Specialist Tree Decay Detection — Nazarene Theological College

CLIENT: Nazarene Theological College

 PROJECT TYPE: Specialist decay detection investigation — European beech trees

SERVICES DELIVERED: IML Resistograph resistance drilling, Arbotom sonic tomography, management recommendations, monitoring programme

THE CHALLENGE:

Lally Tree Management — one of the North West's leading arboricultural consultancies — commissioned Urban Tree Management to carry out specialist tree decay detection investigations at Nazarene Theological College as part of their arboricultural survey programme for the site. Two mature European beech trees had been identified during the initial survey as showing signs of significant internal dysfunction and structural concern requiring advanced diagnostic investigation before management decisions could be made.

Tree T964 — beech 10a — had shown external signs consistent with progressive internal decay and required Resistograph resistance drilling to establish the extent and structural significance of the defect. Tree T1931 — beech 10d — required sonic tomography to map the internal condition of the stem and determine whether the level of decay identified externally warranted immediate management intervention or whether a structured monitoring programme was the appropriate response

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OUR ROLE:

Urban Tree Management attended site and carried out specialist decay detection investigations on both trees using the most advanced diagnostic tools available in arboricultural practice.

For tree T964, IML Resistograph resistance drilling was carried out at multiple points across the stem diameter — measuring the resistance encountered as a fine needle was driven through the wood at a controlled speed and producing resistance profile graphs directly confirming the presence, depth, and extent of internal decay across the critical load-bearing zones of the stem. The resistance profiles clearly showed the extent of wood dysfunction and the thickness of the residual wall at each drilling point. The data confirmed that the extent of internal decay and dysfunction was sufficient to represent an unacceptable structural risk and the management recommendation was that the tree should be removed. The resistance profiles were documented in full in the written report alongside the surveyor's interpretation and a clear explanation of the basis for the removal recommendation.

For tree T1931, Arbotom sonic tomography was carried out — placing sensors at regular intervals around the stem circumference and producing a detailed two-dimensional tomographic image of the internal condition of the wood. The tomogram revealed areas of reduced wood density and early-stage decay within the stem, but the extent and pattern of the decay indicated that the tree retained sufficient structural competence to be managed on a monitoring basis. A structured monitoring programme was specified with a recommended return investigation using both sonic tomography and Resistograph in two years time to assess whether the decay had progressed and whether the management recommendation needed to be revised.

THE OUTCOME:

We produced specialist decay detection report covering both trees — providing the objective, technically robust diagnostic data needed to support their management recommendations to the college. Tree T964 was confirmed as requiring removal based on the Resistograph findings, giving the client a clear defensible basis for the recommendation. Tree T1931 was placed on a structured two-year monitoring programme, allowing the college to make an informed, proportionate management decision based on objective evidence rather than precautionary removal. This project demonstrates Urban Tree Management's specialist subcontract decay detection capability — providing the advanced diagnostic expertise that other consultancies commission when standard visual inspection is insufficient.

Specialist Decay Detection Subcontract — North West & Nationwide

Urban Tree Management provides Resistograph and Arbotom sonic tomography decay detection on a subcontract basis for arboricultural consultancies across the North West and nationally — delivering the objective, technically robust diagnostic evidence that consultants need when visual inspection alone is not sufficient.

Get in contact with our highly experienced and personable team of arboriculturists today, to discuss your requirements and to obtain your zero obligation quotation.