Experts have long studied the water consumption of various plants. One of them is Coster (1938) who examined the water needs of several plants long before oil palm plantations were developed. Using plant evapotranspiration indicators, Coster found that bamboo and lamtoro crops are quite wasteful of water with a need of about 3,000 millimeters of water per year (Figure 1). That is followed by the acacia plant with a need for 2,400 mm of water per year, the sengon tree that uses 2,300 mm per year and pine and rubber trees that need about 1,300 mm per year. Meanwhile, an oil palm only needs 1,104 mm of water per year.
Looking into the portion of rainfall utilized by oil palms, Pasaribu et al (2012) found that the percentage of rainfall used by oil palms is about 40 percent of the annual rainfall. The percentage is smaller than mahogany’s, 58 percent, and pine’s, 65 percent (Figure 2).
Pine, acacia and sengon plants are popularly used as forest plants both in the reforestation program and timber estate development. These forestry plants are relatively wasteful of water.
Meanwhile, oil palms, which have been alleged to be wasteful of water, turn out to be much more efficient in the consumption of water than the regular forestry plants. Oil palms are even more efficient in water consumption than the rubber plant.
Results of research by experts disclose that oil palm can be classified as the group of plants that are relatively efficient in water consumption compared with the forestry plants or the rubber plant. Not only are they efficient in water consumption, oil palm plants store more water in their massive fiber root systems that form natural bio-pores that function to store water and organic substances.