In some cases specialist decay detection equipment may be useful in determining tree stability and management options.
The PiCUS 3 Sonic Tomograph and PD400 Resistograph enables an accurate assessment of internal decay patterns. With this detailed information we can provide the most appropriate and cost effective management recommendations.
PiCUS Sonic Tomograph
In 2003 we were one of the first companies in the UK to purchase the PiCUS Sonic Tomograph. Over 17 years and nearly 1000 tests this non-invasive diagnostic tool has proved invaluable in making informed decisions regarding tree safety and has enabled the retention of many important trees that may otherwise have been removed.
The PICUS 3 measures the time taken for sonic stress waves to pass through the wood of a tree between sensors that are placed around the tree stem. The differing velocities of these waves help determine the wood density of a cross-section of the tree (sound waves generally travel faster through sound wood than through decayed wood). These velocities are then calculated and interpreted to produce a colour image of the internal decay patterns.
Resistograph
To complement the PiCUS system, we use an IML PD400 digital wood inspection micro drill, more commonly referred to as a Resistograph. This instrument is slightly more invasive and is generally only used where confirmation of very extensive decay is required or for aerial inspections where use of the PiCUS is not possible.
This system is based on the principle of measuring the drilling resistance of wood. A very fine needle is driven into wood and the energy required along the drilling path is measured and presented as a digital line graph. As the drill moves forward through the wood it may encounter variable degrees of resistance depending on wood density. These variations are highlighted on the line graph and are interpreted to provide an assessment of the ratio of sound wood to decayed wood.
