As the year winds down, we’ll be looking back at some of the project case studies we’ve completed in 2011. This case study — written in British English, for those of you in North America — discusses a trees and stormwater Silva Cell project in a Derby car park. You can find the original case study, in addition to all other featured projects, on the Case Studies page of our website.
Connecting Derby is a government-funded integrated transport project that aims to improve transport links in and around the Derby city centre. High on the Council’s agenda for the site was to improve the aesthetics of the Abbey Street car park following the removal of the original London plane trees from the site.
Shaun Phillips, Derby’s Arboricultural Officer, wanted to create an environment where the newly planted trees could thrive. The Council, searching for the best possible way to establish the replacement trees, was focused on nourishing long-term growth and creating a lasting legacy for the site. Typically, Derby street trees are under enormous stress due to inadequate access to oxygen rich soils. As a result, average life expectancy for recently planted trees is around 20 years, and they remain stunted and incapable of environmental or aesthetic impact. Longevity of the new trees was of paramount importance.
Mr. Phillips and the Council settled on the use of Silva Cells to provide the new car park trees with generous volumes of uncompacted, nutrient- and oxygen-rich soil that could also help manage stormwater at-source. A total of 20 trees — Oriental Plane Platanus orientalis ‘Digitata’ and Silver lime Tilia tomentosa ‘Brabant’ — were planted in the Derby car park within the Silva Cell system, which was installed by UPM Tillhill in conjunction with A and M Landscapes in October 2010.
The trees, some of which have shared planters, have an average of 13m3 of soil each. With proper care and maintenance, they will exceed a fifty year lifespan. The Council and Derby residents, meanwhile, will be able to enjoy their beauty and environmental benefits for many years to come, all while avoiding the costs of short-term tree replacement or sacrificing any parking spaces.
In addition to the benefits offered to those who use the Connecting Derby car park, this project is part of the overall green infrastructure plan for Derby, which includes moving traffic away from existing roads and onto the new ring road to create a more pleasant walking environment. There will also be pedestrian-friendly controlled crossing points along the new road.
As a result of the smooth and quick installation of the Silva Cells at the Abbey Street car park, the upgrading and inclusion of the Silva Cells for a second project at the Wilmot Street Car Park was also realized as part of the Connecting Derby Project.
Total soil volume: 257 m³ (13 m³ per tree)
Number of Silva Cells: 838 frames, 419 decks
Client: Derby City Council
Main Contractor: BAM Nuttall
Sub Contractor: UPM Tillhill
For more information on this and other UK Silva Cell projects, please contact Steve Chatwin-Grindey ([email protected]).
A worthy project. However, I wonder why native trees were not selected?
Great question, Clare. Unfortunately we were not involved for the tree selection for this project, so that’s not a question we can answer. If I can find out anything more about why these particular trees were selected, I will be sure to let you know.
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