BS 5837 Tree Survey
Tree Decay Detection
Whether you manage a veteran oak on a private estate or a lime avenue flanking a busy highway, TMA’s decay-detection service provides the evidence to balance public safety with tree retention, keeping landscapes safe, legally compliant and environmentally rich.
Tree decay testing using PiCUS Tomography
In-depth tree risk decisions rely on looking inside a stem, not just at its bark. Modern tree-decay detection pairs non-invasive imaging like PiCUS tomography with targeted micro-drilling, giving tree owners a clear picture of hidden cavities, fungal degradation and structural weakness before failure occurs.
How decay detection fits within risk assessment
After a visual survey highlights suspect features (e.g., cavities, fungal brackets or cracks), further investigation quantifies strength loss so that duty-of-care actions are proportionate rather than precautionary. The tools fall into two broad categories—non-invasive and minimally invasive—each selected according to species, stem size and site constraints.
Why work with us
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Decades of practical experience deploying both non-invasive and invasive systems ensures the right tool— and only the necessary tool— is used.
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Integrated workflow: results feed directly into our Quantified Tree Risk Assessments (QTRA), giving you auditable risk values alongside remediation options.
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Digital reporting: MyTrees links every reading to GPS coordinates and attaches tomography or drill-trace images, creating a single, defensible record planners and insurers recognise.
Decay Detection Tool
PiCUS Tomography
Thermal (infra-red) imaging
Ground-penetrating radar (GPR)
What it does
Typical use-case
Sensors placed around the stem transmit sound waves; software reconstructs a colour image showing intact wood (green) versus decayed or hollow zones (red).
Large amenity trees where excavation or drilling is undesirable.
Detects temperature differentials that reveal sap-flow disruption, decay pockets or bark injuries long before they are visible.
Rapid screening of tree populations.
Sends radio waves through trunk or soil; reflections map internal voids and major roots without excavation.
Assessing below-ground buttress roots near utilities or hard surfacing.
Resistograph® micro-drill
A 1.5 mm bit measures drilling resistance; sudden drops indicate decay or cavities, while high resistance marks intact wood.
Verifying the residual wall thickness on high-value trees identified as borderline by non-invasive scans.
Why do we measure tree decay?
Internal wood decay is often invisible from the ground, yet it can critically weaken a stem long before external symptoms appear. Using objective tools such as sonic tomography or Resistograph® micro-drilling lets arboricultural specialists quantify the extent and location of cavities, fungi and structural loss, supplying hard evidence for proportionate tree-risk decisions. This evidence base helps landowners meet their legal duty of care, avoid unnecessary felling and target budgets where they deliver the greatest safety return.
When decay-detection data adds value
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Risk management of individual trees — converts hidden defects into clear insights that align with QTRA or similar frameworks.
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Tree Preservation Order (TPO) evidence — provides the robust structural data local authorities require when considering works on protected trees.
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Veteran and ancient tree management.
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Baseline for monitoring progressive decay — repeat tests track deterioration over time and inform tree maintenance budgets.
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Insurance and duty-of-care compliance — documents the tree’s structural condition, satisfying insurers and demonstrating proactive management.
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Pinpoints sound wood, allowing targeted pruning instead of wholesale removal and preserving canopy value.
Non-invasive decay detection
Bedford Estates, London
Bedford Estates have 3 large squares, smaller gardens and individual properties in Bloomsbury. TMA have been employed to manage the estates trees since August 2016. We provide tree risk assessment, ecological bat and bird assessment in relation to trees, contract management services, tree work auditing and PiCUS and resistograph testing and reports.
During our PiCUS tomography assessment, we placed a series of sensors around the tree trunk. Each sensor was tapped, sending a stress wave across the wood to the other sensors, in order to develop a detailed 2D and 3D picture of the internal condition of tree. Additionally, we utilised micro-drilling (RESI Power Drill) to corroborate findings.
TMA have both sets of equipment and bring them at no extra cost to the customer, enabling us to provide reports with detailed information to safely manage decayed trees.
Invasive decay detection
PROJECT NAME
Typical warning signs of tree decay include open cavities, patches of missing or wounded bark, swollen “ribs”, reaction wood on limbs or the main stem, and external fungal fruiting bodies emerging from the trunk, buttress or root zone.
RESI Power Drill testing involves measuring the levels of resistance to drilling by passing a very fine drill through the wood to determine its consistency. The results show high peaks and low peaks for relatively high and low resistance. Decayed wood normally has lower resistance to drilling.
The RESI PD can be used to confirm PiCUS test results or to test areas where the PiCUS is not suitable, such as buttress roots or small trees.
1. BS5837 Tree Surveys for Planning
Primary audience: developers, architects, homeowners, planning consultants
High-value keywords:
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BS5837 tree survey
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tree survey for planning
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arboricultural report for planning
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tree survey planning application
Example URL
/bs5837-tree-surveys
This is usually the biggest traffic driver for UK consultancies.
2. Tree Surveys & Inspections
Primary audience: estates, landowners, councils, organisations
High-value keywords:
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tree survey
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tree inspection
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tree condition survey
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tree risk assessment
Example URL
/tree-surveys-inspections
This captures ongoing management work rather than development.
3. Arboricultural Impact Assessments (AIA)
Many developers search directly for this, not just BS5837.
High-value keywords
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arboricultural impact assessment
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AIA report
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arboricultural planning report
Example URL
/arboricultural-impact-assessment
This page often ranks for technical planning searches used by architects and planners.
4. Tree Risk Management
Very important for estates, councils, schools, golf courses, utilities, and infrastructure.
High-value keywords
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tree risk assessment
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tree safety inspection
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duty of care tree inspection
Example URL
/tree-risk-management
This attracts long-term contracts and repeat work.
5. Veteran & Ancient Tree Management
This is a high authority niche and aligns with consultancy expertise.
High-value keywords
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veteran tree assessment
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ancient tree management
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veteran tree survey
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tree conservation consultancy
Example URL
/veteran-tree-management
It positions your firm as specialists rather than generalists.
The Ideal SEO Structure for TMA
/services
/bs5837-tree-surveys
/tree-surveys-inspections
/arboricultural-impact-assessment
/tree-risk-management
/veteran-tree-management
These pages together target the majority of commercial arboricultural search demand in the UK.
One Page That Gives a Big Competitive Advantage
Many consultancies miss this:
/tree-constraints-planning
Target keywords:
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tree constraints plan
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arboricultural constraints plan
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tree constraints planning
Architects search this a lot.