Judul: Komposisi Jenis Mangrove dan Pengetahuan Masyarakat tentang Kawasan Mangrove, Desa Sayoang, Halmahera Selatan
Abstrak: The area of mangrove forests in Indonesia is currently only spanning as much as 3.4 milion acres, so there is a need for the participation of the government and community to maintain its sustainability. South Halmahera is the district with the largest mangrove area in the North Maluku province. One of the mangrove areas in the district of South Halmahera is located at Sayoang Village, East Bacan District. Up until its eleventh founding anniversary, this district have never conducted an inventorizing of its mangroves, both ecological and social studies in the field of public. This study aims to analyze the compotition of mangrove species in Sayoang Village, East Bacan District, South Halmahera, and identify the knowledge of surrounding communities of mangrove areas as protected areas. Data were retrieved using sampling method with applications terraced paths, and analyzed by calculating its important value index (INP) and its index value diversity (IVD). The public social data were taken using in-depth interviews and questionnaires. Results obtained from this study show that the mangrove forest in Sayoang village, East Bacan district, Halmahera, consists of major mangrove species with as many as eleven species belonging to families Rhizophoraceae, Sonneratiaceae, Aviceniaceae, Meliaceae and Myrtaceae, and as many as three species of minor mangrove belonging to families of Lorantaceae, Acanthaceae, and Pteridaceae. The mangrove's species diversity and richness is and low, but it has high evenness. 60% of total respondents know the benefit of mangrove as fish habitat, while for mangrove area as conserving areas, 50% of total respondent don't know the status of the area. The cutting problems happened in mangrove areas, 90% of total respondent know the activity and 85% of total respondent think that the logging activities in mangrove area is still allowed. The management activity of mangrove area in Sayoang village hasn't been conducted, either by the community or by local Dinas Kehutanan, and 53% of total respondent still wishing the mangrove can give more benefit economically.
Keyword: Bogor Agricultural University (IPB), community knowledge, mangrove protected areas, Mangrove forest

Judul: Komposisi jenis dan struktur tegakan hutan di areal IUPHHK-HA PT Bina Ovivipari Semesta, Kalimantan Barat
Abstrak: Ekosistem mangrove memiliki peran penting dalam menjaga keseimbangan alam di kawasan pesisir sampai daratan. Salah satu pemegang konsesi hutan alam mangrove di Kabupaten Kubu Raya, Kalimantan Barat adalah PT. Bina Ovivipari Semesta (BIOS). Metode yang digunakan yaitu metode jalur transek dengan penentuan jalur menggunakan cara purposive sampling. Komposisi jenis pohon di hutan mangrove sebelum tebangan terdiri dari enam yaitu jenis Bruguiera gymnorhiza, Excoecaria agallocha, Rhizophora apiculata, R. mucronata, dan Xylocarpus granatum. Pada hutan bekas tebangan tahun 2006 terdapat empat jenis yaitu B. gymnorhiza, R. apiculata, X. granatum dan E. agallocha, hutan bekas tebangan tahun 2009 terdapat lima jenis yaitu B.gymnorhiza, R. apiculata, X. granatum, Candelia candel, dan Ceriops roxburgiana. Pada hutan bekas tebangan tahun 2012 terdapat dua jenis yaitu B. gymnorhiza dan R. apiculata. Struktur tegakan yang ada di PT. BIOS sebelum tebangan tidak menunjukkan huruf “J” terbalik sedangkan pada tegakan bekas tebangan berbentuk huruf “J” terbalik yang artinya hutan masih tergolong normal.
Keyword: mangrove ecosystem, species composition,, standing structure

Judul: Best Difference Equation Aproximation to Duffing 's Equation
Abstrak: Persamaan Duffing merupakan persamaan yang sering muncul sebagai model masalah sistem ayun mekanis atau pada masalah rangkaian listrik. Umumnya penyelesaian persamaan ini secara numerik memberikan hampiran dengan gala! yang tinggi, seperti dengan metode Runge-Kutta. Tulisan ini mengkonstruksi suatu persamaan beda untuk menghampiri persamaan Duffing tersebut. Penyelesaian dari persamaan beda ini melibatkan fungsi-fungsi eliptik Jacobi. Berdasarkan penyelesaian ini diperoleh basil bahwa penyelesaian hampirannya persis sama dengan penyelesaian analitiknya. Penyelesaian analitik yang diperolehjuga melibalkan fungsi-fungsi eliptik Jacobi.
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