Picus Resistograph

Does your tree have internal decay/defects? Has an external inspection not reached a firm conclusion; Don’t want to fell a tree without a high degree of confidence of the necessity? Then we have just the answer; the arboreal equivalent of a CT scan. We now have the latest specialised equipment for detecting and assessing internal decay within standing trees. Our experienced arboriculturists are fully trained in its use and interpretation providing you with a confident assessment as to any tree’s present condition.

PICUS sonic tomograph. This device uses multiple sensors placed around the tree, which record the relative speed of sound waves travelling through the trunk. It produces a multi-coloured image (tomogram) of areas of denser, sound wood, and areas of decay or hollowing within the trunk. Examples of the images produced are shown below: the image on the left is of a sound trunk, while the one on the right shows extensive internal decay and hollowing.

Treetonic electrical resistance tomograph.  Similar to the sonic tomograph, this assesses the chemical and physical condition of the wood within the stem being tested, by measuring the different electrical resistance of the wood between sensors placed around the stem. This enables a more complete assessment of the tree stem at the point under investigation. The images below compare a sonic tomogram and an electrical resistance tomogram taken from the same tree. 

IML-Resi PD400 Resistograph. This instrument measures the resistance of wood to a very fine (2mm) drilling bit to a depth of 40cm. Where resistance falls, this indicates decayed wood. The device records the results as a graph which distinguishes between resistance to forward motion of the drill, and torsional drilling resistance, enabling an accurate assessment of internal wood condition. The images below show an example on which extensive decay has been recorded at 15cm depth, the right-hand end is the outer edge of the trunk; the second image shows a section of the same stem after it was felled, with the line of the resistograph trace superimposed.