Judul: Metode pengaturan hasil hutan tanaman eucalyptus berdasarkan optimasi tegakan persediaan nyata dan erosi tanah
Abstrak: The grouping of site quality and controlling of soil erosion in eucalypt plantation forest is very important to be considered in the yield regulation method establishment. The objective of this research is to establish the yield regulation method that can provide the same yield every year with soil erosion constraint that does not exceed determined threshold. To achieve this objective the following stages are required: preparation of site quality class, determination of erosion hazard level and determination of residual stand density so that soil erosion can be tolerated. Data were collected from permanent sample plots and observations in the field. Stand characteristics, soil runoff and erosion were analyzed using regression, clustering site quality and soil erosion hazard level. The research results showed that yield regulation method based on optimization between growing stock and soil erosion control may giving both the optimal sustainable annual wood production and soil erosion control, so that land productivity can be maintained continuously. With this yield regulation method, the site quality is getting better, cutting cycle is getting shorter. Group of site index (Bonita) I and II has a maximum volume increment at the age of 8 years, while the bonita III and IV have a maximum volume increment at the age of 7 years. Soil erosion will increase with the increase of sloping terrain. While increasing stand age will decrease soil erosion. The maximum limit of tolerable soil erosion was at the slope of 33%. Slopes of 34-45%, 46-58%, and more than 58% , require crown cover of 21%, 38%, and 53% respectively which are equivalent to residual stand density of 288 trees/ha, 530 trees/ha, and 735 trees/ha respectively. The study found that the optimum cutting cycle in the eucalypt plantation forest is 7 years. The yield regulation method based on modified Von Mantel formula is AY’ is annual yield based on modified Von Mantel formula, AY is annual yield based on Von Mantel formula, AG is actual growing stock, R is cutting cycle, and FkD is Darwo correction Factor for soil erosion constraint.
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Judul: Study on Site Quality of Industrial Plantation Forest of Eucalyptus urograndis hybrid as Raw Materials for Pulp Industry, in Sustainable Forest Management (Case Study in PT Toba Pulp Lestari, Simalungun, North Sumatera)
Abstrak: Eucalyptus urograndis (E. urophylla x E. grandis) is a hybrid resulting from cross mating between species E. urophylla S.T. Blake and species E. grandis W.Hill ex Maid and constitutes one of the fast growing species being used as pulp industry raw materials in Sector of Aek Nauli, PT Toba Pulp Lestari, North Sumatra. With the progressive decrease in length of cutting rotation, it is feared that there would be negative impacts on site quality which will ultimately influence productivity, if there is no proper management. The objective of this research was studying site quality of industrial plantation forests of E. urograndis hybrid. This research used survey method by collecting field data in first and second rotation (stand ages of 1, 2, 3, 4 and 5 years). Research results showed that up to age of 5 years, stand growth of E. urograndis hybrid at first rotation reached utilizable volume of 159.89 m3/ha, whereas at second rotation the volume acquired 142.49 m3, so there was volume decrease by 10.8 %. Rotation of maximum volume for first rotation occurred at age of 5.4 years with average volume increment of around 31.85 m3/ha/year, and that of second rotation occurred at age of 6 years with average volume increment of 28.80 m3/ha/ year. There was biomass decrease by 6.3 % for stems with diameter ≥ 5 cm between first and second rotation. There was decrease in site quality from first to second rotation as reflected by decrease in nutrient content in soil, up to depth of 40 cm by 24% for N, 16% for K, 6% for Ca and 16% for Mg. Nutrient elements P and Ca in soils had positive correlation with dominant height of E. urograndis hybrid. On the basis of results of leaf analysis, it could be shown that nutrient N was highly deficient, whereas nutrients Ca and Mg were categorized as deficient so they constituted the limiting factors for growth of E. urograndis hybrid which were planted in Inceptisol soils. Dynamics of nutrient balance with cutting rotation of 5 years was predicted to have negative balance, since the end of first rotation, up to rotation 5. At cutting rotation of 6 years, nutrient balance of N, K and Ca were positive, only at the end of rotation 1, whereas nutrient balances of P and Mg were still positive up to rotation 2. At cutting rotation of 7 years, nutrient balances of N, K and Ca had been negative since the end of rotation 1, except the nutrient balances of P and Mg which were still positive at the end of rotation 1. Quality of site with rotation of 5 years decreased more rapidly as compared with those with cutting rotation of 6 and 7 years. Fertilizer application and several silvicultural techniques are required for recovery of sites and nutrient balance. On the basis of maximum volume rotation, it could be suggested that the optimum rotation for hybrid of E. urograndis in Inceptisol soils is 6 years.
Keyword: Forest management, Forestry, North Sumatera

Judul: Trichomonas Gallinae Penyebab Trichomonosis Pada Unggas
Abstrak: Trichomonas gallinae adalah protozoa yang bergerak aktof dengan keempat flagella yang mempunyai layar dan pada salah satu sisinya terdapat membran seperti sirip ikan yang berombak. Spesies dari genus Trichomonas ini mempunyai arti penting pada unggas, karena dapat menyebabkan infeksi pada alat pencernaan bagian atas.
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