Project Overview

Dortmund Square, located off The Headrow in Leeds City Centre, was refurbished in 2013 as part of a broader effort to create a more welcoming, pedestrian-friendly public space. The project improved walkways, lighting, seating, and the overall visitor experience while introducing a signature London plane tree in front of the entrance to St. John’s Centre.

Because Dortmund Square is one of the city centre’s busiest thoroughfares, Leeds City Council needed to make sure the new hardscape could support heavy pedestrian use without compromising the long-term health of the tree. Silva Cells were installed beneath the pavement to provide the tree with access to uncompacted soil volume, helping the renovated square deliver both public amenity above ground and healthy growing conditions below.

Signature London Plane Tree

The highlight of the Dortmund Square renovation is its signature London plane tree, planted in honor of Her Majesty The Queen’s Diamond Jubilee. From the beginning, this tree was intended to be more than a decorative addition. It was a defining feature of the revamped square, bringing shade, greenery, and long-term canopy potential to a busy city-centre space.

Because the tree was planted within a heavily used pedestrian environment, the design team needed to protect the soil from compaction while maintaining a durable, accessible surface above. Silva Cells made this possible by supporting the pavement while creating an underground growing area filled with quality soil. In total, the system provides approximately 28 cubic meters (1,000 cubic feet) of soil volume for the London plane tree — a strong foundation for long-term root growth in a constrained urban setting.

The results have already been impressive. At the time of planting, the semi-mature tree was approximately 6 meters (20 feet) tall. Eight years later, it had grown to approximately 17 meters (55 feet), tripling in size. In a busy hardscape setting where compacted soil often limits urban tree growth, the Dortmund Square tree shows what can happen when below-ground conditions are designed with the same care as the public realm above.

Site Flexibility

Silva Cell was especially well suited to Dortmund Square because the site presented significant underground constraints. Existing utilities included a historic water main first laid in 1850, along with a large concrete slab that had to be removed carefully due to the square’s proximity to the city’s main water supply. A specialist team used vibration-free technology to reduce the risk of disturbing these sensitive utilities during construction.

Once the slab was removed, the available excavation area turned out to be smaller than originally anticipated. Rather than compromising the soil volume target, the design shifted from a 2x Silva Cell system to a 3x configuration. This allowed the project team to reduce the footprint while still providing the intended soil volume for the tree. In a tight, utility-heavy urban site, that adaptability was essential: Silva Cell gave the project flexibility below ground while preserving the refreshed, pedestrian-friendly square above.