Trees growing on masonry stone walls are a special landscape in Hong Kong, but the rapid urban development has largely reduced the number of this precious treasure. As such, the conservation of the hundred-year-old Forbes Street tree walls and trees in Western District has been taken into consideration since the preliminary design stage of the West Island Line (WIL) in 2005. Following the guidelines specifically developed for the WIL by the tree expert - Professor C Y Jim of HKU, the MTR Corporation assessed each and every tree affected by the construction of the WIL. A certified arborist contractor was employed to oversee all arboriculture works. Information on the tree assessment has been uploaded to the WIL project webpage www.mtr.com.hk/eng/projects/treedata/wil-treedata.html.

Before major excavation works of Kennedy Town Station commenced in Forbes Street Playground, temporary support structures were erected to support the tree walls. Hoardings were set up along the work sites in order to keep the tree walls away from any possible impact. Moreover, Professor Matthew Pryor from Faculty of Architecture of HKU was appointed as an independent tree specialist to monitor the protection works. As the Kennedy Town Station overrun tunnel will be constructed 11 meters underneath the tree walls, the roots of the trees will not be affected.

The MTR Corporation has been working together with various government departments to identify suitable receptor sites within the Western District for transplanting. A total of 44 trees have been successfully transplanted as of March 2010. When WIL’s construction work is completed the Corporation will replant trees in the district.