The Leaning Maple Over the Playground

This is not a walk-by. A Level 1 limited visual assessment is inappropriate when there is a specific defect set and a high-occupancy target.

Level 2 basic assessment on site, now: a full 360-degree walk-around; clear the soil from the root flare and the cavity margins; sound the trunk and buttresses with a mallet; probe the cavity and the crack with a thin tine to find the depth of decayed wood; measure the lean and check it against the surrounding trees and any historic photographs; look for reaction wood, for a gap opening or closing at the crack, and for fresh soil displacement. Photograph all of it.

Level 3 advanced assessment is then indicated - resistograph, sonic tomography, or a decay assessment by a qualified arborist - because a conk plus a cavity plus a soil crack is a combination that basic inspection alone cannot quantify.

But do not wait for the appointment with the playground open. The interim message to the director:

• I cannot tell you today that this tree is safe.
• The fastest thing to change is the target, not the tree. Close or relocate the play equipment, or fence a radius at least equal to the tree's height - the crown edge at 6 m is not a safe radius, because an 18 m tree can throw material well beyond its drip line, and a root-plate failure moves the whole tree.
• The tree stays fenced and untouched until the advanced assessment is reported in writing.

Also record the process: date and time, who was notified, what was said. That record is as much a part of the job as the diagnosis.

Likelihood of failure: probable to imminent. Not because of the lean - trees lean and hold themselves with reaction wood, and lean alone is not a defect - but because there are several indicators pointing the same way: a large open cavity at the flare, a fresh conk, soil heave, and a radial crack in the ground. Those are consistent with root or butt decay plus root-plate movement rather than with a single historic injury. The soil crack is the most serious item on the list.

Likelihood of impact: high. The target is a playground with 30-40 children daily, and the effective target zone is not the crown projection. For an 18 m tree, a conservative zone extends at least the tree's height from the trunk in the direction of the lean.

Consequences: severe. Serious injury or death of a child, with everything that follows for the owner.

Combined. Probable or imminent failure, high occupancy, severe consequence puts this in the high or extreme cell of any standard matrix, whichever one you use. State which matrix you used so the rating is auditable.

What would change the rating: evidence that the crack is desiccation cracking rather than shear; a conk that is old and dead with sound wood beneath it; a cavity that proves to be shallow and walled off. All of those are possible - which is exactly why the advanced assessment is needed. But the interim rating must reflect what is visible today, and today it is a high-risk tree with a high-consequence target. The same tree in an empty field would be a low-risk tree with a re-inspection interval: the target, not the tree, drives the rating.

Ranked, most to least reliable:

1. Eliminate the target - relocate the play equipment or fence off a radius. It removes the risk completely and it is the only option that works today. In risk management the target is always the cheapest thing to move.
2. Remove the tree - decisive, removes the target, but irreversible and costly; check for ordinance protection, permits, and whether the species is worth retaining elsewhere on site.
3. Reduce the load - end-weight reduction on the long limbs of the lean side reduces the bending moment on the stem, but it does nothing about root-plate failure and must not be sold as a cure.
4. Cables or bracing - only as a supplement to structural pruning for a specific stem defect, and only if the root plate is sound. Irrelevant here until the root plate question is answered.
5. Monitor with a defined interval - the weakest option on its own, but appropriate once the target has been removed and evidence is being gathered. A monitoring recommendation without a stated interval, a named person and a trigger for action is not a recommendation.

In the written report: date; assessor and qualifications; the level of assessment and its limitations; every defect described and measured, with the cavity dimensions, lean, crack length and conk photographed; a description of the target and its occupancy; the matrix used and the category assigned; the mitigation recommended with the reasoning and the residual risk after each option; and a re-inspection interval with a named responsible person.

Flag the governance issue separately. A three-year inspection interval with no written record is a duty-of-care problem for the owner that is independent of what happens to this tree, and the director should hear that clearly - not as a threat, but as the reason the file needs to be complete from today.