Rinntech Resistograph R650 — Resistance Micro-Drilling for Internal Tree Assessment
Urban Tree Management uses the Rinntech Resistograph R650 resistance micro-drill as the confirmatory instrument in every decay detection investigation — physically measuring the condition of the wood and the thickness of the residual structural wall at each zone identified by the Arbotom sonic tomography. Completely independent from any tree surgery contractor — our findings are based entirely on the diagnostic data, with no financial interest in the outcome.
All investigations are carried out personally by Carl Riva — we do not subcontract decay detection work. You get the consultant who operated the equipment, interpreted the findings on site, and wrote the report.
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What the Rinntech Resistograph R650 Does
The Resistograph R650 is a resistance micro-drill. A very fine needle — 3mm diameter — is advanced into the stem at a precisely controlled feed rate. As the needle passes through the wood, the resistance encountered is recorded continuously and displayed as a trace — a resistance profile of the wood from the bark surface to the point of maximum penetration and back out again.
Different wood conditions produce different resistance profiles — making it possible to physically confirm the condition of the wood at any point in the stem and to measure the thickness of the residual structural wall with precision that no other instrument currently available can match.
The R650 — What Makes It Different
The Rinntech Resistograph R650 is the current-generation professional specification resistance drill — part of the same integrated Rinntech ecosystem as the Arbotom sonic tomograph and ArboRadix root plate analysis system. Key features of the R650 that directly improve the quality and defensibility of the investigation:
- Bluetooth tablet integration — resistance profile data is transferred wirelessly to a tablet in real time as the drilling progresses. No cables, no data entry errors, immediate on-site review of the trace before the needle is withdrawn.
- GPS-tagged drilling points — every drilling point is recorded with GPS coordinates, linked directly to the resistance profile. Drilling locations are precisely documented and reproducible — essential for monitoring investigations where the same points need to be reassessed at a later date.
- DECOM analysis software — professional decay analysis software processes the resistance profiles and produces graphical outputs suitable for inclusion directly in the investigation report. The DECOM analysis identifies and annotates the bark zone, structural wood zone, transition zone, decay or cavity zone, and residual wall measurement on every trace.
- Single-platform Rinntech ecosystem — the R650 operates on the same software platform as the Arbotom and ArboRadix systems. All instrument data is managed in a single environment, producing coherent integrated reports rather than outputs from multiple incompatible software packages.
Why the Resistograph Is Essential Alongside the Arbotom
The Arbotom sonic tomography system — even with the impulse sensor system at over 100 measurement points — cannot definitively confirm the condition of the wood in a zone of reduced mechanical cohesion. Reduced sound velocity can indicate decay, cracks, cavities, or ring rot. In ring rot particularly, intact wood can display as red on the tomogram because it is not contributing to bending load compensation — not because it is absent or decayed.
The Resistograph resolves this ambiguity. By drilling at the exact point the tomogram has identified as a zone of concern, the Resistograph physically confirms what is actually in that zone — and measures the thickness of the residual structural wall with precision that acoustic tomography alone cannot provide.
The residual wall is one of the most important factors in any structural tree assessment. Even where the core of a stem is severely damaged, a tree can remain structurally stable if the load-bearing residual wall is intact and of sufficient thickness. The Resistograph is the instrument that quantifies this — and the Arbotom alone cannot reliably do so.
What the Resistance Profile Shows
The Resistograph R650 produces a graphical trace — a graph of resistance against drilling depth — showing the full profile of the wood from bark to maximum penetration:
- Bark zone — the distance from the surface to the first wood contact
- Structural wood zone — high, consistent resistance indicating intact load-bearing wood
- Transition zone — where resistance begins to reduce, indicating the boundary of sound wood
- Decay or dysfunction zone — significantly reduced resistance — wood losing or has lost structural integrity
- Cavity — near-zero resistance — no wood present
- Residual wall measurement — the distance of intact structural wood between the outer surface and the inner decay or cavity boundary — the critical measurement for any structural assessment
Where We Drill
Drilling points are not placed arbitrarily. Urban Tree Management always drills at the sensor locations used in the Arbotom tomography — so that the resistance profile directly corresponds to and corroborates the tomographic findings at those exact points. The GPS-tagged drilling locations on the R650 ensure every point is precisely documented and can be relocated exactly for future reassessment visits.
This cross-validation is explicitly reported in the discussion section of every investigation report.
When the Resistograph R650 Is Used Without the Arbotom
In most investigations Urban Tree Management uses both instruments together. However there are situations where the Resistograph R650 is used as the primary or sole diagnostic instrument:
- Where acoustic tomography would produce unreliable results — frozen stems, concrete-filled cavities, or codominant stems
- Where the location of suspected decay is already well defined by visual assessment and a targeted single-point investigation is the most proportionate approach — for example where Ganoderma brackets are present at the base and the question is simply whether sufficient residual wall remains
- For branch assessments where the concern is a specific branch junction or large branch showing signs of internal dysfunction
What the Report Contains
Every Rinntech Resistograph R650 investigation report from Urban Tree Management includes:
- Visual tree assessment findings — the context for the instrumental investigation
- Full drilling methodology — drilling points, depths, GPS coordinates, corresponding tomogram zones
- DECOM resistance profiles — graphical traces for every drilling point with annotated zones
- Residual wall measurements at every drilling point
- Correlation with Arbotom tomogram findings — explicitly stated
- Discussion — what the findings mean in plain English
- Management recommendation — specific, proportionate, based entirely on the diagnostic data
- Limitations — clearly stated
The report is suitable for planning authority submission, insurance purposes, legal proceedings, and duty of care documentation.
FAQ
What is the difference between the Arbotom and the Rinntech Resistograph R650?
The Arbotom is non-invasive — the impulse sensor chain is placed around the outside of the stem producing a cross-sectional map of mechanical cohesion at over 100 measurement points with no drilling. The Rinntech Resistograph R650 is a resistance micro-drill — a very fine needle is advanced into the stem recording resistance as it passes through different wood zones. The Arbotom locates the zone of concern. The Resistograph R650 physically confirms what is in that zone and measures the thickness of the residual structural wall.
Why does the R650 use GPS-tagged drilling points?
GPS-tagged drilling points mean every drilling location is precisely documented with coordinates — essential for monitoring investigations where the same points need to be reassessed at a later date to track whether decay is progressing or stable. It also provides unambiguous documentation of where the investigation was carried out for legal, insurance, and planning purposes.
s the Resistograph R650 invasive?
The Resistograph R650 requires drilling a 3mm diameter hole at each assessment point. This is minimally invasive — the wound is small, precisely located, and is typically compartmentalised by the tree without significant lasting effect.
Can you use the Resistograph R650 without the Arbotom?
Yes — in specific situations where acoustic tomography is not appropriate or where a targeted single-point investigation is sufficient. Urban Tree Management will advise on the most appropriate combination of instruments before any investigation begins.
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. The GPS-tagged drilling points and DECOM analysis outputs provide independently reproducible, precisely documented evidence.
Rinntech Resistograph R650 Decay Detection — North West & Nationwide
Urban Tree Management uses the Rinntech Resistograph R650 to provide physical, independently reproducible confirmation of wood condition and residual wall thickness — GPS-tagged drilling points, Bluetooth tablet integration, and DECOM analysis as standard. Essential alongside Arbotom sonic tomography for a complete and defensible decay detection investigation. Independent, Level 6 qualified, completely independent from any tree surgery contractor.
Get in contact with our highly experienced and personable team of arboricultural consultants today, to discuss your requirements and to obtain your zero obligation quotation.
