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: Analysis of Tree Crown Health in Planting Plot XXIVA at Bogor Botanical Garden
Abstrak: Kebun Raya Bogor (KRB) merupakan salah satu bentuk hutan kota yang memiliki visi menjadi kebun raya kelas dunia, terutama dalam bidang konservasi tumbuhan. Pohon sebagai obyek utama daya tarik KRB diharapkan terjamin kesehatannya sehingga memberikan rasa aman dan nyaman bagi pengunjung. Pengelolaan kesehatan ekologis diperlukan untuk memantau kesehatan pohon, dengan salah satu metode yang dapat digunakan adalah Forest Health Monitoring (FHM). FHM dapat digunakan untuk memantau dan menerangkan kondisi tumbuhan karena dapat menilai kesehatan hutan berdasarkan kesehatan pohon penyusun serta memberikan informasi terkait kondisi kesehatan hutan melalui penilaian indikator dan kuantifikasi parameter kesehatan hutan. Salah satu indikator yang dinilai adalah kondisi kesehatan tajuk. Penilitian ini bertujuan mengukur tingkat kesehatan kondisi tajuk pohon pada petak tanam XXIVA KRB dengan menggunakan metode FHM. Hasil penelitian menunjukkan pohon-pohon klaster plot FHM KRB pada petak tanam XXIVA memiliki Skor VCR sebesar 7 dengan kategori kesehatan tajuk baik. Klaster plot FHM KRB memiliki nilai rata-rata CSI sebesar 15,3 dan nilai rata-rata CDI sebesar 23,8. Terminalia sp. menjadi spesies dengan nilai CSI tertinggi sebesar 45,8 dan Artocarpus sp. menjadi spesies dengan nilai CDI tertinggi sebesar 55,0., Bogor Botanical Garden (KRB) is a form of an urban forest that has a vision to become a world-class botanical garden, especially in the field of plant conservation. Trees as the main object of KRB attraction are expected to be in healthy condition to guarantee a sense of security and comfort for visitors. Ecological health management is needed to monitor tree health; one of the methods that can be used is Forest Health Monitoring (FHM). FHM can be used to monitor and explain trees conditions because it can assess forest health conditions through indicator assessment and quantification of forest health parameters. One of indicator assessed is trees crown health. This study aims to measure the health level of tree crown conditions in the planting plot XXIVA of KRB using the FHM method. The results showed that the trees the FHM KRB plot cluster at planting plot XXIVA had a VCR Score of 7 with a good crown health category. The FHM KRB plot cluster has an average CSI value of 15.3 and an average CDI value of 23.8. Terminalia sp. became the species with the highest CSI value of 45.8 and Artocarpus sp. became the species with the highest CDI value of 55,0.
Keyword: forest health monitoring, health level, tree quality

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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