PiCUS Sonic Tomography Testing In London

London Tree Surgeons has the specialised equipment and certified tomography experts required to provide advanced PiCUS Sonic Tomograph testing in London.

Tree Decay Detection: You Can’t Judge Tree Health on Looks Alone

A tree may look the picture of health on the outside, with a full canopy of leaves and solid-looking bark, yet be completely hollow or structurally compromised on the inside. For London landowners, this can present a worrying situation. How do you know if that massive London Plane tree next to the road or the Oak looming over your house is actually safe?

In the past, tree surgeons had to rely on “sounding” the tree with a mallet or, in worst-case scenarios, drilling into it to check for rot. Those days are gone. At London Tree Surgeons, we use PiCUS Sonic Tomography to inspect the inner health of your trees. Think of it as an MRI scan for your tree, allowing our consultants to look deep inside the trunk and map decay, cavities, and structural weaknesses with incredible accuracy, without harming the tree.

Using Sound to Map Decay In London Trees

The science behind PiCUS sonic tomography appears complicated, but this method of internal decay investigation is actually quite simple. The laws of physics dictate that sound travels at different speeds depending on the density of the material it passes through. Sound waves move rapidly through solid, healthy wood, but slow significantly when they encounter decayed wood, and even more so when they encounter a hollow cavity.

To perform the test, our consultants attach a series of small sensors around the circumference of the tree trunk. We then tap these sensors with a specialised hammer. The system measures exactly how long it takes for the sound wave to travel from one sensor to another across the wood.

The data is fed instantly into a laptop, which generates a full-colour cross-section image of the tree’s interior, known as a tomogram. On this map, solid wood usually shows up as dark brown or black. As wood density decreases due to fungal decay, the colours shift from green to violet, and finally to blue or white in hollow areas. This gives us a definitive “look” inside the trunk, removing the guesswork from tree safety.

Protecting People and Property in London

In a dense urban environment like London, the margin for error is nonexistent. A falling tree in a rural woodland might be part of the natural cycle; a falling tree in a London borough is a potential catastrophe involving cars, buildings, and pedestrians.

You generally need this level of advanced testing if a basic visual inspection has raised concerns. Perhaps one of our tree surveyors has spotted a fungal bracket at the base of the tree, or there is a large cavity that we can’t see the bottom of. In these cases, the PiCUS Tomograph is the best tool for determining whether the tree is safe or poses a risk to its surroundings.

PiCUS Tomograph Testing provides the hard evidence needed to determine the tree’s fate. If the scan shows the tree is solid, we can save a tree that might otherwise have been felled “just in case.” Conversely, if the scan reveals extensive internal decay that puts the tree at high risk of failure, we have scientific justification to remove it before it harms someone. This is vital for satisfying your legal “Duty of Care” as a tree owner.

Expert Interpretation Matters

Owning a PiCUS machine is one thing; knowing how to interpret the complex data it produces is another. A tomogram is only as good as the consultant reading it. At London Tree Surgeons, our certified arboricultural consultants are trained to analyse these images in the context of the whole tree.

We don’t just hand you a colourful picture and wish you luck; we combine the PiCUS data with a full visual assessment, considering wind load, tree height, and the “target” (what would be hit if the tree fell). We then provide a comprehensive report with clear recommendations, which are insured by our comprehensive £2 million Professional Indemnity insurance. Whether the recommendation is to monitor the tree, reduce the crown to relieve weight, or fell it entirely, you will know the decision is based on hard data, not just an opinion.

FAQs About PiCUS Sonic Tomograph testing

Does PiCUS testing harm the tree?

The PiCUS system is considered non-invasive. We do have to use small pins (about the size of a nail) to ensure the sensors make contact with the wood through the bark, but this causes negligible damage to the tree, far less than the old-fashioned method of drilling boreholes.

How long does a PiCUS test take?

The test duration depends on the tree’s girth. A standard test on a medium-sized tree usually takes about an hour to set up, execute, and dismantle. We can often provide a preliminary verbal assessment on-site, with the full written report following shortly thereafter.

Are PiCUS Tomography reports legally accepted?

Yes. PiCUS Tomography reports are widely recognised by Local Authorities and insurance companies as robust evidence of a tree’s structural condition. If you are dealing with a TPO (Tree Preservation Order) application for a dangerous tree, a PiCUS image showing internal decay is often considered sufficient enough evidence to obtain permission to carry out the work.

What is the difference between PiCUS testing and Resistograph testing?

Both detect hidden decay, but in different ways. PiCUS sonic tomography maps the whole cross-section of the trunk externally using sound waves, while Resistograph testing measures wood density along a single line with a fine micro-drill. We often use the Resistograph to confirm a specific area of concern that the PiCUS tomogram has identified. Our consultants will recommend the right test, or combination, for your tree.

If you are worried about a tree’s health or structural integrity, use our professional PiCUS sonic tomography testing service for definitive tree decay detection and get the facts.