Abstract. Amirta R, Yuliansyah, Angi EM, Ananto BR, Setiyono B, Haqiqi MT, Septiana HA, Lodong M, Oktavianto RN. 2016. Plant diversity and energy potency of community forest in East Kalimantan, Indonesia: Searching for fast growing wood species for energy production. Nusantara Bioscience 8: 22-30. Nowadays, there is an increasing interest in intensifying the production and use of biomass to replace fossil fuels for the production of heat and electricity, especially for a remote area that generally abundance with the wood biomass resources including in East Kalimantan, Indonesia. In this work, diversity of plant species that commonly growth in community forest area of East Kutai District, East Kalimantan, Indonesia had been studied to point out their energy potency to be used as biomass feedstock for the electricity generated. Diversity of plant species in the community forest was evaluated by making 13 sampling plots with 20mx20m size approximately. Concurrently, the energy properties of plant biomass such as proximate and ultimate compositions were also analyzed using ASTM methods. Results showed that more than 30 species of tropical trees and wood shrubs were grown in the community forest. The presence of them was classified into two different growths of origins: natural and artificial plantation, and also three different categories of plant resources: tree species from logged over forest, commercial fast growing plant tree species for the fiber production and woody shrubs. The highest dominancy and productivity was found in Paraserianthes falcataria (L.) Nielsen since the wood biomass was artificially planted for the commercial purposes. Among the 31 plant species analyzed we found the highest energy potency was obtained from Cratoxylum cochinchinense (Lour.) Blume that produced 3.17 MWh/ton, and the lowest was from Trema orientalis (L.) Blume 0.97 MWh/ton. The woody shrubs species such as Vernonia amygdalina Delile., Piper aduncum L., Gliricidia sepium (Jacq.) Kunth ex Walp., Calliandra calothyrsus Meissner., Bridelia tomentosa Blume, Vitex pinnata L., Vernonia arborea Buch.-Ham. and Bauhinia purpurea var. corneri de Wit. were suitable to be used as sustainable feedstocks for the electricity generated and promising to be developed as energy plant species in the future using Short Rotation Coppice system (SRC).

Abstract. Ramadhan R, Kristanti AN, Amirta R, Kusuma IW, Phuwapraisirisan P, Haqiqi MT, Saparwadi. 2019. Screening for potential antidiabetes and antioxidant activities of selected plants from East Kalimantan, Indonesia. Biodiversitas 20: 1820-1826. Ten selected plants in this study have been used traditionally in West Kutai, East Kalimantan as medicinal plants. This study aimed to screen and evaluate the in vitro antidiabetic and antioxidant activity of methanol extracts of selected plants from East Kalimantan. The antidiabetic activity was carried out by α-glucosidase inhibitory activity with maltose and sucrose as substrates while antioxidant activity was determined by free radicals scavenging activity against DPPH, ABTS and Nitric Oxide (NO). The results showed that Garcinia riedeliana extract had strong inhibitory activity with an IC50 value of 0.04 mg/mL followed by  Shorea laevis, Pternandra azurea and Bridelia tomentosa with IC50 values of 0.12; 0.15 and 0.16 mg/mL in maltose respectively, while quercetin as positive control had an IC50 value of 0.08 mg/mL. G.riedeliana extract also showed good α-glucosidase inhibitory activity with an IC50 value of 0.23 mg/mL in sucrose as substrate. The results on antioxidant activity showed that all extracts have IC50 value against free radicals DPPH, ABTS, and nitric oxide. The most active extract as α-glucosidase inhibitory activity and antioxidant activity was G. riedeliana extract. These findings provide the scientific evidence that one species of medicinal plants from East Kalimantan might be potential as an antioxidant and α-glucosidase inhibitor.

Abstract. Amirta R, Haqiqi MT, Saparwadi, Septia E, Mujiasih D, Setiawan KA, Sekedang MA, Yuliansyah, Wijaya A, Setiyono B, Suwinarti W. 2019. Searching for potential wood biomass for green energy feedstock: A study in tropical swamp-peat forest of Kutai Kertanegara, Indonesia. Biodiversitas 20: 1516-1523. Recently, much attention has been focused on finding suitable plant species, from different forest ecosystems, having the potential to be used as sources of renewable energy. Most of such information was reported from the lowland forest area and only limited information is available regarding swamp-peat forest species, including their energy potency. Therefore, in this paper, plant diversity and energy potency of swamp-peat forest wood biomass were studied to reveal their potential as green energy feedstock. Physico-chemical characterization of wood biomass was performed using the American Society for Testing and Material (ASTM) protocols. Twenty-seven species of plants, consisting of 23 trees and 4 shrubs, belonging to 19 families were identified, amongst which Shorea balangeran had the highest importance value index (87.72%). The results showed that T. obovata exhibit the highest suitability to be used as energy feedstock indicated by the highest energy production of 4.60 MWh per ton of dry biomass, followed by L. indica (4.56 MWh/ton), D. excelsa (5.52 MWh/ton), F. rukam (4.20 MWh/ton), P. galeata (3.66 MWh/ton), S. caudatilimbum (3.61 MWh/ton), A. elmeri (3.59 MWh/ton), G. nervosa (3.49 MWh/ton) and G. bancana (3.42 MWh/ton). The high density of wood species correlated with the high value of energy potency. In contrast, the fast-growing tree and shrub species, such as K. hospita (1.76 MWh/ton), C. odorata (1.36 MWh/ton) and O. sumatrana (1.17 MWh/ton), showed lower energy potency. The most dominant plant species, S. balangeran gave only 2.96 MWh energy per ton of dry biomass and it was classified in the middle group of plant species suitable as green energy feedstock, along with other species, such as C. brachiata, C. rotundatus, P. javanicum, V. umbonata, L. speciosa, V. pinnata, and A. longifolius. Due to suitable energy properties, growth rate and also adaptability of this woody biomass, they can be exploited to support sustainable supply of biomass feedstock for the green electricity program in the study area.

Abstract. Yuliansyah, Haqiqi MT, Septia E, Mujiasih D, Septiana HA, Setiawan KA, Setiyono B, Angi EM, Saparwadi, Sari NM, Kusuma IW, Rujehan, Suwinarti W, Amirta R. 2019. Short Communication: Diversity of plant species growing during fallow period of shifting cultivation and potential of its biomass for sustainable energy production in Mahakam Ulu, East Kalimantan, Indonesia. Biodiversitas 20: 2236-2242. Fallow period is a time gap, as long as 15 years, for improving natural soil fertility of land used for traditional shifting cultivation, in the tropical areas commonly used by Dayak People in Borneo Island. During this period, many biomass plant species naturally grow and develop a new forest vegetation community with shrub and medium trees, dominated by fast-growing pioneer species. In this study, we investigated the plant diversity in fallowed shifting cultivation area in Batu Majang Village, Mahakam Ulu District, East Kalimantan Province, followed by analysis of the suitability of wood characteristics for energy production. We classified the study area according to the age of fallow period as: 1-3 years, 4-6 years, 7-9 years and 10-15 years. We found 29 species among which 13 were identified as the top species according to the highest value for important value index. Potential wood biomass production increased from 3.01 m3 ha-1 to 399.62 m3 ha-1. V. pinnata and M. pearsonii showed the highest dominance which is present in almost all area based on age classification groups. Wood from V. pinnata achieved the highest calorific valueof18.00 MJ kg-1 whereas N. cadamba and M. sericea were in the second and third places with the value of 17.30 MJ kg-1 and 17.28 MJ kg-1, respectively. Therefore, V. pinnata was an important species among all other species observed because of high adaptability and high energy content. In addition, possible energy production at the end of the fallow period of 15 years was 2.92 GJ ha-1.

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