The Cendil tropical heath forest (kerangas) geosite is one of the unique forest characteristic of the tropical rain forests. “Kerangas” was introduced by Dayak Iban Tribe to distinguish the poor nutrient soil for the rice cultivation. This forest spread in Kalimantan, Sumatera, Bangka, Belitung, and Natuna (Whitten et al, 1984). This forest contains 224 species of flora which consists 101 species have been used for the traditional treatments. The Callophyllum lanigerum contains Calanolide A which can treat HIV virus (Cragg et al, 1995).
Those forests are characterized by the the extreme poor nutrient condition and adpat as the pygmies which remain the low regeneration progress ranging 1 to 2 cm per annum. Therefore, the species survive on this condition encourages those trees to absorp the nutritions by using the bacteria symbiosis from the root nodules to maintain the nitrogen supply (Syuharni et al, 2016). In this area, they are mainly associated with parasitism such as pitcher plants (Nepenthes spp) , sundews (Drosera ssp), and bledderwort (Utricularia ssp) (???).