Arbor Australis Consulting

AQF 5 Arborist Brisbane

Brisbane | 07 3379 7793

Sunshine Coast | 0438 007 761

Diagnostic Assessment

Assessing Tree Structure

A visual arboricultural assessment of tree structure is based on experience, knowledge, and a subjective but professional appraisal. The use of diagnostic tools allows us to examine the tree, soil, and roots and collect objective data. These assessments facilitate a full appraisal of the tree where a visual tree assessment has identified tree structures of questionable integrity. These tools are often used when a tree potentially poses an unacceptable risk to property and/or people.

  • Resistograph: A fine drill that measures the density of the timber by graphing the timber’s resistance to the drill bit.
  • Picus Tomograph: An ultrasound that shows an image of the internal tree structure at the point of testing  
  • Ground Penetrating Radar: Provides a three-dimensional image of the tree’s root structure

Resistograph - for testing tree structure

The Resistograph is a way of determining tree structure at a point using a small diameter drill. The graph represents the resistance on the drill bit as it progresses into the wood. This type of diagnostic testing is only carried out when a visual tree assessment raises a concern that requires further information to ascertain the tree structure at this point.


PICUS Tomograph - for mapping decay in trees

The PICUS provides non-invasive testing of the tree structure through ultrasound technology. This specialised testing is conducted by specialists once an initial visual assessment is completed and concern is raised over a suspected fault in a tree structure. The test will produce an image of the structure, mapping the sound wood. From this data, an accurate assessment can be made about the structure at this point and recommendations made on both suitability for retention and ongoing management requirements.

Ground Penetrating Radar - for mapping roots to inform design.

Ground Penetrating Radar is used to provide accurate evidence of root presence within a survey area. This highly specialised service provides detailed images of the root structure and location. This information is used, in Arboricultural Management Plans, to guide the design process by influencing the location of excavation based on accurate root location data.

GPR Scan
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