Risk assessment of an oak tree

Risk assessment of an oak tree

Species: English Oak / Quercus robur
Age: approx. 130 years
Location: Lawn
Measurement: Tomogram and drilling resistance measurement on the trunk
Inspector: Dipl. Ing. Henning Schwarze

Tree inspection: Detailed examination of a “Bismarck oak”

The common oak or “Bismarck oak” was planted in 1890 in honor of the founder of the Reich, Otto von Bismarck, according to the memorial stone at the base of the tree. Due to its privileged position, the oak has formed a particularly expansive crown of about 27 metres in diameter.

The reason for the detailed inspectionis to determine potential safety hazards of the oak and to evaluate the impact of planned construction work in the tree environment.

In addition to the infestation by the hero buck beetle (Carambyx cerdo), an extensive cambium necrosis of approx. 160cm height and 80cm width with partial loss of the bark can be observed at first glance.

The goal is to determine the exact size of the defect and the remaining wall thickness by using acoustic tomography and drilling resistance measurement methods. This allows to take safety precautions in order to increase the road safety. The results of the drilling resistance measurement method can be displayed and evaluated within the IML-PD-Tools software.

Measurement results for detailed inspection

Measurement data tomograph by Dipl.-Ing. Henning Schwarze

Drilling resistance measurement & feed measurement by Dipl.-Ing. Henning Schwarze

Dipl.-Ing. Henning Schwarze – expert for the care of trees:

“The IML-RESI PowerDrill® 400 helped me during the risk assessment to determine the residual wall thickness and cavities inside the trunk that were not visible from the outside. Afterwards, the results can be evaluated with the IML software in a way that is understandable for the client and can be included in an expert report.
The RESI gives me assurance for my final conclusion in my risk assessment report and verifies the tomography results.Especially older oaks may show larger hollows during the tomography measurement, although there are only so-called “star cracks” in the wood core or in this case frass grooves”. – Dipl.-Ing. Henning Schwarze

Contact details Dipl.-Ing. Henning Schwarze

Dipl.-Ing. Henning Schwarze
Publicly appointed and sworn expert for tree care,
Traffic safety of trees and tree evaluation

Schillerstraße 8b
77154 Northeim

Phone: 05551 – 4092694
Mail: info@baumvisite.de
Website: https://www.baumvisite.de/


  • Measurement data (graphs) data tomograph, drilling resistance, feed measurement – Dipl.-Ing. Henning Schwarze www.baumvisite.de
  • Authors: Alexander Bauhuis
  • Review: Dipl.-Ing. Henning Schwarze

Author ofPosts

Author of the article:
Alexander Bauhuis

Alexander Bauhuis has been responsible for Germany-wide sales and the management of international sales partners at IML since 2018. He advises IML customers according to their needs and finds the right solution for every area of application in close cooperation with the customer. For any questions about the wood testing system - from advice to the current order - Alexander Bauhuis is your right contact.


  1. IML
  2. Dipl.-Ing. Henning Schwarze


Posted in News, Tree Inspection