Oil palm (Elaeis spp.) is one of the worlds 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).
