Hidden Decay or Cavity Found Mid-Climb Response
Purpose
A cavity found from the ground is a diagnostic question. A cavity found mid-cut, thirty feet up, with a climber's full weight already loaded onto the tree, is a live structural question about the exact piece of wood a person is standing on. This standard guarantees that a climber who discovers soft, hollow, or cavity-marked wood while already working in the tree stops and independently confirms their own support system before another cut is made, rather than finishing the limb because the tie-in three feet away still feels fine. Skipped, this is how a ground-based risk assessment that correctly cleared a tree still ends in a climber going down with a limb the assessment never saw the inside of.
Scope
The moment a climber, already positioned and working, finds decay, a cavity, punky or soft wood, or a hollow sounding tone at or near a load-bearing point, the tie-in, a rigging crotch, a limb about to be walked out on, or the trunk itself. Applies across pruning, removal, cabling, and storm-damage climbs.
This standard does not cover the ground-based, pre-climb decision to remove, monitor, or mitigate a tree, which the tree risk assessment reference owns in full under the TRAQ framework; this response starts once a climber is already aloft and finds something that assessment did not catch. It does not cover scheduled sounding performed as part of a routine inspection cycle, which the commercial property inspection standard owns.
Roles and the handoff between them
| Role | What they own | What they hand off |
|---|---|---|
| Climber | The discovery, the independent anchor test, the continue-relocate-descend call | A described location and severity to ground crew before descending |
| Ground crew | A backup line or belay if requested, watching for movement, keeping the drop zone current | Confirmation the new drop zone and escape route are clear |
| Crew lead or second climber | Whether to send up a second person, a lift, or stand the job down entirely | The scope decision and re-authorization for any later climb |
| Office | Documentation, scope conversion, the customer conversation | A closed-out job record before any crew returns to that tree |
Stop before anything else moves
The moment decay, a cavity, or a hollow, dull sound turns up at or adjacent to any point currently bearing the climber's weight or about to bear it, all cutting stops and no additional weight shifts onto that section until it is independently tested. Do not treat the tie-in that got you here as proof of anything; it is a different piece of wood than the one you are about to cut into, and it gets its own test in step 3 below.
The procedure
Stop cutting and go static the instant a hollow tone, soft resistance, a visible cavity, or fungal sign turns up. Kill the saw or engage the chain brake, settle full weight onto the confirmed tie-in only, and take hands off the suspect section. Acceptance: saw silent, weight fully on the tie-in, no contact with the suspect wood. Wrong looks like finishing the current cut because it is already started. Stop rule: any cut in progress on or adjacent to the suspect wood stops immediately, even mid-kerf, even if the bar ends up pinched, because a pinched bar is retrievable and a failed limb under a climber is not. Hazard: chainsaw kickback risk rises on wood of inconsistent density, so any further bar contact near punky wood keeps extra clearance from the body.
Sound the suspect area with a mallet or the back of an axe, working outward from the softest point until the tone returns solid. Acceptance: a clear resonant thud on sound wood against a dull, hollow tone on the suspect area, mapped from at least three strike points around the section. Wrong looks like one tap taken as conclusive. Stop rule: if the hollow tone extends across more than roughly a third of the circumference at that point, a widely used field guideline in tree mechanics research, treat the section as structurally compromised regardless of how solid the far side sounds, because sounding maps the boundary of decay, not its depth. Hazard: swinging a mallet one-handed while the other hand is your only anchor point; brace against the tie-in line, never against the suspect limb, before swinging.
Test your actual current support point independently, not a nearby branch that looks fine. Bounce-test the tie-in and any secondary anchor with a firm, gradual, controlled load before committing full weight, and check the bark and cambium at the anchor crotch itself for the same soft or hollow signs found elsewhere. Acceptance: the point you are actually loaded on confirmed sound by both a visual check and a controlled load test, independent of the defect that triggered the stop. Wrong looks like assuming the tie-in is fine because it is a different branch than the one that failed. Stop rule: if the tie-in itself shows any of the same signs, relocate to a new, independently tested anchor before doing anything else, including before finishing the sounding started in step 2. Hazard: a controlled bounce test still loads the anchor above static body weight; apply it gradually, never with a hard drop, and keep a second point of contact throughout.
Reassess the escape route and the drop zone against the new information, and say the new plan out loud to ground crew. Acceptance: a confirmed descent path and a drop zone clear of the section now known compromised, communicated before anything else happens. Wrong looks like keeping the plan made before the defect was found. Stop rule: if the compromised wood sits between the climber and the original descent path, a new route is established before any further work, not worked around on the fly. Hazard: ground crew standing in what was a safe zone five minutes ago is now under wood of unknown integrity; call it out before anyone below assumes the old plan still holds.
Decide, out loud to ground crew, one of three states: continue past the defect on a verified alternate support, relocate to finish from a different tie-in and skip the compromised section, or descend and stand the climb down. Acceptance: one of the three stated, with its reason. Wrong looks like an unstated decision that just quietly resumes work. Stop rule: where the compromise sits at or above the current working position and no alternate anchor tests sound, the answer is descend, full stop, never "work around it carefully." Hazard: none new; this step is the decision made from the now-verified anchor established in step 3.
Where the decision is to continue, cut only with the compromised section fully outside your own support chain and outside anyone's position below. Acceptance: the compromised wood is not part of the tie-in, the rigging anchor, or anything a foot or lanyard rests on, verified again immediately before the first cut. Wrong looks like treating "sounds mostly fine three feet over" as good enough. Stop rule: if the cut plan requires stepping onto or loading the compromised section even briefly, the plan is wrong and gets revised, not attempted once carefully. Hazard: rigging a compromised limb for a controlled lower still applies dynamic load at the moment of the cut, so rig from a separate sound point, never from the defect itself.
Where the decision is to descend, communicate the standing hazard to everyone on site before coming down, and mark the tree. Acceptance: ground crew told the specific location and nature of the defect, and a visible mark left at the base or the affected section. Wrong looks like climbing down and mentioning it later in the truck. Stop rule: nobody re-climbs that tree, that day or any later day, without a second person independently confirming the marked defect and the plan for it; a solo climber does not re-authorize their own descent. Hazard: the defect that stopped this climb is now a standing hazard for anyone who approaches the tree afterward, including a different crew on a later day if the finding is not closed out.
Update the job scope and get it re-authorized before any further work resumes on that tree. Acceptance: the crew lead or office records whether the job converts, prune to removal, standard removal to crane-assisted, and confirms it with the customer before the next visit. Wrong looks like the next crew showing up and reworking the exact plan that already failed once. Stop rule: a tree marked from this response does not get climbed again under the original scope; it gets a fresh plan built around the confirmed defect. Hazard: none new; skipping this step is how the same hazard gets rediscovered by whoever never read the first report.
The record this produces
Date and time, the defect's location on the tree by height and side, sounding results, the decision made and why, whether descent occurred, any scope change, and who was notified. This is what keeps a second crew from re-climbing a tree that already failed a load test once.
Worked pass: deadwood removal on a white oak
A climber is 35 feet up removing deadwood from a mature white oak, tied in on a crotch near the main leader that sounded solid on the way up. Mid-cut on a large lateral limb, the saw bites into unexpectedly soft, stringy wood at the limb's base.
Step 1 passes: saw off, chain brake engaged, weight stays on the tie-in. Step 2: sounding around the limb base finds a dull tone across roughly half the circumference, past the one-third flag, so it is mapped and treated as compromised. Step 3 passes: the tie-in crotch, eight feet away on the main leader, sounds solid on all sides and holds a controlled bounce test cleanly.
Step 4 fails on the first attempt. The climber calls down "coming down the same way I went up," without checking whether that path passes under the now-known-compromised limb, which the acceptance condition requires. The ground crew lead catches it and calls up that the original descent line runs directly beneath the bad limb. Under the stop rule, the climber re-routes around the far side of the trunk before starting down, and the step is redone correctly rather than proceeding on the first, incomplete answer.
Step 5: the climber calls down "relocate and skip," finishing the remaining accessible deadwood from the verified tie-in and leaving the compromised limb untouched. Step 6 is satisfied by exclusion: every remaining cut stays clear of the compromised wood, confirmed before each one. Step 7: descent follows the corrected route, the limb is flagged at the trunk, and ground crew is told exactly where and what. Step 8: the crew lead converts the remaining scope to a removal quote for that limb using aerial lift access instead of a re-climb, and the office confirms the change with the customer before scheduling the follow-up visit.
References
- See related: Tree Risk Assessment (ISA TRAQ Framework) reference, which owns the ground-based, pre-climb decision this response does not re-derive.
- See related: Commercial Property Arborist Inspection Cycle SOP, for scheduled sounding as part of a routine cycle rather than an unplanned mid-climb discovery.
- ANSI Z133, in the edition your program has adopted, for tie-in redundancy and two-point suspension requirements this response falls back on.
- ISA Best Management Practices: Tree Risk Assessment, for the sounding technique and the wall-thickness guideline referenced in step 2.