Case Studies

Case Study - Site Clearance

Project: Greyfriars Bus Station Redevelopment

Client: Kier Construction

Project Information:

Wilby Tree were appointed to remove vegetation in order to prevent nesting birds from two neglected roof top garden court yards, 38 planters running around the exterior of the premises and self-set trees and scrub growing out of the buildings on the fifth floor and rooftop of the nine story premises of the Greyfiars Bus Station. These works were required before demolition could commence.

Additional work included the felling of trees and vegetation from an area of wasteland adjacent the bus station frontage in order to remove and prevent anti social behaviour, along with improving the aesthetics of the local area.

Due to anti social behaviour, hypodermic needles were present within the vegetation on the area of wasteland near the bus station; these were removed with assistance of a third party Environmental Contractor.

Project Challenges:

Roof top garden courtyards

The vegetation to be removed was located on the fifth floor of the bus station. Further to this, access to the roof was only possible via a small service list measuring just 1.85m in length and width with a maximum payload of 1500Kg. Wilby Tree investigated the possibility of utilising a crane to lift a wood chipper on and off the roof top courtyards. Unfortunately, due to restrictions around the bus station, the height of the building and offices surrounding the courtyards, this was not viable without creating a hole in the roof of one of the pedestrian bridges to the fifth floor of the building, something which the client was keen to avoid. Helicopter access was considered but dismissed due to the costs and permits involved given the location of the project.

We exhausted the possibilities of purchasing or hiring a chipper small and light enough to fit into the access lift but still capable of processing material at a viable rate. To overcome this, our experienced fabricator and fitter redesigned one of our existing tracked chippers. He shortened the frame of the machine by removing both the battery and fuel tank tray, additionally the feed hopper was removed. Fuel valves were fitted to stop the flow of fuel between the engine and fuel tank. The machine was refabricated, including the full safety frame and was now convertible to 1.82m long. This meant that within the course of 30 minutes we were able to dismantle the machine, transport it to the fifth floor in two trips and re-assembled ready for use.

The offices had been disused for a number of years, Pigeons colonised the rooms resulting in large volumes of detritus and strong ammonia which presented a bio-hazard to our employees. For the duration of the roof top works, all members of staff wore Tyvek overalls and respirators while in the building.

Once all ground vegetation had been cleared in the courtyards, we stripped the pillars which were covered with dense Ivy. In order to do this climbing arborists abseiling down the pillars from fixed anchor points on the roof.


Access of balconies

Around the perimeter of the 5th floor offices were 38 overgrown planters. Vegetation overhung the walls and the public highway beneath. The vegetation had clogged gutters and drains resulting in gangways featuring 30cm deep stagnant water. Under the canopy overhangs were further piles of Pigeon detritus.

Vegetation was carefully removed to ensure no debris fell into the carriageway beneath. All arisings had to be manually dragged into the buildings to be chipped. Overhanging Ivy was removed on a Sunday with two 30m MEWP’s. This involved a lane closure around the entire bus station.


Roundabout Wasteland

Around the perimeter of the roundabout a public footpath had to remain open. This severely restricted the use of machinery. In order to reduce the amount of time chipping the arisings we utilised our large crane fed Heizohack 14-800 wood chipper and 20t grain trailer.

The roundabout was well known for anti social behaviour. Along with general litter we found fresh and used hypodermic needles and human excrement. In order to ensure the safety of our operatives we enlisted the services of an Environmental Contractor to remove the needles and excrement. A challenging task in itself given the dense vegetation.


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“Wilby Tree Surgeons Ltd are running a very professional tree surgery business with a willingness and desire to do the very best in terms of arboricultural practices, legislative and industry good practice requirements. On site work practices and paperwork have been maintained to a very high standard.”

Chris Cooper-Abbs – Arboricultural Association Approved Contractor Scheme Assessor