TREES are often depicted as shelters from a storm, but they are not a driver's best friend.

Studies have found that people inside a car that has rammed into a tree are more likely to be hurt than in a collision between cars.

Trees are more dangerous than guard rails and poles.

They often prove deadly because they are stationary, rigid and do not absorb the impact of a crash.

When a vehicle hits a tree, the impact is concentrated. So cars tend to be badly mangled, with passengers suffering serious injuries, according to a 2006 study by the International Society of Arboriculture. Arboriculture is the science of growth and development of trees.

In a crash involving two cars, the "impact energy" is absorbed by both and distributed over a wider area.

Last Thursday, a Singaporean family, the Bongs, were on their way to Kuala Lumpur for a holiday when their Mitsubishi Grandis slammed into a tree, then another, along the North-South Expressway near Muar.

The accident left the seven-seater vehicle in a crumpled mess against one of the trees. The impact was so strong that it flung three of its passengers out, over distances of between 10m and 36m.

Of all car collisions with trees in the United States in 2002, nearly half caused severe injuries or death.

But such collisions come a close second to non-collision accidents such as rollovers - when cars turn turtle - and driving into a ditch, which tend to cause greater injury, said the 2006 study.

In the past year, there have been at least eight reported car accidents in Singapore involving trees, six of them fatal.
Three weeks ago, two police officers were hurt - one seriously - when their patrol car smashed into a tree along Jurong West Avenue 5.

The vehicle was so mangled that Singapore Civil Defence Force officers had to use tools to extricate the two policemen.

This article was first published in The Sunday Times on Mar 30, 2008.