Internal Decay Detection Tools
In certain situations, a tree’s condition or structural integrity cannot be fully understood through visual inspection alone. Where concerns exist, further investigation may be required to provide accurate, reliable information on which management or safety decisions can be based.
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Jason Bellenger Tree Surveys offers specialist internal tree assessment using advanced arboricultural diagnostic equipment, including tomographic imaging and resistograph testing. These tools allow the internal structure of a tree to be assessed and measured, providing objective data on the presence, extent, and significance of internal decay or defects.
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This evidence-led approach supports clear, proportionate decision-making, helping to avoid unnecessary removal while ensuring public safety and responsible tree management. Assessments are carried out in the context of the tree’s characteristics, site conditions, and intended use of the surrounding area.
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Further details on the specific equipment and methods used are available below.
IML- RESI PD 400 Resistograph
The Resistograph is a specialist diagnostic tool used to assess the presence and extent of internal decay or structural defects within trees. It works by measuring the resistance of the wood as a fine probe is inserted into the stem.
The device uses a very narrow drill probe (approximately 1.1 mm in diameter) which is driven into the tree to a controlled depth of up to 400 mm. As the probe advances, the resistance encountered is continuously recorded and displayed as a graph.
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Variations in resistance provide clear, measurable data on internal wood condition, allowing areas of decay, cavities, cracks, or compromised wood to be accurately identified and assessed. The minimal probe size ensures the test is low-impact, while providing valuable structural information to support informed management and safety decisions.
Arborsonic 3D Sonic Tomography
The Arborsonic 3D Sonic Tomograph is a non-invasive diagnostic system used to identify internal defects such as hollows, decay, or areas of compromised wood within a tree stem.
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The system works by measuring the speed of sound waves as they pass through the tree. Sensors are positioned at multiple points around the trunk, transmitting and receiving sound waves across
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the stem. Because sound travels more slowly through decayed or weakened wood than through solid wood, variations in sound velocity can be accurately measured.
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Using these measurements, specialist software generates a two-dimensional cross-sectional image of the tree, highlighting areas of differing internal condition. Colour mapping is used to indicate relative wood density, with higher-density, sound wood shown separately from areas of lower density associated with decay or structural weakness.
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Sonic tomography provides valuable information on internal wood density and structural integrity, allowing a more accurate assessment of a tree’s stability and supporting informed, proportionate management decisions.