TREE DIAGNOSTICS

Tree decay testing using Resistograph & Sonic Tomography

There may be occasions where advance risk assessment is required to assess the condition of the tree and there are a variety of tools available for this purpose. This may be a simple climbed inspection or a more technologically advanced solution such as a sonic tomography, resistograph to help determine wood density and strength. 

Following the initial tree assessment in situations where significant internal decay-causing organisms, cracks, holes or cavity is suspected but where external signs are limited it may be necessary to undertake further detailed inspections & internal examinations.  We are have years of experience of using all different forms of this equipment. Decay detection testing equipment falls into 2 categories, Non-invasive & Invasive.

Non-invasive decay detection

SONIC TOMOGRAPHY

Sonic tomography, where a series of sensors are placed around the tree trunk or limb. Each sensor is tapped, which sends a stress wave across the wood to the other sensors, in order to develop a detailed 2D or 3D picture of the internal condition of trees.  Sonic tomography is an impressive diagnostic tool for evaluating decay patterns and ascertain the presence, extent and significance of internal defects and possible implications for tree safety and help to inform prognosis in tree risk management. Additionally, using multiple decay detection tools, when appropriate, such as micro-drilling to corroborate findings by corresponding the results of each.

We also use additional software for determination and comparative evaluation of windload and the the safety effect of reduction prunin, stability reduction by deteriorations in trunk/branch cross-sections, tipping-stability reduction by root decay and/or trenching.

Invasive decay detection

RESISTOGRAPH

Signs and symptoms of decay, might be obvious cavities, areas of wounded tissue, or areas of response growth such as unusual ribs of wood on limbs or the trunk, or simply the presence of fungal fruiting bodies.

Next the surveyor considers how these factors might interact and decides where on the tree a reading might be taken to confirm the presence or absence of decay.

Using the Resistograph®, data can then be collected and analyzed. In some cases, drilling points will be at the sensor locations used in tomography as a means of confirming the tomogram image. Decay detection testing involving the Resistograph is used in order to measure the thickness of the residual wall of trees with internal defects such as cavities or decay invasively.