Heavier rain, stronger winds prompt closer checks on trees on Sentosa, mainland S’pore
A tree branch fell onto the road in Gunner Lane at about 6pm on May 28. PHOTOS: SCREENGRAB FROM ROADS.SG/FACEBOOK
Christie Chiu
Jun 23, 2024
SINGAPORE – Checks on trees on Sentosa are being stepped up amid changing climate patterns, including a prolonged monsoon season, increased rainfall and other extreme weather events in recent months.
The heightened measures, introduced in November 2023, include inspecting trees and pruning them more often, especially those in areas with high human traffic and where the trees are exposed to strong winds.
A spokesman for the Sentosa Development Corporation (SDC) said that so far in 2024, there have been four reported cases of fallen trees and 11 incidents of falling branches on Sentosa that were caused by inclement weather and intense rainfall.
In one recent incident, a tree branch fell onto the road in Gunner Lane at about 6pm on May 28, the spokesman said. No guests were hurt, and no property was damaged, he added, but video footage posted on social media showed the branch had blocked a road exit next to Yue Private Dining restaurant.
Experts warn that changing weather patterns caused by climate change could lead to more incidents of trees falling or branches snapping. Stronger winds and bouts of more intense rain, for instance, could result in more trees toppling over.
Technological tools like
tree-tilt sensors are used to monitor tree movement and stability, the SDC spokesman said.
These sensors help detect when trees start to lean early and could be headed for a fall after gradual weakening over the years. Early detection paves the way for preventive measures to be taken, such as improving soil conditions and pruning tree crowns.
Another strategy has been to plant more native tree species, which are better adapted to local weather patterns and climate conditions.
In Singapore, the National Parks Board (NParks) has stepped up efforts to ensure the health of trees in public areas since the early 2000s, including putting in place measures to protect the trees against drastic weather caused by climate change.
In response to queries, an NParks spokesman said that in 2024, there have been nearly 140 “tree incidents” so far, including reported cases of fallen trees and branches. Such incidents are likely to cause obstructions in urban areas.
NParks manages about six million trees, out of a total of about seven million on the island.
There has been an annual average of about 400 tree incidents in Singapore over the last five years, NParks said. It added that most of the incidents involved snapped branches. That is a drop of nearly 87 per cent compared with the 3,100 reported incidents in 2001.
In 2023, there were 430 cases, down from 480 cases the previous year, said NParks streetscape group director Oh Cheow Sheng.
He said: “In anticipation of the challenges posed by climate change, NParks is committed to sustaining our comprehensive tree-management programme, which involves a robust regimen of inspections and pruning, to proactively address potential vulnerabilities in our trees and enhance the overall resilience of our urban green spaces.”
According to V3 –
Singapore’s third national climate change study, published in January 2024 – wind speeds could increase by up to 20 per cent by the end of the century.
Climate change could also cause erratic rainfall patterns, including longer periods of dry spells and periods of more intense rain.
As more water vapour evaporates into the atmosphere owing to increasing global surface temperatures, it becomes fuel for more powerful storms to develop, according to the United States Geological Survey.
In Singapore, rainfall patterns are expected to experience more drastic swings, the V3 study found. Extreme daily rainfall is expected to increase across all seasons. The rise is likely to range from about 6 per cent to 92 per cent during the inter-monsoon months of April and May.
Longer-lasting dry spells are also expected to become more frequent – there will most likely be an average of one dry spell every 10 to 60 months by 2100 in Singapore, the V3 study said.
Other than long-term climate change, weather phenomena like La Nina can also result in more rain falling on Singapore.
Mr Oh said trees are
generally assessed by trained inspectors once every six to 24 months under the NParks tree-monitoring regimen, which is based on guidelines by the International Society of Arboriculture.
The frequency of inspections depends on the locality and age of the trees. Trees are also pruned regularly to improve their structure and balance.
“This is stepped up during periods of adverse weather conditions to reduce the risk of tree-failure incidents,” Mr Oh said.
In addition to using technology like wireless sensors to manage its trees, NParks has been replacing diseased trees and those vulnerable to storms in forested areas bordering roads since 2003. Native species, which are better suited to Singapore’s weather conditions, are planted instead.
Other than the six million trees under NParks’ management, the remaining one million trees in Singapore are managed by private landowners and several other government agencies, which generally follow the advice of NParks.
For instance, national water agency PUB manages more than 1,000 trees in areas like reservoirs and pipeline reserves, while the Housing Board and town councils manage trees in new and existing HDB estates.
HDB, when asked about its tree-management programme and whether it has stepped up checks, cited a 2021 reply to a parliamentary question. In the reply, the National Development Ministry said that since 2018, HDB has been securing trees planted on rooftop gardens with anchors at their roots, embedded in the soil, to further reduce the risk of tree-fall incidents.