs for poles, and confirm compatibility with the tree and the manufacturer’s instructions.
- Fit the climbers to your boots and legs. Seat the leg iron against your shin, set the foot attachment over a sturdy boot, and tighten the straps until the climber can’t rotate or shift — without restricting circulation. Follow the model’s own strap routing.
- Establish fall protection before you leave the ground. Attach the arborist climbing line, then set the positioning lanyard or second line around the trunk. Spikes give footing, not fall arrest.
- Ascend deliberately. Set each gaff fully into sound bark before shifting weight, keep three points of contact, and hold the positioning system engaged the whole way.
- Descend under control. Keep the lanyard or second line positioned, pull each gaff out cleanly, and don’t let yourself swing or slide.
Once your feet are back on the ground, fit the gaff covers, clean and dry the components as directed, and replace anything worn. Never drop climbers from height.
What Mistakes Cause Most Spikes Accidents?
Almost every serious failure traces back to one of three moves: climbing with no second fall-protection system, using the wrong gaff for the surface, or trusting worn gear. All three are avoidable.
Treating the harness as a substitute for a climbing line is the most dangerous of them — OSHA explicitly calls for a second means of fall protection, and a saddle alone doesn’t satisfy that. Mixing gaffs across surfaces runs a close second: pole gaffs in a tree, or tree gaffs on a utility pole, create a compatibility hazard, and OSHA’s cited guidance is clear that gaffs must match what’s being climbed.
Then there’s the tree itself. Wood that’s rotten, loose-barked, or otherwise compromised won’t hold a gaff, no matter how good your form is. And if you’re tempted to spike a healthy tree for routine pruning, remember what you’re doing: opening the cambium and rolling out a welcome mat for pests. Use a rope-and-saddle system with proper pruning technique instead, and save the spikes for removals.
Sources
- Occupational Safety and Health Administration. “Tree Care Work: Know the Hazards” Source for training, inspection, fall-protection, and gaff-compatibility requirements.
- Occupational Safety and Health Administration. “Tree Care Industry Safety and Health Topics” Supports equipment-control and PPE guidance for climbers.
- U.S. Forest Service. “National Tree Climbing Guide” Background on climbing systems, tie-in practice, and inspection habits.