Measurement system for pulling tests on trees

The tree pulling test is performed to get information about the breaking stability of the trunk and the stability of the roots. It is used to assess a tree’s stability with regard to stem fracture and uprooting precisely and non-invasively.

In a pulling test, a load (substituting for the wind) is exerted on a tree using a winch and a steel cable. The reaction of the stressed tree under this defined load is measured with high resolution devices (elastometer and inclinometer), and the data obtained are compared with those of sound trees. The major components to be considered in such calculations are the wind-load (the surface of the load-bearing structure, tree height, etc.) and the material properties of green wood.

The TreeQinetic System is designed to collect data during tree pulling tests. The complete system consists of at least:

One Forcemeter that measures the pulling force.
At least one Elastometer that measures alterations in length of the marginal fibres
At least one Inclinometer that measures the inclination of the tree.
Evaluation software ArboStat (http://www.tree-consult.org/)

Advantages

• Easy, wireless measurement and continuous data transmission
• User can calculate results autonomously using the ArboStat software supplied  by http://www.tree-consult.org/
• Easy-to-understand graphical results
• Direct information about the breaking stability of the stem
• Direct information about the stability of the root system

The tree pulling test was developed by WESSOLLY and SINN at the University of Stuttgart in the mid 1980’s.

Specifications of the TreeQinetic Components

Elastometer

Resolution: 0,1 µm
Measuring range: +/- 2 mm
Accu capacity: ~ 20 h bei 20°C (radio on)

TreeQinetic Elastometer @ work

Inclinometer

Resolution: 0,005°
Accuracy: 0,005°
Measuring range: +/- 15°
Accu capacity: ~ 20 h bei 20°C (radio on)

        

TreeQinetic Inclinometer @ work

Forcemeter

Resolution: 0,1 kN
Measuring range: 0 – 40 kN
Accu capacity: ~ 20 h bei 20°C (radio on)

TreeQinetic Forcemeter @ work

Anemometer

One further option of the TQ system is the “dynamic wind sway motion logging” function. This requires a wind-meter (anemometer) to measure wind speed. At present we can only record the sway motion (inclination of root plate and strain of marginal fibres and wind speed). It is not yet possible to obtain direct stability information from this data. 

Resolution wind speed: 0,1 m/s
Measuring range wind speed: 0 – 30 m/s
Resolution Wind direction:  16 Windrichtungen (22,5°)
Measuring range Wind direction:  360°
Accu capacity: ~ 10h

        

Communication Unit

Accu capacity: ~ 20 – 40 h (depending on connection to PC (Bluetooth or USB))

TreeQinetic Measuring Case

Producing Area:Germany