PiCUS Report

Overview

The PiCUS test provides a cross-sectional image of the internal wood condition by measuring the velocity of sound waves as they travel through the trunk. Areas of decay, cavities or cracks are identified by slower sonic transmission, allowing arborists to assess:

• Extent and location of internal decay.
• Residual wall thickness and load-bearing capacity.
• Risk of structural failure.
• Justification for retention, pruning, bracing or removal.

It is often used in conjunction with a resistograph or visual tree assessment (VTA) to support a comprehensive tree risk appraisal.

Methodology

• Small sensors (transducers) are placed around the tree’s stem at a selected height.
• Sound pulses are transmitted between each pair of sensors.
• The system measures the transit time of the sound waves, which varies based on wood density and integrity.
• The data is converted into a tomographic image using PiCUS software, showing colour-coded zones representing solid wood, decayed wood and cavities.

PiCUS Report Contents Typically Include

• Site and tree details (species, location, condition).
• Images of the sensor setup and test area.
• Tomogram outputs (cross-sectional decay images).
• Interpretation of results by a qualified arborist.
• Conclusion and management recommendations, including whether the tree is safe to retain, requires intervention (e.g. reduction, bracing) or should be removed.

PiCUS assessments are particularly valuable for high-value or protected trees where internal decay is suspected but not visually apparent. They offer a low-impact way to support evidence-based decisions and comply with duty-of-care and health and safety obligations.