IN CASE YOU MISSED IT

Risking falling trees for roti prata

This story was first published in The Straits Times on Aug 4, 2013

Time was when a clump of trees was occasion for wonder and solace. I often choose my abode allowing for proximity to greenery. Better still if it offers a full frontal view of foliage. In my current apartment, I spend many idle moments just gazing into trees.

But lately, as reports of falling trees damaging property and hurting people sprout, I can feel my Falling Tree Anxiety Level rising.

I live in an area surrounded by majestic trees. Sometimes, as I drive down Upper Thomson Road towards Sembawang, I look at the rows of leafy trees with rich canopies and wonder if they belong to the Albizia species, a species known for its lush canopy that can grow to over 40m tall. But as the National Parks Board (NParks) website indicated: "Compared to other tree species, the wood tissues of Albizias are relatively soft, brittle and prone to breakage during storms. They are also known to suffer from pest and disease problems, such as root rot. Hence, Albizias are prone to uprooting, especially during storms."

Click for a bigger image.

Albizias are known to fall in calm weather too. Two Sundays ago, one that grew on state land fell onto a Bukit Timah house. Luckily, no one was injured.

Government agencies have been quick to say they've culled 3,000 of the Albizia trees, replacing them with species like the Tembusu and Jelutong, which are hardier.

That got me wondering: Were those trees in my area Albizia? Would I have to risk injury to car, self and passengers, daily?

Not many people share my anxiety about falling trees. I've seen people shift and glance at one another uneasily when I bring up the subject, in the way people do when they're in the presence of odd behaviour.

Maybe I'm a little paranoid. But I do think falling trees must be taken seriously in a city as green and as densely-packed as Singapore.

The scaredy cat that I am - and as a good journalist - I asked NParks about the trees in my neighbourhood and sent them pictures of the said trees to be identified.

It turned out my fears were unfounded. Those trees are not the dreaded Albizia, but are rain trees, which are known to be hardier.

But hang on. Wasn't it a rain tree that fell and killed a young man a few years ago, on a stretch of Yio Chu Kang Road in the vicinity?

I read past news reports from July 2010: Indeed it was a rain tree. But it fell in a storm, not from rot or decay.

This led me to wonder: How robust is Singapore's overall system of managing trees? Will tree rot be discovered and treated? And how unique is Singapore in facing this problem of falling trees?

It turns out falling trees is an issue in many cities. In Hong Kong, an angry reader wrote to the South China Morning Post last March, after a 15m tree fell in Sha Tin, injuring the reader's brother-in-law.

"Immediately after my brother-in-law was hurt, the government, rather than trying to offer our family comfort or timely assistance, tried to shirk its responsibilities. Officials argued over whether the Leisure and Cultural Services Department or the Highways Department should take the blame (for the tree's collapse). The tree in question was suffering from serious internal trunk decay that had infected half of it. This meant it could have collapsed at any moment."

Does Singapore have similar inter-agency problems? After all, tree maintenance comes under different agencies. NParks takes care of 1.4 million trees in parks, road verges and some vacant State land. The Singapore Land Authority maintains trees land under its care, including forested state land. The Ministry of Defence maintains trees in army training areas. Town councils maintain those in common areas of Housing Board estates. NParks arborists and specialists provide advice to the other agencies.

But so far, response to fallen trees has been prompt and agencies have not tried to finger-point.

Next, I started wondering: Does Singapore have a robust tree management programme?

In America, shrinking budgets have hit tree maintenance programmes: "Preventive care of urban trees has been a budget casualty from Philadelphia to Chicago to San Jose," reported the New York Times, which ran a series of articles last year on falling trees. In one, it said the city had about 10 legal suits either settled quietly (with amounts in the millions) or still before the courts.

Does Singapore face similar budget pressures on its tree management programme, I asked NParks. It didn't respond to this question directly, but gave details of its tree management programme by e-mail.

Said NParks' Oh Cheow Sheng, Director (Streetscape): "Mature trees along expressways and major roads are inspected at least once in 12 months, an improvement over once in 18 months previously. Our frequency of tree inspections is in line with the Best Management Practices of the International Society of Arboriculture. In addition, big trees with dense crowns are also given crown reduction to reduce the weight of the crowns and to enhance the trees' stability during rainstorms.

"The trees along Upper Thomson Road are subjected to the same stringent level of care as the ones along all major roads, and are inspected once every year. The intensified regime has shown results: in 2000, there were 3,100 incidents of branch breakage and tree uprooting; this has been brought down to 1,050 in 2012."

Well and good. But with 1.4 million trees, is NParks sufficiently staffed? Its reply: "More than 200 staff are involved in tree management. On average, each staff inspects a few hundred trees every month."

Like human beings with symptoms, trees suspected of being sick are inspected and scanned by something called a Resistograph or a PICUS tomograph "to detect internal cavities or decay".

Piecing things together, I concluded that the risk of falling trees damaging people was not yet at the crisis stage. But even the best maintenance programme can't prevent trees from being uprooted in a storm. And since I chose to live in a tree-lined area, I may just have to live with the risk of falling branches and trees.

I fed all the pros and cons into my cost-benefit machine: My area has many rain trees. But at least they're not storm-vulnerable Albizia.

I came up with this rule of thumb: Driving out for my prata and Ampang yong tau foo should be safe most days. And stormy days too.

Keep my fingers crossed.

muihoong@sph.com.sg

This story was first published in The Straits Times on Aug 4, 2013

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