Chaucer Landscape Management

Tree Inspection and Hazard Evaluation including high-tech Sonic Tomography and Resistograph decay detection:

In broad terms, tree owners have a duty of care in both civil and criminal law to take reasonable management measures to avoid foreseeable injury or harm. Negligence (and liability for harm) would result if it could be established that a competent check would have identified an unacceptable risk of harm and resulted in remedial works that would have prevented that harm occurring.

Holding professional certification and accreditations, I provide detailed condition assessments, providing short and long term management advice for individual trees. 

Where a potential problem is identified, it can be qualified using a PiCUS Sonic Tomography and/or Resistograph test. These high-tech approaches enable many otherwise perfectly sound trees to be retained, saving the owner the cost of felling, while providing peace of mind that the legal duty of care has been satisfied. Alternatively of course it can prove that tree works are necessary to prevent injury, and inform the extent/nature of those prescriptions. 

Where outward signs of decay (e.g. bracket fungi) or features such as cracks are visible in the lower stem, high-tech Sonic Tomography and Resistograph testing can be provided to give a detailed picture of what's happening inside the tree and assess its residual strength. For each test, I provide a detailed report including results interpretation and a risk of harm assessment (failure probability) based on the  TreeCalc and QTRA tree risk assessment methodology, for which I am a registered user.

The PiCUS system sends soundwaves through the stem of the tree and presents an image showing the impedence levels presented by the wood. Sound waves travels faster through solid wood, so we can produce a tomogram of areas of potential dysfunction. Dark brown colour indicates sound wood whereas blue and white shows decay/hollowing. The maroon and green areas are often signs of incipient (progressing) decay.

The following are the results of a tree I tested at a primary school in Essex - this showed a main stem weakness at c2m and tree works were commissioned in this instance to avoid injury to pupils.


To ensure the results were correctly interpreted, I carried out Resistograph micro-drill testing to compliment the PiCUS test (shown as blue lines on the above). The Resistograph readout registers the wood density as a very narrow (3m) drill bit passes through the stem, monitoring the feed force (speed of transit) and the tortional reisitance as the bit turns. Solid wood is shown on the right of graph, but confirmed the Tomograph results after c10cm. In this case, the remaining sound wood wasn't sufficient to deliver an acceptable level of risk, but in the majority of cases I'm able to show that even quite decayed trees can be retained with an acceptable degree of safety, thus protecting our veteran trees which are hugely important for biodiversity.


Chaucer Landscape Management holds Professional Tree Inspector (PTI), Lantra certification. By observing these strict standards I’m able to provide management advice to ensure trees are maintained in optimal condition, with health and safety issues addressed and management advice provided to maximise the longevity of trees.

As a subcontractor for Hertfordshire County Council I have surveyed thousands of highways trees over the years, ensuring the Local Authority meets its stakeholder obligations, as well as optimising the health of the tree stock and safety of the public.


Here are a couple of short videos from Sorbus International Ltd showing  the PiCUS Sonic Tomograph and Resi PD400 in action on a tree - :  PiCUS Sonic Tomograph | Sorbus International Ltd. (


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Chaucer Landscape Management and Tree Consultants Kent are trading styles of Chaucer Consultancy Services Limited, Registered Company number 6486735

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