Rinntech DynaTim — Static Pull Testing & ASR Analysis
Urban Tree Management carries out static tree pull testing using the Rinntech DynaTim system — providing quantified safety assessments for uprooting and stem fracture, with ASR wind-load-independent analysis included as standard in every report. Completely independent from any tree surgery contractor.
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Tree Stability Testing
What Is Static Pull Testing?
A controlled, measurable load is applied to the tree using a hand winch and rigging line at a measured height. The Rinntech DynaTim system records two parameters continuously:
Stem inclination at the base — high-precision inclinometers measure root plate movement to one-thousandth of a degree, producing a tipping curve showing the relationship between applied load and base inclination.
Fibre strain at the stem — an elastometer measures longitudinal strain in the outer wood fibres, allowing fracture safety to be assessed alongside uprooting safety.
Established research demonstrates that the load required to incline a stable tree to 0.25° at the base equates to approximately 40% of the load required for actual failure — allowing safe extrapolation to the calculated failure load without ever loading the tree near its failure point.
Wind-Load-Independent Analysis
Most pull test reports calculate a safety factor based on an estimated wind load — and that estimate carries unavoidable error. Urban Tree Management includes ASR — Allometric Self-Referencing — analysis as standard alongside the conventional assessment in every pull test report.
ASR compares stem inclination at the base against stem inclination at the upper trunk under the same controlled load — producing a stability assessment that does not rely on any wind load assumption. The result is a second, methodologically independent line of evidence. Where both agree the conclusion is doubly defensible. ASR is used by very few UK consultancies and is included at no extra cost.
Crown Reduction Modelling
Once the tree's response has been measured the DynaTim data can model the effect of a proposed crown reduction on stability — quantifying exactly what level of reduction would bring the safety factor to an acceptable level. This often supports retention rather than removal.
When Static Pull Testing Is Not Appropriate
Confirmed root plate decay — where Meripilus, Kretzschmaria, or advanced Ganoderma is present, applying a pull test load risks triggering failure. These cases require PiCUS dynamic monitoring instead.
No suitable anchor point — where site conditions prevent rigging, dynamic monitoring is used instead.
Veteran trees where artificial loading is prohibited — Urban Tree Management checks this before any investigation begins.
What the Report Contains
- Visual tree assessment
- Pre-test inspection confirming pull testing was appropriate
- Methodology — equipment, rigging geometry, calibration
- Tipping curve plot
- Uprooting safety factor
- Fracture safety factor
- ASR wind-load-independent analysis
- Crown reduction modelling where requested
- Management recommendation
- Limitations
Suitable for planning, insurance, legal proceedings, and duty of care documentation.
FAQ
Is the pull test damaging to the tree?
No. The test applies approximately 40% of the load required for actual failure. The tree is not stressed beyond a safe threshold.
What is ASR and why is it included?
ASR produces a stability assessment that does not rely on any wind load assumption — a second methodologically independent line of evidence. Included at no extra cost.
Can the pull test model a proposed crown reduction?
Yes — the data models exactly what level of reduction would bring the safety factor to an acceptable level.
How long does it take?
Three to four hours on site for a two-person team. Reports delivered within ten working days.
Rinntech DynaTim Static Pull Testing — North West & Nationwide
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.
