Smart load sensor to test strength of tree roots

Highway engineers and horticulturalists have adapted the latest in helicopter technology to solve a safety problem in their own industries, namely tree viability. Trees present a potential hazard in that if they fall, they could block a highway or even kill someone. As a result, professionals responsible for trees like to test the strength of the tree roots, usually by fixing a sling around the trunk and pulling with a tractor!

Tony Ingham of Sensor Technology, who has been working on ways to improve the technique, states: "This procedure lacks some finesse. The basic idea is to put a strain gauge in line with the sling, then convert the readout from Newtons to a wind speed equivalent. This is perfectly achievable, but the concept needs refining to make it attractive enough to become widely adopted."

Tractor crews will not want to spend time setting up instruments, taking readings, recording them and then making complex calculations. If they cannot rope up a tree, pull it and move onto the next one in a matter of minutes, they will not be interested.

Smart load sensor

Sensor Technology realised that they had the solution to this problem with its LoadSense smart load sensor with wireless communications. Ingham continues: "This is actually an intelligent cargo hook for helicopter pilots who need to underslung carry loads. This may seem like a different world, but the concept is that the hook has on-board electronics for measuring the load and a wireless transmitter for sending the live data to a nearby ruggedised PC or custom built handheld readout.

"We replaced the hook with one more suited to the tree work, recalibrated the strain gauge and wrote some software appropriate to the job in hand. The procedure with our equipment is to pull the tree until the first suggestions of movement, with the load force being automatically displayed as wind speed and a pass/fail signal."

In the second stage of calculation, the software can use a look-up table to suggest how often such a wind is likely to be experienced. Ingham says that for a future development Sensor Technology is talking to the Met Office about using wind maps of the UK, together with GPS (global positioning system) readings, to produce results tailored almost to the individual tree: "All the data handling and calculations are transparent to the crew; they get simple pass/fail reading. But the data can be stored and further resolved into high-level management information which will help with developing long-term maintenance programmes."

Follow the link for more information about the LoadSense smart sensor or use the form on this page.