Judul: Economic Value Estimation and Management Strategy of Community Forests (Case Study: Megamendung Organic Forest, Bogor)
Abstrak: Jumlah penduduk Indonesia yang selalu mengalami peningkatan setiap tahunnya menyebabkan kebutuhan akan lahan turut meningkat, sehingga berpotensi terjadinya alih fungsi lahan. Perubahan fungsi lahan dari pertanian ke non pertanian akan berdampak pada menurunnya kualitas lingkungan dan mengakibatkan terjadinya lahan kritis. Salah satu upaya yang dapat dilakukan untuk merehabilitasi lahan kritis adalah dengan melakukan rehabilitasi hutan dan lahan (RHL). Salah satu hasil dari RHL yang berada di Kabupaten Bogor, Jawa Barat adalah Hutan Organik Megamendung. Keberadaan hutan organik memberikan banyak manfaat, di antaranya sebagai tempat penyerapan karbon, daerah resapan air, hingga sumber keanekaragaman hayati. Berdasarkan hal tersebut tujuan dari penelitian ini, yaitu (1) mengestimasi nilai guna ekonomi dari Hutan Organik Megamendung; (2) mengestimasi nilai non-guna ekonomi dari Hutan Organik Megamendung; (3) merumuskan alternatif strategi pengelolaan Hutan Organik Megamendung yang berkelanjutan. Metode yang digunakan dalam penelitian ini adalah pendekatan harga pasar, benefit transfer, dan PROMETHEE. Hasil penelitian menunjukkan, (1) nilai guna Hutan Organik Megamendung sebesar Rp1.589.532.870 per tahun; (2) nilai non-guna Hutan Organik Megamendung sebesar Rp8.845.125 per tahun; dan (3) alternatif pengelolaan yang dapat diprioritaskan adalah pengoptimalisasian lahan dengan sistem agroforestri., Indonesia's growing population is driving a need for more land, leading to potential land conversion from agricultural to non-agricultural uses. The change in land use will have significant environmental implications, including a potential decrease in environmental quality and the occurrence of critical land. Efforts can be made to rehabilitate critical land through conducting forest and land rehabilitation (RHL). One of the results of RHL in Bogor Regency, West Java is the Megamendung Organic Forest. The existence of this organic forest certainly has many benefits, including carbon sequestration, water catchment areas, and a source of biodiversity. The objectives of this study are to (1) estimate the use value of the Megamendung Organic Forest; (2) estimate the non-use value of the Megamendung Organic Forest; and (3) formulate alternative strategies for sustainable management of the Megamendung Organic Forest. The methods used in this research are market price, benefit transfer, and PROMETHEE. The results showed, (1) the use value of Megamendung Organic Forest is IDR 1.589.532.870 per year; (2) the non-use value of Megamendung Organic Forest is IDR 8.845.125 per year; and (3) alternative management that can be prioritized is land optimization with an agroforestry system.
Keyword: alternative strategies, critical land, market price, PROMETHEE

Judul: Nilai Ekonomi Kegiatan Rehabilitasi Dalam Menghasilkan Air Dan Menyerap Karbon Di Blok S Cipendawa Megamendung, Bogor
Abstrak: INTRODUCTION. High rate of deforestation which occurs in Indonesia, accompanied by land degradation, causes the progressive increase of critical land area size. One effort to overcome this problem is by conducting forest and land rehabilitation (RHL), so that land function can be hopefully restored. Results of RHL activities in Block S, Cipendawa have produced benefits in the form of tangible and intangible benefits. Direct benefits from this RHL activity which were not realized by the people, were the values of environmental services, namely the ability of trees to absorb carbon dioxide and increase the water yield. For obtaining comprehensive information on the benefits of RHL activities, there is a need for evaluation of tangible and intangible benefits produced from such activities, particularly those related with the ability of trees to produce water and absorb carbon. The objective of this research was determining the economic value of area of land rehabilitation activities, in producing water and absorbing carbon (in block S, Cipendawa, Megamendung, Bogor). MATERIALS DAN METHOD. This research was conducted in the period between June – July 2008 in rehabilitation land of Block S, Cipendawa, Megamendung, District of Bogor, with area size of approximately 4.2 ha. Object in this research was rehabilitation land which contained water spring and stand of trees with diameter of > 5 cm. On the other hand, subject in this research were people living around the rehabilitation area, namely the community of Kampung Bengkok (Hamlet of Bengkok). Equipments used in this research comprised measurement tape, haga, tally sheet, writing materials, measurement stick, stopwatch, pail, questionnaire, GPS, software Microsoft Office 2007, software Arcview 3.3 + extensions, Software Minitab 14, data of village monography, and camera. The collected data comprised species, numbers , height, diameter at breast height, and specific gravity of trees; yield of water, price of various kinds of wood, price of water (tariff imposed by water company of Bogor district), base tariff of electricity from State Electric Power Company, the quantitative need for water, cost for water procurement, and evaluation of water by the people. RESULTS AND CONCLUSIONS. Total economic value of environmental services produced by rehabilitation land of Block S, Cipendawa was as much as Rp 49.121.460 /year. Such values consisted of economic value of carbon dioxide absorption as much as Rp 16.270.266 /year, economic value of water as much as Rp 24.483.600 /year, and economic value to avoid an erotion as much as Rp 9.092.670 /year. If the land owner wanted to obtain direct benefit in the form of wood products, the total economic value for rehabilitation land of block S, Cipendawa would be Rp 58.332.652 /year. Key words: Megamendung, rehabilitation, economic value.
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Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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