Tree Decay Detection.
Evidence Before Tree Work.

Tree decay detection is specialist arboricultural investigation used when visual inspection leaves an important question about internal wood condition, cavities, structural roots or another defect. The method should be selected to answer that specific uncertainty.

Advanced testing may help where a cavity, fungal fruiting body, wound, previous failure, unusual response growth or another feature raises a structural question that cannot be resolved confidently by visual assessment alone.

No. A cavity does not automatically mean advanced testing is necessary. The first step is to assess the tree, defect, target and management decision, then choose further testing only if it is likely to add useful evidence.

Sonic tomography is a non-invasive diagnostic method that measures stress-wave travel between sensors positioned around a tree stem or branch. Software uses those measurements to construct a cross-sectional image of zones with different sound-transmission characteristics.

Arbotom tomography measures how stress waves travel through the tested cross-section. Reduced transmission can be associated with decay, cavities, cracks or other structural features, so the tomogram is evidence to interpret rather than a literal photograph of decay.

No. Colour zones represent the software interpretation of sound-transmission behaviour. Management decisions must consider the whole tree, residual functional wood, defect geometry, targets, species, loading and adaptive growth.

The acoustic tomography stage is generally treated as non-invasive because the diagnostic assessment does not require drilling a test path through the cross-section. Correct sensor attachment and measurement are still important.

No diagnostic method detects every defect equally well. Geometry, cracks, cavities, species characteristics, test height and sensor layout can affect interpretation. Testing should be selected and interpreted by an experienced consultant.

Yes, repeat testing can sometimes help monitor change over time, provided the test level, geometry and measurement positions are documented carefully enough to make comparison meaningful.

Resistograph testing uses a fine drilling needle to record changes in resistance as it passes through wood. The trace can help investigate decay, cavities and changes in wood condition along that particular drilling line.

It is minimally invasive because a fine needle penetrates the wood. The number and position of drilling paths should therefore be targeted to the question being investigated rather than used indiscriminately.

Sonic tomography assesses a cross-section through acoustic measurements, while a Resistograph gives detailed information along selected drilling paths. They answer different questions and can sometimes be used together.

No. The diagnostic method should match the defect and management question. Some trees may need only one method, while others may benefit from complementary testing.

Residual wall thickness describes remaining sound or mechanically functional wood around a cavity or degraded zone. It can be useful, but it should not be treated as a universal pass/fail number for every tree.

No test can guarantee that a living tree will never fail. Diagnostic testing reduces uncertainty and supports a professional management decision within the limitations of the method and inspection.

Testing can identify or help quantify structural concerns, but the conclusion still depends on the defect, tree form, target, exposure, adaptive growth and other evidence.

Some fungal fruiting bodies can be associated with wood decay, but significance depends on fungal identity, host species, location and tree condition. Fungal presence can be a reason for closer assessment rather than a conclusion by itself.

Fungal features observed during inspection can be recorded and interpreted within the arboricultural assessment. Where identification is uncertain or critical, more specialist mycological input may be appropriate.

A visual tree assessment examines form, crown, stem, unions, root collar, visible defects, fungal features and site context. It is normally the starting point before advanced diagnostic testing is considered.

The instrument does not decide where to test or what the result means. Visual assessment identifies the defect, relevant test plane and management question the diagnostic method is intended to answer.

Yes. Better information can sometimes show that a tree with an alarming external feature still has enough functional structure for retention or proportionate management rather than precautionary removal.

Yes, where combined evidence shows the defect is significant and the risk cannot be managed acceptably by retention, monitoring or proportionate work. The recommendation should follow the evidence.

Potentially. Where a protected tree has a disputed structural defect, diagnostic evidence can help explain internal condition and support the arboricultural reasoning behind proposed work. The Local Planning Authority still determines the application.

Yes. Specialist evidence can support professional advice where tree condition is relevant, but the statutory notice or TPO process still needs to be followed where applicable.

Yes. On development sites, diagnostic testing can help resolve uncertainty about the condition and realistic retention of important trees, improving evidence available to the design team and planning authority.

Sometimes. If a property report identifies a genuine structural tree concern that cannot be resolved visually, targeted diagnostic testing may add evidence. It should not be added automatically to every property instruction.

Yes. Schools, estates, hospitals, commercial sites and other duty holders may commission specialist testing for significant trees where a visual inspection has identified a defect needing closer investigation.

Tree owners and duty holders are generally expected to take reasonable care in managing foreseeable risks from trees. The standard is not a guarantee of absolute safety; proportionate inspection and action are important.

No. Proportionate tree risk management does not mean advanced testing every tree. Specialist diagnostics are appropriate where competent inspection identifies a specific uncertainty that matters to the management decision.

Air Spade investigation uses compressed air to move soil from around roots with less mechanical disturbance than conventional excavation. It can help expose root collars, structural roots or soil/root relationships where below-ground investigation is justified.

No. It is a method of exposing soil and roots for direct inspection. It can complement structural assessment where root condition or root-collar defects need to be seen.

Tree vitality testing provides physiological information about how a tree is functioning. It addresses a different question from structural decay testing and should be used where physiological condition matters to management.

No. A vigorous tree can still have a structural defect, and a physiologically stressed tree is not automatically unsafe. Structural condition and physiological condition are distinct.

Yes, subject to the site, defect and appropriate method. Diagnostic evidence can be particularly valuable where a high-value tree has heritage or amenity significance and unnecessary removal should be avoided.

Yes, where the chosen equipment and sensor configuration are suitable. Larger or irregular stems may require careful measurement, sensor placement and interpretation.

Some diagnostic techniques can be used at branches, unions or other accessible parts of a tree where the defect and safe working method justify it. The scope should be agreed from the actual concern.

The agreed output can include site observations, photographs, diagnostic plots or tomograms, interpretation, limitations and management recommendations. Report format depends on the client and purpose.

Where those methods are used and the reporting scope includes them, relevant diagnostic outputs can be included or referenced so the conclusion is linked to the underlying evidence.

Fees depend on tree numbers, diagnostic method, tree size, access, testing locations, reporting needs and whether specialist access or additional methods are required. Arbor Cultural provides a fixed-fee proposal after reviewing the scope.

Site time varies with tree size, geometry, number of test levels and diagnostic method. Reporting time also depends on complexity of interpretation. Include any genuine deadline with the enquiry.

Send the site address or postcode, clear photographs of the whole tree and area of concern, any existing tree report or council request, and explain what decision the testing needs to support.

Not always. However, if another arboriculturist has recommended advanced testing, sending that report is very useful because it explains the defect and question the diagnostic work is intended to answer.

Specialist diagnostic work can be scoped as a technical input to another consultant wider instruction where roles, reporting and interpretation are agreed clearly.

Arbor Cultural provides expert arboricultural services. Where decay testing forms part of a legal or disputed matter, the scope and evidential requirements should be agreed specifically rather than treating a standard diagnostic report as expert evidence automatically.

Yes. Arbor Cultural provides tree decay detection across Greater London, Surrey, West Sussex, East Sussex, Kent, Hampshire, Berkshire, Buckinghamshire and Oxfordshire, subject to project scope.