The Promenade trees form a significant design statement, framing The Promenade which runs on a North / South axis along the length of the the South Park Plaza.
In order to provide the optimum growing conditions, the Promenade trees, which were containerised, were planted into a pair of parallel trenches that run the full length of the park. Excavated to a depth of 1.2m and a width of 3.25m, the trench was backfilled with a 100mm drainage capped with 700mm of RH37 tree sand and topped with 400mm of structural tree soil. Linear land drains were installed in the base of each trench and connected to the existing drainage network via catch pits.
In order to minimise disturbance of the planting media, we cast in 2.4m deep sleeves at 16m centres along the length of trench to allow the installation of lighting columns at a later stage in the programme. Due to the size of the trees, it was necessary to install them using a 55 ton crane. Detailed listing plans were produced and fed into the programme to minimise the impact this operation had on the remainder of the works.
The trees were installed over 42 crane days involving a specialist five man Willerby crane team. Once backfilled, the trees were edged with pre‐formed steel edging, enabling the hard landscaping to follow concurrently with the planting operation. These rings were then surfaced with 50mm depth of CEDEC gravel. In total circa 1,000 semi‐mature trees were planted in the transformation of the Queen Elizabeth Olympic Park South Plaza.