We received a dual instruction to carry out the arboricultural and ecological assessment for a major development at Ibstock Place School in Roehampton, London. Consideration of tree and ecological constraints from the outset and clear communication ensured project success.
The following were essential in ensuring project success;
The constraints posed by the mature treescape on the Site were significant. The existing refectory had large mature London Planes and Hybrid Black Poplar growing closely adjacent on the eastern side. We initially surveyed the trees following the guidance of BS5837:2012 and root protection areas plotted. The constraints data was then provided to MaccreanorLavington (project architects) who looked to provide a suitable design to enable the retention of the adjacent specimens.
Once the plans for the Site had been finalised, we were instructed to prepare a detailed arboricultural impact assessment to support the proposals. This included details of demolition, temporary construction requirements and final continued impact to those retained trees.
Due to the close proximity of such large trees to the proposal, the standard BS5837:2012 survey had indicated a high level of incursion into the root protection area. As a result, Sharon Hosegood Associates Ltd were brought in to carry out a Root Radar Assessment. The Root Radar Assessment found minimal rooting within the area adjacent to the proposed refectory, however did discover dense rooting to the south of the refectory. To ensure that the proposal did not have a negative impact on the retained trees, an alternative foundation type was required. After consultation with engineers HRW, it was recommended that within the southern section of the proposal, the refectory should be constructed using engineered pile and beam foundations. The pile and beam foundation will span over the root protection area, creating a void beneath southeast corner of the refectory. This will reduce disturbance within this area and allow for future root extension and good infiltration of ground water run-off to the underlying root system.
As a result of the collaboration between the Architect, Client, Specialists and Wharton Trees and Ecology Consultants, a design was developed that enabled the retention of the mature trees on the eastern boundary. At present, planning permission is still pending, however initial feedback for the scheme has been positive. Following planning permission, a method statement will be produced to ensure that the trees are protection during the development process and continue to enhance the wider environment. We will also provide arboricultural clerk of works to check and monitor the Site throughout development.
There are two potential ecological constraints identified during the PEA & PRA; roosting bats and nesting birds. As part of the planning application, it was advised that an Ecological Method Statement be produced to outline the works required to mitigate the ecological constraints at the Site.
Nesting birds will be dealt with through appropriate timing of vegetation and building removal. All trees proposed for removal or pruning, must be assessed for bird nesting by an ecologist immediately prior to removal.
There were only four trees within the site considered to have bat potential. These trees were due to be removed to facilitate access to the Site during construction. It was therefore advised that further investigation of the four trees be carried out with an endoscope immediately prior to their removal.
One emergence survey will be carried out before the building is demolished, with further surveys and avoidance/mitigation measures designed if roosting bats are discovered. Further mitigation will be implemented to compensate for the loss of the trees with bat potential. Several bat boxes will be installed across the Site to provide alternative roost locations.
“Wharton Tree & Ecology Consultants provided detailed tree and ecology pre-application advice as well as pragmatic solutions which helped prevent a costly 12-month project delay. This included proactive communication with Council Officers and agreeing working methods in relation to both protected trees and species. They continue to work with the planning team in order to assist taking the school towards a successful planning decision.”
– Stephen White, Bursar, Ibstock Place School