Written Answer by Ministry of National Development on inspection of trees in parks

Jan 14, 2019

Assoc Prof Daniel Goh Pei Siong: To ask the Minister for National Development 

(a) what is the inspection frequency for mature trees located in our parks; and

(b) whether there is a need for a review of the tree inspection regime in light of changing climatic conditions and recent incidents of tree failures causing injuries.

Answer:

Trees in parks are inspected every 12 to 24 months, depending on their proximity to event spaces and car parks. Since 2016, NParks also does an additional, more in-depth annual inspection for trees of more than 4 metres in girth, to check for internal decay or cavities in these trees. 

NParks has also implemented other measures in light of changing climatic conditions. First, NParks replaces storm-vulnerable species with hardier trees. Second, NParks regularly prunes its trees to improve their structure and balance. In particular, since 2016, NParks has been conducting crown reduction and pruning prior to periods of more severe weather conditions. Third, NParks uses technology to analyse risks and improve inspection processes. For instance, NParks recently developed a Tree Structural Model to understand the impact of strong winds on the stability of trees. The data helps NParks determine the pruning required to improve tree stability.

With this adaptive tree management programme in place, the annual number of tree failure incidents has fallen by about 85% from 3,000 in 2001 to about 400 in 2018, despite more severe weather. NParks will continue to review its tree management programme to ensure that it remains robust and comprehensive.