PiCUS Tree Motion Sensor 3
The Wind-Reaction-Measurement with PiCUS TMS is used for in depth tree inspections to obtain information about a tree’s stability, defined by its root anchoring force in the ground.
PiCUS TMS 3 – consistently innovative
Bluetooth-communication – control via mobile phone
New inclination measurement – quick and simple installation
Small and stealthy – Even you will have trouble finding it!
Wind-Reaction-Measurement – the method
The Wind-Reaction-Measurement records the dynamic sway motion of a tree in naturally occurring wind, by measuring the root plate tilt.
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.
Typical applications for Wind-Reaction-Measurements
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 (TreeQinetic) 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 (PiCUS Sonic Tomograph) and resistance tomography (TreeTronic3)
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
Technical data of the PiCUS TMS Systems
|Parameter||PiCUS TMS 3||PiCUS TMS|
|weight||73 g||270 g|
|dimensions||61 mm x 41 mm x 20 mm||100 mm x 80 mm x 75 mm|
|protection||Completely sealed against water and dust||Protected against rain and dust|
|min. livetime||5 years||5 years|
|Accuracy tilt measurement||0,03 °||0,03 °|
|Measurement interval||0,05 s (20 Hz)||0,05 s (20 Hz)|
|Type of tilt measurement||3D measurement||2D measurement|
|Accuracy temperature measurement||1 °C||1 °C|
|Temperature range||-20 – +50 °C||-20 – +50 °C|
|Battery capacity and runtime||250 mAh; > 14 days||2900 mAh; > 20 days|
|Charging||wireless||Micro USB cable|
|Charge duration||approx. 2 h||approx. 6 h|
|recommended charging temperature||5 – 35 °C||5 – 35 °C|
|Memory type||MicroSD memory card|
|Memory size||256 MB||Up to 32 GB|
|Memory runtime||20 days||> 130 days (1 GB memory card)|
|Standby- and measuring mode||Bluetooth Low Energy 4.0||Micro USB cable|
|Data download||Bluetooth Classic 2.1||MicroSD card reader|
|TMS power on||Magnetic key||Electrical switch|
BLE-capable mobile phone (Android, iOS)
+ TMS 3 App
|Data download and analysis||
PC with Bluetooth Classic
+ TMS 3 Control software (direct sensor interaction)
MicroSD card reader
+ TMS PC software
|Power supply||230 V AC, 50 Hz (adaptor)||230 V AC, 50 Hz (adaptor)|
|Number of TMS-chargers||10 (wireless charge bays)||10 (MicroUSB cable charger)|
|Maximum number of TMS||20||20|
|weight, filled (screws, cables, 10 TMS)||5,5 kg||11 kg|
|Maße||48 cm x 35 cm x 15 cm||60 cm x 45 cm x 17 cm|
Important software features:
- Visualisation of raw data (tilt angle and direction)
- functions for identifying and analysing of tilt events
- direct comparison of tilt values from different PiCUS TMS (typically base and control sensor on the same tree)
- Automated data analysis and Wind Tipping Curve calculation
PiCUS TMS 3 only
- App for PiCUS TMS 3 control:
- Status display
- Input of tree data in preparation of a measurement
- Live-measurement mode
- Extension of the PC program:
- Automated read out of PiCUS TMS 3 measurement data
- Automated structuring of all tilt and wind speed data by project (data base creation)
- Direct comparison of all PiCUS TMS 3 measured tilt values (on the same tree)
- Direct comparison of Wind Tipping Curves from different trees
- Automated read in and processing of wind measurement data (recorded with TMS Wind Measurement System)
Application of Tree Motion Sensors
Wind causes tilting of the root plate and bending in the tree’s trunk.
The PiCUS TMS are inclinometer which dynamically log changes in root plate tilt over hours, days or even weeks.
- Wind gust speeds > 45 km/h
Implementation of measurements:
- Mount sensors before a wind event, end measurement after the wind calmed down (minimum measurement duration 2h)
2 PiCUS TMS per tree:
base sensor on the trunk base – direct measurement of root plate tilt
control Sensor in 2-3m height – for filtering out ambient noise sources (e.g. road traffic) and for identifying actual wind events
- Comfortable analysis in your office, minimized on site time
If the base sensor shows tilt while the control sensor doesn’t, it is ambient noise.
On an actual wind event the value of the control sensor has to be higher than the base sensors, because the upper sensor not only measures the root plate tilt but also the superimposed bending of the tree trunk.
Analysis and interpretation of measurement data
The included PC software creates diagrams showing the relationship between wind speed and root plate tilt - the Wind Tipping Curve. Wind speed can be measured either on site (TMS Wind Measurement System) or it can be read and added manually from external sources (eg.windfinder.com).
The ability to extrapolate tilt, for wind gust speeds 10 to 20 km/h above the ones measured, allows predicting the tree’s performance at said wind speeds.
Below are wind tipping curves from three Douglas fir measured during hurricane Xaver (wind speeds of up to 93 km/h, measured by a weather station approx. 9 km away).
The red curve is from a Douglas fir which has both a large defect in the trunk base and strong root swellings (see PiCUS sonic tomogram). The other two curves are from neighbouring trees without defects in the trunk base. It can be seen that the Douglas fir with defect shows even less root plate tilt than the reference trees.
The Douglas fir reacted to the internal defect by growing stronger roots.
Comparative analysis of grouped trees
All trees in an alley of acer were fitted with PiCUS TMS. This allows fast and simultaneous testing of all trees with little effort. The comparing analysis identified trees that show unusually high tilt values, compared to others in the same group.
In a direct comparison of the Wind Tipping Curves it is clearly shown that acer 5 has a significantly higher tilt compared to the other four. Therefore, this tree should be inspected much more thoroughly (with other commonly used methods)
Single Tree analysis
The tomogram shows a large defect in the trunk base (tilia with Kretzschmaria deusta).
Point 1 – Root plate tilt in wind speeds > 90 km/h already 0,7° (defoliated)
Point 2 – tilt extrapolation for a wind speed of 110 km/h: 1,4°
The Kretzschmaria deusta already affects the root stability of the tilia. According to the Generalized Wind Tipping Curve (by Sinn / Wessolly / Erb 1998) a tree pulled to a tilt of 2-4° will fall down without further increasing the applied force (uprooting force). Therefore, the tilia will not yet tip in wind speeds of 110 km/h.
To work with the new TMS 3 sensors it is necessary to download the associated App from the app store. Please click on dedicated store button or scan QR Code below.