Judul: Penilaian Kesehatan Kebun Benih Semai Pinus merkusii dengan Metode FHM (Forest Health Monitoring) di KPH Sumedang
Abstrak: Pine (Pinus merkusii) is tree species that provides timber and gum rosin. To meet the needs of wood and non wood (gum rosin) products, planting by using superior or high quality seeds are needed. Seed procurements for planting are obtained from seedling seed orchard (SSO). However, Cijambu’s SSO was attacked by pine woolly aphid (Pineus boerneri). Therefore, assesment of Cijambu’s SSO needs to be done to evaluate the severity pest attacks that could affect to the quality and the quantity of seed production. Forest Health Monitoring (FHM) method is one of the methods to assess the health level of a stand. The number of trees found in all cluster plots in Cijambu’s SSO were 270 trees. Based on the value of the VCR (Visual Crown Rating), the trees located in all cluster plot have health level between low to high. Based on the value of the VCR showed 38.52% (104 trees) having VCR’s value was high, 49.26% (133 trees) having VCR’s value was middle; 12.22% (33 trees) having VCR’s value was low; and no tree having very low VCR’s value. The average of VCR’s value in all cluster plots were 3.25 and classified as middle health. Based on the value of TDLI (Tree Damage Level Index) from 270 trees in all cluster plot showed that 189 trees (70.00%) in healthy condition; 69 trees (25.56%) in slight damage condition; 11 trees (4.07%) in middle damage condition; and 1 tree (0.37%) in heavy damage condition. The value of damage in all cluster plots (ALI) was 261.22 and classified as in health condition. The trees located in all cluster plots were mostly suitable to be seed sources as 242 trees (89.63%), while 28 trees (10.37%) were not suitable for seed sources.
Keyword: Visual Crown Rating, Tree Damage Level Index, seedling seed orchard, Pinus merkusii, Forest Health Monitoring

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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