Oil palm (Elaeis spp.) is one of the world's most rapidly expanding crops. Especially prevalent in Malaysia and Indonesia, oil‐palm plantations are also increasing rapidly across tropical regions as diverse as New Guinea, Equatorial Africa, Central America, and the Amazon (Butler & Laurance 2009; Koh & Wilcove 2009). Oil palm is an important driver of tropical deforestation, in part, because plantation owners often use timber revenues from old‐growth forests to subsidize the initial costs of plantation establishment and maintenance (Fitzherbert et al. 2008). Expansion of oil palm imperils both lowland rainforests and peat‐swamp forests, which are, respectively, among the biologically richest and most carbon‐dense ecosystems on Earth (Butler & Laurance 2009; Koh et al. 2009a). The rapid expansion of oil palm seems likely to continue for many years because of its high profitability and the growing global demands for edible oils and biofuel feedstocks. Proponents of palm oil emphasize that its main alternatives, including soy, sunflower, and canola (rapeseed) oils, have production efficiencies just 10–20% as high as palm oil on a per‐hectare basis and would therefore require much larger areas of cultivated land to have a similar benefit (Basiron 2009). Nevertheless, from climate‐change and biodiversity perspectives, the advantages of palm‐oil production are greatly diminished when it contributes either directly or indirectly to deforestation (Gibbs et al. 2008; Danielsen et al. 2009).