Winter course on instrumental tree assessment

Between January 17 and February 2, 2024 Fakopp Enterprise will host free training courses on instrumental tree assessment.

  • Lecturer: Dr. Ferenc Divos, owner of Fakopp Enterprise and professor at Hungarian University of Agriculture and Life Sciences
  • Language: English
  • Duration: 1 hour each lecture
  • Time: Each lecture is presented twice a day with the same content: 9 AM and 4 PM Central European time, you are free to choose between these two
  • Cost: free, but registration is necessary


  • Registration: send an e-mail to Ms. Blanka Teleki:
  • Please include the lecture date and time: 9 AM CET or 4 PM CET

January 17

Acoustic tomography: Sound propagation in trees, possibilities and limitations

  • Mechanical waves in solids, longitudinal (p), transverse (s) and surface waves
  • Effect of anatomical orientation, radial, tangential, fiber direction
  • Single path stress wave approach, decay/cavity detection
  • 2D acoustic tomography, self-calibration, inversion algorithm
  • 3D acoustic tomography
  • Limitations: acoustic shortcut, ring shake, deep crack visualization

January 19

Acoustic tomography and biomechanics

  • Interpretation of acoustic tomographic image, biomechanical interpretation
  • Mechanical stresses in tree: compression, bending and shear
  • Wind load calculation
  • Bending stress from wind load and tree leaning
  • Compression stress from self-load
  • Safety factor calculation and interpretation

January 22

Acoustic tomography for ArborSonic3D users, new features in the software

  • Ludwig sensors
  • GPS data
  • Controlling the self-calibration algorithm
  • New warning in case of low velocities
  • Low Energy Bluetooth capabilities for new hardware
  • Limitation in the Android software

January 24

Pulling Test basics: Possibilities and limitations

  • Pulling test inclino-method for root investigation
  • Pulling test elasto-method for trunk investigation
  • Evaluating the correctness of the fit between the measured and generalized uprooting curve
  • Reasons for a poor fit (wind, loose inclinometer, too fast pulling, root failure)
  • Correction of the raw data in case of a poor fit

January 26

Pulling test: The uprooting curve

  • Importance of the root investigations, failure mode statistics: breakage of trunk versus uprooting failure
  • Principle of the pulling test
  • How many inclinometers are necessary?
  • Uprooting curve, uprooting test
  • Verification of the uprooting curve
  • Lower limit of the minimum inclination for a measurement to be meaningful
  • Upper limit of the inclination during the measurement
  • Effect of the soil moisture content on the safety factor

January 29

Acoustic root detection

  • Principle of the acoustic root detection
  • The acoustic root detection procedure
  • Velocity limit setting
  • Distance between test points
  • Visualization of the result
  • Recommended application and limitation

January 31

Dynamic version of the pulling test: DynaRoot and DynaTree

  • Pulling test limitations: static/dynamic load, anchor point availability, vertical load
  • Solution: Using wind as loading “device” and consequences
  • Requirements for sensors
  • Chaotic nature of wind and tree interaction
  • Statistical window width
  • Visualization of the test result
  • Safety factor calculation

February 2

DynaRoot and DynaTree users’ meeting to share experience

  • Case studies indicating of the importance of
    • wind direction
    • location of the anemometer
    • the minimum wind speed requirement
  • We are inviting feedback from DynaRoot/DynaTree users:
    • short user presentation about interesting/strange test result: a short PowerPoint presentation or simple explanation of the experience
    • organization of the workflow with regards to wind dependencies
    • finding good/acceptable anemometer location