Judul: Management of Bambang Lanang (Michelia Champaca L.) Community Forest through Agroforestry System in Empat Lawang District, South Sumatra
Abstrak: Hutan memiliki peranan vital dalam kelangsungan makhluk hidup. Peningkatan alih fungsi hutan dan lahan menjadi fungsi lainnya berpengaruh terhadap aspek sosial, ekonomi (pendapatan masyarakat), dan ekologi (komposisi jenis dan struktur tegakan). Hutan rakyat merupakan hutan yang dimiliki oleh masyarakat guna meningkatkan nilai ekonomi. Berdasarkan pola pengelolaannya, hutan rakyat terbagi menjadi tradisional, komersial, dan kemitraaan. Hutan rakyat di Kabupaten Empat Lawang, Sumatera Selatan didominasi oleh pola tradisional dengan mengimplementasikan pengelolaan sistem agroforestri. Sistem agroforestri merupakan sistem pengelolaan lahan yang intensif, produktif dan memiliki kapasitas untuk menjaga keberlangsungan ekosistem. Petani hutan rakyat di Kabupaten Empat Lawang, Sumatera Selatan mengelola lahan dengan sistem agroforestri untuk meningkatkan pendapatan yang diperoleh dari komoditas utama, yakni bambang lanang (Michelia champaca L) dan tanaman pendamping. Akan tetapi, studi terkait pengelolaan hutan rakyat bambang lanang melalui sistem agroforestri di Kabupaten Empat Lawang, Sumatera Selatan masih terbatas. Berdasarkan latar belakang tersebut, tujuan penelitian ini adalah untuk i) menganalisis sistem pengelolaan hutan rakyat bambang lanang melalui sistem agroforestri yang telah diterapkan oleh petani, ii) menganalisis komposisi jenis dan struktur pohon di hutan rakyat bambang lanang, serta iii) menganalisis kelayakan finansial dan faktor-faktor yang mempengaruhi tingkat pendapatan petani hutan rakyat. Metode yang digunakan adalah wawancara menggunakan kuesioner kepada 33 responden, pembuatan plot contoh sebanyak 100 plot, analisis vegetasi dan analisis kelayakan finansial. Pemilihan responden dan hutan rakyat dilakukan dengan purposive sampling. Hasil penelitian menunjukkan bahwa hutan rakyat bambang lanang melalui agroforestri di Kabupaten Empat Lawang, Sumatera Selatan dikelola secara tradisional dengan pola tanam tidak beraturan. Pengelolaan tersebut dilakukan secara turun-temurun. Jumlah spesies tanaman tertinggi ditemukan di Desa Fajar Bakti (26 spesies). Jumlah spesies tertinggi pada tingkat semai, pancang, tiang, dan pohon secara berurutan terdapat di Desa Muara Pinang (17 spesies), Paiker (17 spesies), Muara Pinang (12 spesies), dan Paiker (20 spesies). Komposisi jenis tanaman yang dominan di hutan rakyat adalah bambang lanang yang dikombinasikan dengan dengan duku (4,76), durian (2,44), kopi (0,22), karet (0,24), dan sengon (0,09). Nilai BCR tertinggi Desa Rantau Tenang (3,17), NPV tertinggi Desa Ratau Tenang (Rp242.865,600), dan IRR di Desa Fajar Bakti (20%). Hal tersebut menunjukkan bahwa hutan rakyat bambang lanang melalui sistem agroforestri layak untuk dibudidayakan.
Keyword: Analisis kelayakan, Agroforestri tradisional, Sumatera, Analisis vegetasi, Feasibility analysis, traditional agroforesty, vegetation analysis

Judul: Kontribusi Pengelolaan Hutan Rakyat Terhadap Pendapatan Rumah Tangga Petani dan Analisis Kelayakan Usaha Hutan Rakyat. (Studi di Desa Babakanreuma, Kecamatan Sindangagung, Kabupaten Kuningan, Propinsi Jawa Barat)
Abstrak: According to Hardjanto (2000), income of community forest farmers in Java are still positioned as a by product and incidental. Range of income is not more than 10 % of total revenue and sought simply. It shows that the contribution of community forest have not become the foundation of households subsistence, so it is necessary to conduct a study about how is the contribution of community forests management to total household income and it’s feasibility, especially in the Village Babakanreuma, District Sindangagung, Kuningan Regency, West Java Province. The purpose of this study was to identify the system of community forests management and marketing, knowing the contributions community forests management to households total income as well as examine the linkage of effectiveness of community forests area to the households total income and to determine the feasibility of it’s businesses. Determination of the respondents conducted using stratified random sampling method in which the respondents were 36 people obtained from the slovin formula. This study uses a qualitative approach that conducted by survey method using questionnaire and supported by quantitative techniques. The results shows that the contribution of community forests management to the households income has been very visible, reinforced by the magnitude of the contribution value that become higher and increasing in strata. So that the farmers land area of community forest significantly affected their household income. From the data obtained, in 1st strata , the resulting contribution is Rp. 2,208,333.00 per year (7.79%), 2nd strata is Rp 3.800.000,00 per year (11.98%), and 3rd strata is Rp 5.500.000,00 per year (13.00%). Management of community forests is feasible to run on all three strata. These statements are based on the amount of NPV (Net Present Value) that is not negative, BCR (Benefit Cost Ratio) is greater than one and the IRR (Internal Rate of Return) is greater than the prevailing rates. NPV values in strata I, II and III is Rp 6.378.880,00; Rp 14.134.803,00 and Rp 3.985.918.00. Community forests management systems at the sites are still modest. The harvesting is still based on needs and not according to the Sengon plant cycle which is the staple in this village. The timber marketing is only done by a contract system or the middleman (tengkulak) / buyer and furthermore become the responsibility of the middleman / buyer it self.
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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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