Land use change associated with the expansion of industrial scale oil palm plantations in three regions of Indonesia (Sumatra, Kalimantan, and Papua), in Malaysia, and in Papua New Guinea, was documented using Landsat images that were visually interpreted to create a region-wide map of 22 different land cover types spanning three temporal periods (1990 to 2000, 2001 to 2005 and 2006 to 2009/2010). In 1990, there were approximately 3.5 Mha of industrial oil palm plantations in the three countries, which had expanded to 13.1 Mha hectares by 2010. Growth occurred at an approximately constant rate of 7% per year over twenty years; the absolute rate of expansion was greatest in Sumatra in the first and second period (167,000 and 219,000 ha yr-1), which was surpassed in Kalimantan in the last temporal period (360,197 ha yr-1). When averaged over all regions and temporal periods only 4.1% (397,000 ha) of oil palm plantations originated on land derived directly from undisturbed forests (0.2% upland and 4.0% swamp), while 32.4% (3.1 Mha) were established on land previously covered with disturbed forest (25.6% upland and 6.8% swamp). Conversion of low biomass shrub lands and grasslands was documented at 17.8% (1.7 Mha) with 13.5% from upland soils and 4.4% from swamp soils; plantations and agroforest combined contributed 33.9% (3.3 Mha). A category recognized as bare soil, the result of change involving multiple different classes, including the replanting of mature oil palm plantations and the conversion of forest, represented 8.3% (0.8 Mha); miscellaneous categories including annual crops, mines, settlements, mangrove swamps, water bodies, and persistent clouds totaled 3.4% (334,000 ha).
Forest conversion to establish oil palm, including both undisturbed and disturbed forest in both upland and swamp forest habitats summed over all temporal periods was proportionally greatest in Papua (61%: 33,600 ha), Sabah (62%: 714,000 ha) and Papua New Guinea (54%: 41,700 ha), followed by Kalimantan (44%: 1.23 Mha), Sarawak (48%: 471,000 ha), Sumatra (25%: 883,000 ha) and Peninsular Malaysia (28%: 318,000 ha). In Kalimantan, the largest sources of land for new plantations were actually from shrub and grassland (48%: 1.3 Mha), while other types of plantations were more important in Sumatra (59%: 2.1 Mha) and Peninsular Malaysia (44%: 487,000 ha). In Indonesia, the largest single cause of historical forest loss can be attributed to unsustainable logging followed by the impact of fire, which in combination led to the progressive transition of large areas of forest landscape into agroforest or shrub land. In Malaysia, the direct conversion of forest to oil palm was more common, particularly in Sabah and Sarawak, but in Peninsular Malaysia the conversion of other types of land use; particularly plantation crops such as rubber, were more important.
A separate analysis using an existing data set for peat soils showed oil palm plantations on peat increased from 418,000 ha (12% of total oil palm area) in 1990 to 2.43 Mha (18%) by 2010 for the total study area. Sumatra has the largest absolute extent of oil palm plantations on peat (1.4 Mha: 29%), followed by Sarawak (476,000 ha: 46%), Kalimantan (307,515 ha: 11%), and Peninsular Malaysia (215,984 ha: 8%), with only 2% of oil palm plantations occurring on peat in Sabah (29,000 ha) and Papua (1,727 ha), while there was no conversion of peat soils in Papua New Guinea.