Green-tree adds a touch of green to Edinburgh’s McEwan Hall

PROJECT:Bristo Square, McEwan Hall

LOCATION:Edinburgh

CLIENT:The University of Edinburgh

LANDSCAPE ARCHITECTS:Ironside Farrar Ltd

LANDSCAPE CONTRACTOR:M W Groundworks

PRODUCT/SERVICES SUPPLIED: ArborRaft Tree Pit System & Fortress Tree Grilles

Overview:

Bristo Square sits on part of the estate of The University of Edinburgh, nestled against the southerly edge of Edinburgh’s old town.

Officially opened in 1983, and bordered by the famous McEwan Hall, Reid Concert Hall and the Teviot Building, Bristo Square soon established itself as a communal place where all aspects of Edinburgh society could meet, making it amongst other things, an epicentre for the Edinburgh street skating scene.

In 2015 a £33m redevelopment project was undertaken to include a major refurbishment and expansion of McEwan Hall and also Bristo Square to the front, with the external works and landscaping to make it making it more accessible and safer, designed by Landscape Architects Ironside Farrar Ltd.

In 2017 a completely new outdoor festival arena was unveiled, in keeping with Edinburgh’s reputation as a festival city. Bristo Square is now a customary location for sections of the Edinburgh International Fringe Festival. As part of the design, artist Susan Collis was commissioned to create a meandering sculpture of bronze drips running 68m across the square.

The Project

Works in Bristo Square included tree planting, creation of more social spaces and improved accessibility. It was designed to give a light, open space, with tiered seating steps around the central events area. Bordering this paved pedestrian area are ten semi-mature trees set in hard landscaping. These trees help to soften the cityscape and provide much needed shade during the summer months.

In order to protect the tree pit soil from compaction, Ironside Farrar specified Green-tree’s ArborRaft tree planting system which is widely used across the country in urban tree planting projects. The ArborRaft System combines nutrient-rich ArborRaft soil with exceptionally strong geocellular units.Together they create a healthy growing space for trees in areas subject to vehicle loadings and trafficking. Individual ArborRaft units are locked together to form a raft system that sits within the tree pit. The system works by spreading the load of any vehicle movements around the tree’s rooting area which eliminates soil compaction within the pit and helps to create the ideal growing environment for the trees to establish and mature.

In conjunction with Landscaping and Forestry Contractors M W Groundworks, Green-tree which is part of leading landscape supplier Green-tech supplied over 200 tonnes of Green-tree ArborRaft topsoil and subsoil. Both of these manufactured soils meet British Standards and are regularly tested to ensure quality of composition and consistency across deliveries.

Green-tech Sleeper and Kerbstone tree anchoring systems, along with gt RootBarrier and Mona Relief tree irrigation pipes was also supplied.

The gtSleeper and Kerbstone Anchoring system utilises heavy objects such as sleepers and kerbstones to weigh down the tree and act as anchor points. Well compacted subsoil is then placed over the sleepers and kerbstones to provide added weight and security for the tree. This is a well tried and tested system that has been incorporated into many rail, utilities and urban projects throughout the UK.

gt RootBarrier was supplied to control and protect the tree roots, as well as protecting structures from the root system. This helps the tree to establish quickly and keep it healthy, especially in the first five years of life.

Lack of water at the tree's root ball can be detrimental to the lifespan and survival of the tree so the Green-tech Mona Relief irrigation system was supplied. Installed with a perforated pipe that surrounds the tree's root ball, the Mona Relief system delivers water straight to the tree roots at a consistent level.

Each tree pit was given a contemporary finish with the inclusion of Green-tech’s Fortress tree grilles installed into the surrounding paved surface. These heavy-duty urban grilles enable paving to be laid almost up to the tree trunk, protecting the tree roots, whilst at the same time, allowing rainwater to percolate through. The Mona irrigation pipes are finished off with the aluminium Piazza filler cap, to match the Fortress grilles.

The Outcome

A couple of years’ on and the latest visit to McEwan Hall showed that the tree pits are doing their job well, and the trees are thriving.

“It is always good to work on a project that seamlessly links historic buildings to the client’s needs of today. The ArborRaft tree planting system does the job perfectly, allowing more rooting volume for the tree; and we were very pleased how the Fortress grilles blended in with the surrounding paving.”

Ian Dooner – Ironside Farrar, Associate Project Manager

“This was a great project demonstrating the perfect tree pits. From the Green-tree ArboRaft soil, giving the trees the best chance of establishment, strong geocellular ArborRaft units, Mona irrigation, anchors and grilles; all coming together to form one simple yet stylish solution.”
Mark Browne – Green-tech, Key Account Manager