TROPICAL SECONDARY FOREST OF EAST KALIMANTAN, INDONESIA: DIVERSITY OF PLANT SPECIES AND ITS BIOMASS POTENCY FOR SUSTAINABLE GREEN ENERGY PRODUCTIONYuliansyah, Elis Septia, Muhammad Taufiq Haqiqi, Dewi Mujiasih, Krisna Adib Setiawan, Muhammad Afif Sekedang, Nur Maulida Sari, Elisa Herawati, Saparwadi, Eddy Mangopo Angi, Rico Ramadhan, Rujehan, Wiwin Suwinarti and Rudianto Amirta
In this paper, an attempt was made to find out the diversity, productivity and suitability of plant species in the secondary forests of East Kalimantan, Indonesia which has the potential to be used as high-quality feedstock for sustainable green energy production. Diversity of plant species was studied by making 22 plots with the size of 20 m x 20 m located at secondary forest of Mahakam Ulu, East Kalimantan, Indonesia. The importance value index of plant species found was calculated using the equation of Mueller-Dombois and Ellenberg. The physico-chemical properties and elemental composition of wood biomass collected were determined using the method of American Standards for Testing and Material (ASTM). We found 57 species which belongs of 28 families were growing in the secondary forest area. Among them, the highest Important Value Index (IVI) was Lamiacea, Vitex pinnata (32.72%). V. pinnata was also achieved the highest calorific value of 18.00 MJ kg-1. Due to suitable energy properties, growth rate and also adaptability of the woody biomass, a secondary forest plant species, V. pinnata was recognized as the important species among all other species observed because of its high adaptability and energy content.