8 November 1996

Young inventors on a roll with towable bracken crusher

By John Burns

EQUIPMENT designed to restore bracken-dominated heathland to a habitat more suitable for rare birds, including the Dartford warbler, could also be useful in agriculture, claim its inventors.

The bracken crusher was developed and built by five students at Bicton College, Devon, from a prototype made for local Royal Society for the Protection of Birds warden Peter Gotham.

He is convinced that crushing bracken stems at intervals along their length while they are actively growing in June/July is more effective than mowing as a way of weakening the plant. Stems bruised in this way bleed more sap than the single stumps of mown bracken, he believes.

"In the year after rolling with this equipment bracken grows only half as tall, and we think annual treatment would eradicate it in four or five years," he said.

He also maintains that the crushing treatment before spraying with herbicide would render the bracken more susceptible and give a better result than spraying alone.

The machine, developed by the five Bicton Tech engineering students improved on the prototype in several areas. It was made road-legal by fitting independent wheel suspension units. Stronger T-section steel was used instead of flat bar for the cylinder, and the frame was redesigned to make the crusher more effective.

Light but tough

They used standard parts mostly supplied by a local company, and second-hand car wheels, to produce a machine light enough to tow behind a car but strong enough to operate at speed on rough terrain. They reckon it could be built to sell at under £1000.

"On our BTech national diploma course we are trying to show engineering with imagination rather than just a mundane job," said course manager Tim Hannah.

"We know there are opportunities for young people in engineering. But they need imagination and the ability to get involved in product development and exporting."

The Bicton team, including Matthew Irish, James Poole, Martin Prosser, Ross Retallack, and Oliver Williams, showed they had all that and more by taking the £1500 second prize in the Royal Mails Young Exporter of the Year competition.

They prepared plans to export the bracken crusher to northern Spain where the authorities are establishing wildlife reserves and parks in areas currently infested with bracken.n

This bracken basher was developed by Bicton College students in Devon from a prototype made for the Royal Society for the Protection of Birds.