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: Analisis Kondisi Kesehatan Tajuk Pohon pada Petak Tanam XII dan XIII di Kebun Raya Bogor
Abstrak: Kebun Raya Bogor (KRB) merupakan kawasan konservasi ex-situ tumbuhan yang memiliki berbagai koleksi tanaman yang ditanam di atas areal kebun seluas 87 hektar. Pohon sebagai obyek utama yang merupakan daya tarik KRB diharapkan terjamin kesehatannya melalui pengelolaan yang baik. Penelitian ini bertujuan untuk mengetahui kondisi kesehatan tajuk pohon pada petak tanam XI dan XIII di Kebun Raya Bogor menggunakan metode Forest Health Monitoring (FHM). Sebanyak 37 spesies individu diamati menggunakan parameter kondisi tajuk untuk mendapatkan nilai peringkat visual tajuk (VCR), indeks besar tajuk (CSI), dan indeks kerusakan tajuk (CDI). Hasil penelitian menunjukkan nilai skor VCR 5 yang didominasi oleh individu pohon dalam kategori kondisi kesehatan tajuk sedang. Nilai rata-rata CSI dan CDI pada keseluruhan spesies sebesar 22.87 dan 29.14 yang menunjukkan sebagian besar individu pohon termasuk kedalam tingkat kerusakan tajuk sedang., Bogor Botanical Gardens (BBG) is an ex-situ plant conservation area which has a wide collection of plants grown in a garden area of 87 hectares. Trees as the main object and the main attraction of the BBG are expected to be maintained in a healthy condition through proper management. This study aims to determine the health condition of tree crowns in planting plots XI and XIII of Bogor Botanical Gardens using the Forest Health Monitoring (FHM) method. A total of 37 individual species were observed using the canopy condition parameter to obtain crown visual ranking (VCR), crown size index (CSI), and crown damage index (CDI) values. The results showed that the VCR score of 5, indicated that trees crown in the area are mostly categorized moderate canopy health conditions. The average CSI and CDI values for all species were 22.87 and 29.14 which indicated that most of the individual tree’s crown were classified as moderately damaged.
Keyword: Bogor Botanical Gardens, Crown Damage, VCR, CSI, CDI

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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