Novel High-Suitability Regions for Oil Palm with Basal Stem Rot Estimations in Indonesia and Malaysia

Palm oil is a significant product, predominantly from Indonesia and Malaysia, and is included in many products. However, oil palm (OP) plantations have been associated with deforestation and destruction of peat soil, tending to increase CO2 in the atmosphere and contribute to climate change. The growth of OP may be affected detrimentally by climate change. Also, OP is susceptible to basal stem rot (BSR) caused by the fungus Ganoderma boninense. Previous CLIMEX-modelled scenarios have indicated decreases in suitable climate for growing OP in the future, and narrative models suggest increases in BSR. However, the climate maps show regions in Malaysia and Indonesia that were previously unsuitable, which have become highly suitable climate (HSC) areas and were previously unreported. These areas include the higher altitudes of (a) the west coast of Sumatra, (b) areas between Sarawak, Sabah, and Kalimantan, (c) the central region of Sulawesi, (d) northern West Papua, (e) and the Titiwangsa Mountains of Peninsular Malaysia. These trends are remarkable per se. The incidence of BSR will likely be low because the palms would experience HSC, making them more resistant to infection. For example, HSC is projected to increase from 0% at present to 95% by 2100, while BSR is projected to increase from 0% at present to 30% over the same time period in Sumatra. In Borneo, HSC is projected to increase from 0% at present to 95% by 2100, while BSR is projected to increase from 0% to 7% over the same time period. Higher CO2 fertilisation may occur which would increase OP vigour again leading to greater resistance to BSR. However, many of the regions may be biodiverse and it would be unreasonable to replace them with plantations and whether these areas would be suitable for growing OP requires careful consideration. This report of increasing areas of HSC for growing OP is unique.