Judul: Condition of Damage and Recovery of Pine Trees due to Tapping in Gunung Walat University Forest
Abstrak: Penyadapan getah pinus dapat dilakukan dengan berbagai metode yang salah satunya menggunakan metode koakan (quarre). Sistem koakan dinilai sangat mudah, praktis, tidak memerlukan banyak peralatan dan sangat sederhana. Namun metode sadapan ini mempunyai kelemahan yaitu memiliki tingkat kerusakan yang tinggi. Kerusakan pohon akibat sadapan yang tidak sesuai standar penyadapan getah pinus dapat menyebabkan terganggunya kelestarian tegakan dan proses pemulihan. Penelitian ini bertujuan untuk mengetahui kondisi pohon akibat penyadapan getah pinus, mengukur tingkat pemulihanya dan mengetahui hubungan antara kedalaman sadapan dan lebar sadapan terhadap pemulihan sadapan pinus. Penelitian dilakukan pada 45 plot contoh dari total 28 petak sadapan pinus dengan intensitas sampling 5% pada petak ukur lingkaran 0,1 ha. Hasil penelitian diperoleh data rata-rata kerusakan dan presentase pemulihan sadapan yang terdiri dari jumlah sadapan dengan rata-rata 6 sadapan per pohon, lebar sadapan 6,62cm, kedalaman sadapan 6,17 cm, dan tinggi sadapan 156 cm, serta tingkat pemulihan sadapan sebesar 9,79%. Kata kunci: pinus, penyadapan, kerusakan sadapan, pemulihan sadapan, Tapping pine sap can be done using various methods, one of which is using the quarre method. The quarre system is considered very easy, practical, does not require a lot of equipment and is very simple. However, this tapping method has a weakness, namely that it has a high level of damage. Damage to trees due to tapping that does not comply with pine sap tapping standards can disrupt stand sustainability and the recovery process. This research aims to determine the condition of trees due to pine sap tapping, measure the level of recovery and determine the relationship between tapping depth and tapping width on the recovery of pine sap. The research was carried out on 45 sample plots from a total of 28 pine tapping plots with a sampling intensity of 5% in 0.1 ha circle measuring plots. The research results obtained data on the average damage and percentage of recovery of tappings consisting of the number of tappings with an average of 6 tappings per tree, tapping width of 6.62cm, tapping depth of 6.17 cm, and tapping height of 156 cm, and tapping recovery rate of 9.79%. Key words: pine, tapping, tapping damage, tapping recovery
Keyword: pine, tapping, tapping damage, tapping recovery

Judul: Kerusakan dan Pemulihan Pohon Pinus Akibat Penyadan pada Berbagai Ketinggian Tempat di KPH Kediri
Abstrak: Tingkat kerusakan pohon pinus akibat penyadapan didasarkan pada parameter jumlah sadapan, lebar sadapan, tinggi sadapan dan kedalaman sadapan. Ketinggian tempat tumbuh pohon pinus dapat mempengaruhi pemulihan pada bidang sadapan pinus karena kondisi cuaca, suhu udara dan intensitas sinar matahari di setiap ketinggian berbeda. Penelitian ini bertujuan mengetahui kondisi pohon pinus akibat penyadapan, mengukur persentase pemulihan bidang sadapan pohon pinus dan menganalisis pengaruh ketinggian tempat terhadap pemulihan bidang sadapan. Hasil penelitian menunjukkan rata-rata kerusakan sadapan di setiap ketinggian tidak memenuhi prosedur penyadapan getah pinus yang sudah diterapkan oleh Perhutani kecuali rata-rata ketinggian sadapan. Ketinggian tempat berpengaruh terhadap pemulihan bidang sadapan. Rata-rata persentase pemulihan bidang sadapan yang paling tertinggi terdapat di ketinggian <400 m di atas permukaan laut (mdpl) dengan nilai sebesar 50.40%/sadapan dan rata-rata persentase pemulihan bidang sadapan yang paling terendah terdapat di ketinggian >1.000 mdpl dengan nilai sebesar 36.05%/sadapan., The level of damage to pine trees due to tapping is based on parameters such as the number of taps, the width of the taps, the height of the taps, and the depth of the taps. The altitude at which pine trees grow can affect the recovery of the tapped areas because weather conditions, air temperature, and sunlight intensity vary at different altitudes. This study aims to determine the condition of pine trees due to tapping, measure the percentage of recovery of tapped areas on pine trees, and analyze the influence of altitude on the recovery of tapped areas. The results showed that the average damage from tapping at each altitude did not meet the tapping procedures established by Perhutani, except for the average height of the taps. Altitude affects the recovery of tapped areas. The highest average recovery percentage of tapped areas was found at an altitude of <400 meters above sea level (masl) with a value of 50.40% per tap, while the lowest average recovery percentage of tapped areas was found at an altitude of >1,000 masl with a value of 36.05% per tap.
Keyword: Kerusakan sadapan, Ketinggian tempat, Pemulihan bidang sadapan, Penyadapan, Altitude, Recovery of tapped areas, Tap damage, Tapping

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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