Study Region

The study was carried out close to the equator in the “Harapan region” of the lowlands of Jambi Province, Sumatra, Indonesia (Figure ​Figure11). Annual precipitation averages 2235 mm and average temperature is 26.7°C (Drescher et al., 2016). The terrain is undulating with altitudes varying between 40 and 100 masl at relatively short distance (Figure ​Figure11).

The study region (“Harapan region”) in Jambi Province, Sumatra, Indonesia. Location of oil palm and rubber plot pairs (each consisting of upland and valley sites). Upland sites were part of the larger experimental design of the EFForTS project (Drescher et al., 2016) and had plot codes H (for Harapan) with O for oil palm and R for rubber; numbering goes from South to North. The terrain of the landscape is undulating, as to be seen on a digital surface model (DSM, Naumann, 2015) of a 627 ha region in an oil palm plantation owned by P. T. Humusindo, approximately 10 km south of our study region (indicated by brown rhombus).