Specialist Tree Decay Detection

When a visual tree assessment is not enough — when fungal brackets appear at the base, when a tree has a history of branch failures, when response growth suggests internal structural change — you need objective diagnostic evidence of what is actually happening inside the wood before a management decision can be made.

Urban Tree Management carries out specialist tree decay detection investigations using the Arbotom sonic tomography system with impulse sensor technology and the Resistograph — completely independent from any tree surgery contractor, with no financial interest in the outcome.

Every decay detection investigation is carried out personally by our own consultant — we do not subcontract this work. Carl Riva operates the equipment directly on every investigation, interprets the findings on site, and writes the report. You get the consultant who did the work — not an interpretation of someone else's data.

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When Is Decay Detection Required?

A specialist decay detection investigation is required when a visual assessment has identified signs of concern but cannot determine the extent or significance of the internal condition. Common triggers include:

Fungal brackets or fruiting bodies on the stem or at the base — particularly Ganoderma brackets which indicate structural decay in the support roots
A history of branch failures from the same tree
Visible cavities where the extent of internal decay cannot be determined visually
Response growth — unusual ribs or swelling on the stem — suggesting the tree is compensating for internal structural change
Crown dieback or progressive decline where the cause is unclear
A tree in a high-use location where a precautionary visual assessment is insufficient for a defensible management decision
TPO applications where the local planning authority requires objective evidence of condition
Insurance claims or legal proceedings where independently reproducible diagnostic evidence is needed
Monitoring a known decay condition at intervals to track progression

The Two Instruments We Use

Urban Tree Management uses two instruments on every decay detection investigation — used together they provide a complete and defensible picture that neither instrument can give alone.

Sonic Tomography — Non-Invasive

The Arbotom is a non-invasive acoustic tomography system. The impulse sensor chain is placed around the outside of the stem — no drilling, no damage to the tree.

Urban Tree Management uses the impulse sensor system which allows measurement at over 100 points per cross-section — significantly more than standard acoustic tomography systems which are typically limited to 24 sensors. This dramatically increases the resolution and accuracy of the tomogram, particularly on large diameter stems and in cases where the findings need to withstand professional scrutiny.

→ Read more about how the Arbotom works, the MECH module, ArWiLo wind load analysis, ArboStApp safety assessment, ArboRadix root plate analysis, and the published case evidence that informs our interpretation — Arbotom Sonic Tomography

Rinntech Resistograph R650 — Confirmatory Drilling

The Rinntech Resistograph R650 is a resistance micro-drill. A very fine needle is advanced into the stem at a measured rate and the resistance encountered is recorded continuously as the needle passes through different wood zones. The R650 features Bluetooth tablet integration for real-time data transfer, GPS-tagged drilling points for precise documentation, and DECOM analysis software for professional resistance profile outputs.

The Resistograph confirms what the Arbotom has located — physically measuring the condition of the wood at each zone and confirming the thickness of the residual structural wall. Where the tomogram identifies an area of concern the Resistograph drills at that point to confirm whether decay is present and how much structural wall remains.

→ Read more about Resistograph testing — Rinntech Resistograph R650

Why Both Instruments Together

The Arbotom locates. The Resistograph confirms. Neither instrument alone gives the complete picture:

The Arbotom covers the entire cross-section non-invasively but cannot definitively distinguish decay from other causes of reduced sound velocity such as ring rot, cracks, or frozen wood
The Resistograph physically confirms the wood condition at a specific point but cannot on its own map the extent of the decay across the full cross-section
Together they produce objective, independently reproducible evidence of the tree's internal condition — the standard required for planning, insurance, legal, and duty of care purposes

Every investigation report explicitly states whether the Resistograph findings correlate with the tomogram findings — and whether that correlation supports or modifies the initial tomographic assessment.

What the Investigation Produces

Every decay detection investigation from Urban Tree Management produces a professionally documented written report suitable for planning authority submission, insurance purposes, legal proceedings, and duty of care documentation. Contact us to discuss your requirements and we will advise on the appropriate level of investigation before any work begins.

Who Commissions Decay Detection Investigations

Urban Tree Management carries out decay detection investigations for private homeowners with high-value garden trees, housing associations and local authorities with significant trees in high-footfall public spaces, historic property owners and estate managers with veteran and semi-mature trees of heritage or amenity value, schools, care homes, and healthcare estates where the duty of care context requires objective diagnostic evidence, and other arboricultural consultancies and tree surgery contractors who subcontract specialist decay detection work to us.

We are regularly called in by other arboricultural practices across the North West when this level of investigation is required. We have delivered specialist investigations at Lime Pictures in Liverpool, Nazarene Theological College in Greater Manchester, and historic estate properties across Cheshire, Lancashire, and North Wales.

Related Case Studies

FAQ

When do I need a decay detection investigation rather than a standard tree inspection?

When a visual inspection has identified signs of concern — fungal brackets, cavities, response growth, a history of failures — but cannot determine the extent or significance of the internal condition. A standard visual inspection tells you what is visible. A decay detection investigation tells you what is actually happening inside the stem.
Is the Arbotom or Resistograph invasive?

The Arbotom is completely non-invasive — the impulse sensor chain is placed around the outside of the stem with no drilling or damage to the tree. The Resistograph requires drilling a 3mm diameter hole at each assessment point — this is minimally invasive and the wound is typically compartmentalised by the tree without significant lasting effect.
Can you carry out investigations for other consultancies?

Yes — Urban Tree Management is regularly subcontracted by other arboricultural consultancies and tree surgery contractors across the North West when specialist decay detection investigation is required. Contact us to discuss subcontract rates for regular referrals.
How quickly can you attend site?

Urban Tree Management aims to arrange site visits within five to seven working days of a quote being accepted. Where a tree presents an urgent safety concern contact us directly and we will prioritise accordingly.
Is the report suitable for legal or planning purposes?

Yes — every investigation report is produced to a standard suitable for planning authority submission, insurance claims, legal proceedings, and duty of care documentation. All findings are independently reproducible.