Judul: Tree Health Monitoring using i-Tree Eco in Agroforestry system in Pabuaran Community Forest, Sukamakmur, Bogor
Abstrak: Pohon sebagai penyusun tegakan hutan seringkali mengalami kerusakan sehingga mengganggu fungsi ekosistemnya. Kerusakan pada pohon dapat terjadi secara alami maupun buatan karena aktivitas manusia seperti yang terjadi di hutan rakyat dengan sistem agroforestri. Sejauh mana tingkat kerusakan yang terjadi perlu dipantau secara regular dengan berbagai metode penelitian. Tujuan dari penelitian ini adalah untuk menentukan tingkat kesehatan pohon pada sistem agroforestri di hutan rakyat serta memberikan rekomendasi pemeliharaan yang sesuai dengan kondisi pohon dan tempat tumbuhnya. Penelitian dilakukan melalui beberapa tahapan yaitu, i) pembuatan peta lokasi pengamatan, ii)penilaian kesehatan pohon dengan VTA dan i-Tree Eco iii) analisis kesuburan tanah, dan iv) analisis data. Secara umum, kondisi pohon pada hutan rakyat Pabuaran tergolong buruk dengan persentase pohon sehat dibawah 50%. Oleh karena itu, perlu dilakukan pemeliharaan yang tepat sehingga produktivitas dan fungsi ekosistem pohon tetap optimal., Individual trees as important components of forest stands are often damageddue to many factors that disrupt their ecosystem functions. Damage to trees can occur naturally or artificially due to human activities such as trees in community forests with agroforestry systems. Therefrore, damage levels need to be observed regularly for proper tree care. The objective of this research was to determine the level of tree health with agroforestry systems found in community forests and provide care and maintenance recommendations that are in accordance with the condition of the tree and the site where it grows. The research was conducted through several stages, i) making a map of the observation location, ii) tree health assessment methods with VTA and i-Tree Eco iii) soil fertility analysis, and iv) data analysis. Results showed that the condition of trees in the Pabuaran Community Forest is classified as poor with the percentage of healthy trees below 50%. Therefore, it is important to carry out the right tree care and maintenance so that the productivity of the trees remains optimal.
Keyword: tree health assessment, tree damage, community forest, agroforestry

Judul: Tree Health Assessment at Bogor Botanical Garden and  Dramaga Campus Forest Park using i-Tree Eco
Abstrak: Kebun Raya Bogor (KRB) dan Taman Hutan Kampus (TAHUKA) merupakan area konservasi tanaman ex-situ. Tanaman koleksi yang berada di KRB dan TAHUKA perlu dijaga dan dilakukan pemantauan untuk memberikan rasa aman bagi para pengunjung. Forest Health Monitoring (FHM) dan ISA Tree Risk Assessment (ISA TRA) merupakan metode yang dapat digunakan untuk memantau kondisi kesehatan pohon yang menggunakan beberapa parameter, tetapi kedua metode tersebut jarang dikombinasikan dalam penggunaannya. Penelitian ini bertujuan untuk menilai tingkat kesehatan pohon di Kebun Raya Bogor dan Taman Hutan Kampus Dramaga berdasarkan FHM dan ISA serta dilengkapi dengan i-Tree Eco. Hasil penelitian berbasis FHM menunjukkan nilai Visual Crown Ratio (VCR) rata-rata sebesar 3 di VAK XXB Kebun Raya Bogor dan Taman Hutan Kampus Dramaga dengan skor VCR berada pada rentang 7-9. Adapun, penilaian resiko pohon di VAK XXB Kebun Raya Bogor sebesar 49,21% dan Taman Hutan Kampus Dramaga sebesar 44,23% yang berarti persentase risiko tinggi lebih banyak dibandingkan dengan risiko sedang dan rendah. Serapan karbon yang lebih tinggi terdapat di Taman Hutan Kampus sebesar 1.813,75 ton/ha/tahun, sedangkan di Kebun Raya Bogor sebesar 1.301,25 ton/ha/tahun., Bogor Botanical Garden (KRB) and Campus Forest Park (TAHUKA) are ex situ plant conservation areas. Plant collections in KRB and TAHUKA need to be maintained and monitored in order to provide a sense of security for visitors. Forest Health Monitoring (FHM) and ISA Tree Risk Assessment (ISA TRA) are methods that can be used to monitor tree health conditions using several parameters, but the two methods are rarely combined in their use. This study aimed to assess the health level of trees in Bogor Botanical Garden and Dramaga Campus Forest Park based on FHM and ISA and complemented with i-Tree Eco. The results of FHM-based research showed an average Visual Crown Ratio (VCR) value of 3 in VAK XXB of Bogor Botanical Garden and Dramaga Campus Forest Park with VCR scores in the range of 7-9. Meanwhile, the risk assessment of trees in VAK XXB Bogor Botanical Garden is 49,21% and Dramaga Campus Forest Park is 44,23%, which means that the percentage of high risk is more than medium and low risk. Higher carbon sequestration was estimated in the Campus Forest Park at 1.813,75 ton/ha/year, while the Bogor Botanical Garden at 1.301,25 ton/ha/year.
Keyword: Kebun Raya Bogor, kesehatan pohon, penilaian risiko pohon, Taman Hutan Kampus

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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