While I agree that we should set a target on the number of trees to be planted, this alone is not sufficient in the greening of the environment (Singapore nears 40% mark in goal to plant 1m more trees by 2030, Aug 21).

There are two important factors that must be considered.

First, we should focus on the net number of trees planted rather than the gross number of trees planted.

While the National Parks Board has been busy planting trees, a large number of trees have also been cut down, and this number may not have been reported.

According to the Global Forest Watch website, from 2001 to this year, Singapore lost about 2,600ha of tree cover, equivalent to a 14 per cent reduction in tree cover.

Second, the type of trees being cut down and planted is also important.

I have been living in the north since I was young. I used to enjoy walking along the shady stretch of Upper Thomson Road where Thomson Plaza is.

The sidewalks were lined with rows of rain trees that provided plenty of shade against the harsh noon sun.

Now all those trees have been chopped down, and in their place are new tree species that will never grow to provide the large canopy of the trees they replaced, or remove the same level of carbon dioxide from the atmosphere.

Yeo Chee Kean