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: Post-recovery Pine Tapping Productivity at KPH Bogor Regional Division of West Java and Banten Perum Perhutani
Abstrak: Permintaan produksi getah pinus terus meningkat, namun produksi getah pinus menurun. Salah satu penyebabnya yaitu karena tegakan pinus mengalami jenuh sadap (belum saatnya untuk ditebang namun bidang sadap sudah habis). Produktivitas getah pinus pascapemulihan yaitu sadapan pinus yang dilakukan pada bidang sadap yang telah mengalami penutupan luka belum diketahui. Penelitian ini bertujuan untuk mengukur persentase pemulihan bidang sadapan pinus metode quarre dan menganalisis produktivitas sadapan pinus pascapemulihan pada kedua kelas umur pohon. Rancangan percobaan yang digunakan adalah rancangan acak kelompok terdiri dari dua perlakuan yaitu sadapan pascapemulihan dan kontrol sedangkan kelompok yaitu tegakan pinus kelas umur (KU) IV dan IX. Hasil penelitian menunjukkan rata-rata pemulihan bidang sadapan pinus KU IX lebih tinggi dibandingkan KU IV. Rata-rata produktivitas getah pinus (g/pohon/hari) perlakuan pascapemulihan lebih rendah dibandingkan kontrol pada kedua kelas umur yaitu KU IV dan KU IX perlakuan pascapemulihan berturut-turut 8,11 g/pohon/hari dan 9,15 g/pohon/hari sedangkan perlakuan kontrol berturut-turut 11,42 g/pohon/hari dan 10,59 g/pohon/hari. Perlakuan (pascapemulihan dan kontrol) sadapan getah pinus menghasilkan produktivitas yang berbeda sedangkan kelas umur menghasilkan produktivitas yang sama., The demand for pine resin continues to increase along with the declining of pine resin production. One of the reasons is because the pine trees have become saturated with tapping (it is not proper yet to cut down, but the tapping fields have run out). Post-recovery pine resin productivity, namely pine tapping in a tapping area that had undergone closure of the tapping wound not yet known. This study aimed to measure the percentage of pine tapping field recovery using the quarre method and to analyze the productivity of post-recovery pine resin in both age classes of trees. The experimental design used a randomized block design consisting of two treatments, namely post-recovery and control, while the group consisted of pine stands of age class IV and IX. The results showed that the average recovery of the pine tapping field in age class IX was higher than age class IV. The average productivity of pine resin (g/tree/day) in post-recovery treatment was lower than the control in both age classes, namely age class IV and IX in post-recovery treatment, respectively 8.11 g/tree/day and 9.15 g/tree/day while the control treatments were 11.42 g/tree/day and 10.59 g/tree/day, respectively. Treatments (post-recovery and control) on tapped pine resin had a different productivity, while the groups (age class) had the same productivity.
Keyword: post-recovery, pine resin, productivity, tapping field recovery

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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