Written Answer by Ministry of National Development on investigation into the Tembusu incident at Botanic Gardens

Apr 3, 2017

Mr Melvin Yong Yik Chye: To ask the Minister for National Development 

(a) what is the progress of investigation by NParks on the incident at Botanic Gardens whereby a giant Tembusu tree fell and killed a park visitor and injuring several others;

(b) whether NParks will consider increasing the frequency of inspection for trees above a certain age; and

(c) what measures will be taken to prevent such similar incidents as Botanic Gardens is a popular outing place for locals and tourists.

Answer:

The investigation into the Botanic Gardens incident is ongoing. There will be a Coroner’s Inquiry and NParks is providing the Police with the necessary information. In the meantime, NParks has completed detailed checks on all trees in and near the location of incident, as well as on large trees and other Heritage Trees throughout the Gardens as a precautionary measure. All these trees were found to be safe.

All trees that NParks manages are regularly inspected. NParks continually strives to improve its inspection regime. Since 2012, they have inspected trees more frequently to adapt to increasingly unpredictable and severe weather conditions. Heritage trees are now inspected once in 6 months as opposed to once a year previously.  For trees in areas with constant road or pedestrian traffic, they are now inspected once in 6 to 12 months, as opposed to once in 12-18 months previously. NParks further enhanced its inspection regime in November 2016 by instituting new second-level inspections for old and large  trees1. These detailed second-level inspections are conducted yearly with diagnostic equipment. To support its inspection regime, NParks has built up a pool of qualified arborists. Today, about 200 of the 500 Certified Arborists in Singapore are NParks’ staff.

In addition to inspections, NParks has enhanced its tree maintenance regime to improve the resilience of its trees. First, regular application of fertilisers is now supplemented with routine mulching.  This helps to conserve moisture and improve the fertility of the soil. Second, NParks has strengthened its tree pruning techniques to improve the structure and balance of its trees to help them withstand severe weather conditions. Crown reduction and pruning are undertaken prior to periods of severe weather. 

These measures have proven effective as the number of tree failure incidents have decreased more than three-fold, from around 3,000 in 2001 to 847 last year. That said, NParks will continue to improve its tree management measures. For example, NParks is developing modelling techniques to better understand the behaviour of trees under varying environmental conditions.

¹Defined as trees with girth of more than 4m.