More than one-third of the area on which oil palm is grown in Malaysia, some 1.4 million hectares (http://faostat.fao.org), has already passed peak yields and is due to be replanted. Replanting, which represents a new phase for the industry, must be carefully thought through and implemented to avoid repeating the disastrous effects of the initial clearance of primary forest on biodiversity and the environment.

The productive life of an oil-palm crop is 25–30 years and, because the boom in oil-palm cultivation began in the mid-1980s, large areas of ageing oil palm in southeast Asia now need replacing. However, the long-term nature of the crop has allowed biological complexity to build up around it over time.

There is therefore a risk that the replanting phase — just like the initial clearance for planting — will disrupt natural habitats by indiscriminate removal of vegetation and heavy disturbance of soil and hydrological systems.

We suggest that large-scale replanting operations should be carried out carefully with a view to minimizing such adverse effects on the environment.