Canary Island date palm with a basal conk and a proposal to chisel it off

It removes the visible sign and nothing else.

• The conk is a fruiting body, not the disease. It is the reproductive structure of a fungus that is decaying the interior of the trunk base. Chiselling it off leaves the decay exactly where it was, at the cross-section that carries the whole palm.
• It destroys your evidence. The conk is the specimen that would allow laboratory confirmation of the pathogen. Cutting it off flush and discarding it removes the basis for a diagnosis you may need in writing later.
• It creates a wound at the worst location. A fresh cut surface at the base of a palm is another entry point and another moisture-holding injury at grade.
• Wound paint is not recommended. It does not prevent decay and can trap moisture; on palms it has no demonstrated benefit.
• The real problem with the proposal is the timescale. Six months of re-inspection implies that monitoring will detect a change in time to act. In a palm with basal decay it will not.

Separately, the canopy symptoms deserve their own look. Lower-frond yellowing and a shortening new frond can reflect the decay, but they can also fit a systemic palm decline, so the conk should be sampled for confirmation rather than assumed to explain everything.

Likelihood of failure: possible now and increasing. Palms do not add secondary wood, so any cross-section lost to decay is lost permanently; there is no compartmentalisation and no annual ring of new wood to compensate. Basal decay in a palm means the whole trunk is compromised at its highest-stress point. Failure presents as a whole-palm collapse at or near the base with essentially no warning: no cracking you can see from the ground, no progressive lean you can monitor, no limb to drop first.

Likelihood of impact: high. The walkway is 1.5 m from the trunk and carries about 600 people a day, and the valet podium is staffed 16 hours a day. The fall zone is the palm's height in every direction, which covers the walkway, the podium area and the photo location.

Consequence: severe. A 9 m palm with a heavy crown falling on a pedestrian is a fatal scenario.

Combined: high risk. For palms there is no established method that reliably quantifies remaining sound wood in the base. Sounding and drilling give poor information and can themselves wound the trunk. That means the risk cannot be managed by assessment, only by removing the target or the palm, and the target cannot practically be removed from a main guest route.

What I would say: the palm can stay only if people stop being underneath it. That is the whole of the mitigation.

Physical measures if removal is deferred to a fixed date:

• Reroute the walkway around the palm and install rigid barriers at a radius of at least the palm's height, so guests cannot drift back under it.
• Move the valet podium and any seating outside that radius.
• Relocate the photo bookings and remove the palm from any marketing material that places people at its base.
• Set a removal date and put it in the contract, not in a verbal plan.

What monitoring cannot do: it will not give warning of a basal collapse in a palm. There is no measurable progressive sign to watch, and no non-destructive test that reliably maps internal decay. Offering a six-month re-inspection would give the owner the impression of management without the substance, and would be difficult to defend afterwards.

What goes in writing: the conk description and photograph, the canopy comparison with neighbouring palms, the diagnosis with its level of confidence and the recommendation that the conk be sampled, the risk rating and the reasoning behind it, the fall-zone radius, the specific controls, the removal date, and a clear statement that the residual risk is not reduced while people remain under the palm. If the owner declines, record the recommendation, the date and the decision-maker, and state plainly what risk they are accepting.