In February 2011 the City Council decided to invest an extra six million euros in the replacement of the tram rails along Koninginnegracht in order to preserve the majestic chestnut trees at the water’s edge. Although the new rails will be laid further away from the trees, the installation work will mean some damage to the root system. In order to ascertain what effect the work will have on the stability of the trees, a number of them were subjected to a traction test to check how firmly they are currently rooted in the ground. The results will be compared with a follow-up test after the rail line has been replaced to check whether the stability of the trees has been affected in any way.
Before the work starts preparations will be made to ensure that the trees are in the best possible state to withstand any disturbance the renovation and excavation work may cause. At the beginning of December 2011 approximately 40 deep boreholes were made around each tree in order to introduce fresh soil full of nutrients. This will encourage the downward growth of a healthy root system. Roots continue to grow during winter, which means the trees will have a chance to profit from the soil improvement before work on the tram line starts at the end of 2012.
Source: Bomennieuwsbrief, December 2011 – The Hague Municipal Council: ‘Bodemverbetering voor kastanjes Koninginnegracht’