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.