Mr Francis Cheng says that if we want to replace oil palm with other crops, then we must be prepared to provide at least nine times more land to grow them ("Fighting haze: Boycotting palm oil products not a long-term solution"; Sept 17).

Publicly available United States Department of Agriculture statistics indicate that combined Malaysian and Indonesian palm oil inventories would multiply to record levels, from 1.6 million tonnes in 2008 to an estimated 5.8 million tonnes by the end of this year.

With palm oil prices falling to low levels and inventories bulging, it appears that too much land is being used to grow oil palm - not too little.

Moreover, with world soya bean inventories breaking their all-time record for a second year in a row and soya prices down 55 per cent in three years, no extra farm acreage is required to use soya oil (which does not cause air pollution in growing the crop) in place of palm oil.

Mr Cheng says we do not have the right to tell Indonesia or any other country to forgo economic development through palm oil production.

But consumers have a right to use their purchasing power to persuade private companies to change how they grow oil palm.

The recommendation that consumers buy palm oil products with Roundtable on Sustainable Palm Oil (RSPO) certification is also questionable.

Non-governmental organisations including Palm Oil Investigations of Australia and US-based Palm Oil Consumers Action claim that RSPO certification does not stop oil palm farms from polluting the air and water.

We have nothing against palm oil. It is a perfectly fine, healthy natural oil - but the way oil palm trees are grown has to change.

Eric J. Brooks