• EN1991 Biomechanics in Pulling-test v1.8

    Today we release Pulling-test v1.8 with support for EN1991 based biomechanics. The new version is available form our Downloads page.


    Download PDF manual for using the new EN1991 biomechanics.

    Video demonstration


  • Bluetooth on Windows 11

    We have received several reports from our users telling us that they cannot pair their ArborSonic3D with a Windows 11 PC.

    The reason behind this is that Windows 11 has introduced a new Bluetooth setting that, on its default setting, prevents the pairing of classic Bluetooth devices.

    To resolve this issue, please upgrade to ArborSonic3D 5.3.161: download the update from our Downloads section.

    If, for some reason, you cannot perform the upgrade, follow these steps to resolve the issue manually:

    1. Select Start, then type settings.
    2. Select Settings Bluetooth & devices
    3. Scroll down and make sure that Bluetooth Devices Discovery is set to Advanced
    4. After this ArborSonic3D should show up during pairing

  • 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


  • Wind direction dependency in Dynamic root testing

    The encircled Eucalyptus sp. tree was tested over several days at high wind velocity during February 2022 with DynaRoot dynamic root testing system. The tree is approximately 17 meters tall and has a diamater of 44 cm at breast height. The measurements were conducted in the United Kingdoms by Mr. James Chambers, Tim Moya Asssociates.

    Eucalyptus sp.


    The image on the left shows the satellite image of the surrounding area of the measured tree. The red cross indicates the tree in question, while the yellow cross indicates the location of the wind anemometer. It is clearly visible that the tree is protected from the wind from the south, southwest and southeast by several large buildings, while completely exposed to the wind in any other direction.


    Datemax. wind speed
    wind direction
    Safety Factorcorrelation
    Oct. 27843400.940.95
    Feb. 18/11132083.960.94
    Feb. 18/21192600.960.95
    Feb. 18/3532431.240.72
    Feb. 19/1722591.10.82
    Feb. 19/2682212.890.76
    Feb. 20722152.890.72
    Feb. 20/1942810.920.85
    Feb. 20/2503070.840.68

    The table above shows the measured speed and the direction of the wind, with the corresponding Safety Factor calculated by the software. The results show that from protected directions (S,SW,SE) the Safety Factor is significantly higher. From unprotected directions (West ~ 260°, NW ~ 340°) the Safety Factor is below 1 which is deemed unsafe by the software. On the right the arrows indicate some of the wind directions.

    The graph shows that after the change in wind direction (red line) the inclination measured on the tree became significantly higher.


    Ultimately as the gathered data shows, the results of DynaRoot is highly influenced by wind direction. It is extremely important to always take the wind direction into consideration when evaluating DynaTree measurements. When a high Safety Factor is due to the tree being shielded from the wind (by other trees, buildings), it is recommended to repeat the measurement in unobstructed wind.

  • Pulling test: The effect of cut roots on safety factor

    A brief case study by Tibor Horvath with Fakopp Pulling Test


    • The measured tree stood in a suburban garden and has been marked for removal.
    • The removal has been turned into a series of 6 pulling tests. First we measured the tree in its original state, then before every additional pulling test some of roots have been cut.
    • For the calculation of the safety factors, the wind speed of 33 m/s (cc. 120 km/h) has been used.
    • The purpose of the experiment was to reveal the effect of cut roots on the safety factor.

    Safety factor measurements

    Intact: 1.19

    Excavated: 0.86

    1 root cut: 0.61

    4 roots: 0.33

    7 roots: 0.27

    All 11 roots: 0.14


  • Ludwig sensor test of a Platanus occidentalis

    A Platanus occidentalis tree has been selected for examination in a botanical garden (Sopron, Hungary). First the measurement has been conducted with 12 regular sensors and then with an additional 12 Ludwig sensors.

    The first measurement using 12 regular sensors shows a decayed area in the middle (about 40%).

    The second measurement with additional Ludwig sensors shows a decayed area in the middle (about 32%), and also a strengthened area on the side near sensors 9-12.

    The tree suffered a freeze injury several years ago. This is exactly the part where the strengthened wood has been found.