Advanced Decay Detection Techniques
Looking beneath the bark: advanced decay assessment to support informed tree management. VMT used PiCUS sonic tomography alongside visual assessment to investigate internal decay and provide evidence to support the safe retention and future management of a tree in London.
The challenge: continued decline beside a busy public towpath...
A tree at a London site was showing continued crown decline and leaning towards a nearby property. Its position beside a public towpath and close to a school boathouse meant that people and property were important considerations. A previous visual tree assessment had led to recommended works being completed, but the crown continued to decline. Further investigation was needed to better understand the tree’s internal condition.
The investigation:
examining the tree’s internal condition...
VMT carried out PiCUS testing to investigate the lower trunk. The resulting tomogram provided additional evidence about internal timber condition, allowing the consultant to consider the findings alongside the tree’s visible decline, lean and surrounding land use.
The findings:
lower-trunk condition was only part of the picture...
The PiCUS results indicated that most of the lower trunk tested was sound, represented by darker colours on the tomogram. Small areas suggested early changes in timber condition, but there was little indication of significant decay in the tested section. These findings did not remove the concerns associated with the upper tree.
The recommendation:
reduce risk while retaining the tree...
Significant deadwood in the upper tree and its lean over a frequently used area remained concerns. Taking the visual assessment and PiCUS findings together, the recommendation was to reduce the tree’s height to approximately 7 metres within 12 months. The proposed pruning was intended to encourage new growth lower down and reduce overall risk while allowing the tree to remain. This was the recommended management approach; the case study does not record completion of the works or subsequent monitoring results.
Why advanced investigation matters...
This case demonstrates the value of looking beyond visible symptoms. PiCUS testing helped distinguish the condition of the lower trunk from the concerns affecting the upper tree, supporting a more informed recommendation. The value lies not in the equipment alone, but in combining the test results with arboricultural judgement and the context of the site.
Concerned about decay in a tree you manage?
Speak to VMT about arboricultural consultancy and advanced decay investigation. Our PiCUS sonic tomography and resistograph testing services can help build a clearer picture of internal timber condition and inform practical tree-management decisions.
