Judul: Evaluasi Revegetasi Lahan Bekas Tambang Emas PT. Newmont Minahasa Raya, Manado, Sulawesi Utara
Abstrak: Kegiatan reklamasi lahan bekas tambang yang dilakukan oleh PT Newmont Minahasa Raya (NMR) kini mulai menampakkan hasil. Berdasarkan aturan reklamasi yang lama yakni dengan jarak tanam 3 x 3 meter, maka proses reklamasi di lahan bekas tambang PT NMR bisa dikatakan sudah 96% berhasil. Proses penanaman telah dituntaskan pada tahun 2008, sehingga saat ini PT NMR hanya melakukan perawatan. Seluruh daerah yang wajib direklamasi mencapai 179 hektar, dengan 180 ribu tegakan pohon (Setiadi 2006). Untuk mengetahui status keberhasilan dari revegetasi yang dilakukan PT. NMR, diperlukan sebuah penelitian mengenai evaluasi yang menitikberatkan pada aspek vegetasi agar dapat diketahui sejauh mana kegiatan revegetasi dapat memenuhi tujuan perbaikan yaitu memulihkan kondisi kawasan hutan yang rusak sebagai akibat kegiatan usaha pertambangan sehingga kawasan hutan yang dimaksud dapat berfungsi kembali sesuai dengan peruntukannya. Penelitian ini dilaksanakan selama kurang lebih 2 bulan, dimulai awal bulan Maret 2009 sampai awal bulan Mei 2009. Penelitian dilakukan di lahan-lahan bekas pertambangan emas PT NMR yang telah di rehabilitasi. Jenis data yang dikumpulkan adalah data primer dan data sekunder. Data primer yang diambil adalah data mengenai kondisi tegakan terkini yaitu komposisi dan struktur tegakan (jenis, jumlah jenis, jumlah individu, tinggi dan diameter), kondisi tempat tumbuh (serasah dan penutupan tajuk). Data mengenai tahun tanam, blok tanam dan luasan area blok tanam didapatkan dari data sekunder yang dimiliki PT NMR. Analisis data dilakukan dengan membandingkan secara deskriptif tingkat pertumbuhan sesuai dengan kondisi lahan objek pengamatan. Pengamatan tanaman meliputi tinggi tanaman dan diameter tanaman.
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Judul: Evaluasi Tingkat Keberhasilan Revegetasi Lahan Bekas Tambang Nikel Di Pt Inco Tbk. Sorowako, Sulawesi Selatan
Abstrak: PT INCO has made a borrow and use agreement with the government to do mining activity in forest area. This mining activity has caused severe damage to the forest and the land. With full awareness and to fulfill obligation in borrow and use agreement, PT INCO has done rehabilitation to severely damage forest and lands due to its mining activity. An evaluation is needed to measure the succession rate of rehabilitation effort that has been done by PT INCO. This evaluation put an emphasis on vegetational and biological aspect, enabling to see how far the revegetation activity able to fulfill restoration purpose as mention in Permenhut Nomor 146/Kpts-II/1999 and to restore functions of a forest. Object of this research is forest stand resulted from revegetation planted in 1999-2007, 1985 and 1996. Some of the equipments been used in this activity are brunton compass, measuring band, Sunto clinometer, spherical densiometer, plastic rope. Vegetational analysis done by using 17,8 m diameter circle plot. For each planting year make 2-3 plots with range 50 - 100 meter between each plot, for some cases such as limited land one plot is sufficient enough. In it observation made to plant growth factor such as plant height, plant diameter, root development and crown covering. Another parameter that also observed are local species existances and wildlife presence. Growth percentage in revegetation area range from 95% to 100%. Plant composition are pioneer species as Sengon (Paraserianthes falcataria), Eukaliptus (Eucalytus eurograndis), Sengon Buto (Enterolobium macrocarpum)and local species as Trema (Melochia umbellata), Sandro (Sandoricum kacappeae) dan Uru (Elmerelia sp). This mean it is suitable with goverment rule. Root development, growth, litter decomposition, erotion and crown covering has shown improvement according to succession concept. Same thing happen to wildlife, introduction has happened to revegetation lands. Revegetation at PT INCO in some aspects has fulfill goverment´s criteria and indicator but this revegetation has not reform original forest structure and function as protected forest.
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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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