The Value of Using Non-Invasive Technology for Level 3 Inspections

What benefit is there in using non-invasive diagnostic procedures during level 3 inspections? Trees can be adversely affected by the methods used to evaluate their health, particularly procedures that penetrate the bark.

  • The famous El Palo Alto Redwood Tree dates back to approximately the year 940 and is healthier today than 100 years ago. The state of California has designated this tree as its #2 landmark. The City of Palo Alto is also named after this majestic giant. In 2014 Arborist OnSite was commissioned to perform a non-invasive level 3 tree risk assessment on this heritage tree using radar imaging technology. Here Dave Dockter, City Arborist for Palo Alto and Jeremy Johnson of Arborist OnSite are performing a trunk imaging scan at a 14ft. elevation.
  • non-invasive level 3 tree risk evaluation
    Using radar technology we are creating a non-invasive image of the interior of a Live Oak tree, as part of a level 3 tree risk evaluation.
  • trunk imaging
  • trunk imaging

The establishment of decay in living trees is affected by urban environmental stresses that range from a general weakening of the tree’s natural defense system to injuries that allow wood-rotting agents to gain entry through wounds. Trees have an internal protection system that uses a series of four internal walls, all beautifully designed to block the spread of disease causing pathogens within the tree. It’s referred to as CODIT (Compartmentalization of Decay in Trees).

When invasive testing methods are used, these protective walls can be pierced, allowing decay pathogens which at one time may have been localized or contained to spread within the tree.


Case Study: Tree #830 – Acer rubrum

Location: University of Maryland Campus

Specimen exhibited significant crown dieback and likely internal decay. It was designated for removal before TRU scanning. Excellent opportunity to compare actual and virtual (TRU) sawcuts.

*Images courtesy of Taylor Keene.