The Wind-Reaction-Measurement records the dynamic sway motion of a tree in naturally occurring wind, by measuring the root plate tilt.

Advantages:
The reaction of a tree is measured directly, including all environmental influences.
These include tree specific parameters (size, form of the crown etc.), wind strength and wind exposition (buildings and other trees in the vicinity).

In contrast to this the tree pulling test (Wessolly & Erb, 1998), an established method for assessing root defects, uses an artificial wind replacement load. However, an estimate for the correlation between actually occurring natural wind and the artificial wind replacement load is rather difficult because of the previously mentioned environmental influences.

Confirmation of stability
If trees only show a small root plate tilt, even in strong wind gusts, one can assume a stable root system.

Identification of trees with root anchorage problems
After measuring tree groups comparing the results can identify trees with conspicuously large root plate tilt.

Combination with static tree pulling test with regards to stability
If a tree with increased tilt angles has been identified, it is often meaningful to follow up with a static pulling test to measure the trees reaction to a known force.

Addition to sonic tomography target PiCUS Sonic Tomographand resistance tomography
Trees with large defects in the lower stem area (with assumed root defects) should additionally have their stability tested in natural wind

Surveillance of trees near construction
Sustained changes in a tree’s tilt angle during groundworks (e.g. placing of sheet pile walls) can be detected with the PiCUS TMS.

Long term monitoring of trees
Trees suspected of having root anchorage problems can be inspected in regular intervals to check whether:

• The root plate tilt in wind decreases (tree grows new and stronger roots)
• The root plate tilt in wind increases (roots are dying off or get damaged otherwise)
• The reaction remains constant

The TMS 3 – LITE kit is for those who want to start using this innovative method of wind reaction measurement with a small investment but still using cutting-edge equipment. It offers the opportunity to test out possible applications and demonstrate the capabilities of using TreeMotion Sensors.

The LITE kit includes two PiCUS TMS 3 sensors for data recording, an induction charging bay, all accessories needed for mounting the sensors on the tree and software for the assessment of tree data. So, everything you need to conduct wind reaction measurements on one tree (using control and base sensor to monitor root plate & stem movement) or on two trees (using only one base sensor on each tree if only root plate movement needs to be monitored).

Accuracy: Inclination measurement accurate to 0.03°
Inconspicuous: Less risk of vandalism due to small sensors (61 mm x 41 mm x 20 mm)
Running time: 2 weeks + integrated charging station that can be used to charge 10 sensors wirelessly

*For successful measurement data gusts of more than 45 km/h and a measurement time of at least 2 hours are recommended.

The measuring principle:

The wind reaction measurement records the dynamic swinging movement of the tree in natural wind. The inclination of the root plate is measured.

The advantage:

The reaction of the tree is measured directly, including all environmental conditions! This includes tree properties (size, crown shape, …), the wind strength and direction, as well as the wind exposure of the tree (mainly buildings and other trees in the area). In contrast to this, in the tensile test (Wessolly & amp; Erb, 1998), which is a tried and tested method for assessing defects in the root area, an artificially generated wind substitute load is introduced into the tree. The relation to the actually occurring natural wind is difficult to estimate because of the environmental effects mentioned above.

Technical details

Most important software features

• Presentation of the raw measurement data (inclination value and direction)
• Function for the identification and analysis of inclination events
• Direct comparison of the inclination measurement values ​​of different PiCUS TMS (typ. basic and control sensor on the same tree)
• Automatic data evaluation and generation of the wind slope curve

PiCUS TMS 3 specific

• App for controlling the PiCUS TMS 3:
  • Status display
  • Entry of tree data to start a measurement
  • Live measurement mode

• Extension of the PC program:
  • Automatic reading of the measurement data from the PiCUS TMS 3
  • Automatic structuring of all inclination and wind measurement data according to projects (database)
  • Direct comparison of the inclination measurements of all PiCUS TMS 3 (which were attached to the same tree)
  • Direct comparison of the wind inclination curves of different trees
  • Automatic reading and processing of wind measurement data (recorded by the optionally available TMS wind measurement system)

*NOTE – Wind data needed separately, wind stations available for direct measuring onsite or website like www.windfinder.com can be useful for local weather data.