Judul: Pendugaan Kandungan Karbon pada Tegakan Akasia (Acacia mangium) dan Sengon (Paraserianthes falcataria) di Lahan Reklamasi Pasca Tambang Batubara PT Arutmin Batulicin, Kalimantan Selatan
Abstrak: Indonesia has a vast landscape and abundant natural resources, both renewable and non renewable. Mining is an activity that utilizes the natural resources and potentially change the landscape, so that reclamation should be made as an effort to ensure appropriate land use designation. Reclamation of land by planting trees that will be a forest in the former mining area. Acacia (Acacia mangium) and Sengon (Paraserianthes falcataria) are fast growing species that can be planted on landfill. In addition, Acacia and Sengon also has a function as carbon storage. Acacia and Sengon on land reclamation deliver various carbon savings, so a study on the estimation of carbon stocks of Acacia and Sengon on land reclamation after mining of coal with biomass approach is needed. The research was carried out in reclamation forest of Acacia and Sengon post coal mining in Batulicin, South Kalimantan. Material used is reclamation forest of Acacia and Sengon planted in the post coal mining land in Batulicin, South Kalimantan, since 2005 with 3x4 m planty distance. The tools used in this study including scales, plastic rope, 30 m measuring tape, phiband, knives/machetes, plastic bags, newspapers, cameras and stationery. In both stands 5 plots measuring with 20x20 m plant spacing is made. Then in each corners of the plots a smaller used plot of 4x2x2 m is made for under storey and litter analysis and sample taking. Data acquired is processed though biomass approach then converted to carbon storage in ton/ha. To study the factors that affecting the carbon storage LSD analysis and ANOVA is used. Result shown by this study reveal that carbon storage in Acacia study is greater compared with that in Sengon stand. Carbon storage in Acacia stand is 71,864 ton/ha, while carbon storage in Sengon stand is 31,8853 ton/ha. The carbon storage difference in both stand is affected by tree species. Under storey and litter also the effect of biomass difference in each stand. Based on that data can be concluded that carbon storage potential in reclamation site of PT. Arutmin Batulicin with Acacia study is 117,8695 ton/ha, while carbon storage potential in Sengon study is 31,8853 ton/ha. Acacia vegetation resulting highest carbon content among other vegetation and litter vegetation in Acacia produced higher carbon content compared with litter vegetation in Sengon stand, mean while under storey in Sengon forest resulting higher carbon content compared with under storey vegetation in Acacia stand.
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Judul: Understory Plant Diversity and Carbon Stock Potential in Post-Mining Revegetation Land at PT. Berau Coal East Kalimantan
Abstrak: Inventarisasi tumbuhan dan perhitungan karbon dilakukan untuk mengukur keberhasilan revegetasi lahan pascatambang. Penelitian ini bertujuan untuk mengetahui keanekaragaman tumbuhan bawah serta mengetahui potensi simpanan kabon di atas permukaan tanah serta kaitannya terhadap perbedaan umur lahan revegetasi 2018, 2016 dan 2013. Pembuatan plot menggunakan metode petak contoh berukuran 50 m x 50 m sebanyak 3 plot pertegakan umur. Masing-masing plot terdapat 4 (subplot). Pengukuran biomassa dilakukan dengan metode non destruktif dan menggunakan rumus alometrik. Hasil penelitian menunjukkan keanekaragaman ketiga umur revegetasi yang tidak jauh berbeda. Biomassa total dan kandungan karbon tersimpan tertinggi dihasilkan pada revegetasi tahun 2013 dengan total sebesar 81,61 ton/ha dan total kandungan karbon tersimpan sebesar 38,36 ton C/ha sedangkan biomasa total dan simpanan karbon di lahan revegetasi tahun 2018 adalah 33,23 ton/ha dan 15,62 ton C/ha dan biomasa total dan simpanan karbon di lahan revegetasi tahun 2016 adalah 75,48 ton/ha dan 35,48 ton C/ha. Kata kunci: biomassa, karbon, reklamasi, tambang, tumbuhan bawah, Plant inventories and carbon calculations are carried out to measure the success of post-mining land revegetation. Plant inventories and carbon calculations are carried out. This research aims to determine the diversity of understory plants and determine the potential for carbon deposits above ground and their relationship to differences in the age of revegetated land in 2018, 2016 and 2013. Plots were made using the sample plot method measuring 50 m x 50 m with a total of 3 plots. Each plot has 4 (subplots). Biomass measurements are carried out using non-destructive methods and using allometric formulas. The research results show that the diversity of the three revegetation ages is not much different. The highest total biomass and stored carbon content was produced in revegetation in 2013 with a total of 81,61 tons/ha and the total stored carbon content was 38,36 tons C/ha while the total biomass and carbon savings in revegetated land in 2018 was 33,23 tons/ha and 15,62 tons C/ha and total biomass and carbon storage in revegetated land in 2016 was 75,48 tons/ha and 35,48 tons C/ha. Keywords: biomass, carbon, mining, reclamation, undergrowth
Keyword: carbon, mining, reclamation, undergrowth

Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model